In most cases, the carbon content of the weld metal is reduced to 0.5%, the structure belongs to the annealed steel structure, and it can be completely processed. Technical measures to reduce stress: Preheating temperature controls the preheating temperature of the workpiece before welding. It is generally on the left and right. Small parts are preheated as a whole, and large parts can be preheated locally. The larger the preheating area, the more advantageous it is. For ductile iron, malleable cast iron and gray cast iron, the preheating temperature can be appropriately increased to . The bevel shape and size should be reasonable, such as a narrow bevel with a small angle. For large and thick parts, the bottom of the groove should be roughly flat, or the drill tip shape naturally formed during processing. For thick-walled workpieces, try to use shaped grooves. Stainless steel pipe elbow manufacturers introduce that both sides of the groove should be symmetrical to the crack line position. When welding on one side, the thickness of the blunt edge should be enough to allow penetration. When double-sided welding, focus on the side that is easier to operate, and make a groove with a depth of about the wall thickness. After welding, make a shallow and narrow groove on the other side, and the welds on both sides must penetrate each other. When conditions permit, for large and thick parts, try to use the fastest and best arc cutting bevel method instead of carbon arc gouging. After the bevel is cut, the burrs are removed and the transition bevel is inverted, and an angle grinder is used to grind the transition bevel in the direction of the vertical crack at a spacing of small notches for reinforcement.

Other mechanical reinforcement measures for stainless steel elbow production should be done before cutting the bevel to avoid inconvenience due to high workpiece temperature. Then it is carried out immediately while it is hot in a vertical state with a certain process method. Segmentation uses a segmented and layered cross-dispersion method to disperse heat. For the pits at the bottom of the groove, it is advisable to use a small diameter welding rod or a slightly larger current to smooth the welding, mainly through welding; for other areas, separate the edges of each side of the groove first. At this time, because the welding layer is in direct contact with the base metal, it is advisable to use a welding method that reduces the penetration, that is, use a small-diameter electrode with a smaller current. Be careful not to direct the arc toward the base metal, but toward the welded seam. In terms of metal, stainless steel flange manufacturers recommend that the molten iron melt the base metal indirectly. After both sides of the groove are welded, the groove part is mainly welded with a welding method that has good plasticity and high filling efficiency. When welding is close to the top surface of the groove, which is a more critical welding layer, attention should be paid to using a welding method that prevents the formation of white spots or reduces the thickness of the white spots and the machinability of the weld. Select a certain direction and sequence to distribute the stress to favorable parts. Hammering to eliminate stress: After each arc extinguishing, hammer the welding seam to eliminate stress.

The key points that should be grasped when hammering welds are: the weld metal must have good plasticity; after each arc extinguishing, the moment when the weld turns from red to black, within about 10 seconds, it is the time for the weld metal to shrink sharply and the thermoplasticity is perfect. , use appropriate tools and appropriate force, starting from the end of the weld, quickly hammer toward the beginning of the weld, and hammer the weld back and forth evenly several times until the surface of the weld is covered with plastic deformation pits or marks. , and the stainless steel flange manufacturer introduced that the weld seam will feel hardened, so after the weld seam repair is completed, the weld seam should be polished immediately. Where there are angles, the transition should be smooth. If there is a requirement for geometric accuracy, the geometric accuracy must be restored. If there are welds, they must be repaired in time and then allow the workpiece to cool slowly. After the workpiece has cooled to room temperature and has been inspected without any problems, it can be installed, tested and put into use. Examples of the application of this technology include the Beijing Automobile Manufacturing Plant's air hammer with manipulator, which had a hammer body whose cast iron was severely cracked due to an accident. During welding repairs, welding rods were shared, among which low-hydrogen type ordinary low-steel welding rods were used.