经济型大截面空淬铸钢的成分设计与试验验证

Composition Design & Experimental Verification of Economically Air-quenching Steel for Heavy Section Casting

为解决铸钢件淬火变形和开裂问题，本文基于Bhadeshia奥氏体分解模型和非线性有限元热分析法计算结果，设计和确定了CrMnSiMoTi系经济型空淬钢的化学成分及其淬火尺寸效应，并进行了相关试验验证工作。结果表明：0．45～0．70C-2．50Cr-1．65Mn-1．25Si-0．20Mo-0．15Ti系合金铸钢空淬不出现非淬硬组织的最大许可直径在φ80～φ140mm之间，最终表心淬硬组织均属于贝氏体／马氏体复合组织。合金钢设计计算结果与试验验证数据基本上相符，可作为经济型空淬铸钢的候选材料。

In order to resolve the problem of deformation and cracking of castings during quenching, the design of chemical compositions and the determination of queching size effects for CrMnSiMoTi system economically air-quenching cast steel have been undertaken based on the calculations using Bhadeshia austenite decomposition model and non-linear FEM thermo-analysis, and the experimentally verification has also been carried out. The results show that the allowable maximum diameter in which there is no non-hardened microstructue occurring at the core of 0.45～0. 70C- 2.50Cr-1.65Mn-1.25Si- 0.20Mo-0. 15Ti system cast steel bar during air quenching is about in the range of φ80 mm to φ140 mm and the mirostructures at surface and core of the steel bar are all complex bainite/martensite. The basically agreement between the predictions obtained from the computer calculations and the experiment indicates that the designed steel can be used as the candidate materials for economically air-quenching cast steel.