Welding seams
Welding is one of the main methods of fastening two elements, and welding seams are zones connecting two metal workpieces to each other. Such adhesions are formed during the melting and subsequent cooling of steel.
A good welder must know the types of welded joints and be able to apply all types of seams . Without these skills it is impossible to produce a high-quality and durable structure.
Welding seams
Types of joints
Welds are divided into 5 variations:
- overlap;
- parallel;
- butt;
- corner;
- t – shaped.
Welding seams and their varieties
Lap joints are often used to create cylindrical tanks that are planned to be operated in a horizontal or vertical position. The elements to be welded overlap, but do not completely overlap. The result is a structure that looks like a step. Welding seams are applied to the end sides of the parts .
Parallel application methods are used to increase the strength of the structure. Both components are tightly applied to each other and fastened by welding from the ribs. This technique can be used to strengthen structures whose exterior will be subject to strong mechanical stress. However, such technology is prohibited from being used in the repair of moving mechanisms.
Corner weld
The butt version is the most popular. The parts to be welded must be in the same plane, one opposite the other. This joint is used to fasten water pipes, chimneys, storage facilities or steel columns. This system is also used in mechanical engineering, in the manufacture of air and water transport, and in military factories. Yes, and creating such a “glue” requires a minimum of money and time.
Corner types of welds are well suited for fastening several workpieces that need to be positioned at right angles. The workpiece is made as follows: parts are installed at an angle of 90° (in the form of the “G” symbol), and a weld is applied at the junction of the edges . This welding is common in both industry and private use. And with its help you can make durable supports or boilers.
T-seam
A T or T weld is not like the others because the finished part will look like the letter "T". It will be difficult for an inexperienced person to create this, since in the process it is important to take into account the restrictions related to holding the electrode (it is recommended to adhere to an angle of 60°). In this case, the thickness of the joined sheets may differ. Also, more wire will be required for execution, and elements welded by the T-method may come out with defects.
Operating technique
Moving the rod along a solid line will not be enough for good welding , and to become a master of your craft, you need to understand the technique of using the device. The main features of the technology are constant control of the gap between components.
If the distance is too small, the steel will not warm up well, which will negatively affect its strength. Both the speed of the tripod and the basic soldering procedure should be controlled. The main thing is that the molten metal is evenly distributed throughout the groove.
Weld characteristics
How to suture correctly:
- Cook in a circular or zigzag motion. The trajectory must be maintained throughout the entire adhesion.
- Hold the handle at the correct angle. The sharper the slope, the shallower the depth of steaming.
- Control the pace of movement of the electrode. It all depends on the voltage of the device. Higher current allows the holder to move at higher speeds, and the resulting seams will be thinner.
- Choose the adhesion layers wisely. Several rows can be made in the butt areas, however, a T-weld seam is most often made using this technique.
Taking these rules into account will help achieve the desired result, and the specialist will accurately produce any type of welding seam.
Application methods
Application methods include:
- Horizontal type. According to the rules, you can apply a seam both from right to left and in the opposite direction. Here it is important to maintain an acceptable angle of inclination, since excess molten metal will flow out. If a person has few skills, then the entire procedure can be completed in 2-3 passes.
- Vertical type. The work surface can be located in the ceiling or wall areas. Welding joints can also be made using two methods: top-down and bottom-up. However, it is better to choose the first option, since the heat from the arc contributes to high heating of the alloy.
- Ceiling type. The whole process must be completed very quickly, maintaining a stable pace of guiding the rod. Also, to maintain the alloy in the weld, you will need to make rotational movements. It should be noted that the current version is the most complex, and you should start working after gaining the necessary experience.
Typing of welding seams according to application method
From the first time it is difficult to understand what types there are and to study all the technologies. But regular practice will turn any beginner into a real professional.
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What is a weld
Welded metal joints are among the main methods of fastening structures used in everyday life and production. This is a very reliable method of obtaining a single design, which is also relatively cheap.
Bonds of this type are formed by melting the metal in the joint area and then crystallizing it as it cools. Their quality depends on the correct choice of operating mode of the electric welding machine, electrode, and seam penetration. This is regulated by current regulations and standards. They indicate all types of welds, as well as types of joints and their characteristics.
Numerous metals have their own welding characteristics, different work conditions, and requirements for fastening. For them, appropriate types of electric welded connections are used. When welding metal elements, the main types of electric welding fasteners are used, which are discussed below.
Classification
Welding joints are divided into several varieties, depending on their characteristics. The classification of welds covers the entire range of their uses. According to external parameters they are:
- convex type (with reinforcement);
- concave (weakened design);
- flat type (normal).
According to the type of execution, they are found in one-sided, as well as double-sided, according to the number of passes with the electrode: single-pass, double-pass. In addition, there are single-layer and double-layer welding methods.
According to their length, suture fastenings are:
- unilateral with intermittent pitch;
- solid one-sided;
- spot (with contact electric welding);
- chain double-sided;
- double-sided checkerboard pattern.
Separation by spatial location:
- horizontal, lower;
- vertical, ceiling;
- into a boat;
- semi-horizontal design;
- semi-ceiling type;
- semi-vertical.
According to the force vector:
- longitudinal (flank) – the force has a vector parallel to the penetration;
- transverse - the force acts perpendicularly;
- combined - a type of frontal, as well as flank;
- oblique - the impact occurs at an angle.
According to their purpose and function, electric welding penetrations can be durable, as well as durable and tight, hermetically sealed. Based on their width, they are distinguished into thread type, which does not exceed the diameter of the electric welding electrode rod, and widened, performed using oscillatory movements when welding in the transverse direction.
To simplify the understanding of the classification and application of certain varieties, a special table has been compiled.
All types of seams have strict designations according to GOST. The drawings use special icons that contain complete information about the type of fastening and its method of execution. For those who are thinking of seriously engaging in welding work at a professional level, they should additionally study the drawing symbols of welded fasteners.
Types of welds
Depending on the material used, thickness, and design features, different types of welds are used. To do this, you need to undergo the necessary theoretical training. This will allow you to better understand the specifics of welding parts and avoid defects in work. Novice welders often do not sufficiently weld the joint areas, which affects the weak mechanical resistance of the joints.
By choosing the right operating modes and types of welding, you can obtain welding seams of sufficient strength and quality. Welder training consists not only of practical training, but also of theoretical training with the study of requirements, norms and rules, as well as including the types of welding joints and equipment used.
Knowledge of the principles of using certain electric welding fasteners, the techniques for producing them, the joints will be very strong and durable.
Butt
This connection option is the most used among other types of welding seams. This butt welding is used on end sections, pipes or sheet metal structures. To obtain it, a minimum amount of time, material and effort is spent. These butt joints have some seam features. On thin sheet metal, welding is carried out without bevel of edges.
Products with large thickness of joint sections require preliminary preparation of joints, which consists of bevelling them to increase the depth of welding penetration. This is necessary when the thickness of metal products is over 8 mm and up to 12 mm. Thicker sections must be joined by double-sided welding with preliminary bevel of the edges. Butt welding is most often performed on products in a horizontal plane.
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