Neutral Hardening

cjzhou

中英文对照，顺便学学英文：
Neutral hardening also named martensitic or quench hardening, neutral hardening is a heat treatment used to achieve high hardness/strength on steel. It consists of austenitising, quenching and tempering, in order to retain a tempered martensite or bainite structure.
中性淬火亦称为马氏体化或淬火硬化，是一个用于获取钢材高硬度/强度的热处理过程。该处理包括奥氏体化、淬火与回火处理, 目的是取得回火马氏体或贝氏体组织。
reference: Bodycote website.

cjzhou

根据钢材的类型，可将中性淬火的优势归为以下几种：
实现重载部件的最优化，提高强度、韧性以及耐热性（若有）
强度提高后，此类部件会更轻、更具韧性
工具及模具可在保留其韧性的同时达到要求之耐磨及/或耐热性
需经过磨削处理方可降低粗糙性的部件可达到要求之切削性
无论用在何处，如部件系由马氏体不锈钢生产而成，则只有在热处理之后方具有抗腐蚀性。
工具钢：经过淬火后方具有高硬度、耐磨、耐高温、及理想的切削性能。
马氏体不锈钢：淬火处理后，此类钢材方可达到其最佳的防腐蚀性能。
各类钢材：部件成形期间，（在热处理之前），材料相对较软，因此，易于切削。
here are several benefits of neutral hardening, depending on the steel type:
Heavy loaded parts can be given an optimal combination of high strength, toughness and, if applicable, temperature resistance
Such parts can be made lighter and more stiff, due to higher strength
Tools and dies get the required high wear and/or heat resistance while maintaining toughness
Parts that need grinding to low roughness, acquire the required machinability
For all these purposes, if the parts are made of martensitic stainless steels, the corrosion resistance is only available after the heat treatment
Tool steels: the desired properties of high hardness, wear resistance, heat resistance and machinability can only be given by hardening.
Martensitic stainless steels: these steels only get their maximum corrosion resistance by hardening.
For all steel types: during the shaping of the parts, (takes place before the heat treatment), the material is relatively soft and therefore easy to machine.

cjzhou

此处所述之淬火处理为典型的中性淬火，即，部件的钢表面的化学成分在处理过程中并不会改变。
直接淬火硬化是钢淬火中最常见的做法。
第一步，分阶段将材料加热至淬火温度，淬火温度视钢材的类型而定，一般在800至1220°C之间。在730至900°C（具体温度视钢材类型而定）时，钢的组织结构会转变为奥氏体。
第二步，在淬火温度、奥氏体化温度以同时完全均衡部件的温度，并将微结构转化为奥氏体。NB：降低比容积。
第三步，直接在冷媒介中对奥氏体化温度下的部件进行淬火处理。此类淬火介质通常为水、熔盐、油或高压氮，具体介质则视钢材类型与部件的尺寸而定。淬火速度必须够快以防材料又变回原来柔软的结构。
he hardening processes described here are typically neutral, which means that the chemical composition of the steel surface of the parts is not intended to be changed during the process.
Direct quench hardening is the most common practice for hardening of steel.
The first step is to heat up in stages to the hardening temperature which is, depending on steel type, between 800 and 1220°C. At a temperature between 730 and 900°C (depending on steel type) a transformation of the microstructure into austenite takes place.
The second step is to hold at this hardening, austenitising temperature to simultaneously fully equalise the temperature of the parts, and transform the microstructure into austenite. NB: this gives a reduction in the specific volume.
The third step is quenching the part direct from the austenitising temperature in a cold medium. This kind of quench medium is usually water, liquid salt, oil or high pressure nitrogen, depending on the steel type and part dimensions. The quenching speed must be high enough to prevent the material from transforming back into the original soft structure.

cjzhou

工程钢：
驱动轴、承载环、框架、叉车前叉、螺母与螺栓、调换等重载部件
用于提升温度的类似部件
各类及各种尺寸的弹簧
工具：切割、锤击、滚轧，即，冷却及热处理的各种模具
铸模：切割、滚轧、冲压、锤击，以及塑料与铝铸造，及挤压模具
抗腐蚀性能要求较高的不锈钢（食品与医疗行业）
Engineering steels:
Highly loaded parts, such as drive shafts, carrier bars, frames, fork lift forks, nuts and bolts, lifting eyes etc.
Similar parts, intended for elevated temperatures
Springs of any kind, and any dimension
Tools: cutting, hammering, rolling i.e. any kind of tooling for cold, as well as for hot working
Dies: cutting, rolling, stamping, hammering, but also plastic and aluminium casting, and extrusion dies
Stainless steel parts needing high corrosion resistance (food and medical industry)
reference: Bodytote website

oliver

如果照英文字面生硬的译成 “中性硬化”，中国的 “标准热处理概念” 中既没有这个说法，也不符合英文原意，而且还让人不知所云。
若意译成 "气氛保护加热淬火”，既符合中国的 “标准热处理概念”，也符合英文原意。

zibu

Neutral hardening 相当于保护气氛淬火，
Neutral主要定义碳势为中碳势（气氛Cp设定与工件芯部碳含量一致（或高0.05）），与渗碳的高碳势区别；