【作者】 庞辉勇；

【导师】 张恒；

【作者基本信息】 武汉科技大学 ， 材料学， 2003， 硕士

【摘要】 目前使用的冷轧带肋钢筋轧辊由于诸多原因，寿命很短，这严重制约了冷轧带肋钢筋的使用及生产厂家的经济效益。 为了解决冷轧带肋钢筋轧辊寿命短的问题，通过失效分析发现，轧辊失效多是工作面不耐磨引起的，为了提高轧辊耐磨性，在试验中选用高碳高合金钢Cr12MolⅤ，并且，考虑到生产成本，也尝试对高碳低合金钢9Cr2Mo采用化学热处理的工艺。 在试验中，通过改变Cr12MolⅤ的锻造工艺，采用高频、中频、盐浴、真空淬火、深冷处理等工艺处理试样，以及对试样实施渗氮、渗硼、硼氮共渗等化学热处理，通过做磨损试验、使用试验、X—射线衍射、金相分析、SEM扫描，研究了各种处理工艺对模具耐磨性及使用寿命的影响。 通过试验，得出如下结论： 1)对Cr12MolⅤ采用六面锻造+锻后余热淬火工艺，可以细化碳化物、奥氏体晶粒，促使碳化物均匀分布，可以提高耐磨性； 2)Cr12MolⅤ整体淬火后，采用液氮深冷处理，不但可以提高硬度，减少残余奥氏体量，而且可以减少残余应力，提高耐磨性； 3)Cr12MolⅤ真空淬火后，采用离子渗氮工艺处理，可使表面强化，又消除了淬火应力，耐磨性最好； 4)Cr12MolⅤ钢轧辊采用中频处理，不但淬硬层厚度增加，而且表面硬度的均匀性也提高，经过现场使用，可使其寿命达到80吨以上。 5)9Cr2Mo渗硼后，再采用氮气保护淬火工艺，渗硼层耐磨性与采用深冷处理的Cr12MolⅤ钢耐磨性相当，达到了轧制80吨钢筋的目标。更多还原

【Abstract】 The process of enhancing wear resistance and prolonging the service life of cold roller with rib was studied in this paper.For many factors, presently ,the service life of the cold roller is low, which serviously restricted the application of cold rolling reinforcing steel with rib and economic benefit of enterprise.In order to solve the problem,by analyzing the damaged roller , the cause was that the working layer had poor wear resistance. In order to enhance wear resistance of the roller, high_carbon and high_alloy steel-Cr12MolV steel was adopted. For the sake of cost, high_carbon and low_alloy steel -9Cr2Mo steel was also adopted, and it was treated by thermochemical treatment.In the experiment, common forging process of Cr12MolV steel was substituted with six_facets forging process. And high-frequency hardening, medium-frequency hardening, salt-bath hardening, vacuum-furance hardening, cryogenic treatment were adopted. By means of doing wear experiment , X-ray diffraction, metallographic examination, SEM scaning, effect of each treatment process on wear resistance and the service life of the cold roller with rib was studied.By means of the experiment, the conclusions were summaried as following:1) Cr12Mo1V steel was treated by adopting six-facets forging and ausforging, which made the coarse carbide broken and homogeneously distributed, and which made austenite grain refined. So the wear resistance was enhanced.2) Cr12Mo1V steel was treated by bulk hardening and cryogenic treatment, which didn’t only enhance hardness and decreased the amount of retained austenite, but also decreased residual stresses. So the wear resistance was enhanced.3) Cr12Mo1V steel was treated by vacuum hardening and nitriding , which made surface hardening and decreased quenching stresses. So the wear resistance was enhanced.4) Cr12MolV steel was treated by medium-frequency hardening, which didn’t only enhance the effective depth of hardening, but also enhanced homogeneity of surface hardness. The roller treated by this process could produce eighty tons of reinforcing steel.Our object was archieved.5) 9Cr2Mo steel was treated by boronizing and protective atmosphere hardening, and wear resistance of boride layer was equivalent to wear resistance of Cr12MolV steel treated by bulk hardening and cryogenic treatment. The roller treated by this process can produce eighty tons of reinforcing steel. Our object was archieved.更多还原