20MnCr5齿轮钢氧含量控制及其对钢的疲劳性能影响

Control of Oxygen Content in 20MnCr5 Gear Steel and Its Effect on Fatigue Performance of Steel

提出了100 t EAF-LF-VD-CC-CR全流程控制齿轮钢氧含量的工艺措施;研究了0.00053%~0.00145%氧含量20MnCr5齿轮钢的旋转弯曲疲劳性能、断口和夹杂物尺寸。结果表明,钢中总氧含量越高,最大夹杂物尺寸也越大,疲劳强度越低,当[O]≤0.0010%时,随[O]降低,疲劳强度升高幅度较小;试验钢在表层不产生疲劳裂纹的临界夹杂物尺寸为21μm,距表面深度30~430μm的浅层区域为相对安全区域,其中的夹杂物很难引起疲劳开裂。

The technological measures to control oxygen content of gear steel in 100 t EAF-LF-VD-CC-CR whole process are put forward. The rotary bending fatigue properties, fracture and inclusion size of gear steel 20 MnCr5 with oxygen content 0.00053%~0.00145% are investigated. The results show that the higher the oxygen content, the larger the size of maximum inclusion and the lower fatigue strength of steel, while [O]≤0.0010%, with [O] decreasing, the fatigue strength of steel decreasing within a narrow range;the critical inclusion size of the test steel without fatigue crack under the surface is 21 μm and the shallow zone 30~430 μm away from the surface is relatively safe zone, where inclusions are difficult to cause fatigue cracking.