H13热作模具钢的焊接修复工艺研究
发布时间:2018-01-25 16:19
本文关键词: 模具 焊接 修补 显微硬度 出处:《长春工业大学》2017年硕士论文 论文类型:学位论文
【摘要】:在制造业中,生产成本较高,消耗能源较大的典型代表就是模具钢的生产。模具钢的种类繁多,其中其工作环境恶劣,处在冷热交替环境下工作,使其产生较大应力及变形最终导致生成裂纹以及失效的就是热作模具钢。模具本身生产周期长,生产成本高,如果在其服役过程中出现问题就轻易报废的话,会造成企业生产成本大幅度提高,也是能源过渡消耗的一种体现。由于以上原因,针对模具钢服役过程中出现一些龟裂等现象,已经成为大多数学者研究的课题,主要研究其补救的方法以及提高补救后的使用性能。现在大多数由于产生裂纹的原因导致失效的热作模具钢,普遍采用焊接技术进行局部修复,这不但为企业节约了生产成本,也可以最大程度控制能源上的浪费。可是焊接修补不能单单起到修复裂纹这一层面,还应重视修复后热作模具钢的使用性能,在焊接修复过程中应充分考虑到热作模具钢的焊接性,针对性设计工艺,使修复后的热作模具钢能够满足其服役需求。H13热作模具钢作为最具有代表性的热作模具钢,在机械加工制造业中使用十分广泛。由于其服役环境一直处于冷热交替的状态下,会使其内部产生比较复杂的应力及裂纹,有时严重会致使整个模具失效。因热作模具钢其本身价格昂贵,模具制造生产过程复杂,如果只因为某一处产生裂纹而放弃使用,会使企业生产成本大幅度提高。所以解决磨损或裂纹造成失效后的修复问题,以及延长模具的服役期限有着重要的意义。本文以H13(4Cr5Mo Si V1)钢为研究对象,针对热作模具钢中Cr、Mo、V等主要化学元素对H13钢焊接性能的影响,以及焊接材料和焊接工艺对焊缝组织及性能的影响,采用钨极氩弧焊方法对H13热作模具钢进行焊接修复。根据实际生产中的修补方法和使用要求,确定了H13钢的焊接工艺以及焊后热处理工艺,表征了焊缝微观组织及力学性能。使用三种不同的焊丝分别在有预热以及无预热温度下进行焊接。应用洛氏硬度计及显微硬度计对焊接后的试样进行力学性能综合检测;应用金相显微镜对焊接后的试样进行焊缝形貌观察。分析了预热温度对焊缝组织和力学性能的影响。研究结果表明:与H13钢焊丝相比,采用自制药芯焊丝焊接试样的晶粒更细小,显微硬度分布更均匀,减少了焊缝及热影响区的应力集中,增加了修补后模具的使用寿命。预热对照组实验表明:H13钢焊丝预热焊接试样的晶粒略细小,自制药芯焊丝预热焊接试样的晶粒也略有减小,说明焊前预热也可以在一定程度上起到细化晶粒的作用。
[Abstract]:In the manufacturing industry, the typical representative of high production cost and large energy consumption is the production of die steel. There are many kinds of die steel, among which the working environment is bad, and it works under the alternate environment of cold and heat. The hot work die steel is the main cause of crack and failure. The mould itself has a long production cycle and high production cost, if there is a problem in the service process, it will be easily scrapped. Will cause the enterprise production costs to be greatly increased, is also a manifestation of energy consumption. As a result of the above reasons, there are some cracks in the service process of die steel. It has become a research topic of most scholars, mainly studying the methods of remediation and improving the performance of the remediation. Nowadays, most hot work die steels which have failed due to cracks have been produced. Welding technology is widely used for partial repair, which not only saves the production cost for enterprises, but also can control the waste of energy to the maximum extent. However, welding repair can not only repair the crack level. Attention should also be paid to the performance of hot-working die steel after repair. The weldability of hot-working die steel should be fully considered and the targeted design process should be taken into account in the process of welding and repairing. The repaired hot work die steel can meet its service requirement. H13 hot work die steel as the most representative hot work die steel. It is widely used in the mechanical manufacturing industry. Because of its service environment has been in the state of alternating between cold and heat, it will produce more complex stress and crack inside. Sometimes the whole die will fail seriously. Because of the high price of hot work die steel, the manufacturing process of die is complicated, if it is abandoned because of the crack in one place. The cost of production will be greatly increased. Therefore, the repair problem after failure caused by wear or crack can be solved. It is of great significance to extend the service life of die. In this paper, H134Cr5Mo Si V 1) steel is taken as the research object, aiming at Cr-Mo in hot working die steel. The influence of V and other main chemical elements on the welding properties of H13 steel, and the influence of welding materials and welding process on the microstructure and properties of the weld. The welding repair of H13 hot working die steel was carried out by TIG welding. According to the repair method and application requirement in actual production, the welding process and post-welding heat treatment process of H13 steel were determined. The microstructure and mechanical properties of weld seam were characterized. Three kinds of welding wires were used to weld with or without preheating temperature respectively. The mechanical properties of welded samples were synthesized by Rockwell hardness meter and microhardness meter. Combined detection; The effect of preheating temperature on the microstructure and mechanical properties of the weld was analyzed by metallographic microscope. The results showed that the microstructure of the weld was compared with that of the H13 steel wire. Using self-made flux-cored wire welding sample, the grain size is smaller and the microhardness distribution is more uniform, which reduces the stress concentration of weld and heat-affected zone. The experimental results of preheating control group show that the grain of preheated welding sample of WH13 steel wire is slightly smaller, and that of self-made flux-cored wire preheated welding sample is also slightly reduced. It shows that preheating before welding can also play the role of grain refinement to some extent.
【学位授予单位】:长春工业大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:TG457.11
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