In most cases, the carbon content of the weld metal is reduced to, and the organization belongs to the steel annealing organization, which can be completely cut. Technical measures to reduce stress Preheating temperature Control the preheating temperature of the workpiece before welding, generally about 100000. Small parts are preheated as a whole, and large parts can be preheated locally. The larger the preheating area, the more favorable it is. For ductile iron, forgeable cast iron and gray cast iron, the preheating temperature can be appropriately increased to. Bevel shape and size Use reasonable bevel shape and size, such as narrow bevel with a small angle. For large and thick parts, the bottom of the bevel is roughly flat, or the drill tip shape formed naturally during processing. For thick-walled workpieces, try to use a bevel. The stainless steel pipe elbow manufacturer introduces that the two sides of the bevel should be symmetrical with the position of the crack line. When single-sided welding, the blunt edge thickness should be suitable for penetration. When double-sided welding, the side that is easy to operate is mainly used, and the bevel with a depth of about the wall thickness is opened. After welding, a shallow and narrow small bevel is opened on the other side, and the welds on both sides must be welded through each other. When conditions permit, for large and thick parts, try to use the fast and good arc cutting groove method instead of carbon arc gouging. After the groove is cut, the burrs and the small transition groove are ground off, and the small transition groove is ground with an angle grinder in the direction of the vertical crack to reinforce the small notch spacing.

Stainless Steel Weld Elbow If other mechanical reinforcement measures are made, they should be done before cutting the groove to avoid inconvenience due to the high temperature of the workpiece. Then immediately proceed with a certain process method while hot in a vertical state. The segmentation adopts the segmentation, layering and cross dispersion method to disperse the heat. For the pits at the bottom of the groove, it is advisable to use a thin-diameter electrode with a slightly larger current to weld it smooth, mainly to weld through; for other areas, each side edge of the groove should be separately first. At this time, because the weld layer is in direct contact with the parent material, it is advisable to use a welding method that reduces the penetration depth, that is, use a thin-diameter electrode with a smaller current. Pay attention to the arc not to shoot directly at the parent material as much as possible, but to shoot at the welded weld metal, so that the molten iron can indirectly melt the parent material. After the two sides of the groove are welded, the groove part is mainly welded by a welding method with good plasticity and high filling efficiency. When welding to the top surface of the groove, this is a more critical welding layer. Attention should be paid to the welding method that prevents the generation of white or reduces the thickness of the white layer and the cutting processability of the weld. Select a certain direction and sequence in order to disperse the stress to the favorable part. Hammering should be used to hammer the weld after each arc extinguishing to eliminate or eliminate stress.

The key points to be mastered in hammering welds are: the weld metal should have good plasticity; after each arc extinguishing, the weld changes from red to black, about within this time, it is the time when the weld metal shrinks sharply and the thermoplasticity is just right. Use appropriate tools and appropriate force, start from the end of the weld, quickly hammer to the beginning of the weld, and hammer the weld back and forth evenly several times until the weld surface is covered with pits or marks of plastic deformation, and the stainless steel flange manufacturer introduces that the weld feels hardened as weld repair. After welding, grind the weld immediately. There should be a smooth transition in the angled places. If there is a geometric accuracy requirement, the geometric accuracy must be restored. If there is a weld, it must be repaired in time, and then the workpiece should be allowed to cool slowly. After the workpiece cools to room temperature and is checked for no problems, it can be installed for trial operation and put into use. An example of the application of this technology is that the cast iron hammer body of the air hammer with a manipulator at the Beijing Automobile Manufacturing Plant was severely cracked due to an accident. During the welding repair, a common welding rod was used, among which a low-hydrogen type ordinary low-steel welding rod was used.