【作者】 韩菲；

【导师】 高彩茹；

【作者基本信息】 东北大学 ， 材料加工工程， 2009， 硕士

【摘要】 塑料模具钢的生产几乎都是特钢厂以铸锭-开坯-轧制-预硬化热处理的模块方式生产,其生产环节多,生产周期长,成本高,采用预硬化处理时,浪费能源。本研究工作旨在利用连铸坯,在宽厚板轧机上利用控制轧制控制冷却的方法生产出符合性能要求的替代P20钢的非调质塑料模具钢厚板,提高生产效率,扩大生产规模。本文研究了控轧工艺、冷却速度对实验钢组织和性能的影响规律,实验钢的高温力学行为,耐磨损性能和抛光性能,最终制定出使实验钢满足力学兼使用性能的合理控轧控冷工艺。论文的研究工作及主要结论如下：1.制定非调质塑料模具钢合理的化学成分(质量分数,%)为：C:0.09～0.12, Si:0.32～0.40, Mn: 1.2～1.6, Cr:1.0～1.4, B:0.001～0.005, Mo:0.22～0.27, V:0.04%～0.20%, Ti:0.01%～0.04%.2.通过控轧控冷实验,研究了控轧方式、冷却速度等工艺参数对实验钢组织和性能的影响规律。确定了实验钢控轧控冷最佳工艺参数如下：加热温度为1200℃,保温2小时,两阶段控轧,第一阶段开轧温度为1050℃,第二阶段控轧开轧温度为920℃,终轧温度为860℃,轧后空冷。3.采用单道次压缩热模拟实验,研究了非调质塑料模具实验钢的高温变形行为。得出了800～1050℃温度下的应力-应变曲线；在试验数据基础上回归了金属塑性变形抗力的数学模型：4.摩擦磨损试验结果表明非调质塑料模具实验钢的耐磨损性能优于预硬化塑料模具钢P20。5.对实验钢的镜面抛光性能进行测试结果为空冷工艺条件下的实验钢在既定抛光条件下,达到了镜面抛光性第四级的标准A4=Ra 0.063μm,与P20钢的抛光性相同。更多还原

【Abstract】 The production of steel for plastic mould is almost the same pattern of ingot - breakdown- rolling - pre-hardening and heat treatment. The disadvantages of this pattern are production link multiple, production cycle long, cost high, and it is a waste of energy when pre-hardening. This paper aims at the using of continuous casting billet to product steel plate which was rolled at heavy plate mill meet the properties of pre-hardened plastic mould steel P20 with the process of controlled rolling and controlled cooling. It has a greater significance to achieve a greater efficiency and production scale.In this paper, the impaction of cooling rates and rolling method on microstructure and properties of tested steel was studied; comparison of polishing performance and abrasion resistance between tested steel and pre-hardened plastic mould steel P20 was made; high-temperature mechanical behavior research of tested steel was done by the use of thermal simulation test machine. Finally, an optimal controlled rolling and controlled cooling process is developed with the consideration of laboratory hot rolling situation.The major achievements of the paper include:1) Chemical composition of the non-quenched-tempered steel for plastic mould is successfully designed (mass %):C:0.09～0.12, Si: 0.32～0.40, Mn: 1.2～1.6, Cr: 1.0～1.4, B: 0.001～0.005, Mo:0.22～0.27, V:0.04%～0.20%, Ti:0.01%～0.04%.2) Through the controlled rolling and controlled cooling experiment, the influence of finished temperature and cooling process on microstructure and mechanical properties of tested non-quenched and tempered steel for plastic mold is studied. The determined optimal controlled rolling and controlled cooling process parameters for the tested steel is shown in as follow: reheating temperature of 1200℃and soaking time of 2 hours. Two-stage rolling process is adopted, rough rolling at 1050℃, finishing rolling at 920℃-860℃and air-cooling after rolling.3) Through the single pass compressing deformation experiment done on the MMS-300 thermal simulation testing machine, the High-temperature mechanical behavior of the tested steel was studied. With the consideration of stress-strain curve got between 800℃and 1050℃, the mathematical model of deformation resistant for tested steel is determined. And then the coefficient of equation was got through the regressing of experiment data. Mathematical model of the deformation resistance for tested steel is as follow:4) Friction and wear test results show that the wear resistance of non-quenched and tempered steel for plastic mold is better than the pre-hardened plastic mold steel P20.5) Mirror polishing performance test result show that the test steel in air-cooling process achieve the fourth level of the standard A4= Ra 0.063μm, and pre-hardened plastic mold steel P20 have a equivalent property with test steel.更多还原