普通碳钢材料正火与淬火加回火的区别

star_boy

规范上没有明显区别。实际的机型性能和晶粒结构有很大区别

gl9855

wx_G4k4kBEM 发表于 2018-11-20 14:46
淬火+回火（组织为粒状珠光体）与正火（组织为片状珠光体）一般抗拉强度差异不大（由回火温度决定），但淬 ...

高碳钢淬火加中温、高温回火时得到粒状珠光体，淬火加低温回火后组织为回火马氏体。

/shl撕烤的岩

This kind of steel can be smelted by oxygen converter, open hearth furnace or electric furnace, and is generally hot-rolled into steel plate, steel belt, profile and bar.Steel plates are generally delivered hot rolled (including controlled rolling) or normalized.The chemical composition, tensile properties, impact work and cold bending properties of steel shall comply with the relevant provisions.In China's national standard gb700-88, this kind of steel is divided into 5 grades according to yield point value and 4 grades according to quality.The brand number is composed of the letter Q, the yield point value, the quality grade symbol and the deoxygenation method symbol, which represent the yield point.This kind of steel has a wide range of applications, most of which are used for welding, riveting or bolting steel structural parts, a few for the production of various machine parts.The lower strength Q195 and Q215 steels are used to make low carbon steel wire, steel wire mesh, roof plate, welded steel pipe, anchor bolt and rivet, etc.Q235 steel has medium strength, good plasticity and toughness, and is easy to form and weld.This kind of steel is mostly used as steel reinforcement and structural parts, but also as rivets, railway nails and various mechanical parts, such as bolts, tie rods, linkages.The stronger Q255 and Q275 steels are used in the manufacture of various agricultural machinery, as well as for reinforcing bars and railway fishtail plates.According to the special performance requirements of some industrial steel, the composition of ordinary carbon structural steel is slightly adjusted to form a series of professional steel, such as riveting screw steel, bridge steel, pressure vessel steel, hull steel, boiler steel.In addition to strictly controlling the chemical composition and ensuring the general performance of professional steel, it also stipulates some special inspection items, such as low-temperature impact toughness, aging sensitivity, gas in steel, inclusion and fracture, etc

rocchenlp

退火(Annealing)是一种软化处理用于增加金属的延展性，但要损失强度，为了完成退火，金属被加热到奥氏体区域，
保温按 1 小时/英寸（工件厚度）或最低 1 小时，然后缓慢地冷却。，冷却通常是通过关掉能源，让工件
保留在炉内冷却到室温。

正火(Normalizing)也是软化金属，但不如退火明显，它被认为是均匀化热处理，即使工件的金属结构均匀，正火
处理通过提高金属温度到其奥氏体区域，保温较短的时间，然后让其在静止的空气中冷却，这种冷却比
炉冷快，所以最终的性能与退火相比，硬度和强度稍高一些而延展性有所降低，正火处理的碳钢和低合
金钢通常可焊性是较好的。

淬火处理(Quenching)与退火和正火不同点主要是前者最终的机械性能中强度和硬度明显增高，而延展性有所降
低。这种硬化处理是通过加温到奥氏体区，保温一段时间，然后马上将部件浸入一淬火介质，诸如水、
油、盐水，使其快速冷却，淬火产物主要是马氏体结构，该结构具有高的硬度、强度和低的延展性，为
了改善延展性，同时不明显降低金属的强度，通常采用回火(Tempering)处理，回火是通过加热工件到低相变点，保
温短暂时间，让高应力马氏体结构有某种程度上应力释放，然后冷却。

Paul2018

wcj12wcj 发表于 2018-11-15 07:57
几个热处理状态，正火，调质，淬火加回火，具体啥区别一直没搞得特别明白。。。

淬火加高温回火就是俗称的调质，一般回火都是配合淬火使用的；正火和淬火的主要区别是冷却速度不一样

wcj12wcj

Paul2018 发表于 2018-12-15 13:21
淬火加高温回火就是俗称的调质，一般回火都是配合淬火使用的；正火和淬火的主要区别是冷却速度不一样

虽然还是没明白更多，还是谢谢你。