How to make stainless steel

Welding stainless steel at home: options, tips, videos

When performing a technological operation such as welding stainless steel, it is important to take into account both the physical properties of the material and its chemical composition. Only in this case can you count on the connection being made efficiently and reliably.

Argon welding of stainless steel

Difficulty factors for welding stainless steel parts

Welding stainless steel is complicated by the fact that this material belongs to the category of high-alloy alloys, which means that its composition contains elements in fairly large quantities that affect its basic properties.

In stainless steel, in particular, this element is chromium. Its content in this alloy can be 12–30%.

Chromium, along with elements such as nickel, titanium, manganese and molybdenum, forms the anti-corrosion properties of stainless steel, but at the same time gives it other features that affect weldability.

For those who do not like to read long articles and delve into technical details, we suggest you immediately watch two videos with the most relevant options for welding stainless steel for a home craftsman - with an electrode using an inverter and again with an inverter, but in a shielding gas (argon). Welding of stainless steel must be carried out taking into account the following specific characteristics of this material. Sufficiently high coefficient of linear expansion

For this reason, welding stainless steel is always accompanied by significant deformation of the parts being joined. In some cases, when the parts being welded are of significant thickness and there is no gap between them, such deformations can even lead to the appearance of large cracks.

Low thermal conductivity

The thermal conductivity of stainless steel is 1.5–2 times lower than that of low-carbon alloys. This feature of the material leads to the fact that the parts being connected in the welding zone are melted even at lower (15–20%) current strengths than when welding products made of low-carbon steel.

Intergranular corrosion

With strong heating (more than 500 degrees Celsius), so-called intergranular corrosion occurs in stainless steels. This happens because layers consisting of chromium and iron carbide begin to form at the edges of the grains of the metal structure.

This phenomenon can be avoided not only by careful selection of the welding mode, but also by forced cooling of the stainless steel parts being welded, for which you can use ordinary water.

However, it should be borne in mind that only parts made of chromium-nickel steels that have an austenitic internal structure can be cooled with water.

Overheating of electrodes with chromium-nickel rods

Due to the low thermal conductivity of the materials being joined and their increased electrical resistance, welding of stainless steel parts is accompanied by strong heating of the electrodes, the rods of which have a chromium-nickel composition. To avoid this undesirable phenomenon, use electrodes for welding stainless steel up to 35 cm long.

Welding electrodes Sabaros ME 101 3.2 mm for welding stainless steels

The most common methods of welding stainless steel

Welding of stainless steel products characterized by a high chromium content can be performed using several technologies. This includes, in particular, the following types of welding:

• argon arc (using a tungsten electrode and AC/DC TIG modes);
• performed in MMA mode with coated electrodes;
• semi-automatic arc welding in an argon environment, carried out in MIG mode and using stainless steel wire;
• so-called cold welding for stainless steel, performed under high pressure (the name of this technology is due to the fact that it does not involve melting the metal during the process of joining it);
• seam technology and resistance spot welding.

The technology for welding stainless steel parts involves thoroughly degreasing their surfaces using acetone or aviation gasoline. This is done in order to reduce the porosity of the seam being performed, to make the welding arc more stable, and to thoroughly clean the edges of the parts being joined.

Only after thorough cleaning can you begin to perform the operation using the chosen method. There are several basic methods for welding stainless steel parts, as well as technologies that are used quite rarely.

In any case, the decision on how to weld stainless steel should be based on the specific conditions and requirements for the joint being formed.

Welding with coated electrodes (MMA)

Welding stainless steel parts using MMA technology, which involves the use of coated electrodes, is the most common technology. This method is quite simple, it can be used at home, but it does not allow you to obtain the highest quality seam.

Conveniently, this kind of stainless steel welding can be done even at home, but for this you will need a special welding machine called an inverter. In order for welding stainless steel with an inverter to produce a highly reliable connection, it is necessary to select the correct electrode for a specific grade of stainless steel. All electrodes used to weld stainless steel products are divided into two main types:

• with a rutile coating based on titanium dioxide (welding with such electrodes, which provide small metal spatter and a stable arc, is performed with direct current and reverse polarity);
• with a coating based on magnesium and calcium carbonate (with such electrodes, stainless steel is welded using direct current of reverse polarity).

To understand which electrodes to use to weld stainless steel, just look at GOST 10052-75, which presents all types of such consumables, and also stipulates which one should be used for working with metal of a specific chemical composition. In order to select stainless steel electrodes that meet the requirements of this GOST, it is enough to know the grade of the metal from which the parts need to be connected.

All requirements for electrodes for welding stainless steel can be found by downloading GOST 10052-75 for free in pdf format from the link below.

Manual and semi-automatic welding of stainless steel in argon (AC/DC TIG, MIG)

To perform manual welding of stainless steel in an argon environment, tungsten electrodes are used. This technology, even at home, allows you to obtain high-quality and reliable connections for products that are not very thick. Welding with such electrodes on stainless steel is used mainly for installing communications from pipes through which gases or various liquids will be transported under pressure.

Austenitic stainless steel should be welded with particular care and caution

This technology has certain features.

• To ensure that tungsten, from which stainless steel electrodes are made, does not get into the molten metal in the welding zone, the arc is ignited in a non-contact manner. If it is not possible to do this directly on the part, then the arc is lit on a special coal plate and carefully moved to the workpieces to be joined.
• Welding stainless steel using this method can be performed with both direct and alternating current.
• The modes are selected depending on the thickness of the parts being connected. Such modes, in particular, include the parameters of the cross-section of the tungsten electrode, the diameter of the wire used as an additive, current parameters (strength and polarity), shielding gas consumption, and welding speed.
• It is very important that the alloy level of the filler wire is higher than that of the parts being joined.
• During the welding process, stainless steel electrodes should not make oscillatory movements. If this requirement is neglected, this may lead to disruption of the welding zone and oxidation of the metal in its area.

By using this technology, the consumption of tungsten electrode can be reduced. To do this, you need to keep the argon supply open for some time (10–15 seconds) after the welding process is completed. This procedure helps protect the hot tungsten electrode from active oxidation.

Semi-automatic welding of stainless steel in an argon environment, in fact, has few differences from the conventional manual method. Its main difference is that the wire is fed into the welding zone using special equipment. Thanks to mechanization, the process proceeds much more accurately and at greater speed.

Thanks to the use of semi-automatic equipment, the following welding techniques for stainless steel parts can be implemented:

1. jet transfer method, which allows you to effectively weld parts of large thickness;
2. short arc welding - for connecting parts of small thickness;
3. Pulse welding is a universal technology that allows you to obtain high-quality and reliable connections and is the most profitable option financially.

Tig welding of stainless steel

Other stainless steel welding technologies

There are several other methods of welding stainless steel that demonstrate themselves better in certain situations, that is, they are not universal. This includes the following methods, which involve the use of special equipment.

Source: http://met-all.org/stal/svarka-nerzhaveyushhej-stali-sovremennye-tehnologii.html

DIY stainless steel products - Metals, equipment, instructions

Stainless steel is a product that is not subject to corrosion, oxidation, or destruction by aggressive environments. Stainless steel products have an aesthetic appearance, practicality, environmental safety and durability. The metal lends itself well to polishing and grinding. The surface can be matte, mirror, chrome, colored.

The physical and technical characteristics of the product depend on the percentage of chromium. The standard alloy contains 12−20% of the component.

Under the influence of oxygen, the additional component is converted into chromium oxide, which creates an inert protective film of insoluble oxides on the surface of the rolled product. In addition to chromium, stainless steel may contain C, Mn, P, Si, S.

To increase the physical and mechanical properties, Ni, Mo, Nb, Ti, Co may be present in the alloy.

Rolled metal is produced in different grades that can satisfy the requirements of almost all areas of human activity: from construction to the manufacture of decorative elements.

Depending on the percentage of additives, stainless steel is divided into several types:

1. chromium;
2. chromium-nickel;
3. chromium-manganese-nickel.

Easy processing, high melting point, resistance to ultraviolet radiation, mechanical damage and moisture allow the metal to be used for the production of products for various purposes . The alloy, resistant to chemicals, is used in the manufacture of pipes , parts, and components for various objects:

1. chemical and electronic industries;
2. mechanical engineering;
3. production of food products, medicines, cosmetics;
4. surgical instruments and cutlery;
5. decorative designs;
6. fencing.

Manufacturing of products to order

Based on the client’s sketches, stainless steel products are produced to order after the design of the future product has been developed. According to individual sizes, specialists can quickly and at an affordable cost produce:

1. containers;
2. entrance groups;
3. awnings;
4. fencing;
5. racks;
6. elements of office and home furniture;
7. handrails;
8. gratings;
9. benches;
10. countertops;
11. supply and exhaust systems.

Products are manufactured to order from different grades of steel , the choice of which depends on the purpose and operating conditions. For products intended for indoor installation, inexpensive alloy AISI 430 is suitable, which has a pleasant appearance and durability. Rolled metal combines well with plastic, wood, glass and stone.

Interior and exterior items made of stainless steel combine aesthetics, reliability and environmental friendliness.

According to the customer's drawings, it is possible to manufacture barbecues, heating and water supply pipes, smokehouses, stair railings, and decorative grates for the fireplace.

Austenitic stainless steel is used for storage tanks, mirror frames, car brackets, table tops, vacuum chambers, and shoe stands.

Positive traits

The main positive properties of alloy steel varieties are light weight, the ability to paint, bend, drill, laser cutting, turning, rolling, casting and welding. According to the project of the enterprise, a range of goods is produced from stainless steel , among which the following can be noted:

1. roof rails;
2. columns;
3. flagpoles;
4. bicycle parking;
5. lamps;
6. tables;
7. chairs;
8. floor coverings;
9. fastenings;
10. accessories;
11. heat screens.

A unique project for a home, restaurant, cafe and other organizations can be the production of a stainless steel aquarium of the appropriate size and shape. The design can fit into any interior, provide access to maintenance systems for an artificial reservoir, and allow you to replace the glass bowl without dismantling the frame.

Popular brands

The most popular grades of metal for production purposes are steel 300 and 400 series. The 300 series includes austenitic, austenitic-ferritic and austenitic-martensitic steel. AISI 304 alloy grade is produced for the food and pharmaceutical industries; the material is easy to weld and is resistant to aggressive environments.

AISI 316 stainless steel for the chemical, shipbuilding and oil and gas industries can withstand high temperatures and retain its properties when in contact with an acidic environment and sea water.

AISI 316 T steel contains titanium, which increases the strength characteristics and resistance of the metal to chlorine ions.

Stainless steel is used in the manufacture of equipment and components for the chemical and food industries, and welding of gas turbine blades.

AISI 321 alloy metal can withstand heating up to 800 C, and is used in the production of seamless pipes, elbows, tees and adapters from stainless steel in hot water supply systems, sewage systems, as well as in pipelines for transporting mildly aggressive chemicals.

  Is stainless steel magnetic?

From ductile steel 400 series AISI 430, the customer can order decorative elements for the interior or exterior , as well as parts intended for use in the oil and gas industry. In special cases, specialists can select a cheaper “analogue” with chemical and mechanical properties in accordance with technological conditions.

Product manufacturing process

The production of stainless steel products is carried out on modern equipment by high-class specialists, since working with the material requires professional training.

In the production workshop the following is carried out: perforation, bending, cutting, engraving, grinding, polishing of sheet material before or after cutting to the size and configuration of a pipe, profile, angle.

At the installation site of the part, the weld seam is additionally cleaned, polished and painted.

Steel structures in combination with other building and finishing materials will help emphasize the style of the room. Computer graphics processing or 3D imaging will help produce products in the correct proportions, allowing you to create an image of the future part and make the necessary changes.

Food-grade steel does not oxidize, does not allow pathogens to multiply, and lends itself well to sanitary and heat treatment. The cost of custom-made products depends on the steel grade, purpose, operating conditions and complexity of the work process.

Source: https://spb-metalloobrabotka.com/izdeliya-iz-nerzhaveyki-svoimi-rukami/

Burnishing stainless steel at home - Metalworker's Guide

The information presented in this article will be useful for materials scientists, technologists and engineers involved in the processing and study of the properties of metals. The production of decorative coatings is increasingly being used in various branches of mechanical engineering, the automotive industry, and in the production of household items. Let's consider one of the most popular methods of creating a film - oxidation of stainless steel.

Terms, definitions, types of stainless steel oxidation

By definition, this term refers to the creation of a film of oxides on the surface of stainless steel due to redox reactions. In addition to the protective function and decorative finishing, the use of this process is involved when it is necessary to create dielectric layers and change surface physical processes occurring in an environment of high magnetic and electric fields. Depending on how the oxidation was obtained, they are distinguished:

• Thermal process
• Chemical exposure
• Electrochemical process
• Plasma oxidation

Let's look at these processes in more detail.

Thermal process

The thermal oxidation process involves treating metal at certain temperatures in an environment of oxygen or water vapor. Low-alloy steels and iron, when exposed to this effect, obtain a film called bluing. The temperature for bluing is 300-350 degrees Celsius. For high-alloy and high-chromium steels, this figure increases to 700 degrees.  

Interesting information: bluing stainless steel at home is quite possible for anyone. There are several ways to do this. Any method must be preceded by grinding the metal and degreasing it. Dip the part or product into oil. It can be olive, machine, or best of all, weapon.

After making sure that the application is even and that the oil gets into hard-to-reach places, we remove the workpiece and let the oil drain. After this, we begin heating with a blowtorch. The lower the heating rate, the higher the probability of complete removal of light fractions and obtaining a uniform bluing layer. After overcoming the threshold of 400 degrees, a characteristic black color appears on the surface.

When finished, polish with soft felts and paste.

Chemical oxidation

Chemical oxidation is the production of a protective film through the interaction of metal and melts, often solutions, of oxidizing substances. The advantages of this method include:

• relative simplicity
• absence of high temperature sources
• simplicity of equipment
• low labor costs

The only and most significant disadvantage of this method is the low protective characteristics of such a film and low resistance to mechanical stress. The primary use of chemical oxidation is to apply a touch-up layer, as well as to preserve mechanisms and parts when stored in production workshops and heated warehouses.

The need to use large amounts of water, its subsequent purification, the high cost of water and cleaning reagents leads to gradual displacement from production, in the face of stricter environmental standards. Cold chemical oxidation of stainless steels has become available thanks to the commercial availability of two-component chemical reagents.

Please note: The higher the concentration of active chemical elements, the faster the reaction rate, but the penetration depth is less. Accordingly, the film thickness will be less.

Electrochemical oxidation

Electrochemical oxidation of stainless steels is a method that is widely used in industry. It consists in the fact that the parts are suspended on special holders.

Using this device, they are lowered into a solution with alkali, after which the bath in which it is located is connected to the negative cathode. The parts are connected to the positive anode.

When direct current is passed, according to a physics course, electrolysis processes occur, accompanied by an increase in temperature. The speed of application and the thickness of the resulting film depends on many factors. Main influencing factors:

1. Density of flowing current.
2. Electrical conductivity of the solution in which the parts are placed
3. Electrolyte temperature
4. Geometry and part configuration

Interesting fact: at the end of the previous decade, one of the giant Japanese automakers used galvanic blackening of stainless steel on the body of their cars. Research has shown that in the area where the roof bends into the pillars, the oxidized layer was of insufficient thickness.

Long-term research into changing the place where the electrodes are attached to the body, changing the current density, and changing the exposure time did not lead to the expected result.

Only by changing the electrical conductivity of the alkaline solution and adding special additives did the layer become uniform and sufficient for the quality level of the enterprise.

Complex geometry, sharp corners, curved shapes in the contours of the part lead to differences in potentials arising on the surface of stainless steel and, accordingly, lead to differences in film thickness. For such parts, it is advisable to use the previous oxidation method.

Plasma oxidation

Plasma oxidation occurs under conditions similar to galvanic blackening. When a certain critical value of polarization is reached, a plasma microdischarge occurs on the surface of the anodized part.

Unlike electrochemical nitriding, not only the alkali solution, but also the cathode material participates in the formation of the resulting film.

A characteristic feature of the presented method is deep penetration into the layer of stainless metal and the ability to obtain a uniform coating on objects of complex geometric configuration.

An interesting fact: at the point of spark breakdown during plasma oxidation, the temperature is about 10,000 K, and the pressure is comparable to 102 MPa. After the spark ceases, a sharp cooling of the surface occurs, which leads to the emergence of new physical properties and their study as elements of nanotechnology.

The coatings that are formed when using this method are characterized by increased adhesion to the base and properties close to ceramics.

Considering the price of the equipment and the lack of research in this area, its labor intensity and the need for highly qualified personnel do not allow this process to be widely used in industry, being limited to expensive industries and piece products.

For aluminum, titanium and magnesium alloy, plasma oxidation is finding niches and widespread use in industry.

Please note: the terminology for this process has not been established to this day. Therefore, having encountered oxidation in the sparking mode, anodic deposition, maximum voltage mode, plasma-electrolytic oxidation in the literature, one must understand that this is the same process - plasma oxidation.

Difficulties of blackening work associated with stainless steel

All the methods described above are ideal for ferrous alloys and low alloy steels. A special approach is required, a set of measures for blackening stainless steel as a conditionally inert alloy. The scattered data in the literature on direct blackening of stainless steel is contradictory and does not always work in practice.

On a production scale, it is customary to solve this issue with a two-step approach. The first stage is anodizing stainless steel with another metal that is more prone to oxidation. This is mainly nickel, less often copper. The second stage is oxidation of the resulting surface.

  Brushed stainless steel

Chemists in many countries are developing special passivating pastes and compositions for blackening stainless steels that can induce them to oxidize.

To apply a decorative film that does not work when exposed to temperature changes, on a surface that does not experience large mechanical loads, the following oxidation method can be used:

1. Etching in 10% oxalic acid solution
2. Washing and processing in 1% sodium sulfide solution to the required degree of blackening
3. Oiling a stainless steel sample.

Based on the information presented, we can conclude that the use of blackening for stainless steel is in the nature of a commercial decorative coating. The use of oxidation to achieve higher metal characteristics is not justified and cannot be guaranteed. To obtain protective films that expand the scope of application of stainless steels, it is worth considering other methods and methods.

Source: https://ssk2121.com/voronenie-nerzhaveyuschey-stali-v-domashnih-usloviyah/

How to make stainless steel soft?

Stainless steel comes in different varieties. After all, it contains several different metals. The basis of stainless steel is iron, titanium, nickel, molybdenum, manganese, and this is not the entire list. Chromium, which is also present in its composition, helps this steel resist corrosion.

What prevents steel from rusting

When chromium interacts with oxygen, a protective film is formed on the surface of stainless steel; it is this film that protects the alloy from exposure to aggressive environments.

The amount of chromium will determine the degree of corrosion resistance of steel.

For example, in the manufacture of refrigerators, an alloy with an average chromium content (10-17%) is used. But if the device is constantly in contact with water or is subjected to temperature loads, then an alloy with a high chromium content, up to 26%, is used. Such appliances include washing machines, dishwashers, sinks, hoods, cookers and kettles.

In order for the surface of the alloy to be beautiful and smooth, you need to polish the stainless steel. Nowadays, there are many companies whose specialization is this particular procedure; they put in order various products made from this alloy. But it turns out that you can polish stainless steel at home.

Of course, if you need better quality work, it is better to seek help from specialists. For example, a polished square stainless steel pipe will look much more impressive after factory processing than after home processing.

Any company that specializes in polishing will easily perform this procedure.

How to process steel

How to polish stainless steel to a mirror shine? Here is a list of everything you will need:

• polishing paste;
• felt or felt circles;
• wood glue;
• grinding wheels with different grain sizes;
• sandpaper or stone;
• Bulgarian.

Main stages of the process

The process takes place in several stages. First you need to do some rough cleaning. Next comes a wheel with a fiber base and an angle grinder. But this procedure can be skipped provided that the surface of the product is already quite smooth.

Grinding wheels come next. The surface must be processed several times, and each time the size of the abrasive should decrease.

If such circles are not available, then you can easily make them yourself. To do this, you can use a felt circle or felt. You need to apply wood glue to it with a spatula, and then rub it over the abrasive chips.

This operation will make the steel surface perfectly smooth. Under no circumstances should any roughness remain. After all, after polishing it will be much more difficult to seal them.

The next step is to apply polishing paste and a felt wheel. Here it is better to consult a specialist, since a specific brand of alloy requires a specific paste.

Of course, it is best to use diamond, the grit of which is suitable for the metal intended for processing. Final polishing is carried out until there are no visible flaws left.

A polished stainless steel pipe should look just perfect.

Stainless steel in everyday life

No kitchen is complete without stainless steel appliances and interior parts. This is not surprising, since this particular alloy is quite strong and durable, especially since it does not require special care. Stainless steel is often used to make dishes, cutlery and stoves, as this metal has a fairly high thermal conductivity.

But there are also some disadvantages to stainless steel: with regular use, it noticeably tarnishes. The kitchen is losing its shine. To prevent this from happening, it is necessary to periodically polish the stainless steel. There are many different ways to solve this problem. An important point in this procedure is the correct selection of polishing agent for stainless steel.

When cleaning steel products, never use bleach or abrasives. Also, do not use metal sponges or brushes with stiff bristles.

There are several alternative polishing methods.

Olive oil

This method is just for those who are thinking about how to polish stainless steel at home. Tarnished dishes will begin to shine again, like new. All you need is oil and rags, preferably made of soft fabric.

1. First of all, you need to moisten a rag with oil.
2. Using this cloth, it is necessary to apply oil to the product so that it is completely covered with an oil film.
3. Next, you can begin polishing by pressing the oiled rag firmly against the metal.
4. To prevent the steel from becoming dull again, excess oil is removed using dry towels or napkins. They need to rub the surface until the product is completely dry.

Polishing with flour

You can also use flour to polish metal products. It is good for cleaning flat surfaces, such as a sink or pan.

1. The product is sprinkled with flour so that there are no gaps left at all.
2. The flour should be distributed evenly.
3. Using a dry cloth, polish the surface in a circular motion.
4. Next, the flour is very easy to remove from the surface.

Mechanical method

Some devices and fixtures have hard-to-reach areas. This is where the question arises, how to polish stainless steel to a shine. There is a way, but you will have to spend a lot of time and make every effort.

You need to purchase a piece of felt and abrasive paste. Apply the paste to the fabric and polish the surface until the metal becomes bright and shiny.

Polishing with chemicals

This method is most often used when you need to clean small items. The main thing is that polishing takes little time and is very simple to do. Below are several recipes for solutions.

Recipe 1

It is important to maintain proportions here. Contains: 230 ml of sulfuric acid, 70 ml of hydrochloric acid, and 40 ml of nitric acid. The rest is water.

For one liter of solution you need another 5 g of sodium chloride, 5 g of acid black dye and 10 grams of wood glue.

The resulting liquid must be heated to 70 degrees Celsius and the part must be lowered there. The product can be left in the solution for a maximum of half an hour.

Recipe 2

You will need orthophosphoric acid, it should make up 20-30 percent of the total volume. Hydrochloric acid (3-4%), nitric acid (4-5%), methyl orange (1%). The rest is water. The solution should be at room temperature, and keep the product in it for no longer than 10 minutes.

Recipe 3

acids are indicated per liter of solution. Acid orange dye - 25 g, sulfuric acid - 230 g, hydrochloric acid - 660 g. Heat the liquid to seventy degrees and keep the metal in it for no more than three minutes.

Polishing rules are given below:

1. The metal must be thoroughly cleaned before polishing. Next, place the product in the solution. It should be remembered that only distilled water can be used here.
2. During the procedure, the solution must be constantly stirred, only in this case the chemical reaction will take place 100%.
3. When the required time has passed, the part is removed and washed well with running water. After this, the product must be well rubbed with a napkin soaked in polish.

After this treatment, all roughness is eliminated.

It is not enough to polish stainless steel correctly; it also needs to be cleaned regularly.

Cleaning the sink

Often stains remain on sinks - this is limescale. It is very easy to remove with a vinegar solution. You need to dilute the acid one to five and wipe the surface with it, and then rinse with running water. To give the metal a bright shine, the surface must be rubbed in a circular motion.

Cleaning the stove

Stains from sauces, fat and burnt food remain here. They will have to be removed with a special steel polishing agent. Be sure to remove the heating elements before cleaning. It is best to use the polish while wearing gloves. Otherwise, there is a risk of getting burns on the skin of your hands. After the procedure, it is advisable to rub the surface well with a dry cloth.

Cleaning the hood

This is not an easy task. But quite doable. To prevent dirt and soap from staining the stove, it is better to cover it with newspapers or old towels.

To clean the hood, you can use a specialized product or prepare a solution yourself. You will need bicarbonate of soda, lemon juice and water. The product must be rubbed in carefully so as not to damage the surface.

It is enough for the solution to remain on the hood for several minutes, after which it must be washed off with clean running water. Next, you need to polish the surface well with a dry cloth.

  Cleaning stainless steel welds

After this procedure, the hood will shine like new.

Source: https://varimtutru.com/kak-sdelat-nerzhaveyku-myagkoy/

How to weld stainless steel with ferrous metal?

Not every welder can handle the process of welding stainless steel. This is due to the technical characteristics of this material. More difficulties arise when welding stainless steel with ferrous metal. To create a strong connection between these materials, it is necessary to choose the right welding mode and take into account a number of features.

Welding pipes from different metals

Is it possible to weld ferrous metal with stainless steel?

If we talk about production, technology for welding stainless steel with ferrous metal, then it is initially incorrect due to the difference in materials, their properties, and technical characteristics. However, the connection can be made.

Since enterprises require compliance with GOSTs, this method of joining metals is in demand in small workshops. But to obtain a good connection, you need to know the chemical composition of the components being welded and have practical experience working with them.

Difficulties in welding dissimilar steels

Welding stainless steel with ferrous metal causes certain difficulties. This is due to differences in the technical characteristics and chemical composition of the two steels. These include:

1. The weakest point after the work is the solder joint. This is explained by the fact that the two materials have a difference in the coefficient of linear expansion. Because of this, internal stresses remain after the welding process.
2. Uneven penetration occurs due to differences in thermal conductivity. This negatively affects the strength of the finished seam.
3. Effect of carbon migration. Impairs the anti-corrosion protection of the finished product. Because of this, the seam will quickly become covered with a layer of rust.

Tool

To carry out the work, it is necessary to prepare a welding machine, additional tools, consumables, and wire of a certain chemical composition. List of required devices and materials:

1. Inverter welding machine.
2. Stainless steel filler wire.
3. Electrodes (the quantity depends on the size of the seam, the number of parts to be welded).

Separately, it is necessary to talk about the choice of electrodes. There are several main types of consumable metal rods with a special coating:

1. OZL-25B - used for joining heat-resistant steels.
2. NIAT-5 - used for welding austenitic materials.
3. TsT-28 - used for welding nickel-based alloys.
4. E50F - used for joining heat-resistant metals.

We must not forget about setting up the welding material. Principles for selecting modes:

1. For a part thickness of 1 mm, direct current of up to 60 A is used (electrode 2 mm in diameter).
2. With a workpiece thickness of 2 mm, an alternating current of up to 80 A is set (electrode 3 mm in diameter).
3. With a part thickness of 4 mm, a direct current of up to 130 A (4 mm electrode) is used.

If the current is too high, the materials will be damaged.

Inverter with mask and electrodes

Technologies for welding stainless steel and ferrous metal

There are several features of welding stainless steel with ferrous metal:

1. Stainless steel has a high coefficient of linear expansion. Because of this, large gaps are required between the workpieces being connected.
2. It is necessary to quickly cool the metals being welded to maintain corrosion resistance.
3. Work only with short electrodes, up to 350 mm long. Using long coated rods will cause them to overheat during the work process.
4. The welding current should be reduced by 20% due to the low thermal conductivity of stainless steel. This will help maintain the technical characteristics of the finished product.

How to weld stainless steel with ferrous metal?

There are two methods to weld stainless steel to ferrous metal:

1. Use high alloy steel electrodes to fill the joint. Nickel-plated rods can be used.
2. Use of alloyed electrodes for surfacing edges made of black steel. The seam is then created using clad steel that fills the seam.

Recommendations from experienced welders:

1. Use consumables made on a nickel base.
2. Before starting welding, calcinate the electrodes. The optimal temperature is up to 210 degrees for 1 hour.
3. Use direct current.
4. Before starting work, clean metal surfaces from dirt, plaque, scorch, and rust.
5. If gas welding is used, rapid cooling of the finished seam cannot be performed. The part should cool on its own.
6. It is recommended to apply flux to the work area to make a better connection.
7. When using a tungsten rod, do not forget to sharpen its tip.
8. Gas shielded welding is preferred because the finished weld will be stronger.
9. When welding, you need to capture more ferrous metal. This will create a stronger seam at the molecular level.
10. Movements should be careful and unhurried.

How to check the quality of the connection?

There are three ways to check a seam:

1. Cover the joint surface with kerosene. You should not skimp on the amount of liquid during testing. If kerosene comes out on the other side, the seam is bad.
2. The second option is to use acetone. It is applied in the same way as kerosene. Droplets appearing on the other side of the seam indicate the presence of microcracks and through holes.
3. The industrial method for testing the strength of seams is the hydraulic method. After this is done, you need to inspect the connection visually. If defects appear, the part is rejected.

If the master knows that the connection is weak, he will not use testing methods associated with the destruction of parts. Any unevenness, cracks, or depressions indicate improper work.

Security measures

Welding work is carried out in strict compliance with safety regulations:

1. Never use faulty equipment. Check the device in advance, inspect the working elements and wires for possible breakdowns.
2. The electrodes must be new, with the working layer intact. Cracked rods should not be used.
3. Prepare your workplace in advance. Remove all flammable mixtures away and clear the table of unnecessary objects that may interfere with welding work.
4. Welding is considered a harmful technological process. Therefore, you need to use a welder’s mask, protective overalls, gloves, and durable shoes.
5. Place a rubber mat under your feet to prevent electric shocks.
6. The room in which welding work is carried out must be equipped with a good ventilation system.
7. For convenience, it is advisable to carry out work on a metal work table.

When working with cylinders filled with inert gases or oxygen, it is necessary to wipe off any oil leaks in the work area.

Welding stainless pipe with black pipe

Any welder knows how difficult it is to weld stainless steel parts together. The process becomes more complicated if you need to connect stainless steel with ferrous metal. Therefore, it is necessary to accurately determine the components of materials, select electrodes, and the operating mode of the device. During the work process, you need to take into account the advice of professionals.

What is the best way to weld stainless steel with black metal? How to weld stainless steel with ferrous metal? Link to main publication

Source: https://metalloy.ru/obrabotka/svarka/nerzhavejki-s-chernym-metallom

Stainless steel products of different brands: production, advantages of stainless steel

Stainless steel is a product that is not subject to corrosion, oxidation, or destruction by aggressive environments. Stainless steel products have an aesthetic appearance, practicality, environmental safety and durability. The metal lends itself well to polishing and grinding. The surface can be matte, mirror, chrome, colored.

The physical and technical characteristics of the product depend on the percentage of chromium. The standard alloy contains 12−20% of the component. Under the influence of oxygen, the additional component is converted into chromium oxide, which creates an inert protective film of insoluble oxides on the surface of the rolled product. In addition to chromium, stainless steel may contain C, Mn, P, Si, S. To increase the physical and mechanical properties, Ni, Mo, Nb, Ti, Co may be present in the alloy.

Rolled metal is produced in different grades that can satisfy the requirements of almost all areas of human activity: from construction to the manufacture of decorative elements.

Depending on the percentage of additives, stainless steel is divided into several types:

1. chromium;
2. chromium-nickel;
3. chromium-manganese-nickel.

Easy processing, high melting point, resistance to ultraviolet radiation, mechanical damage and moisture allow the metal to be used for the production of products for various purposes . The alloy, resistant to chemicals, is used in the manufacture of pipes , parts, and components for various objects:

1. chemical and electronic industries;
2. mechanical engineering;
3. production of food products, medicines, cosmetics;
4. surgical instruments and cutlery;
5. decorative designs;
6. fencing.

Welding stainless steel with ferrous metal - welding technology

Welding stainless steel with ferrous metal - work technology

Not every welder can weld stainless steel with ferrous metal. This is due, first of all, to the heterogeneous composition of stainless steel and ferrous metal, and the special technology of electrode welding.

And although almost half of stainless steel consists of ferrous metal, it also contains non-ferrous metals that require a special approach when welding. However, it is possible to weld stainless steel with ferrous metal, you just need to adhere to the correct technology.

What you need to weld stainless steel and ferrous metal

If there is a need to weld stainless steel and ferrous metal at home, then for these purposes you will need to use:

• DC welding inverter;
• Electrodes (what electrodes to use to weld stainless steel and ferrous metal will be discussed below, in this article on the website about welding mmasvarka.ru);
• Stainless steel wire (it will be used as filler material).

Electrodes for welding stainless steel and ferrous metal deserve special attention.

What electrodes to cook stainless steel with?

To weld stainless steel with ferrous metal, you need electrodes that are used for welding heat-resistant steels and nickel-based alloys.

The following brands of electrodes meet these standards and requirements:

• Electrodes OZL-25B - used in cases where it is necessary to weld heat-resistant steels;
• NIAT-5 electrodes are the most popular electrodes for welding austenitic steels;
• TsT-28 electrodes are used for welding various alloys, including nickel-based ones.

Welding stainless steel with ferrous metal

The technology for welding stainless steel with ferrous metal must be observed in accordance with the following requirements:

• Stainless steel has a high expansion coefficient, so it is necessary to maintain sufficient gaps between the workpieces being welded;
• When welding stainless steel and ferrous metal, the workpieces must be cooled quickly. This will prevent them from losing their corrosion resistance;
• For welding, it would be better to use short electrodes, no more than 35 cm. This way, you can prevent excessive overheating of the metal;
• It is recommended to reduce the welding current by at least 20%, taking into account the low thermal conductivity of stainless steel.

Speaking of current strength, since this indicator is very important when welding stainless steel and ferrous metal. In many ways, it all depends on the thickness of the materials and the electrodes used for welding.

So, when welding stainless steel and metal, it is recommended to adhere to the following parameters in the inverter settings:

• Thin stainless steel, up to 1 mm thick, is welded with electrodes no more than 2 mm in diameter, while setting the current on the welding inverter to 60 Amperes;
• Metal from 2 to 3 mm, it is recommended to weld with 3.0 mm electrodes, and set the current strength on the inverter to around 80 A;
• Thick workpieces, the thickness of which is 4 or more millimeters, are welded with a 4 mm electrode, and the current strength on the inverter ranges from 100 to 130 A, depending on the spatial position of the welding.

It is imperative to take into account the current strength when welding stainless steel with ferrous metal, since if it is too high, it will lead to the formation of a burn through the weld.

Welding technology

The process of welding stainless steel and ferrous metal looks like this:

• For welding, you can use nickel-coated electrodes and electrodes whose rod is made of high-alloy steel. These electrodes are used to first fuse the edges of ferrous metal, after which a weld is created using clad steel. It is possible to obtain a high-quality connection using nickel electrodes;
• Before starting welding work, it is recommended to calcinate the electrodes in the oven at a temperature of at least 200 degrees. Electrode calcination time - 1 hour;
• For welding stainless steel with ferrous metal, only direct current is applicable;
• As required, before cooking stainless steel and ferrous metal, their surface must be cleaned of rust, dirt and plaque.
• When welding, it is recommended to capture as much ferrous metal as possible, which will make it possible to obtain a high-quality and reliable weld.

You can check the weld using kerosene. It will be enough to apply kerosene with a brush on one side of the welded joint, wait a while, and then turn the part over. If kerosene appears on the other side of it, then this will mean only one thing - a low-quality weld.

Source: https://mmasvarka.ru/svarka-nerzhavejki-s-chernym-metallom.html

How to make stainless steel matte

Stainless steel comes in different varieties. After all, it contains several different metals. The basis of stainless steel is iron, titanium, nickel, molybdenum, manganese, and this is not the entire list. Chromium, which is also present in its composition, helps this steel resist corrosion.

Stainless steel production + technology as they do it for 2019 – Business Hub

Steel production today is carried out mainly from waste steel products and pig iron. Steel is an alloy of iron and carbon, the latter containing from 0.1 to 2.14%.

Exceeding the carbon content of the alloy will cause it to become too brittle.

The essence of the process of producing steel, which contains a much smaller amount of carbon and impurities compared to cast iron, is to convert these impurities into slag and gases during the smelting process and subject them to forced oxidation.

Steel production process

Process Features

Steel production, carried out in steel furnaces, involves the interaction of iron with oxygen, during which the metal is oxidized.

Carbon, phosphorus, silicon and manganese contained in pig iron are also subject to oxidation.

Oxidation of these impurities occurs due to the fact that iron oxide, formed in a molten metal bath, gives oxygen to more active impurities, thereby oxidizing them.

Steel production involves three stages, each of which has its own significance. Let's take a closer look at them.

Melting rock

At this stage, the charge is melted and a bath of molten metal is formed, in which iron, oxidizing, oxidizes the impurities contained in the cast iron (phosphorus, silicon, manganese).

During this production stage, phosphorus must be removed from the alloy, which is achieved by containing molten calcium oxide in the slag.

Under such production conditions, phosphorus anhydride (P2O5) creates an unstable compound with iron oxide (FeO), which, when interacting with a stronger base - calcium oxide (CaO), decomposes, and phosphoric anhydride turns into slag.

In order for steel production to be accompanied by the removal of phosphorus from the molten metal bath, it is necessary that the temperature is not too high and that the content of iron oxide in the slag is not too high.

To satisfy these requirements, scale and iron ore are added to the melt, which form ferrous slag in the molten metal bath.

The slag containing a high amount of phosphorus that forms on the surface of the molten metal bath is removed, and in its place new portions of calcium oxide are added to the melt.

Boiling bath of molten metal

The further process of steel production is accompanied by boiling of a bath of molten metal. This process is activated with increasing temperature. It is accompanied by intense oxidation of carbon that occurs when heat is absorbed.

Steel production process in electric furnaces

Steel production is impossible without the oxidation of excess carbon; this process is started by adding scale to the molten metal bath or injecting pure oxygen into it.

Carbon, interacting with iron oxide, releases bubbles of carbon oxide, which creates the effect of boiling the bath, during which the amount of carbon in it decreases and the temperature stabilizes.

In addition, non-metallic impurities adhere to the floating bubbles of carbon monoxide, which helps reduce their amount in the molten metal and leads to a significant improvement in its quality.

At this stage of production, sulfur, present in the form of iron sulfide (FeS), is also removed from the alloy. As the temperature of the slag increases, iron sulfide dissolves in it and reacts with calcium oxide (CaO). As a result of this interaction, a CaS compound is formed, which dissolves in the slag, but cannot dissolve in iron.

Metal deoxidation

Diffusion deoxidation involves the introduction of ferrosilicon, ferromanganese and aluminum into the molten metal slag. Such additives, by reducing iron oxide, reduce its amount in the slag. As a result, the iron oxide dissolved in the alloy passes into the slag, disintegrates in it, releasing iron, which returns to the melt, and the released oxides remain in the slag.

The production of steel with precipitation deoxidation is carried out by introducing ferrosilicon, ferromanganese and aluminum into the melt. Due to the presence in their composition of substances that have a greater affinity for oxygen than iron, such elements form compounds with oxygen, which, having a low density, is discharged into the slag.

Steel production in open hearth furnaces

By adjusting the level of deoxidation, it is possible to obtain boiling steel that is not completely deoxidized during the melting process.

The final deoxidation of such steel occurs when the ingot solidifies in a mold, where the interaction of carbon and iron oxide continues in the crystallizing metal.

The carbon monoxide that is formed as a result of this interaction is removed from the steel in the form of bubbles also containing nitrogen and hydrogen. The boiling steel obtained in this way contains a small amount of metal inclusions, which gives it high ductility.

Steel production can be aimed at producing the following types of materials:

• calm, which are obtained if the deoxidation process in the ladle and furnace is completely completed;
• semi-quiet, which in terms of the degree of deoxidation are between calm and boiling steels; It is precisely these steels that are deoxidized both in the ladle and in the mold, where the interaction of carbon and iron oxide continues in them.

If steel production involves introducing pure metals or ferroalloys into the melt, the result is alloyed iron-carbon alloys.

If in steel of this category it is necessary to add elements that have a lower affinity for oxygen than iron (cobalt, nickel, copper, molybdenum), then they are introduced during the smelting process without fear of them oxidizing.

If the alloying elements that need to be added to steel have a greater affinity for oxygen than iron (manganese, silicon, chromium, aluminum, titanium, vanadium), then they are introduced into the metal after its complete deoxidation (at the final stage of smelting or during ladle).

Necessary equipment

Steel production technology involves the use of the following equipment in steel mills.

Oxygen converter section:

• argon supply systems;
• converter vessels and their supporting rings;
• dust filtration equipment;
• system for removing converter gas.

Electric furnace section:

• induction furnaces;
• arc furnaces;
• containers with which it is performed;
• scrap metal storage area;
• converters designed to provide induction heating.

Secondary metallurgy site where:

• cleaning steel from sulfur;
• steel homogenization;
• electroslag remelting;
• creation of a vacuum environment.

Boiling steel

Area for implementation of bucket technology:

• LF equipment;
• SL equipment.

The bucket facility providing steel production also includes:

• bucket covers;
• casting and pouring ladles;
• gate valves.

Steel production also requires equipment for continuous casting of steel. Such equipment includes:

• rotating frame for manipulating pouring ladles;
• equipment for continuous casting;
• trolleys on which intermediate buckets are transported;
• trays and vessels intended for emergency situations;
• tundishes and storage areas;
• plug mechanism;
• mobile mixers for cast iron;
• cooling equipment;
• areas where continuous casting is performed;
• internal rail-type vehicles.

Source: https://hub-bs.ru/na-2019/proizvodstvo-nerzhaveyushhej-stali-tehnologiya-kak-delayut-dlya-2019.html

How to cook stainless steel at home

During installation and repair work, welding of stainless steel is often necessary. The use of corrosion-resistant alloy steel alloys has long become widespread. You can weld stainless steel in several ways using household equipment. Some require expensive industrial machines. A short overview briefly presents all types of hot joining of alloy steels.

Features of welding stainless steel parts

First, let’s talk about whether alloyed metal can be welded as ferrous. Yes, MMA, TIG MIG - all these methods are relevant. But when welding stainless steel, you need to take into account some features of the alloys:

• high coefficient of thermal expansion, stainless steel parts must be folded with a gap;
• high thermal conductivity of stainless steel, so as not to create a high temperature in the working area, workpieces with a carbon content of less than 0.2% are preheated, the welding current is reduced by 20%;
• high resistance of stainless steels, the metal heats up quickly, so special electrodes 35 cm long are selected for welding work;
• When heating chromium-nickel stainless steel, heat-resistant films of oxides of alloying elements are formed, which makes the welding process more difficult, and the working area must be cooled.

It is necessary to weld stainless steel at home, taking into account the characteristics of steel, otherwise the connection will turn out to be of poor quality.

Preparatory work

In order to properly weld stainless steel, a number of works must be carried out before carrying out work:

• the workpieces are first cleaned of dirt and dust, the oxide layer is removed from the surface to a metallic shine with a brush, fine file or sandpaper;
• edges thicker than 4 mm are cut with a grinder or cut at an angle;
• stainless steel thicker than 7 mm is preheated, the temperature depends on the grade of steel;
• the parts are laid with a gap, its size is determined from the reference book.

Before welding the seam, the joint is clamped in several places so that the parts do not move during work.

Common welding methods for stainless steel

Any methods of hot joining high-carbon alloys are suitable for welding stainless steel at home, but the strength of the joint will vary. Electric arc surfacing welds are reliable, but are not designed for multidirectional loads.

It is better to cook thin-sheet stainless steel with argon; they do not require surfacing, the main thing is to protect the metal from burns. Semi-automatic using an inverter - universal, suitable for many brands of stainless steel, working with parts of different thicknesses.

Each of the methods is worth considering in more detail.

Source: https://svarkaprosto.ru/tehnologii/chem-varit-nerzhaveyushhuyu-stal