Construction of Materials Database on High Temperature Inelastic Behavior of Metallic Materials and the Application to Numerical Analyses

在淬火、焊接、铸造等包含相变的工程过程中，要模拟确定温度、金属组织和应力/应变的耦合场，需要大量的材料数据：导热系数和导热比热、CCT或TTT图、相变温度-膨胀图、应力-应变本构关系和弹性常数，它们都依赖于温度。该项目推动了与日本材料科学学会工程塑性委员会材料数据库小组委员会合作的材料数据库的建设，以及对数值模拟的有效性和适用性的评估。本文以50多种用于热处理的钢材为研究对象，从文献和实验中收集了以下材料数据：5%应变下的应力-应变曲线、导热系数、比热、弹性模数、CCT和TTT图、温度-伸长图。基于MS-EXCEL的数据库工具采用层次化设计，便于用户使用，将开发的数据库中的材料数据转换成数据库MATEQ，该数据库包含了S-S曲线的1000多种数据系列和其他性质的50-100种数据系列，这引发了更复杂的数据库的进一步发展。通过对几种相变过程的模拟，验证了该数据库的有效性和对数值模拟的适用性。

Simulation to determine coupled fields of temperature, metallic structure and stress/strain in the course of engineering processes incorporating phase transformation, such as quenching, welding, casting and so on, needs so many material data ; thermal conductivity and specific heat for heat conduction, CCT or TTT diagram, temperature-dilatation chart for phase change, and Stress-strain constitutive relation, elastic constants, all of which depend on temperature. This project motivates the construction of a materials database cooperating with the activity of Subcommittee of Materials Database, Committee of Engineering Plasticity, the Society of Materials Science, Japan, and the evaluation of the validity and applicability to numerical simulation. More than 50 kinds of steel used for heat treatment are focused here to accumulate the following material data, which are taken from documents and experiments ; stress-strain curve under 5% strain, thermal conductivity, specific heat, elastic modulus, CCT and TTT diagram, temperature-elongation diagram. The database tool built on MS-Excel is designed in a hierarchical structure so that users can easily approach, and the material data in the developed database are converted to a database, MATEQ.This database contains more than 1000 kinds of data series for s-s curves and 50-100 for other properties, which triggers future development of more sophisticated database. The validity of the database and applicability to numerical simulation is also examined by simulating several kinds of processes with phase transformation.