The change of steel surface chemistry regarding oxygen partial pressure and dew point

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• 作者：Martin Norden ; ^{martin.norden@thyssenkrupp.com} ; ^{martin-norden@arcor.de} ; Marc Blumenau ; Thiemo Wuttke ; Klaus-Josef Peters
• 关键词：Selective oxidation ; Advanced High Strength Steels (AHSS) ; Continuous hot-dip galvanizing ; Sub-surface ; Heterogeneous gas/metal reaction
• 刊名：Applied Surface Science
• 出版年：2013
• 出版时间：15 April, 2013
• 年：2013
• 卷：271
• 期：Complete
• 页码：19-31
• 全文大小：4621 K

文摘

By investigating the surface state of a Ti-IF, TiNb-IF and a MnCr-DP after several series of intercritical annealing, the impact of the annealing gas composition on the selective oxidation process is discussed. On behalf of the presented results, it can be concluded that not the general oxygen partial pressure in the annealing furnace, which is a result of the equilibrium reaction of water and hydrogen, is the main driving force for the selective oxidation process. It is shown that the amounts of adsorbed gases at the strip surface and the effective oxygen partial pressure resulting from the adsorbed gases, which is mainly dependent on the water content of the annealing furnace, is driving the selective oxidation processes occurring during intercritical annealing. Thus it is concluded, that for industrial applications the dew point must be the key parameter value for process control.