Failure Analysis on Interior Cracks of 42CrMoA Steel Forging Parts

The failure cause on interior cracks of 42CrMoA steel forging parts was investigated by means of chemical compositions analysis, macroscopic inspection, metallographic examination, energy spectrum analysis and micro-hardness test. The results show that the interior cracks of 42CrMoA steel forging parts belonged to hydrogen white flake cracks. Because dehydrogenation treatment was not in time after forging and defective pinetree structure after forging promoted hydrogen diffusion in the forging. Shatter cracks were initiated and expanded. The suggestion was that dehydrogenation treatment should be in time after forging and forging parts need increasing forging ratio to improve the material structure.