【摘要】 <正> 某些含有生成特殊碳化物元素的工具钢或耐热钢,当在淬火后的高温回火过程中,会有硬度重新升高的现象,称之为次生硬化。 关于形成次生硬化的原因,有人认为是由于介稳渗碳体和特殊碳化物间的互相作用而引起,也有人认为仅是由于在钢中析出了高温弥散的特殊碳化物所致,在高碳合金钢中,残余奥氏体的分解,也有助于除了上述原因外的次生硬化现象的发生。但是,我们可以认为。在低碳合金钢的高温回火过程中(500～650℃),某些高度弥散的更多还原

【Abstract】 The influence of Cr to secondary hardening effect of Mo-steel in temp-ering was investigated with hardness tester. and X-ray analycis. It wasfound that: 1. There is marked secondary hardning effect in case of Mo-steel, but not to Cr-steel. 2. For the experimental Mo-steel （0.21%C） 2.29%Mo),the max. hardness is found after tempering at 575℃, but there is softening effect exists when tempering below 500℃. 3. the softaning effect of Mo-steel when tempered below 500℃ may desmated by adding Cr while the max. hardness value will be som- what decreaced. 4. The more the Cr added to the Mo-steel the lower the temperature at which the maximum hardness is found. 5. the Cr contained accelerate the process of hardness decreassing while tempering above certain temperture, after that the steel has the maximum hardness value. 6. The more the Cr contained, the less the will the Mo₂C precipitate recipted in the tempered specimens, and the greater the diameter of the debye rings of Mo₂C.更多还原