How to weld stainless steel to ferrous metal

Welding stainless steel with ferrous metal

Welding stainless steel with ferrous metal products is very problematic, because stainless steel itself is a material that is very difficult to weld. It happens that it is not possible to connect single-plane products made of stainless steel.

Welding work involving the need to weld ferrous metal and stainless steel can only be performed by a very experienced welder. The fact is that a material such as stainless steel has very high fluidity compared to ordinary metal, in addition, they have different melting points.

The ability to weld such products appears only if you have special equipment, its correct settings, and a competent approach to the selection of consumables.

For example, filler wire is taken only from stainless steel, to which nickel and manganese must be added. If these elements are missing, the quality of the welded joint will be significantly lower.

During the work process, they try to make the seam at the greatest depth so that the welded dissimilar products exchange particles throughout their entire thickness.

Is it possible to weld steel with stainless steel?

Welding stainless steel and ferrous metal in industrial production conditions in compliance with all technological features is not something particularly difficult. It is worth noting that from a physical point of view, such a process is quite feasible.

In home welding conditions, this is also very feasible, especially since in this case the most serious requirements for the quality of the welded joint are not imposed. To make the connection as durable as possible, it is advisable to have some experience in welding stainless steel.

What technology to use?

Black and stainless steel parts are most easily connected to each other using special electrodes and electric welding. This is done quite quickly and does not require any additional funds, however, the quality of the seam leaves much to be desired. This is due to the fact that when exposed to high temperatures, stainless steel becomes very liquid, while steel continues to maintain viscosity.

It is almost impossible to make a ceiling or vertical seam in this case, since the molten material will simply flow down. To carry out the work, only high-quality stainless steel electrodes are used, which must have appropriate coating.

In the case of gas welding, you will have to use flux, which will approximately equalize the fluidity of steel and stainless steel. This technology is much more complicated in terms of preparatory work; you will need to follow certain safety regulations regarding the use of gas cylinders.

Welding stainless steel with ferrous metals is often carried out in an argon atmosphere. This method is considered to be the most reliable, since it allows you to obtain a welded joint of the highest quality. There may not be a wire coating here, since the argon gas environment will reliably protect the weld pool from air ingress. However, this technology itself is very complex and expensive, so using it for such purposes does not always make sense.

Work technology

Before you start welding stainless steel and black steel, you need to properly prepare not only the products themselves, but also all the necessary equipment. The areas of the parts near which the seam will be formed are cleaned of the oxide film using a metal brush on an angle grinder. There should be no traces of corrosion processes on the steel workpiece.

Movements must be confident and very precise. This is due to the fact that steel will melt much more slowly compared to stainless steel. You should try to capture as much ferrous metal as possible so that the products penetrate each other well at the molecular level.

Approximately the same thing is done in the process of making a seam using gas welding, but everything here will happen much more slowly. The seam is made as wide and as deep as possible so that the material in the area where it is formed is as uniform as possible. After the work is completed, allow the product to cool completely.

How to check the quality of the connection?

When the welded joint reaches an acceptable temperature (at least 40 degrees), they begin to control its strength and a number of other parameters. You can do this as follows:

• Using kerosene, the principle of operation of which is based on capillary penetration through the crystal lattice of steel;
• Ammonia: here control is based on the principle of coloring indicators when directly exposed to it;
• Hydraulic methods, which allow not only to obtain information regarding the reliability of the seam, but also to check how strong it is.

If the connection is obviously quite weak, then destructive testing methods are used.

Security measures

Safety precautions are very important when carrying out welding work. First of all, you should reliably protect your eyes from exposure to intense ultraviolet radiation.

In addition, wear thick clothing on your arms and legs to prevent molten metal from coming into contact with your skin.

It is very important to follow the rules for using electrical installations, gas cylinders and other equipment, since if used incorrectly, they can pose a threat to the life or health of a person working with them in the production of welded joints of various kinds.

Source: https://electrod.biz/splav/metall/svarka-nerzhaveyki-s-metallom.html

Welding stainless steel and ferrous metal: process features and choice of electrodes

Welding two parts from different types of metal is associated with certain difficulties: differences in melting temperature, chemical and physical properties. To solve these problems, various methods are used. Most often the question arises of how to properly weld stainless steel and ferrous metal together. To do this, you should familiarize yourself with the features of the process.

Difficulties in welding dissimilar steels

To ensure a high-quality weld, it is necessary to take into account the thickness of the workpieces, the direction of welding, the operating mode of the apparatus and the brand of electrodes. At the junction, when exposed to temperature, specific processes will occur.

It is necessary to take into account the following nuances of welding stainless steel and ferrous metal:

• Using a stainless steel additive. It should contain more nickel, manganese and chromium. This will ensure good bonding with metals.
• Filling the seam with the base metal - up to 40%, 20% each for black and stainless steel. The remaining volume is filled with additive. The indicator for the base material can be changed downward using automatic or semi-automatic welding mode.
• When choosing an electrode, the chemical composition of the materials being welded and their physical properties during melting are taken into account.

Description of methods for welding stainless steel and ferrous metal

The most common method of high-quality joining of workpieces made of stainless metal and ferrous metal is electric arc welding. This can be done using an inverter or other device. For a stable arc it is necessary to use direct current, its value is determined by the width and depth of the seam. You can also use additional features of the welding machine: forced start, arc stabilization, prevention of electrode sticking. This will help make a quality connection.

When performing work, you should pay attention to the following subtleties:

• Welding direction. It is important that the molten additive does not flow out of the weld area. Therefore, it is not recommended to choose a vertical or overhead position of the workpiece.
• The connection point must be uniform. The point method in this case will be ineffective and will significantly reduce the quality of joining of metals.
• Connection cooling technology. Do not expose to low temperatures, as the difference in temperature expansion will cause defects. Cooling should occur naturally, at a positive temperature.
• Due to the difference in properties, the seam will rust. This must be taken into account during further operation of the metal structure.

To obtain a truly high-quality connection, it is recommended to use argon welding. Stainless steel wire is used as an additive. The complexity of this process lies in the precise setting of the temperature regime of exposure. Doing this at home is problematic. But a similar technology is used for welding stainless steel to ferrous metal in a factory environment.

Selecting Electrodes

To form a high-quality seam using electric arc welding, it is necessary to analyze the composition of the materials - stainless steel and ferrous metal. Based on the data obtained, the optimal electrode model is selected. If you have doubts about the correct choice, it is recommended to buy several test rods for trial welding.

Popular models of electrodes for welding various types of metal:

• E50A. They are used for connection with heat-resistant steel grades.
• OZL-25B. Recommended for use when working with heat-resistant types.
• NIAT-55. With the help of these electrodes, stainless steel and austenitic steels are connected.
• TsT-28. Area of ​​application: working with materials with a high nickel content.

Read about the rules for choosing electrodes for welding stainless steel here.

The main characteristics are indicated by the manufacturer on the packaging. It is important to be able to decipher the markings. When choosing, the possible volume of slag and surfacing is taken into account. These parameters can be compared with the declared ones only after the formation of a test seam.

Source: https://ismith.ru/welding/svarka-nerzhavejki-i-chernogo-metalla/

How to weld stainless steel to ferrous metal

03.04.2019

During repairs and installation work, it is sometimes necessary to combine dissimilar alloys. Welding of stainless steel with ferrous metal is carried out using surfacing material. When choosing it, it is important to know the brand or at least the category of the stainless alloy. The resulting layer should be as close in chemical composition as possible to stainless steel and contain alloying metals. Only in this case will a strong connection be achieved.

Is it possible to weld stainless steel with ferrous metal?

Stainless alloys differ significantly from carbon alloys. When welding stainless steel and ferrous metal, the difference in several physical parameters is taken into account:

• The thermal conductivity of stainless steel is lower than that of ferrous metals, it heats up more strongly and cools down more slowly;
• stainless alloys have a higher resistance, the electrode above the stainless steel heats up more than above the ferrous metal, the melt pool is formed to a greater extent by the ferrous metal;
• Stainless steel expands more when heated, a small gap must be left between the workpieces so that internal stresses do not arise;
• in stainless steel, when heated to 500°C, carbides are formed, which causes cracks and internal defects; workpieces must be cooked at a low temperature;
• When heated, black carbon steel becomes viscous, and alloy steel becomes liquid, like water; it is better to cook workpieces in a horizontal position.

Welding of ferrous metal and alloy alloy can be carried out in several ways, taking into account the characteristics of stainless steel.

What technology is welding used?

The welding method depends on the type of alloy and the required strength of the seams. At home, traditional direct current electric arc is more often used. The seam, which must withstand pressure and high dynamic loads, is welded under a cloud of protective gas. It is not necessary to use argon; carbon dioxide supplied by a semi-automatic device is sufficient. Argon welding is not economically feasible.

How to weld stainless steel with ferrous metal:

1. The MMA electric arc welding method is the most common; electrodes are chosen that are used to work with stainless steel. The alloying components must match, only in this case a reliable connection is formed.
2. Semi-automatic MIG welding is used in industrial environments. The strength of the connection depends on the brand of filler wire; it must be made of stainless steel. The brand is selected for the workpiece based on its chemical composition.
3. The TIG method using refractory electrodes is used for critical connections. Gas welding produces strong, tight seams.

The use of stainless filler materials reduces the fluidity of alloyed alloys by almost three times and makes the liquid metal viscous.

Methods and technologies for welding stainless steel with ferrous metal

Welding stainless steel with ferrous metal is a rather complex process that requires the performer to have high professional skills in the field of joining dissimilar materials.

Methods

When doing work at home, you have to use what is at hand. Practice shows that semi-automatic or welding with a non-consumable electrode in an argon environment is best suited. However, such equipment is not available in every home, and purchasing it for a one-time job is impractical due to its high cost.

Inverters are cheaper, but their performance characteristics are higher than those of welding transformers. Compact dimensions, combined with stability of operation, have caused their spread among residents of the private sector.

Manual arc welding is used only for horizontal seams, since under the influence of high temperature the stainless steel quickly melts and flows out of the seam, while the temperature of the steel has not yet reached the required degree of heating.

An important factor is the correct selection of consumables.

Tools

There is no equipment on the market designed for welding dissimilar materials. When choosing an inverter, you should focus on the general technical characteristics and the presence of additional properties that facilitate the work process.

Modes

Before welding the workpiece, it is necessary to select electrodes of the desired diameter and set the correct ampere characteristics:

1. When welding elements with a thickness of 1 mm, the diameter of the electrode should not exceed 2 mm. The current should be in the range of 30-60 A.
2. For 2 mm products, you can take 3 mm electrodes. You need to cook with a current of 50-80 A.
3. Products 4 mm thick are cooked with 4 mm electrodes with a current of 90-130 A.

All work is carried out on direct current.

How ordinary?

For welding high-alloy steels, there are many suitable simple electrodes, both domestic and foreign manufacturers.

Among foreign companies, it is worth highlighting the Swedish company ESAB. Their products have long been in demand due to their high quality, fast arc ignition and stable welding arc. According to information from the manufacturer, OK 61.30 electrodes with rutile coating are designed to work with the following types of steel:

• 12Х18Н10;
• 12Х18Н10Т;
• 08Х10Н10.

In addition to excellent performance characteristics, the slag that forms on top of the seam is very easy to remove manually, without the use of auxiliary equipment.

Electrodes from domestic manufacturers occupy the middle price segment. Working with them requires certain skills, since products from Russian factories tend to stick and oscillate the arc. At the same time, the properties of the resulting joint are not inferior to the best foreign analogues - if the technology is followed, the seam will be reliably protected from external and intercrystalline corrosion.

Transition electrodes

The main difficulty when welding ferrous metal and stainless steel lies in the different melting temperatures: the high-alloy alloy begins to spread over the surface, while the structure of the steel remains viscous. Using transition electrodes to connect dissimilar metals will help overcome this problem. All domestically produced electrodes must be manufactured in compliance with the requirements of interstate GOST standards.

Conclusion

Welding dissimilar metals at home is not an easy task even for an experienced welder. As a consumable material for manual arc welding, we recommend using adapter electrodes for welding stainless steel and ferrous metals.

Source: https://svarka.guru/tehnika/opredelennih-metallov/nerzhaveyka-s-chernym-metallom.html

Is it possible to weld ferrous metal and stainless steel?

When carrying out a process such as welding stainless steel and ferrous metal, you need to be prepared for a number of difficulties that you may encounter during work. Despite the fact that both of these materials are characterized as varieties of steel, they are completely different.

In order to weld stainless steel with ferrous metal as efficiently as possible, you initially need to stock up on the correct electrodes. In addition, in order to ultimately form a good weld, it is necessary to pay attention to such an indicator as the weldability of these metals.

In other words, it is important to take into account the possibility of forming strong and reliable joints formed by welding stainless steel and ferrous metal.

Is it possible to weld dissimilar steels?

Before proceeding directly to welding work, you need to have an idea of ​​the welding features associated with the different chemical composition of materials, which must be taken into account:

• different thermal conductivity of stainless steel and ferrous metal, which can affect poor penetration of one of the metals,
• linear expansion coefficients, these indicators also vary. Stress may remain in the area where the materials are joined even after heat treatment. Such areas will be the weakest,
• “Carbon migration” from Cr-Mo steel, which this metal contains in large quantities, makes stainless steel more susceptible to corrosion processes.

Note! Due to the wide variety of steels with different compositions, it is not possible to give clear recommendations on the welding process

Based on the large number of contradictions, many users constantly wonder: is it still possible to weld stainless steel and ferrous metal?

Considering this issue from the point of view of physics, we can come to the conclusion that it is possible to carry out such a procedure.

When using transition electrodes for welding stainless steel and ferrous metal parts at home, you need to adhere to stainless steel welding technology, and it is also recommended that welding work be carried out by a person who has experience in this matter.

In any case, it is important to know the chemical composition of both metals in order to make the correct choice of consumables.

Welding methods

In most cases, welding of stainless steel and ferrous metal with an electrode using electric welding is used. The popularity of this method is due to its simplicity and minimal number of auxiliary actions. However, the quality of this connection is not very good.

Due to the high temperature, stainless steel will flow, while ferrous metal will be viscous. Ultimately, it will not be possible to make a vertical or ceiling seam, because... everything will flow down. Therefore, it is necessary to use transition electrodes for welding stainless steel and ferrous metal.

Note! Ferrous metal electrodes used in the welding process must be made of stainless steel

Another method is gas welding; stainless steel wire is also used as an additive. This method is more suitable because in this case, the material will be less fluid. When carrying out welding work, you need to use flux, which will ensure better melting of the ferrous metal. However, gas welding requires preliminary preparation and strict adherence to safety precautions for using gas cylinders.

It is believed that the most durable and reliable seam can be obtained using a method such as welding stainless steel with ferrous metal with argon. In this case, wire coating is not required, because argon independently copes with the function of protection from the negative influence of the external environment.

Note! It is not always advisable to weld workpieces made of stainless steel and ferrous metal, since this technology is quite expensive

Choosing a method

When choosing which welding method to resort to, you need to decide on the goals you are pursuing.

In the case when you need to do something for your home or you just want to check whether it is possible to weld ferrous metal and stainless steel, it is recommended to resort to the method of conventional electric arc welding with stainless electrodes. As practice shows, this method is well suited for this.

If the parts to be welded are subject to serious loads, then in such a situation the best option would be gas welding. Argon welding is used very rarely and only when absolutely necessary.

What electrodes should I use for welding?

To obtain the highest quality seam formed during the welding of stainless steel and ferrous metal products, you need to take into account some nuances. It is important to select filler wire of a specific chemical composition.

In the metal of the filler wire, the degree of alloying of which must exceed the identical indicator of the material of the product being welded, the composition must necessarily include elements such as manganese, nickel and sometimes chromium

Technology

Before you start cooking stainless steel, you need to carry out a number of preparatory procedures. The surface of both parts must be well cleaned. To do this, you can use a brush or sandpaper; after cleaning, be sure to wipe the products from dust. If the equipment and parts are prepared, you can begin to apply flux to the area where the connection is expected to be formed.

It is very important to place everything horizontally. This is necessary for even distribution of the material. When welding stainless steel and ferrous metal with an inverter, maintain maximum precision of movements, because the steel will begin to melt earlier and it is necessary to capture as much of the ferrous metal side as possible.

All these requirements are put forward for gas welding, only each process is carried out at a slower pace. The resulting seam should be as wide and deep as possible, this is necessary to increase the uniformity of the material at the place where it passes. When the welding work is completed, you need to wait some time until the product cools down.

Safety regulations

When welding stainless steel and ferrous metal with a semi-automatic machine, electrical safety rules must be strictly observed. Protective clothing is also important. Be sure to work in a special suit, gloves and mask, because... If steel splashes, accidental contact with the skin can result in serious burns.

To summarize, we can come to the conclusion that welding ferrous metal and stainless steel is quite possible. The main thing is to observe all the nuances that arise in the process of working with these materials.

Source: https://svarkaed.ru/svarka/svarka-metallov/mozhno-li-svarit-chernyj-metall-i-nerzhavejku.html

How to weld stainless steel with ferrous metal: technology features

The difficulties associated with welding products made from stainless steel with ferrous metal are mainly explained by the fact that these materials, although they belong to steel, are, in fact, dissimilar.

In order to qualitatively weld such metals, that is, to obtain a weld whose mechanical characteristics will be close to the base metal of the products being joined, you must first select the right electrodes.

In addition, it is necessary to take into account such a parameter of the metals being joined as their weldability, that is, the ability to form high-quality and reliable permanent joints obtained by welding.

Welding a stainless flange with a carbon steel elbow

Principles of welding stainless steels

The weldability of stainless steels - the ability to form high-quality welded joints (including with ferrous metals) - is influenced by certain characteristics of such alloys.

• The thermal conductivity of stainless steels, when compared with the same parameter of alloys with low carbon content, is low. Due to the fact that stainless steel is not able to quickly remove heat, it becomes very hot during welding, and this negatively affects the characteristics of the joint being created and the base metal. To avoid overheating of stainless steel products when welding them with ferrous metal parts, it is necessary to reduce the welding current (by an average of 20%).
• Stainless steel alloys are characterized by a high coefficient of linear expansion, which leads to significant deformation of the metal during welding. In addition, this factor causes deformation of stainless steel products even at the moment when they are already connected by welding and are cooling. To avoid this, it is necessary to provide wider gaps between the parts being connected.
• The high electrical resistance that stainless steel has causes significant overheating of welding electrodes. This is especially true if electrodes made of high-alloy steel are used for welding. To avoid these problems, welding of both homogeneous and dissimilar steel alloys should be performed with short electrodes (no more than 350 mm), the rod of which is made of chromium-nickel alloys, characterized by low electrical resistance.
• The tendency to form intergranular corrosion, to which high-chromium steels are especially susceptible, leads to a deterioration in the anti-corrosion properties of stainless steel and the appearance of cracks in its internal structure. This type of corrosion also occurs due to overheating of the metal during welding. This phenomenon, the essence of which is that solid carbide compounds appear at the boundaries of the crystals of the base metal, is combated in various ways. The most effective of these methods is the rapid cooling of metal that has undergone significant heating during the welding process. However, it should be noted that the rapid cooling method, for which ordinary water is used, is effective only in cases where the material to be joined is chromium-nickel steel.

Methods of welding products made of stainless steels and ferrous metals

In order to weld workpieces made of stainless steel and ferrous steel alloys, thereby obtaining high-quality and reliable connections, the following types of welding are used:

• covered with piece electrodes in MMA mode;
• non-consumable electrodes made of tungsten;
• in a protective gas environment, which is predominantly argon.

If welding of ferrous metal and stainless steel products is carried out using the first technology (MMA), then it is necessary to take electrodes specifically designed for making connections of non-ferrous metals and alloys.

Brands and application of high-alloy electrodes

However, it is best to cook stainless steel and ferrous metal in an argon protective gas environment. For this, of course, you will need a special welding machine. In this case, argon provides reliable protection of the zone of the weld being formed from excessive saturation of the metal with nitrogen and its oxidation. If such protection is not provided, the metal of the formed weld will be very brittle, which will significantly reduce the reliability of the resulting joint.

Argon welding scheme for stainless steel

In order to qualitatively weld products made of stainless steel and ferrous metal, during the operation it is necessary to monitor the position of the electrode. The latter, in order for the weld to be high-quality and reliable, must be kept perpendicular to the surface of the workpieces being joined.

How to weld stainless steel to regular metal - Forging, welding, blacksmithing

The connection of parts made of homogeneous metals does not raise any special questions in terms of the use of electrodes. However, when welding parts made of non-uniform metals, the issue of selecting the brand of electrode to create high-quality connections must be approached more carefully and carefully. For example, welders often have to decide how to weld stainless steel to ordinary metal and at the same time ensure a high-quality, reliable seam.

Features of welding stainless steel to ordinary metal

• Welding stainless and black steel always involves nuances. When performing this work, for a high-quality weld, it is always necessary to use a stainless steel additive, which must necessarily contain much more manganese and nickel, and in some cases, chromium, than in the stainless steel being welded itself.
• One of the most important points is the presence of a minimum amount of base metal in the weld. The weld must consist of an additive - the maximum allowable amount of base metal is 40%, that is, 20% of each. With semi-automatic welding, it is possible to achieve 20-30% mixing (the share of the base metal in the weld).
• It is necessary to do approximately the same when selecting a piece electrode, but in each individual case it is important to know exactly the chemical content of both steels, according to which the additive should be selected.

Dissimilar metals and alloys are characterized by unequal weldability, differences in physical and mechanical properties and alloying processes.

This group most often includes alloys with nickel and iron-nickel composition. They can be divided into four categories:

• highly alloyed;
• alloyed with increased and high strength indicators;
• low alloy and carbon;
• heat resistant.

Of course, the electrodes used for welding dissimilar steels differ from the electrodes that are used for welding homogeneous metals.

The main problem that welders have to face when welding dissimilar steels is that cracks form in the weld and its structure becomes heterogeneous.

To obtain a weld with an austenitic structure, when welding dissimilar metals, electrodes are often used, which are intended for welding high-alloy steels and alloy alloys with increased and high strength values.

Is it possible to cook stainless steel with a regular electrode?

Sometimes, as practice shows, it is permissible to cook stainless steel with a rusting electrode. Details here.

Brands of electrodes used for welding ordinary metal with other steels (for dissimilar steels, more details here):

• with heat-resistant steels, electrodes of type E50A-E85 are used;
• with austenitic high-alloy steels, electrodes EA-395/9, as well as NIAT-5, are used;
• OZL-25B electrodes are used with heat-resistant high-alloy steels;
• For alloys with a nickel base, OZL-25B and TsT-28 electrodes are used.

Sections: Welding work - how to cook

Source: https://kovka-svarka.net/2014/03/kak-privarit-nerzhavejku-k-obychnomu-metallu/

Is it possible to weld ferrous metal with stainless steel?

Even at the dawn of electric arc welding, inventor Nikolai Gavrilovich Slavyanov presented to the public the well-known “Slavyanov’s Glass”.

This glass is notable because it is composed of seven metals that cannot be fused by natural methods. Despite the different characteristics of ferrous metal and stainless steel, it is still possible to weld them.

How stainless steel is welded to simple ferrous metal, the main difficulties of the process and methods for solving them will be discussed below.

Scheme of welding stainless steel with ferrous metal

Difficulties in welding dissimilar steels

As mentioned above, when welding alloys of different grades, as well as when welding steels of different grades, some difficulties may arise. The main difficulties that may arise:

• Different thermal conductivity. May cause burn-through of parts during the welding process. The worse the metal removes heat from the weld pool, the higher its temperature. Reducing the welding current reduces the temperature, but may lead to lack of fusion in the joint.
• Different linear extension. When heated, all bodies increase in size, and when cooled, they respectively take on their previous dimensions. Thus, changes in size during the cooling process can cause the weld to rupture or cause cracks to form in it.
• The difference is in electrical resistance. Affects overheating of the electrode during the welding process. This also affects the strength of the seam.

Dissimilar layers during welding

Overheating of some types of metals leads to dire consequences. Stainless steel, for example, loses its properties at temperatures above 500 degrees. That is, it turns from stainless steel into ordinary ferrous metal. Welding leads to overheating of the steel at the seam, so rust often appears at the weld site. Despite the apparent difficulties, welding stainless steel and ferrous metal is possible if a number of certain rules are observed.

Before answering the question “how to weld stainless steel with ordinary ferrous metal,” you should consider existing methods for producing a welded joint. The most common methods are:

• MMA. Manual electric arc welding using an electrode in a special coating.
• MIG. Semi-automatic gas-shielded welding using special wire.
• TIG. Welding in an inert gas environment with a non-consumable tungsten electrode.

MMA welding

Almost all types of metals, including stainless steel and black, can be welded with an electrode; however, you will need to select an electrode that has certain characteristics. In principle, this produces a good connection, however, in industrial conditions, welding of dissimilar stainless steels is carried out in a shielding gas environment. This is due to the fact that the weld, upon contact with air, is saturated with nitrogen and becomes quite brittle.

This is unacceptable when creating critical or load-bearing structures; therefore, for example, methods for welding channels together provide for the exclusion of air from entering the cooling weld. When welding most products made from stainless steel, argon is used as a shielding gas. It is highly inert and does not react with molten metal in the weld area.

Argon also has a molecular weight higher than that of air, so it completely displaces it from the welding zone.

Technology of welding stainless steel with ferrous metal

During the welding process, stainless steel melts more, and black just becomes viscous. To evenly distribute the molten metal and obtain a strong and beautiful seam, the parts to be welded must be positioned strictly horizontally. In principle, this is required by all stainless steel welding methods.

Additionally, it is worth mentioning that during the welding process, the electrode must be strictly perpendicular to the surface to be welded.

Welding is always carried out only with direct current; alternation when welding stainless steel and black steel is unacceptable. All this will allow you to achieve high quality and strength of welds. In addition to technology, an important factor that plays a big role in obtaining a strong seam is the correct choice of filler wire or electrode.

Having understood the welding technology, you can move on to the question of what electrodes and filler wire should be used for welding ferrous metal and stainless steel.

The wire used in the process of welding two different steels must contain at least 30% of the base material. The degree of alloying must be the same or higher than that of the metals being welded.

In the case of stainless steel and black, the main material is stainless steel (as it has the highest degree of alloying). The rest of the filler material is nickel and manganese.

Electrodes for welding

In principle, a good welded joint for not very critical structures can be obtained without the use of special consumables. Most often, a stainless electrode or a stainless filler wire is used to connect stainless and ordinary steel. Such electrodes contain an increased amount of alloying components, which make it possible to compensate for their burnout during the heating process.

If you need to weld any critical structure, you should pay attention to special transition electrodes for welding dissimilar or difficult-to-weld steels. When using them, a special intermediate (or buffer) layer is fused, which allows the parts to be connected. The most commonly used electrodes are OZL-312 (in cases where the chemical composition of steels is generally unknown) and NII-48G.

The resulting seam is checked after it has completely cooled. First of all, a visual inspection of the surface is carried out for the presence of cracks or burnt parts. If the tightness of the connection is required, then the test is continued using kerosene or ammonia. Using kerosene, microcracks that may have arisen during the welding process are checked.

To do this, a chalk solution is applied to one side of the seam being tested, and kerosene tinted with dye is applied to the other side. If the chalk solution has changed color, the seam is not sealed. In the place where staining has occurred and there is no seal. The coloring effect is based on the capillary penetration of kerosene through microcracks. Kerosene was also not chosen by chance; this liquid has very high fluidity.

Testing with ammonia is no different from testing with kerosene, only in this case the chalk solution is replaced with special indicators that change color.

Seam connection quality

Critical closed structures can also be tested for tightness and strength at the same time. For this purpose, artificially created hydraulic pressure is used.

It is important to remember that if there is a suspicion of an obviously weak weld, then using this method is strictly prohibited.

Checking the quality of the seam will allow you to be sure that you managed to weld the parts well.

Safety regulations

When carrying out any welding work, safety regulations must always be followed. This is especially true for the process of welding stainless steel and black steel.

Safety precautions

Stainless steel is very fluid when molten and can spatter a lot, so you should always wear a protective welding suit and gloves.

It is also advisable to choose a closed welding helmet.

Source: https://stankiexpert.ru/spravochnik/svarka/svarka-nerzhavejjki-s-chernym-metallom.html

Difficulties in welding dissimilar steels

It is worth noting the following welding features associated with different chemical compositions:

• Different indicators of thermal conductivity of materials, and as a result, insufficient penetration of one of them;
• Different linear expansion coefficients. Stresses in the fusion zone can remain even after heat treatment - this is the weakest point of the welded joint;
• “Carbon migration” from Cr-Mo steel, which has a sufficient amount of it, into the weld metal, thereby reducing the anti-corrosion properties of stainless steel.

 Important! The great variety of steels with different compositions does not allow us to make clear recommendations for welding that would give good results in 100% of cases.

The question arises how to overcome these nuances and whether it is possible to weld stainless steel with ferrous metal.

Technologies for welding stainless steel and ferrous metal

Quite good results in this process can be achieved by using steels with good weldability and applying some recommendations.

Two principles for welding corrosion-resistant steels with low-alloy and low-carbon steels have received practical application:

1. Filling the seam with electrodes made of high-alloy steel (even more alloyed than stainless steel) or Ni-based electrodes.
2. The second method involves surfacing a black steel edge with alloy electrodes, then the clad layer and the stainless edge are welded using stainless steel electrodes.

Weld structure during surfacing

If you are going to weld stainless steel to ferrous metal at home, you should pay attention to the following recommendations:

• welding is carried out with direct current of reverse polarity in any spatial position. The exception is the ceiling seam from the bottom up;
• welding is carried out using a short and extremely short arc;
• use highly alloyed filler materials and nickel-based compounds;
• be sure to calcinate the electrodes before welding for at least 1 hour, t = 190-210 ° C;
• Thoroughly clean the surfaces to be welded.

We recommend! How to cook cast iron using electric welding. Welding with inverter

Preheating is usually not required. The next step is to find out which electrodes are suitable in this case.

Electrodes used

Common brands of electrodes in the connection of stainless steel and ferrous metal are:

ANZHR-1; ANZHR-2

Welding modes with ANZHR-1 electrodes; ANZHR-2

TsT-28 electrodes for joints of the fourth group of weldability.

In cases where the use of Ni-based filler materials is not required, welding consumables based on high-alloy steels such as (2325)%Cr-(1115)%Ni (with or without Mo addition) are most often used. The most common ones are OK 67.70, OK 67.75 or OK Autrod/Tigrod 309L.

Used ESAB electrodes for welding dissimilar steels

Source: https://svarkagid.ru/tehnologii/svarka-nerzhaveyushhej-stali-i-chernogo-metalla.html

Welding stainless steel and ferrous metal

There are never any questions when welding metals of identical composition is performed. Problems arise when two different workpieces are welded. And, most likely, not problems, but difficulties related to the correct selection of welding technologies and modes, as well as consumables.

For example, welding stainless steel and ferrous metal. It seems like two steels, but with different technical properties. Therefore, to weld these two alloys correctly means to accurately select the parameters of the welding process.

After all, the welded seam will hold both workpieces firmly only if it consists of the same metal as the parts being welded.

With black metal everything is more or less clear. This is the most common material that can be easily welded with any type of welding. With stainless steel everything is much more complicated.

Features of stainless steel welding

There are four technical characteristics of stainless steel that make its welding special.

1. Low thermal conductivity of metal. If we compare this indicator with black steel, then it is two times lower for stainless steel. This suggests that in the process of heating the metal, it does not remove thermal energy, but accumulates it. And this is fraught with an increase in temperature in a certain area, which during welding will certainly lead to burn-throughs. This problem can be solved simply - you need to reduce the current by 20-30%.
2. The linear expansion of stainless steel is higher than that of ferrous metal. Why is this value so important? The thing is that after a large expansion, when heated, the reverse process will occur - shrinkage by the same amount as the expansion. That is, two workpieces can break the welding seam, or a large number of cracks will appear in it. The way out is a large gap between the parts being welded.
3. Electrical resistance. This indicator for stainless steel is also high. It affects the electrode, or rather its overheating during the welding process of stainless steel and steel. Therefore, it is necessary to reduce the length of the consumable to a limit of 35 cm, no more.
4. Stainless steel changes its properties when exposed to high temperatures. That is, it turns from stainless steel into ordinary steel. Therefore, it is very important not to overheat it. At +500C, a carbide compound is formed on the metal grains, which reduces the anti-corrosion properties of stainless steel. Essentially, corrosion begins to occur at the intercrystalline bonds. This problem is solved in different ways, for example, the parts being welded are cooled with water.

Is it possible and how to weld stainless steel with ferrous metal? A question that requires a special approach. The main thing is to choose the right welding technology. To do this, you can use:

• Manual arc welding with a consumable electrode.
• Non-consumable tungsten electrode in a protective gas environment with or without an additive.

By the way, you need to use stainless wire as a filler material.

It is impossible to say that the first welding method is better and the second is not, or vice versa. Each technology has its own characteristics and nuances. For example, in order for the weld seam in manual electric arc welding to be of high quality, you need to use electrodes with which you can weld the stainless steel itself.

The second technology predetermines the use of additives only made of stainless steel. Moreover, its composition must necessarily include alloyed additives: nickel and manganese, rarely chromium. But there still needs to be more stainless steel in the weld.

An ideal seam is made if its metal contains 40% pure stainless steel.

As for consumable electrodes, they are selected taking into account the composition of both metals being welded: stainless steel and ordinary steel. The thing is that two workpieces may differ not only in technical and mechanical parameters, but also in different degrees of weldability, the presence or absence of alloyed materials, and their percentage content.

In addition, the presence of nickel in the two alloys divides them into several categories: alloyed, low- or high-alloyed, carbon or heat-resistant. Therefore, when choosing an electrode, you will have to take all this into account.

Although there is a certain rule for welding stainless steel and black steel. If you want to get a high-quality weld without internal cracks, use consumables that are used for welding high-alloy steels.

The rod of such electrodes has high strength characteristics.

Which electrode brands are suitable for welding black steel and stainless steel:

• NIAT-5 – perfectly welds austenitic metals.
• TsT-28 – for stainless steel.
• E50A – for alloys with high heat resistance.
• OZL-25B – for heat-resistant metals.

The peculiarity of joining two different types of steel is that during the process of heating, a melt occurs. Metals become soft, but stainless steel in this regard becomes fluid, like water, and black steel acquires a viscous consistency. This is the big problem.

There is only one way to solve this - use a stainless steel welding electrode to make the connection. For example, OK61.30 is a universal brand, or OK67.

45 - This electrode is typically used in the most difficult situations, which include welding stainless steel and ferrous steel.

By the way, manual arc welding with a consumable electrode in this situation is the simplest compared to other technologies. But the use of gas welding is considered a better option in terms of obtaining a high-quality seam. The thing is that stainless steel filler wire reduces the fluidity of the base metal by almost three times. From this we can conclude:

• If you need to join stainless steel and ferrous metal parts at home, then choose electric arc welding.
• If you need the connection to be able to withstand significant loads, then it is better to use gas-shielded welding.

By the way, it is often better not to use argon welding for these purposes; such a connection will be too expensive. It can be replaced by conventional gas welding using stainless wire as an additive. It would be ideal if the welding area is protected with flux. But it will also have to be chosen based on the welding of two different alloys.

Welding modes

Thickness of joined workpieces, mm	Electrode diameter, mm	Type of current	Welding current strength, A
1	2	constant	30-60
2	3	constant	50-80
4	4	constant	90-130

Welding technology

As in all welding processes, the workpieces to be welded must be prepared: clean the edges or ends with a wire brush until shiny, degrease, if necessary. For degreasing, you can use solvent or alcohol. If gas welding is performed, then flux is placed in the joint.

It is better to weld ferrous metal and stainless steel in the lower position. This prevents metal from spreading. Welding with a melting electrode must be carried out in compliance with the precise movements of the welder’s hands. Basically, the electrode should be located closer to the ferrous metal because it is less likely to become fluid than stainless steel.

During gas welding, all the same processes occur in exactly the same way, only slower. The seam must be deep and wide. The more homogeneous metal between the workpieces, the better. The most important thing is that there are no quick cooling methods; the metal of the weld must cool slowly.

Of course, in order to achieve the quality of the final result, you must have experience in welding dissimilar metals. Therefore, after completing the welding procedure, it is recommended to carry out quality control of the seam. This can be done in several ways.

1. Using regular kerosene. It is applied to the surface of the seam, and on the other side it is checked whether it has passed through the joint of the workpieces. If there is no kerosene on the reverse side, then the welding was completed at a high level.
2. The same can be done using acetone. You can tint it with pigment for better appearance on the back side of the weld.
3. There is a so-called hydraulic control method. Usually it is used to check the strength of the seam. If joint defects were detected purely visually, then it is better not to use this quality control option.

It becomes clear that welding stainless steel to ordinary steel is a rather responsible process. Without knowing the intricacies of welding technology, without knowing the rules for choosing consumables, it will not be possible to make a high-quality steel joint. The most important thing, as practice shows, is to catch that middle when the molten stainless steel does not become very fluid. And at the same time, the black metal did not remain solid.

Source: https://svarkalegko.com/tehonology/kak-svarit-nerzhavejku-i-chermet.html

How to weld stainless steel and ferrous metal

Welding materials that are similar in their physical and chemical properties usually does not cause difficulties. Even for “capricious” metals with low weldability, certain algorithms have been developed that make it possible to obtain a high-quality connection. But when it comes to working with dissimilar metals, a number of serious problems arise. All these problems come down to the need to select the correct welding mode, work technology and consumables.

A striking example of a problematic issue is welding stainless steel with ferrous metal. Even though both materials are steel, their technical properties are significantly different.

To implement a high-quality welding process, you need to know exactly how to select the optimal parameters. The paradox is that the weld, as is known, has maximum reliability only when it consists of the same material as the workpiece. First of all, we note that working with stainless steel has its own specifics, and this will have to be taken into account when welding dissimilar materials.

• Peculiarities
• Methods
• Selecting Electrodes
• Process technology

Peculiarities

All reference books and recommendations contain such a concept as weldability. This is the ability of a metal or metals to form high-quality and durable joints through electric welding. As for the weldability of stainless steel, it directly depends on a number of material characteristics.

• The relatively low thermal conductivity of stainless steel negatively affects the quality of the connection. Since heat exchange with the environment occurs much more slowly than with ferrous metals, stainless steel gets very hot. Overheating of the weld pool is fraught with the appearance of cracks or through burns that weaken the seam. To weld materials with different thermal conductivities, it is necessary to reduce the current strength by about 20%.
• Thermal expansion is inherent in any metal, however, a mismatch in the linear expansion coefficients will lead to deformation of the part, especially during the cooling process of the weld. Often defects are discovered at this stage of the process. The way out of the situation is to maintain the gaps between the parts. This feature of the technology should also be remembered when welding dissimilar parts.
• The resistivity of steel is high, so when an electric arc forms, the electrodes overheat. This phenomenon is especially observed when welding with high-alloy steel electrodes. The way out of the situation is to use electrodes of short length (as the length decreases, the resistance decreases) or the use of chromium-nickel electrodes with low resistivity.
• High temperatures negatively affect the anti-corrosion properties of steel. Steels containing high amounts of chromium are prone to corrosion in the internal structure. Cracks form between the crystals. A similar phenomenon is often observed when performing welding work. The most effective way to deal with carbide compounds is intensive cooling of the metal. But there is one nuance in this method. Water serves as a means of heat removal. It is only applicable to chromium-nickel steels.

Process technology

Like any welding process, working with stainless steel requires a preparatory stage. First you need to clean the surfaces and process the edges of the parts. They are processed until shiny and then degreased. Alcohol or solvent is ideal as a solution.

It is recommended to carry out gas welding with flux, which is placed in the gaps between the edges. Work is carried out in the lower position, since the increased fluidity will not allow vertical or ceiling seams. This process requires the welder to have skill. So, the consumable electrode should be located a little closer to the surface of the ferrous metal than to the stainless steel edge.

When cutting edges, it is important to remember that the strongest seam will be obtained by increasing the area of ​​the weld pool. Passive cooling of the metal is preferred. Quality control of the resulting seam involves examining for the presence of through leaks.

Kerosene or acetone is applied to the surface on one side. Tinting of liquids is allowed. If it is necessary to check the strength of the seam, then liquids are supplied under pressure.

However, overpressure should only be applied after there have been no leaks during normal fluid application.

Source: https://svarkoy.ru/texnologiya/svarka-nerzhavejki-i-chernogo-metalla.html

Welding stainless steel and ferrous metal: features, technology, equipment and electrodes for performance

Connecting parts made of homogeneous metals by welding seems to be commonplace.

But sometimes it is necessary to create a stable weld between elements made of materials of different chemical compositions, for example, ferrous and alloyed metal - stainless steel.

Welding stainless steel with ferrous metal is possible subject to certain technological and warning conditions.

Welding of dissimilar steels

Combining materials with different chemical structures implies preliminary consideration of their properties. These are:

• different thermal conductivity of corrosion-resistant and black steels, which affects the unsatisfactory melting of one of the articulated parts;
• the coefficients of thermal expansion differ in the dimension of the inverse temperature, as a result of which stresses remain in the connected areas, affecting the strength of the seam;
• various mechanical characteristics;
• degree of alloying;
• migration of carbon from chromium-containing steel leads to the formation of cracks and susceptibility to corrosion processes.

Experts cannot give specific information for welding materials of various chemical compositions, due to their great diversity. It is recommended to adhere to several general rules for heat treatment of ferrous and alloy metals.

The conditions for the operation are as follows:

• use technology for welding high-strength steels;
• work is carried out by a qualified welder.

However, in any case, you need to know the chemical structure of both elements being processed in order to select the necessary consumables.

Operation methods

The connection of corrosion-resistant (stainless) and ferrous metals is often carried out using electric welding. The method does not require complex actions, which affects the ease of its implementation.

But you should also take into account the relative poor quality of the weld bead.

The low temperature of the weld pool will make iron or cast iron only viscous, while stainless steel will spread over the area.

Therefore, there is no need to talk about the formation of a vertical or ceiling seam. Adapter electrodes will help ensure a reliable connection.

Gas welding is a more suitable method for joining iron or cast iron to stainless steel, due to the prevention of fluidity of the latter.

The additive will be alloyed wire; the use of flux will provide better melting of the carbon-containing material.

Welding stainless steel and ferrous metal will require preliminary preparation of the elements being processed and compliance with safety rules when using gas cylinders.

To obtain a good weld bead, it is practiced to use an atmospheric controlled environment - argon, which does not require the use of stainless wire.

The inert gas protects the weld pool from the external atmosphere and does not affect the structure of the material.

Selecting a method

Before you begin any method of welding stainless steel and ferrous metal, you need to determine the task being performed.

Arc welding with stainless electrodes is suitable for joining materials of various chemical structures in a home workshop.

Industrial production places increased demands on metal connections due to their exposure to heavy loads. In this case, you need to choose a gas burner.

Electrodes

The degree of alloying of the electrode must be higher than that of the element being processed.

The following conductive rods are suitable for this:

• E50A - operations with heat-resistant steels;
• HIAT - heat resistant;
• OZL-25B - austenitic stainless steel.

Grade CT-28 is intended for working with metals containing a significant addition of nickel.

Safety precautions

Heat treatment of alloy steel (stainless steel) and ferrous metal is highlighted by the possible splashing of the molten area.

Therefore, work must be carried out in a protective suit, mask, and gloves. If splashes accidentally come into contact with the skin, a severe burn will form.

Checking the connection

After complete crystallization is complete, the seam between the stainless steel and ferrous metal should be checked for strength. The following methods are suitable for this:

• visual inspection of parts;
• apply kerosene to the roller; if there is no tightness, traces of liquid will appear on the back side of the connection;
• using acetone with a bright dye also checks the uniformity of the seam structure.

Industrial enterprises use a more reliable method of verification - hydraulic, by testing the structure with pressure.

Source: https://prosvarku.info/tehnika-svarki/svarka-nerzhavejki-i-chernogo-metalla