回火

Temperature rang: 500～650℃, tempered organization is tempered sorbite.

回火温度范围为500～650℃，回火组织是回火索氏体。

The results show that quenched steel treated at 1000~1040℃ is more reasonable, quenched at 1030℃, tempered at 300~350℃, the microstructures are small uniform martensite, which has high strength and certain toughness; quenched at 1030℃, tempered at 600~650℃, The microstructure of the steel is tempered sorbite which has good mechanical properties.

结果表明：1Cr16Ni4Nb钢在1000~1040℃淬火较合理，在1030℃淬火、300~350℃回火时，组织为均匀细小的回火马氏体，其具有较高的强度和一定的韧性；在1030℃淬火、600~650℃回火时，1Cr16Ni4Nb钢的组织为回火索氏体，其具有较高的综合力学性能。

With the increased of tempering temperature, the content of tempering troostite decreased, meanwhile tempering sorbite and particles precipitation increased.

且随回火温度的升高，回火屈氏体含量降低，回火索氏体含量增加，第二相粒子析出增加。

The results show that: with the increase of tempered temperature, the quenched martensite transforms into the tempered martensite, tempered martensite + tempered sorbite and tempered sorbite; the strength of samples decreases continuously but yield ratio increases a little.

结果显示：随回火温度的升高，其组织由淬火马氏体逐渐转化为回火马氏体、回火马氏体+回火索氏体及回火索氏体；试样的强度连续下降，屈强比略有上升。

It has been investigated that the process of annealing influences the properties of carbides,and that the precipitated phase separated from supersaturated solid solution.

研究了回火工艺对热处理产品的影响，系统地分析了回火时过饱和固溶体的析出物，从而制定合适的回火工艺。

T emperature rang: 350～500℃, tempered organization is tempered troostite.

回火温度范围为350～500℃，回火组织是回火托氏体。

The steel selected for this investigation is spring steel 50CrVA for automobile in this paper,the appropriate duplex microstructure of lower bainite and martensite was obtained through isothermal quenching and low temperature tempeing heating treatment,then the effect of duplex microstructure and tempered troostite on strength-toughness of spring steel 50CrVA is compared.

以汽车用弹簧钢50CrVA为研究对象，通过等温淬火+低温回火热处理工艺获得适当比例的回火马氏体和下贝氏体的复合组织，并在此基础上比较复相组织和回火屈氏体对弹簧钢50CrVA 强韧性的影响。试验结果表明：在弹簧要求的HRC硬度在50~54范围内，在910℃保温30 min+360℃等温20 min淬火+300℃保温60 m in回火工艺得到复相组织的强韧性最好

Through a series of quenching, tempering, tensile testing, low-temperature impact test and metallographic analysis, we ultimately came to the following conclusions:(1) low-carbon alloyed steel 20CrMn2NiMoV quenching at 870℃ and tempering at 200℃, whose structure contains tempered dislocation lath martensite and few small bainite under mixed, has the best obdurability;(2) Carbon Steel 45CrMn2NiMoV quenching at 850℃ and tempering at 620℃, whose structure is sorbitic, has a performance less than that of low-carbon Alloyed steel, but it can also meet the basic design requirements.(3) Mn can substitute for the role of Ni within limited extent.

通过一系列淬火、回火、拉伸试验、低温冲击试验以及金相分析，最终得出以下主要结论：（1）低碳合金钢20CrMn2NiMoV经870℃淬火+200℃回火，得到回火位错型板条马氏体+少量细小下贝氏体的混合组织，具有最佳的强韧性配合；（2）中碳合金钢45CrMn2NiMoV经850℃淬火+620℃回火，得到回火索氏体组织，综合性能虽然不及低碳合金钢，但也能基本满足设计要求；（3）Mn在一定程度上能够替代Ni的作用，适量的Mn和Ni相互配合可以得到最佳的低温韧性，因此&以Mn代Ni&是低温钢材料研究开发中一条可行的适合我国资源状况的合金化思路。

Materials and Methods: Under the best annealing condition treatment and making sure the surface characteristics and cooling process after vacuum annealing had no significant effects to thermoluminescent response, TLD samples were put into the ABS TLD holder in the vacuum chamber.

材料与方法：将以最佳回火条件回火完成之CaF2：Dy (TLD-200)及CaF2： Tm (TLD-300)，确保其表面性质及真空回火后冷却过程对热发光反应无影响后，将其置於真空腔内之一压克力置装器内。

RPC steel and RQ steel are constituted by bainite and martensite microstructures before tempering. The microstructure of RPC steel did not change obviously except some bainitic laths coalescing were detected by means of SEM during tempering, while the boundary of bainitic laths of RQ steel disappeared quickly and finally formed polygonal ferrite forms accompanied a dramatic decrease in hardness.

回火前两种钢板组织均为贝氏体和马氏体的复合组织，经RPC处理后的钢板随回火温度的提高组织没有明显变化，只是一些板条出现合并现象，而经过RQ处理后的钢板随回火温度的升高板条很快消失最终演变成多边形铁素体，硬度也随之大幅度下降。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷