Study On Cr10 Cold Work Die Steel

Because of its high hardness and well wear resistance,D2 steel has been in use for a long time even since its introduction in 1981.However, due to the high content of carbon and chromium elements D2 steel produce large amounts of network eutectic carbides in the process of solidification from liquid and lead to the reduce of its workability and toughness, even lead to die early failure. To maximize the life of the die, it must be taken into account of both wear resistance and toughness, D2 steel is unable to meet the user’s needs. In order to improve the distribution of carbides,we must take full advantage of the thermodynamic software-aided design to adjust the content of alloying elements reasonablely on the basis of ensuring the strength and wear resistance, and significantly improve the toughness of cold work die steel.Through these we try to design a new kind of cold work die steel.And the influence of different heat treatment process on new steel was studied by metallurgical microscope, hardness tester, scanning electron microscope, phase analysis, transmission electron microscopy, impact toughness and bending strength testing,then we seted the best heat treatment process of testing steel.We design a new type of cold work die steel Cr10MolSiV independently.It has less precious content of alloying elements to reduce the cost of production. After the same forging and spheroidizing annealing process,The carbides of Cr10MolSiV is relatively uniform, spheroidizing effect is significantly better than that of D2 steel.The highest quenching hardness of Cr10MolSiV appeared at 1050℃,about 64.8 HRC.Both D2 and Cr10MolSiV exist secondary harding phenomenon when terpering at differente temperature,and the peak is abaut 500℃. This kind of phenomenon is more obvious in Cr10MolSiV.The reson of secondary hardening phenomenon is mainly due to the dispersion of Mo2C phase.The area of carbides after annealing is about 7.23%, slightly less than D2 steel.Carbides under 1.6 um of mean particle size is 88.9%,while D2 is 55.7% only. The difference between direction of maximum size and average particle size of Cr10Mol SiV is smaller than D2 steel.The average impact toughness and bending strength of Cr10MolSiV are about 1.5 and 1.2 times more than D2 steel. Cr10MolSiV has higher hardness and impact toughness when tempered at low temperature. When tempered at 540℃ the impact toughness and bending strength of Cr10MolSiV are much higher than D2. Therefore for higher toughness die, we can choose a lower temperature tempering, while when both wear resistant performance and toughness are required we can choose the high-temperature tempering.The impact toughness and bending strength of Cr10Mo1SiV is still higher than D2 steel even when the hardness of Cr10Mo1SiV is higher. In certain cases,the real season of lower toughness and plasticity of cold work die steel is the distribution of carbides...