Abstract

High-strength bainitic steels are considered potential candidates for the 3rd generation of advanced high-strength steels (AHSS). The main characteristic of silicon-alloyed steels is the presence of carbide-free bainite, obtained by low-temperature austempering. Salt bath boriding is an effective method for increasing wear resistance and provides high corrosion resistance. The combination of these two treatments is called boro-austempering and is a promising alternative to increase the wear resistance of AHSS. In the present work, samples were borided at 900 °C for 2 h, direct-cooled from that temperature and isothermally held in a salt bath at 360 °C for 1 and 3 h. The substrate and the layers produced were characterized by optical microscopy (OM), scanning electron microscopy (SEM), x-ray diffraction (XRD), Vickers microhardness (HRV) and microadhesive wear tests. The tribological characteristics of the layers were compared with those of the substrate. The microscopic analysis showed the effectiveness of boro-austempering treatment in the production of carbide-free bainite microstructure and the surface borided layers. As a result, there were increases in surface wear resistance up to 115% when compared to the substrate.

中文翻译：

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高强度贝氏体钢的硼奥氏体回火处理

摘要

高强度贝氏体钢被认为是第三代高级高强度钢（AHSS）的潜在候选者。硅合金钢的主要特征是存在无碳化物的贝氏体，这种贝氏体是通过低温回火获得的。盐浴硼化是提高耐磨性并提供高耐腐蚀性的有效方法。这两种处理方法的结合称为硼奥氏体回火，是提高AHSS耐磨性的有前途的替代方法。在本工作中，将样品在900°C的温度下硼化2 h，从该温度直接冷却，然后在360°C的盐浴中恒温1和3 h。通过光学显微镜（OM），扫描电子显微镜（SEM），X射线衍射（XRD），维氏显微硬度（HRV）和微胶粘剂磨损测试。将各层的摩擦学特征与基底的摩擦学特征进行比较。显微分析表明，在无碳化物的贝氏体组织和表面渗硼层的生产中，进行了渗硼回火处理是有效的。结果，与基材相比，表面耐磨性提高至高达115％。