Prediction of flow stress of Mg-Nd-Zn-Zr alloy during hot compression

Isothermal hot compression tests were carried out on Mg-3.0Nd-0.2Zn-0.4Zr （mass fraction, %, NZ30K） alloy using a Gleeble-3500 thermo-simulation machine at temperatures ranging from 350 to 500 ℃and strain rates from 0.001 to 1 s^-1. A correction of flow stress for deformation heating at a high strain rate was carried out. Based on the corrected data for deformation heating, a hyperbolic sine constitutive equation was established. The constants in the constitutive equation of the hyperbolic sine form were determined as a function of strain. The flow stresses predicted by the developed equation agree well with the experimental results, which confirms that the developed constitutive equations can be used to predict the flow stress of NZ30K alloy during hot deformation.

钾、钠在铁碳铸造合金中作用机理的探讨

以试验研究为基础，着重分析了钾、钠在Ｆｅ—Ｃ合金中细化结晶组织，改善第二相形态及促进固、液态石墨化的作用机理，并对钾、钠在Ｆｅ—Ｃ合金中其它作用进行了简要讨论．

优质低铬白口铸铁生产新工艺

优质低铬白口铸铁生产新工艺其核心就是将变质处理、孕育处理、微合金化技术三位一体,互为作用。笔者以优质低铬白口铸铁生产新工艺内容的形式来体现冶金处理技术还应具备哪些相关的动力学条件才能充分发挥其本身工艺效果展开了讨论。

氨碱法生产中的防腐措施探讨

文中阐述了氨碱法纯碱生产中主要腐蚀和防腐蚀情况;通过研究认为,最有前途的防腐方法是使用表面合金化材料,与传统防腐措施相比,它的使用寿命可延长3倍左右.

Q345C钢Mn含量减量化试验研究

为降低Q345C钢中的Mn含量,拟通过加大控冷过程中的水量,实现晶粒的细化来提高钢的强度。为此,计算了不同化学成分Q345C钢的CCT曲线,为制定冷却工艺提供参考;并用经验公式对钢的强度进行了估算。同时对试验钢(Mn质量分数从1.4%降至1.2%)进行了控轧控冷试验,终冷温度从630℃降至580℃,并对其组织性能进行了分析。结果表明:试验钢组织为铁素体+珠光体+少量贝氏体,强度满足标准要求。