中文摘要：

针对采用复合元素添加法生产工程机械用钢成本较高的问题，介绍了鞍钢中板厂利用超快速冷却工艺开发Q550CFD高强工程机械用钢的情况，主要介绍了化学成分设计、生产工艺及产品组织性能。实践表明，采用超快速冷却工艺生产的钢板热轧态、回火态力学性能均满足标准要求，实现了低成本、减量化生产。

英文摘要：

To the problem of high cost of construction machinery steel produced by composite elements adding, the development of Q550CFD using ultra-fast cooling process in Angang Medium Plate Plant was indicated. The chemical composition design, production process, microstructure and properties of Q550CFD were introduced. The practice indicated that the mechanical properties of the plate with ulstra-fast cooling process can meet standard require for low cost and reduction producing.