Is stress relieving needed

[rakuday]

Dear members,

Is stress relieving required for large castings (1.5m x 1.5m x 1.0m), weighing about 1.5MT. The material is SG400. Can the SR be done after machining process or is it mandatory to do the SR before machining. Can vibratory stress reliving be adopted instead?

Any literature on this subject will also help.

Thanks

 

[metengr]

Stress relieving of large castings really depends on end use. For example, if the end use of a casting requires holding specific tolerances for service, stress relief of the castings would be prudent. There is a significant cost associated with stress relief of large castings and this must be carefully evaluated in terms of need and benefit. Stress relieving should be done before final machining. This is typically done for large industrial turbine rotor forgings and cast turbine shells most of the time.

Most of the time, the client's engineering specification will provide the above requirements.