Failure Analysis on Cracked Cr8Mo2SiV Mold Parts. Issue 3 (March 2021) - Qiu, Huaxing
Abstract: Cr8Mo2SiV cold work die parts cracked early during machining process. In order to find out the reason of cracking failure of the die parts, the macro crack analysis, chemical composition analysis, hardness test and microstructure analysis of the parts were carried out by stereo microscope, direct reading spectrometer, digital Vickers hardness tester, metallographic microscope and scanning electron microscope. Some results are obtained: the chemical composition of cracked parts was tested and found similar to Cr8Mo2SiV, compared with standard Cr8Mo2SiV, it contains 3.81%W, and its hardness is 229 HV1, means that the cracked parts are not hardened. By observing the micro morphology of the crack, there are oxide and decarburization layer on the crack surface of the parts. It proves that the crack was formed before spheroidizing annealing. It is a typical raw material crack.