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发表于 2020-6-3 09:16:32
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本帖最后由 JG_Wen 于 2020-6-3 09:23 编辑
the black layer should be oxide layer, it comes from the raw part skin or the cleaning/cooling fluid remained before hardening. but it shall be thin and hard, it's difficult to remove completely. you could add an inert gas shield to avoid the oxide skin.
Additionally, as per dealing with the skins in the quenching medium, to add a paper band filter.
by the way, please write Eng. or other language in this BBS channel. |
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