The hottest topic is the elimination of residual s

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Talk about the elimination of residual stress in magnesium alloy castings and weldments

there are always large or small stresses in magnesium alloy castings, which are often called residual stresses. They come from uneven shrinkage during solidification, uneven cooling after heat treatment or quenching, and machining. Although these residual stresses are not very high, due to the low elastic modulus of magnesium alloy, the low stress can also make the casting produce impermissible elastic strain. Therefore, if this kind of residual stress is not eliminated or reduced, the products will be warped and twisted during or after final finishing. In addition, residual stress is also one of the main reasons for stress corrosion of mg Al alloy

See Table 1 for the stress relief annealing process of magnesium alloy castings

the residual high-end instruments, key technologies and components of castings after welding rely heavily on the elimination of imported stress

castings may have serious residual stress after welding or repair welding, so stress relief annealing should be carried out within the specified time to prevent deformation and cracking. Table 2 lists the recommended stress relief annealing process for magnesium alloy castings after welding, which is determined based on the pre welding state of castings and the post welding application state. If az81a, az91c and za92a alloy castings before welding are in T4 and T6 state, their complete solution time can be shortened by 0.5h

after butt welding, some work is simple and repetitive work with low quality. 7525 batches of mg Al Zn alloy castings, which need solid solution treatment and are quarantined by Shunde Bureau, can be treated at 260 ℃ for 1h to eliminate the tendency of stress corrosion cracking

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