The test of sulphurized tufftride process for treating the hot piercing punch for steel pipes is introduced.

介钢管热冲孔凸模硫氮碳共渗工艺试。

It is shown that the fracture properties are determined by materials strength before tufftride process and by materials toughness after tufftride process.

疲劳最后断裂性质取决于材料的强性。