| 1. |
- Wu, Guangxin, et al.
(författare)
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Effect of Hot Rolled Substrate of Hydrogen Reduction on Interfacial Reaction Layer of Hot-dip Galvanizing
- 2018
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Ingår i: Journal of Materials Processing Technology. - : Elsevier. - 0924-0136 .- 1873-4774. ; 259, s. 134-140
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Tidskriftsartikel (refereegranskat)abstract
- The effect of morphology of substrate on intermetallic layer is studied in this work by combining the hydrogen reduction descaling of hot rolled steel and galvanizing process. The results show that the morphology of iron reduced at different temperatures can be divided into porous and dense iron surface. The interfacial reaction layer on steel strip with porous iron is composed of xi phase and delta phase, and the phase in coating is invariable with the increasing of soaking time. However, the interfacial reaction layer on steel strip with dense iron is considered to be Fe2Al5Znx intermetallic layer. As the time goes up, a columnar xi phase forms on the intermetallic layer of steel strip reduced at 700 degrees C and the Fe-Al intermetallic layer disappears gradually. In addition, the bursting phenomenon of intermetallic layer occurs after dipping for 10s on steel strip reduced at 800 degrees C, and the delta phase forms on the interface between the "outburst" Fe-Al phase and substrate. The possible mechanisms involved in the formation of Fe-Al and Fe-Zn alloys were also discussed.
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| 2. |
- Wu, Guangxin, et al.
(författare)
-
Effect of water pressure and soaking time on the selective oxidation of DP980 advanced high strength steel
- 2018
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 453, s. 252-262
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Tidskriftsartikel (refereegranskat)abstract
- Due to the limited heating power in non-oxidation furnace of continuous strip processing facilities of heating stage, selective oxidation with higher oxygen pressure is practically inevitable, which will greatly influence the quality of coating during immersion into the zinc bath. In this paper, the oxidation behaviors of DP980 advanced high strength steel are studied during annealing in a pure H2 atmosphere with controlled water pressure ranging from 0.033 to 0.094 bar (PH2O/PH2) and soaking time from 30 s to 2 h. The oxidation proceeds as a combination of external formation of Mn oxides and internal formation of Mn2SiO4, MnSiO3 and SiO2 from the subsurface of the steel into the matrix. As the water pressure increases from 0.033 to 0.094 bar, it can be seen that the amount of oxide particles and coverage on the surface of the steel seems to decrease initially and increase afterwards. The sequence of oxides determined by oxygen partial pressure was calculated and illustrated using thermodynamics with alloys activity. Oxide growth mechanism during annealing and the effect of water pressure on the amount of oxide particles were also discussed.
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