Al-Si镀层热冲压钢的研究现状  

Research status of Al-Si coated hot stamped steel

作　　者：曾林林 杨达朋 易红亮[1,2] ZENG Linlin;YANG Dapeng;YI Hongliang(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;Easyforming Materials Technology Co.,Ltd.,Suzhou 215123,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]育材堂(苏州)材料科技有限公司,江苏苏州215123

出　　处：《轧钢》2022年第6期121-131,共11页Steel Rolling

基　　金：国家自然科学基金项目(52101128);中国博士后科学基金项目(2022M710021);东北大学博士后基金项目(20220202)。

摘　　要：热冲压成形解决了钢材强度与成形性之间的矛盾,目前抗拉强度超过1 500 MPa的汽车零件只能通过热冲压工艺生产。为避免钢板在热冲压加热过程中的氧化与脱碳,通常在钢板表面涂镀一层Al-Si合金。结合Al-Si镀层热冲压钢的研究现状,综述了热冲压过程中Al-Si镀层微观组织演变及其对热冲压钢弯曲韧性的影响机理。奥氏体化加热过程中,Al-Si镀层与钢基体发生Fe、Al、Si元素相互扩散,镀层组织转变为由Fe-Al或Fe-Al-Si金属间化合物组成的多层结构,部分基体组织转变为富Al的α-Fe相互扩散层。Al-Si镀层通常会降低热冲压钢的弯曲韧性,目前学术界对Al-Si镀层降低热冲压钢弯曲韧性的原因尚未形成统一的认识,主要解释有:(1)镀层中裂纹尖端产生的应力集中促进了裂纹在基体的扩展;(2)奥氏体化过程中镀层与基体界面迁移导致的界面C富集使界面处容易产生裂纹。Al-Si镀层对热冲压钢弯曲韧性的影响机理以及提高Al-Si镀层热冲压钢弯曲韧性的方法尚需进一步研究。Hot stamping solves the contradiction between steel strength and formability. At present, auto parts with tensile strength exceeding 1 500 MPa can only be produced by hot stamping. In order to avoid oxidation and decarburization of the steel plate during hot stamping process, a layer of Al-Si alloying is applied on the surface of the steel plate. The microstructure evolution of Al-Si coating during hot stamping and the influence mechanism of Al-Si coating on the bending toughness of hot stamped steel are reviewed. During the austenitizing heating process, the Al-Si coating and the steel matrix undergo interdiffusion of Fe, Al, Si elements. The coating structure is transformed into a multilayer structure composed of Fe-Al or Fe-Al-Si intermetallic compound phases, and part of the matrix structure is transformed into Al-rich α-Fe interdiffusion layer. Al-Si coating usually reduces the bending toughness of hot stamped steel, and the reasons why Al-Si coating reduce the bending toughness of hot stamped steel have not yet formed a unified understanding. The main explanations are as follows:(1) the stress concentration generated by the crack tip in the coating promotes the expansion of the crack in the matrix;(2) interface C enrichment caused by the migration of the coating and the matrix interface during austenitization makes the interface prone to crack. The mechanism of the influence of Al-Si coating on the bending toughness of hot stamped steel and the method of improving the bending toughness of Al-Si coated hot stamped steel need to be further studied.

关 键 词：热冲压钢 Al-Si镀层 金属间化合物 裂纹扩展 弯曲韧性 

分 类 号：TG306[金属学及工艺—金属压力加工]