摘要：水是最清洁和廉价的淬火介质，但由于合金钢件水淬开裂问题的制约，对环境造成污染的油和各类有机水溶性介质仍被大量采用。本研究团队在传统水-空断续淬火基础上，提出了清洁的水-空交替控时淬火冷却（ATQ）技术，在解决合金钢件水淬开裂问题方面已进行了15年的持续研究和工程应用。本文首先介绍淬火介质的特性，然后介绍ATQ技术取代油或有机类介质淬火、工艺和设备设计的3个基本原理，随之论述ATQ避免淬火开裂和获得高强韧性的机制。最后从ATQ技术几十个成功应用中遴选出几个典型例子，分析它们各自在淬火所遇到的瓶颈问题，阐明在淬火避免开裂的前提下如何获得预期力学性能的解决方法。

摘要：Low cost,high strength and high elongation steel is always the major trends of steel development especially for automotive ***,raising strength usually brings about loss of ductility,which is known as the strength-ductility trade-off[1].Solving strength-ductility trade-off by increasing low cost carbon content is the century-long pursuit of ***[2]pointed out that investigation since 1900s indicates that the increase of carbon content leads to enhancing strength,but deteriorating ductility and other properties of steels.