The TTT diagrams of the pre-hardened plastic die steels P20 and 718 from a steel plant were measured by dilatometer method.

• 针对厂方设计并生产的P20和718钢,利用膨胀法测定了它们的等温奥氏体转变曲线(TTT曲线),并对曲线进行了分析和讨论,为制订合理的预硬化工艺建立了依据。