Stainless steel and carbon steel are quite different in chemical properties. The welding technology of the two materials in the industry belongs to the welding of dissimilar steels, and professional industrial technical measures are required. The thermal conductivity of stainless steel is worse than that of carbon steel. When it is cooled directly from high temperature to normal temperature, cold cracking will occur. This has a bad impact on the performance of new materials. At the same time, due to the effect of thermal cycles, stainless steel tends to overheat and crystallize. The grains are easy to coarsen, and ferrite and carbide structures are likely to appear. Once cooled, embrittlement will occur. When welding, enterprises must first confirm the possibility of welding, especially in fusion welding conditions, and ensure that there is an available welding Joints, of course, many other problems will be encountered in practical applications.

(1) Melting point difference. Stainless steel and carbon steel materials have different melting points. When the melting points of the two metals are greatly different during the explosive welding process, the welding performance may be reduced. The metal with a lower melting point may cause metal loss, and there may also be evaporation and alloying elements. A large amount of burnt damage will cause many practical operational problems. This kind of problem needs to be controlled and prevented, otherwise the final result will be a welded joint that does not meet the conditions.

(2) Differences in thermal conductivity and specific heat capacity. The thermal conductivity and specific heat capacity of metal are important factors affecting welding technology in modern industry, affecting the melting of the welded material and the solidification and crystallization of the weld. The thermal conductivity of stainless steel is about one-third that of carbon steel, and the difference is obviously very different. This difference will cause the melting time of the two metal substances to be out of sync, and the metal bonding effect will not be very good, which will affect welding in industrial production. process, resulting in poor weld performance.

(3) Difference in linear expansion coefficient. The linear expansion coefficients of stainless steel and carbon steel are different. This different performance will cause different reactions after the two metals are cooled after the explosive connection. The shrinkage of the weld is different, and a high stress state will appear at the joint. This state It has a bad effect on welding, eventually causing cracks in the weld or heat-affected area, and even causing the weld to peel off from the metal.

(4) Electromagnetic differences. The electromagnetic differences between the two metals are different, which may lead to instability during welding. The electromagnetic properties of stainless steel and carbon steel are very different, which can easily lead to arc deflection or arc burning instability. This will The worst result is deformation and deterioration outside the burst joints.

(5) Formation of brittle compounds. In the chemical industry, new substances are formed at the weld after metal is welded, becoming intermetallic compounds. Some of these substances have brittle physical properties, which may have a greater impact on the mechanical properties of the joint, and even reduce the plasticity and toughness of the weld. .

After some metals are welded, the performance of the joints is good, but other substances are easily generated, such as a chromium-poor layer formed on the grain boundaries of the heat-affected zone. This substance contains carbides. Once generated, it will cause the equipment to malfunction during use. The intergranular corrosion effect occurs between the two parts. In order to avoid a series of problems in enterprise production, low-carbon substances will be used for welding.