1Cr11MoNiW1VNbN钢盐浴渗铬性能研究

为提高超(超)临界汽轮机气缸高温螺栓的抗咬死性能,对高温螺栓材料1Cr11MoNiW1VNbN钢进行盐浴渗铬处理,利用光学显微镜(OM)、扫描电镜(SEM)观察了渗层的组织,利用显微维氏硬度计和纳米硬度计分析了渗层的硬度、弹性模量和韧性,利用摩擦磨损试验机测试了渗层的耐磨性能,利用动电位极化曲线和高温氧化实验研究了渗层耐腐蚀性能.结果表明:1Cr11MoNiW1VNbN钢盐浴渗铬处理后的组织由Cr23C6和Fe-Cr铁素体(柱状晶)组成,渗层硬度和弹性模量较低,韧性较高,材料的耐磨性、耐电化学腐蚀和抗高温氧化性能得到了明显提高,这将是一种防止高温螺栓咬死的有效方法.

Study on the properties of 1Cr11MoNiW1VNbN steel by salt bath chromizing

To prevent scuffing of bolts in a steam turbine cylinder at a high temperature,the salt bath chromizing process of 1Cr11MoNiW1VNbN steel was studied.The microstructure of the chromizing layer was observed by optical microscopy(OM) and scanning electron microscopy(SEM).The hardness,elastic modulus,and toughness were obtained by a micro-hardness and nano-hardness tester.The wear resistance was evaluated by pin-on-disk wear tests.Potentiodynamic polarization curves and high-temperature oxidation tests were conducted to investigate the corrosion behavior.The results indicate that the chromized layer consists of Cr23C6 and Fe-Cr(columnar grains) phases after salt-bath chromizing and subsequent heat treatment and exhibits lower hardness and elastic modulus but higher toughness.The salt bath chromizing process is expected to be an effective way to prevent bolts from scuffing at high temperatures due to it significantly improved wear resistance,electrochemical corrosion resistance,and high temperature oxidation resistance.