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等温淬火球墨铸铁在制造齿轮的大量生产中成功地代替钢,它还可以作为高强度材料来代替其它材料,特别是在要求节约成本和重要的场合,它优于锻件或机械加工件。众所周知,齿轮材料要求高的弯曲疲劳强度和高的接触疲劳强度。弯曲疲劳强度随着等温淬火温度而变化,随着由下贝氏体到上贝氏体的组织变化而增加强度。弯曲疲劳寿命亦可通过等温淬火后锤击来提高。另一方面,接触疲劳强度随着等温淬火温度提高而下降。锤击对接触疲劳强度没有影响,故当采用锤击来提高弯曲疲劳强度时,锤击的面积一般应限制在齿根,该部位对弯曲疲劳较敏感.
Austempered ductile iron has succeeded in replacing steel in the mass production of gears and can be used as a substitute for other materials as high-strength materials, especially for forgings or machined parts where cost-saving and critical applications are required. It is well known that gear materials require high bending fatigue strength and high contact fatigue strength. Flexural fatigue strength varies with the isothermal quenching temperature, increasing strength as the microstructure changes from lower bainite to upper bainite. Bending fatigue life can also be increased by hammering after isothermal quenching. On the other hand, the contact fatigue strength decreases with increasing isothermal quenching temperature. Hammering has no effect on contact fatigue strength, so when using a hammer to increase flexural fatigue strength, the area of hammering should generally be limited to the root of the tooth, which is more susceptible to bending fatigue.