在不同变形温度（900，1 000，1 100，1 150，1 200 ℃）和变形量（10%~80%）下对Cr12MoV模具钢进行应变诱导裂纹扩展（SICO）试验，观察其表面裂纹产生的情况，分析变形温度和变形量对裂纹产生的影响。结果表明：当温度一定时，Cr12MoV钢达到一定变形量时才会出现裂纹。随着变形量的再增加，试样表面的裂纹数量增多。在不同温度下，Cr12MoV钢具有不同的临界变形量，高于该临界变形量时，裂纹数量随着变形量的增大而增多，直至造成试样开裂。试样在低温条件下出现开裂的原因主要为网状碳化物析出较多，在晶界形成薄弱区，导致试样在一定变形量下开裂；试样在高温条件下出现开裂的原因主要为过热引起碳化物的聚集长大，造成应力集中，降低了材料的塑韧性，导致材料开裂。通过SICO试验和热拉伸试验得到的Cr12MoV钢最宜加工温度范围相同，均为1 100~1 150 ℃，且1 150 ℃为最佳锻造温度。

Cr12MoV die steel was tested for strain induced crack opening (SICO) experiment at different deformation temperature (900, 1 000, 1 100, 1 150, 1 200 ℃) and deformation amount (10%-80%). The formation of surface crack was observed and the effect of deformation temperature and deformation amount on crack was analyzed. The results show that when the temperature was constant, cracks would appear only when Cr12MoV steel reached a certain amount of deformation. With the increase of deformation, the number of cracks increased. At different temperatures, Cr12MoV steel had different critical deformation. When the deformation was higher than the critical deformation, the number of cracks increased with the increase of deformation until the specimen cracked. The main reason for the specimen to cracking at low temperature was that many net carbides precipitated and weak areas formed at the grain boundary, leading to the specimen to cracking under a certain amount of deformation. The main reason for the specimen to cracking at high temperature was that the carbides gathered and grew up due to overheating, resulting in the stress concentration, which reduced the plastic and toughness of the material and led to cracking. The range of the best processing temperature for Cr12MoV steel obtained by SICO test and hot tensile test was same, both of which were 1 100-1 150 ℃, and 1 150 ℃ was the best forging temperature.