Experimental Study on Nitrogen-Spray Water Quenching for 9SiCr

Alloy steel 9SiCr is quenched by a certain proportion of mixture gas of nitrogen and spray water at atmosphere, and the continual cooling curve during quenching is determined, the rigidity of quenched workpiece is measured and the metallographic map is captured. The results show that it can improve the cooling effect of quenching medium on the one hand; on the other hand, it can decrease the deformation and residual stress of workpieces. The results show that the rigidity of quenched workpiece is about 62 (HRC), which is corresponding with the rigidity after oil quenching. Martensite phase transformation occurs at the end of quenching that can be seen from the metallographic map.