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发表于 2013-4-15 16:13:28
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本帖最后由 所以因为 于 2013-4-22 11:06 编辑
leomet 发表于 2008-3-3 08:34
我中文打字很慢, 僅分享我典藏的相片. 並不想討論.
如果有人帮忙解释给新手学习学习, 我不反對. 有不足处 ...
Hello WU Lao! I would like to introduce these beauties (Microstructure picture) to these old or young Heat Treatment Men. I will do the job by the way of expressing my understanding about these pictures and ask some questions and you can give your comments.
Question 1: Why does the carbide precipitate inside the high temperature ferrite but not inside the austenite in stainless steel as cast condition (Fig.固溶前.jpg)? Cr% does the job? I ever detected decarbonization of a fusion line of a weld joint with different base material. The two kinds of base material have different Cr% equivalence. This phenomenon is called "carbon removal". is there other explanation from you ?
Highest esteem !!!!!
After solution treatment, the carbon goes into the austenite and Delta ferrite (= high temperature ferrite) lattices as the C atom. So no carbide reveals any more.I think the C% is the same between austenite and ferrite because there is no diffusion. The delta ferrite is in rich of Cr% equivalence, it will transfer to be a new substance under some conditions, that is a bad thing. |
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