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研究了４Ｃｒ２ＮｉＭｏＶ热作模具钢热疲劳裂纹的扩展特性．试验结果表明４Ｃｒ２ＮｉＭｏＶ钢热疲劳裂纹属沿晶型的，裂纹扩展是主裂纹与裂纹前端显微裂纹不断合并的结果．随着热循环次数的增加，裂纹扩展速率遵循快一慢一快的规律．９１０℃淬火、５８０℃回火的试样与９６０℃淬火、６１０℃、回火的试样相比，９１０℃淬火、５８０℃回火的试样具有较高的热疲劳裂纹扩展的抗力．
The thermal fatigue crack growth characteristics of 4Cr2NiMoV hot work die steel were studied. The experimental results show that the thermal fatigue crack of the 4Cr2NiMoV steel is along the crystal form, and the crack propagation is the result of the continuous integration of the main crack and the crack tip. With the increase of the number of thermal cycles, the crack growth rate follows a fast, slow and fast rule. The specimens quenched at 910 ℃ and tempered at 580 ℃ exhibited higher resistance to thermal fatigue crack propagation than the specimens quenched at 960 ℃ and tempered at 610 ℃ and tempering at 910 ℃ and 580 ℃ respectively.