Considerations about tempered martensite embrittlement

There have been many quite meritorious studies made about the present subject. However, there are still some open questions: whether the mechanism of plastic deformation is the same in the Charpy test and in the slow static test, and what is the effect of the rate of work-hardening. The material selected for the tests was a common Cr–Mo steel. The long time tempering was carried out in a salt bath. A welding simulator was applied for the very short tempering. The stress–strain curves at some interesting tempering temperatures were determined by torsion tests. The Charpy impact tests were accomplished using V and U shaped specimens. The deformation and fracture of the specimen were studied with optical and scanning electron microscopes. There was no tempered martensite embrittlement in the specimens in the very short tempering time.