How much effect does post weld heat treatment of 10.9 grade steel structure bolts play

In the whole welding process of grade 10.9 steel structure bolt, due to the asymmetry of heating and cooling, and the restraint caused by the component itself or additional restraint, the welding stress will be caused in the component after the welding work is completed. The existence of welding stress in the component will reduce the specific bearing capacity of the welded joint area, resulting in plastic deformation, and will continue to cause damage to the component when it is more serious.  
The solution of hydrogen elimination after welding refers to the ultra-low temperature quenching and tempering treatment carried out when the welding is not cooled to below 100 ℃. The general standard is heating to 200 ~ 350 ℃ for 2-6 hours. The key effect of hydrogen elimination after welding is to accelerate the release of hydrogen in welding and heat hazard zone. The actual effect of avoiding welding crack in high alloy steel welding is extremely obvious. Stress relief quenching and tempering treatment is to reduce the tensile strength of welded steel parts at high temperature, so as to relax the welding stress.

There are two common ways: one is overall high temperature tempering, that is to put the welding parts into the heat treatment furnace, slowly heat up to a certain temperature, then heat insulation for a period of time, and finally cool in the air or furnace. In this way, 80% - 90% of welding stress can be removed. The other way is partial high temperature tempering, that is, only heating the welding and surrounding areas, and then cooling slowly, so as to reduce the maximum value of welding stress, and make the stress spread more gently and have a part of the purpose of removing welding stress.  
Main products: steel structure bolts and nuts, high strength bolts and nuts, hexagon bolts, hexagon nuts, chemical bolts and nuts and other special-shaped parts.