Surface and Coating Analysis of Press-Hardened Hot-Dip Galvanized Steel Sheet
Surface and Coating Analysis of Press-Hardened Hot-Dip Galvanized Steel Sheet
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DOI：
10.1002/srin.201200068
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发表时间：
2012-11-01
影响因子：
2.2
通讯作者：
Hassel, Achim Walter
中科院分区：
文献类型：
--
作者：
Autengruber, Robert;Luckeneder, Gerald;Hassel, Achim Walter
使用连续镀锌钢板作为压制硬化的原材料，可使部件具有非常高的强度水平，并具有经典的阴极腐蚀保护。目前的工作提供了一个深入了解这种技术，特别注重在表面氧化和金属间相的形成过程中的结晶过程。为此，将坯料厚度为1.5 mm且平均涂层重量为70 g/m2的热浸镀锌22 MnB 5钢板在400-900 ℃的温度范围内以50 ℃的步骤退火，而在水中淬火之前不进行浸泡。通过SEM、EDX和XRD分析表面和横切面，以说明热处理过程中的相形成和表面变化。还根据电化学研究和称为VDA的加速、循环、汽车腐蚀测试研究了腐蚀行为，VDA是盐雾测试和交替气候测试的混合物。结果发现，镀锌钢板的热处理导致涂层的显著变化。生成的涂层仍然为钢基材提供阴极保护，并且具有比标准镀锌钢板更高的耐腐蚀性。在压制硬化过程中也发生表面氧化，导致表面覆盖有连续排列的Al 2 O3和ZnO层，还包含进一步氧化的合金元素。
The use of continuous galvanized steel sheet as feedstock material for press hardening leads to components of very high strength levels with classical cathodic corrosion protection. The present work provides an insight into this technology with special focus on surface oxidation and intermetallic phase formation during the austenisation process. For that reason hot dipped galvanized 22MnB5 steel sheets, with a blank thickness of 1.5 mm and an average coating weight of 70 g m(-2), were annealed in a temperature range of 400-900 degrees C in steps of 50 degrees C without soaking before quenching in water. Surface and cross-cuts were analyzed by SEM, EDX, and XRD to illustrate the phase formation and the surface changes during thermal treatment. Corrosion behavior was also studied based on electrochemical investigations and an accelerated, cyclic, automotive corrosion tests called VDA, which is a mixture of salt spray test and alternating climate test. It was found that austenisation of galvanized steel sheet causes a significant change of the coating. The generated coating still offers cathodic protection for the steel substrate and has higher corrosion resistance than standard galvanized steel sheet. Surface oxidation also occurs during the press hardening process leading to a surface covered with successively arranged layers of Al2O3 and ZnO, containing also further oxidized alloying elements.