【作者】 王艳；

【导师】 李宁；

【作者基本信息】 四川大学 ， 机械制造及其自动化， 2000， 硕士

【摘要】 新型低合金抗磨铸钢具有硬度高、耐磨性好的优点，已广泛用于建筑机械等领域中。但因其切削加工性极差，对于那些需经切削加工方能保证尺寸精度和互换性的易损件，制造非常困难。为扩大该抗磨材料的应用范围，解决切削加工的困难，本文根据异种钢焊接原理，用焊接复合的方法克服了抗磨铸钢件在制造的上述难题。文中对该抗磨铸钢与20钢异种金属的焊接方法、焊接材料、焊接工艺及其参数等进行了全面的试验研究，做了一些创新性工作，获得了一些具有科学指导意义及工程应用价值的研究成果：指出了合理设计焊接接头可避免或减少异种钢焊接接头缺陷，在生产及设计中，应尽量避免采用短小、不规则的焊缝；抗磨铸钢与20钢焊接时，选用碱性低氢型焊条，直流反接，焊后缓冷，是防止裂纹产生的有效措施。同时还阐述了后热处理对减小或消除延迟裂纹有利，异种钢焊后缓冷至200～250℃时，再保温2～4小时，对控制延迟裂纹，改善接头组织，提高接头力学性能是十分重要的。文中还就异种钢焊接缺陷的产生及形成机理、控制措施；组织的形成过程及对力学性能的影响等作了详细的分析论证。本文所得焊接接头的拉伸强度与抗磨铸钢相等或接近（σ_b≈400 MPa），冲击韧性优于抗磨铸钢(α_k≈25 J.cm^～2)。应用所得试验结果制造了40余块磨耗板，经10余家用户装机运行两年多证明，该磨耗板工作可靠，效果良好，有较高应用价值和显著的经济效益，其综合经济效益较进口混泥土输送泵磨耗板高5～7倍，已部分代替此类进口件。更多还原

【Abstract】 The new-style mild alloy wearing resistant cast steel combines the advantages of high hardness and good wearing resistant capability and has wide application in fields of architecture and mechanism etc. But ,at the same time , it’s mechanical properties are worse , and it’s very difficult to manufacture and assure dimension precision for the damageable workpiece when machining. For the sake of broadening the applied range of such wearing resistant material, this paper is about the work on solving the above-mentioned mechanical difficult problem with the method of weld-compound according to the principium of heterogeneous-steels-welding. In this paper, we roundly tested and researched the welding methods, electrodes, programme and parameters employed on wearing resistant cast steel and 20 steel, and, we made some innovations and acquired many instructional returns which have their applied cost: rationally designed weld tie-in can avoid or abate the flaws of heterogeneous-steels-weiding; avoiding small and irregular weld gaps in design and manufacture to the best of our abilities; selecting alkaline and low-hydrogen welding-rods and direct-current reverse-connection and slowly cooling after welding. These measures can effectively prevent the weld flaws. Simultaneously, we expatiated that the later-heat-treatment(slowly cooling down to 200-250C after welding and then keep temperature for 2~4 hours) is in the favor of abating and eliminating the weld flaws, and this is very important to improve the weld microstructure and the mechanical properties of weld tie-in. In addition, we detailedly analyzed and demonstrated the generation and growing mechanism of the heterogeneous-steels-welding flaws and the restraining measures; we discussed the way to modify weld microstructure and then- influence on the mechanicalproperties. The weld tie-in acquired in this research is equal or close to the wearing resistant cast steel in tensile strength( o b=400 MPa) and precede in impact ductility(ak=25J.cm-2). We have manufactured forty or more abrasion-plates and these plates have been applied in ten or more factories for two years. As a result, such abrasion-plates can work well and economically and remarkably course economic benefit which is 5~7 times of the imported concrete conveying pump abrasion-plate, and even part of them can substitute the imported ones.更多还原