The latest generation of high-performance engine blocks are produced with the precision sand casting process (PSCP). Their enhanced mechanical properties are provided by an integrated cast iron chill in the bulkhead section and thus result in large variations in secondary dendrite arm spacing (λ₂) throughout the whole casting, providing unique challenges in both heat treat (T7 temper) development and compliance to the CQI-9 protocol. This research examines the influence of chemistry, controlled solution/quench, residence time between quench and the start of artificial age and artificial age temperature, on the mechanical properties and cryogenic testing observations on PSCP engine blocks. The results are obtained from large population engine block castings (n = 204), heat treated within an industrial plant environment with strict control over furnace temperature gradients. The results indicated that age temperature differences of as little as 4 °C (within CQI-9 for furnace temperature specification of ± 5 °C) can alter yield strength and elongation significantly, which in turn changes crack susceptibility (warranty issues). In addition to the above analysis, it was found that extending the time between the solution/quench operation and the start of artificial age results in a continual drop in yield strength due to the influence of natural aging.

最新一代的高性能发动机缸体是通过精密砂型铸造工艺（PSCP）生产的。其增强的机械性能是由一个集成的铸铁寒意在舱壁部提供，从而导致在二次枝晶臂间距大的变化（λ ₂在整个铸造），在这两个热处理（T7状态）的发展和遵守提供了独特的挑战符合CQI-9协议。这项研究研究了化学，受控溶液/淬火，淬火与人工年龄开始之间的停留时间以及人工年龄温度对PSCP发动机缸体的机械性能和低温测试观察的影响。结果是从大型发动机缸体铸件（n = 204），在工厂环境中进行热处理，并严格控制炉温梯度。结果表明，时效温度差仅为4°C（在CQI-9内，炉温规格为±5°C）可以显着改变屈服强度和伸长率，进而改变裂纹敏感性（保修问题）。除上述分析外，还发现由于自然时效的影响，延长固溶/淬火操作和人工时效开始之间的时间会导致屈服强度连续下降。