【作者】 敖晓春；

【导师】 孙凤莲；

【作者基本信息】 哈尔滨理工大学 ， 材料加工工程， 2005， 硕士

【摘要】 本论文选题是针对大型化工设备高压热壁加氢反应器的主体件—筒节材料(3Cr-1Mo-1/4V钢)难于切削加工的问题,是黑龙江省重大科技攻关项目的一个子课题,由于该材料具有超高韧性、热强性好等特点,在切削加工中断屑困难,刀具粘结破损严重,刀具损耗大,加工效率低。 为攻克刀具粘结破损难题,在实验室试验与现场试验相结合的基础上,对切削该材料刀具的粘结破损机理及刀具材料的选择进行了研究。 对不同牌号的硬质合金刀具进行断续切削难加工材料3Cr-1Mo-1/4V钢的对比试验,通过对所选的刀具产生的粘结破损形貌和破损区域大小进行比较分析,优选出适合加工3Cr-1Mo-1/4V钢的刀具材料。在初选出的12种硬质合金刀片基础上,进行了刀片材质的多次优选,最终确定YG546和M2为加工该材料的最佳材质。 借助普通金相显微镜及扫描电镜,对硬质合金刀具进行铣削试验后的破损表面进行低倍、高倍破损形貌观察及组织分析,研究刀具在断续切削过程中粘结破损的机理。指出硬质合金刀具在切削3Cr-1Mo-1/4V钢时,由于切削力大,切削温度高,加之其所含元素Fe、Cr、Mo与硬质合金粘结相Co之间的亲和力较大,因此刀-屑间发生严重粘结,造成粘结破损。这种粘结实质是切削过程中刀具与工件元素之间的相互扩散及形成再结晶所致。另外元素间的扩散和亚表层的损伤对粘结破损也有一定的影响。 为防止硬质合金刀具在切削过程中刀具的粘结破损,可通过选用合适的切削用量,避开产生粘结的切削温度;选用涂层刀具、带槽型的刀具以及组织致密、晶粒细小均匀的超细晶粒材料作为刀具。提高刀具性能,减少刀具的粘结破损,增长刀具寿命,提高生产效率。更多还原

【Abstract】 This paper studies the difficult-to-machine problem of the cutting tools which cuts the main part of the large chemical engineering equipment high-pressure hot wall hydro-processing reactor—cylinder materials (3Cr-1Mo-1/4V steel). It is a subtask of the research, which is financial supported by Key Research Fund of Heilongjiang Province of China. Because this material has super toughness, high heat intensity and the heat resistance, during the spot machining, the chip breaking is difficult, cutting tools adhere fracture down badly and the machining efficiency is low.In order to deal with the adhering and fracture of cutting tools, based on combining lab and spot experiment, we study on the selection of the cutting tools material and the adhering and fracture mechanism of the cutting tools which were used to cut 3Cr-1Mo-4V steel.A group of contrast cutting experiment for different types of hard alloy cutting tools of which discontinuous cutting the 3Cr-1Mo-1/4V steel was done. By comparing the adhering fracture outline and the size of fracture range, tools materials adapted to cut such workpiece materials was optimized. Based on the first selected 12 kinds of hard alloy cutting tools, many optimization experiments of the insert materials were done. At last the YG546 and M2 were deemed to the best materials to cut such workpiece materials.Using SEM, we have observed the low and high multiple adhering fracture outline on the surface of the hard alloy cutting tools and analyzed its microstructure and composition after the cutting experiment. The adhere fracture mechanism of cutting tools in the process of discontinuous cutting was studied. We found that bigcutting force, high cutting temperature and the interaction between the Fe, Cr, Mo of the workpiece materials elements and hard alloy adhering element Co are the most key factor when the hard alloy cutting tools cuts 3Cr-lMo-l/4V steel, so the serious adhering phenomena occur. In fact the cause of adhere mechanism is the diffusion between the elements of the cutter and workpiece as well as the re-crystallization.Otherwise, the diffusion of atoms and subsurface fracture can influence the adhering fracture in a certain condition.In order to prevent the adhering fracture of hard alloy tools in the cutting process, we can improve the cutting behavior and avoid the adhering temperature, select the cutters with coat and grooves, and select cutters with super-fine grains materials. So to improve the capability of the cutter, reduce the adhering fracture, prolong the cutter life, and improve the produce efficiency.更多还原