9Cr2Mo钢冷轧辊断裂分析

本文所介绍的9Cr2Mo钢冷轧辊断裂事故,起因于中心孔部位的分层断口缺陷和针孔。而分层断口的形成,则与钢中碳化物沿奥氏体晶界大量析出有关。     

过渡金属碳化物的研究与应用进展

综述了过渡金属碳化物的结构与性质以及在各类反应中的应用研究进展,总结了碳化钨及碳化铝的催化性能,并预测了今后的发展方向和应用前景。     

碳化物陶瓷的研究现状及发展趋势

本文综述了现阶段碳化物陶瓷超细粉末的主要制备工艺以及烧结方法,同时指出了碳化物陶瓷今后的发展趋势。     

Evolution of carbides and carbon content in matrix of an ultra-high carbon sintered steel during heat treatment process

DTA, thermal expansion, XRD, and SEM were used to evaluate the effect of quenching temperature on the mechanical properties and microstructure of a novel sintered steel Fe-6Co-1Ni-5Cr-5Mo-1C. Lattice parameters and the mass fraction of carbon dissolved in the matrix of the steel quenched were investigated. It is discovered that the hardness of the steel increases with quench-ing temperature in the range of 840-900℃ and remains constant in the range of 900 to 1100℃. It decreases rapidly when the tem-perature is higher than 1100℃. The mass fraction of carbon dissolved in the matrix of the steel quenched at 840℃ is 0.38, but when the quenching temperature is increased to 1150℃, it increases to 0.98. The carbides formed during sintering are still present at grain boundaries and in the matrix of the steel quenched at low quenching temperatures, such as 840℃. When the quenching temperature is increased to 1150℃, most of the carbides at grain boundaries are dissolved with just a small amount of spherical M23C6 existing in the matrix of the quenched steel.     

用有机酸清洗碳化物垢层

本文叙述碳化物垢层对设备装置的危害以及给生产长周期运转带来的不良后果及我厂采用有机酸清洗除尿素循环加热器上碳化物垢层获得的效果。     

Effect of vanadium and chromium on the microstructural features of V–Cr–Mn–Ni spheroidal carbide cast irons

The objective of this investigation is to study the influence of vanadium（5.0wt%–10.0wt%） and chromium（0–9.0wt%） on the microstructure and hardness of Cr-V-Mn-Ni white cast irons with spheroidal vanadium carbides. The alloys＇ microstructural features are presented and discussed with regard to the distribution of phase elements. The structural constituents of the alloys are spheroidal VC, proeutectoid cementite, ledeburite eutectic, rosette-shaped carbide eutectic（based on M7C3）, pearlite, martensite, and austenite. Their combinations and area fraction（AF） ratios are reported to be influenced by the alloys＇ chemical composition. Spheroidized VC particles are found to be sites for the nucleation of carbide eutectics. Cr and V are shown to substitute each other in the VC and M7C3 carbides, respectively. Chromium alloying leads to the formation of a eutectic（γ-Fe ＋ М7С3）, preventing the appearance of proeutectoid cementite in the structure. Vanadium and chromium are revealed to increase the total carbide fraction and the amount of austenite in the matrix. Cr is observed to play a key role in controlling the metallic matrix microstructure.     

行星轮轴承载表面激光强化

对行星轮轴的承载表面激光淬火后的强化层进行了分析和研究。结果表明，激光淬火时，当表层区所需能量密度为40J／mm^2时，表面硬度最高，组织为隐针马氏体和弥散分布的合金碳化物；过渡区由于发生托氏体转变，硬度明显下降。强化层的显微组织有利于提高行星轮轴的耐磨性和抗冲击性，从而延长了其使用寿命。     

含共晶碳化物Fe—Cr—Mn合金在高温含硫气氛中的腐蚀研究

对含碳量为０．５０－２．６３％的Ｆｅ－Ｃｒ－Ｍ合金在８００℃下含硫混合气氛中进行腐蚀试验。用Ｘ射线物相分析法分析了腐蚀产物种类及其相对含量，观察测定了元素在腐蚀产物中的分布及试样亚表层共晶碳化物的腐蚀行为。     

钢中碳化物在锋利农机刀片磨损过程中的利弊

应用光学显微镜和扫描电镜对多种锋利农机刀片的上百条刀刃进行失效分析，在分别查明刃口和刃面磨损机理的基础上，指出粗粒状碳化物对刃口有害；而有适当数量和形态、与基体结合牢固的碳化物，则能提高刃面抗划伤能力。据此，提出含氮马氏体化处理和姜块状索氏体化处理两种改变碳化物分布及形态的热处理工艺，取得很好的效果。