几条笔记丨不锈钢：啥样用作耐蚀钢，啥样作耐热钢？

好几天没更新了，因为前两天电脑崩了，开不了机，今天上螺丝刀硬拆，然后可以了~~~

以下摘自参考文献，因为比较短，也就不翻成中文了，大家随便看看。

The selection of stainless steels … corrosionresistance and mechanical properties are usually the most important factors inselecting a grade for a given application.

耐蚀性和力学性能是不锈钢选材时最重要的两个因素。

Stainless steel castings are usuallyclassified as either corrosion-resistant castings (which are used in aqueousenvironments below 650 °C, or 1200 °F) or heat-resistant castings (which aresuitable for service temperatures above 650 °C, or 1200°F).

耐蚀钢、耐热钢常以650°C为界。

However, this line of demarcation in termsof application is not always distinct, particularly for steel castings used inthe range from 480 to 650 °C (900 to 1200 °F).

然而，分界也并不绝对，特别是一些用于480 ~650 °C的不锈钢。

The usual distinction betweenheat-resistant and corrosion-resistant cast steels is based on carbon content.

耐蚀钢、耐热钢的分界线取决于碳含量。

Carbon is useful to the extent that itpermits hardenability (淬透性) by heat treatment, which isthe basis of the martensitic (马氏体) grades, and providesstrength in the high-temperature applications of stainless steels. In all otherapplications, carbon is detrimental to corrosion resistance through itsreaction with chromium. In the ferritic grades, carbon is also extremelydetrimental to toughness.

碳元素对高温下的强度有力，对耐蚀性不利。

These steels （注：304L、316L等）tend to be used for their‘stainlessness’ rather than their mechanical properties. … they are notintended for service above about 450 °C.

These steels 304H（ASTM）tend to be used for their high-temperature scaling resistance andlong-term thermal stability and creep rupture strength rather than their corrosionresistance.

参考文献：

ASM Handbook Vol. 1

The alloy tree