Influence of Cr Addition on Selective Oxidation Behavior of Mn-Added High-Strength Steel Sheet
Influence of Cr Addition on Selective Oxidation Behavior of Mn-Added High-Strength Steel Sheet
复制标题
Cr添加量对Mn添加高强度钢板选择性氧化行为的影响
作者：
Y. Fushiwaki;T. Kawano;Y. Nagataki
近年来，人们对汽车车身重量的减轻和碰撞安全性的提高非常关注，这鼓励了汽车用高强度钢板(HSS)的积极使用。1)为了获得高强度和延展性，在HSS的制造中添加了各种元素，如硅、锰和铬。5)高速钢的制造工艺通常包括在连续炉中进行再结晶退火，在5-20Vol%H2−氮气气氛中进行再结晶退火，退火温度控制在700℃以上。在这种气氛下，铬和锰都应该作为选择性表面氧化物被热力学氧化，而铁氧化物可以被还原。众所周知，这些选择性表面氧化物恶化了高速钢与熔融锌的润湿性，并在退火热浸镀过程中立即导致高速钢表面出现裸露斑点等涂层缺陷。到目前为止，不同的作者已经报道了含锰和含铬高速钢表面的选择性氧化行为，但没有提到选择性表面氧化物的差异与高速钢与熔融锌的润湿性之间的关系。此外，添加铬对加锰高强度钢板的选择氧化行为也有影响
Recently, there has been great concern regarding reduction of the weight of the automotive body and improvement of collision safety, which has encouraged active use of high-strength steel sheets (HSS) for automobiles.1,2) Various elements such as Si, Mn and Cr are added in order to obtain high strength and ductility3,4) in the manufacture of HSS. The HSS has also been applied to galvannealed components to obtain excellent anti-corrosion properties.5) The manufacturing process of the HSS typically includes recrystallization annealing in a continuous furnace controlled to an annealing temperature of more than 700°C in a 5–20 vol% H2−N2 gas atmosphere. In this atmosphere, both Cr and Mn should be thermodynamically oxidized as selective surface oxides, whereas Fe oxide can be reduced. It is well known that these selective surface oxides deteriorate the wettability of the HSS with molten Zn and lead to coating defects such as bare spots6–10) on the HSS in the hot-dip galvanizing process immediately after annealing. Various authors have so far reported the selective surface oxidation behavior on the surface of the HSS containing both Mn and Cr.11–13) However, they have not mentioned the relationship between the difference of the selective surface oxide and the wettability of the HSS with molten Zn. Furthermore, there Influence of Cr Addition on Selective Oxidation Behavior of Mn-Added High-Strength Steel Sheet