What to cook stainless steel? Welding technology, equipment
Than to cook a stainless steel - a question it is enoughrelevant for modern industry. It should be noted that this type of steel is a fairly strong material, so its processing has certain nuances. The choice of welding method depends on the thickness of the workpieces, and on the chemical composition.
Stainless steel. Main characteristics
Stainless steel is an alloy of carbon and iron,alloyed with chrome. The high content of the last element provides a high resistance of the material in a corrosive environment. Chromium oxides form a special protective film, due to which the base metal maintains its durability. In addition, steel is alloyed with nickel, cobalt, and titanium. The main advantages of stainless steel are high resistance to contact with an aggressive environment, high strength, respectively, and a long period of operation. In addition, steel has a good aesthetic appearance.
Features of welding steel, resistant to corrosion
This material has a large linear expansion. As a consequence, with the thermal action of the workpiece can deform, change its size. To avoid such a situation, you must clearly adhere to the optimal gap between the parts that connect. The action of high temperature can lead to the fact that the alloyed steel somewhat loses its properties, corrosion resistance decreases. In this case, the weld should be cooled in time. The low thermal conductivity of steel requires a reduction in current strength of about 25%. It is also worthwhile to select the welding electrodes correctly, since they can overheat if they are long. Another difficulty is the appearance of refractory carbides on the surface, intergranular corrosion.
Ways of cooking stainless steel
There are many welding methodscorrosion-resistant steel. With a small thickness of metal (1.5 mm), it is advisable to use arc welding (in an inert gas environment). What to cook stainless steel with a thickness of less than 0.8 mm? In this case, a pulsed arc method is used. Thin metals are also connected by an arc with a jet transfer of material. Increasingly, the plasma method of welding is used. It can be used for a wide range of thickness of blanks. Cross sections over 10 mm are cooked under the ball of flux. Still use welding with high frequency currents, laser method.
Argon material welding
This process occurs in the protective gas environment -argon. It protects the material from the effects of oxygen. In a special device, an arc is formed between the part and the tungsten electrode. During the heating process, the edges melt, a protected welding bath arises. A special wire for welding stainless steel is also continuously fed into the arc. The process of joining is made at an angle of 90 °. For the most qualitative work, it is necessary to exclude any oscillating motion of the electrode. As a result, a seam free from slags is obtained. Such a connection is of high quality, durability, satisfies all aesthetic demands. Welding of stainless steel gas is used in many industries: chemical, food industry, automotive, aviation, and power engineering. Among the shortcomings can be identified only a large expenditure of time on the process itself. Also, technology requires special skills and experience from employees.
Equipment for argon-arc welding
First of all, for this type of connectionmetals an inverter is needed. Its modifications and models are quite numerous: Svarog, KEMPPI Master, BRIMA, etc. The main advantages of the device are its ease of operation, small size and weight, stable arc. Inverters can be used for welding almost any metal, with the connections being of high quality. How to cook stainless steel inverter and what should I consider? First of all, it is necessary to choose the right operating temperature range. Some models do not work in the open space in cold weather. Also worth considering the power of the device. For household use, an inverter with a current of up to 160 A (eg "Svarog TIG 200 P", PRO TIG 200 P) is suitable. The parts are cleaned before cleaning and degreased. For welding, a gas cylinder with argon is required. Although in practice it is allowed to use dilute gas. A burner is attached to the gas hose, into which a tungsten electrode is inserted. On the handle of the burner there are buttons for supplying current and gas. Requires also a welding wire made of the same material as the parts to be connected.
How does semiautomatic welding occur?
What to cook stainless steel for car repair, inlife? In this case, the semiautomatic welding method is often used. It can occur both in a protective environment and without the use of gas. Semiautomatic machines are also used in large automobile enterprises, which indicates the high quality of the welded joint. The electrode and the filler material in this case is a special wire. You can work with equipment in several ways: short arc, jet transfer, pulse welding of stainless steel. The technology provides for operation without protective gas, however, in this case, special powder electrodes should be chosen. This method is suitable for work in the air. There is no need to buy (and, correspondingly, spend additional funds) a gas cylinder. This has its drawback - over time, the welded joint can become rusted. Therefore, experts recommend using special stainless steel electrodes and welding with argon. To date, there are many varieties of semiautomatic machines as domestic ("FEB", "Svarog"), and foreign (BRIMA, EWM, TRITON, etc.). The choice of apparatus depends on the tasks assigned, the amount of welding and the characteristics of the materials to be connected.
Use of electrode welding
What to cook stainless steel, if special requirements forquality of the seam is not provided? As a rule, electrode welding is used in domestic conditions, when connecting all kinds of pipes, in small-scale production, and also for obtaining a short weld. The essence of this process is the formation of a connection from the material of the workpiece and the metal of the electrode.
How to choose welding electrodes
Electrodes for stainless steel are widely used forcompounds of corrosion-resistant alloys that operate at high temperatures. As a rule, the rods are made on the basis of nickel, chromium. With manual arc welding, two types of electrodes can be used. The first ones work under conditions of direct current. The main coating most often consists of magnesium, calcium carbonate. Welding electrodes with rutile coating can work with alternating current. When welding using argon, various tungsten rods are used. Due to their high operating temperature, they do not melt. There are many varieties of them. Green electrodes (WP) consist of pure tungsten. They provide a sufficiently high stability of the arc. White - WZ-8 - doped with zirconium oxide. Thorium oxide is added to the red electrodes. This is the most common group, the rods have a high resistance. Also, tungsten electrodes can include lanthanum, cerium.
Welded joint processing
After the process of connecting the partsit is necessary to clean the seam. This should be done in order to improve the appearance, extend the life. Otherwise, corrosion may occur in this area. First of all, mechanical cleaning of the welded joint is carried out. A more aesthetic connection place looks after sandblasting. The next step involves grinding the surface. It is not recommended to use abrasives based on corundum, as it can provoke the appearance of corrosion. It should be noted that all these manipulations are aimed at improving the appearance of the part. Protect the weld seam from damage by etching, passivation. Etching is the surface treatment with special chemical agents that destroy the resulting scale. When passivated, a special substance is applied to the joint site. Under its influence, a protective film (of chromium oxide) appears.
Laser method of welding alloys
One of the most modern and technological methods of connection is laser welding of stainless steel.