【作者】 白万真；

【导师】 魏世忠；

【作者基本信息】 河南科技大学 ， 材料加工工程， 2007， 硕士

【摘要】 本文以河南省耐磨材料工程技术研究中心开发的一种成分的高钒高速钢为基础，在淬火温度为900～1100℃，回火温度为250～600℃的条件下进行热处理，测定热处理后试样的机械性能；利用自制的模拟冷轧辊实际工况的WM-1型滚动磨损试验机，测定经不同热处理工艺处理后试样的滚动磨损性能；应用SEM，分析了热处理工艺对其显微组织的影响；应用X射线衍射仪测量了高钒高速钢的残余奥氏体含量；并采用SEM和TEM，探讨了高钒高速钢滚动磨损机制。经过研究分析、归纳，得到以下的结论：热处理对高钒高速钢中碳化物的形态、类型、分布影响较小；对基体组织，尤其是马氏体和残余奥氏体的相对含量影响较大。淬火加热温度升高，高钒高速钢的残余奥氏体量升高，马氏体量降低；回火温度升高，其残余奥氏体量减少。热处理后，高钒高速钢的硬度在(51～66.5)HRC之间波动。高温淬火(高于1050℃)，高温回火(高于500℃)，硬度得以提高。热处理后，高钒高速钢的冲击韧性值在(6～12)J／cm~2波动。低温淬火(低于950℃)，不论在什么温度回火，冲击韧性值均较低。1100℃高温淬火，250℃回火，冲击韧性最高；1050～1100℃淬火，450～550℃回火，冲击韧性得以较大地提高。淬火加热温度对滚动磨损性能有重要的影响。淬火加热温度升高，滚动耐磨性提高；但耐磨性数据波动范围加大。淬火温度为900～1000℃时，回火温度对耐磨性的影响不大；淬火温度为1050～1100℃时，回火温度对耐磨性的影响较大。1100℃淬火，450℃回火时，滚动耐磨性最好；550℃回火，耐磨性居第2位。1050℃淬火，550℃回火，耐磨性也较大的提高。以滚动耐磨性为评价指标，综合考虑热处理工艺对硬度、冲击韧性、滚动耐磨性及设备损耗、生产成本的影响，最适宜的热处理工艺为：淬火加热温度1050℃，回火温度450～550℃。本文采用X射线衍射仪测量残余奥氏体量，分析了残余奥氏体量对高钒高速钢硬度、冲击韧性和滚动磨损性能的影响：硬度与钢的残余奥氏体量呈开口向下的二次曲线关系，残余奥氏体量在45～55(Vol.％)时，硬度达峰值。残余奥氏体量过多过少时，都使高钒高速钢的硬度下降；冲击韧性与残余奥氏体量近似呈线性关系，残余奥氏体量增加，冲击韧性升高；耐磨性与残余奥氏体量之间呈开口向上的二次曲线，残余奥氏体量增加，耐磨性逐渐升高。但与此同时，耐磨性数据波动范围明显加大。综合考虑残余奥氏体量对其滚动耐磨性、耐磨性数据波动范围，以及硬度、冲击韧性等的影响，残余奥氏体量以45～55(Vol.％)为宜，有利于提高其滚动磨损性能，其相应的淬火温度为1050℃，回火温度为450～550℃。测量了残余奥氏体量在磨损前后的变化，发现滚动磨损后，高钒高速钢中的部分残余奥氏体转化为马氏体，使裂纹源附近材料强度提高，增加裂纹扩展阻力，提高接触疲劳寿命，为进一步揭示接触疲劳机制打下基础。更多还原

【Abstract】 One type of high vanadium high speed steel, which has been researched by Henan Engineering Research Center for Wear Resistant Material, was selected. On the condition of quenching temperature at 900℃to 1100℃and tempering temperature at 250℃to 600℃, mechanism properties were measured. By WM-1 rolling wear machine, which can simulate work condition of the cold roll, the rolling wear properties were measured after different heat treatment. The scanning electron microscope was used to analysis the effects of heat treatment on their microstructure. Also, retained austenite amounts of high vanadium of high speed steel were measured by X-ray diffraction instrument. By the scanning electron microscope and the transmission electron microscope, the rolling wear mechanisms of high vanadium high speed steel were discussed.By researched and analyzed, some conclusions can be drawn as follows:After heat treatment, the effects on morphology, types and distribution of carbide is very little; but for their matrix, the comparatively amounts of the martensite and the retained austenite have greater effects. When quenching temperature increases, the amounts of retained austenite increase and correspondingly martensite decrease. When tempering temperature increases, the retained austenite amounts decrease.Hardness of high vanadium high speed steel fluctuates between 51 HRC and 66.5 HRC after heat treatment. High quenching temperature (above 1050℃) and high tempering temperature (above 500℃), hardness is higher. Impact toughness of high vanadium high speed steel fluctuates between 6 J/cm~2 and 12 J/cm~2 after heat treatment. Lower quenching temperature (under 950℃), tempering at any temperature, the impact toughness is lower. Quenching at 1050℃to 1100℃and tempering at 250℃, their impact toughness is highest. Quenching at 1050℃to 1100℃and tempering at 450℃to 550℃, impact toughness is higher. The effects of quenching temperature on rolling wear properties are important. When quenching temperature increases, the rolling wear properties increase too, but fluctuation bound of wear resistance data increases. At the quenching temperature of 900～1000℃, the effects of tempering temperature on wear resistance are little; when quenching at 1050～1100℃, their effects are important. The best wear resistance is quenching at 1100℃and tempering at 450℃, the better one is quenching at 1100℃and tempering at 550℃, and quenching at 1050℃and tempering at 550℃, its wear resistance also raises. Considering the effects of heat treatment on hardness, impact toughness, wear resistance, equipment loss and production costs, the proper heat treatment is quenching at 1050℃and tempering from 450℃to 550℃.In this paper, X-ray diffraction instrument was used to measure retained austenite, the effects of retained austenite amounts on hardness, impact toughness and rolling wear properties were analyzed. Retained austenite amounts and hardness are in curvilinear regression of second degree of shedding down. Retained austenite amounts at 40 to 60 volume fraction, hardness reaches peak value. More or less amounts of retained austenite all reduced the hardness of high vanadium high speed steel Retained austenite amounts and impact toughness are in approximately linear regression. Along with retained austenite amounts increase, their wear resistance gradually increases. The amounts of retained austenite and rolling wear resistance are in curvilinear regression of second degree of shedding up. Followed the retained austenite amounts increasing, wear resistance increases. Simultaneously, the fluctuation range of rolling wear resistance obviously increases. Considering the effects of retained austenite on its rolling wear resistance, the range of rolling wear resistance, hardness and impact toughness, proper volume fraction of retained austenite at 45 to 55 is propitious to their rolling wear properties, and its corresponding quenching temperature at 1050℃and tempering temperature at 450℃to 550℃.Retained austenite amounts of before tested and after tested samples were measured. It has been discovered that after rolling wear certain austenite of high vanadium high speed steel has been translated into martensite, which makes the material intensity improved near the crack source, increases cracks extension resistance, prolongs contact fatigue life. These can make foundation for further demonstration of contact fatigue mechanisms.更多还原