金属型镶铸采煤机截齿的组织与性能研究.pdf

专专 业业 学学 位位 硕硕 士士 学学 位位 论论 文文 金属型金属型镶铸采煤机截齿镶铸采煤机截齿的的组织与性能研究组织与性能研究 Research on Structure and Properties of Metal Mold Cast-in Shearer Cutting Pick 作 者 姓 名 张敬业 工 程 领 域 材料工程 学 号 31705017 指 导 教 师 王轶农 教授 完 成 日 期 2019.5.10 大连理工大学 Dalian University of Technology 万方数据 大连理工大学学位论文独创性声明 作者郑重声明 所呈交的学位论文， 是本人在导师的指导下进行研究工 作所取得的成果。 尽我所知， 除文中已经注明引用内容和致谢的地方外， 本 论文不包含其他个人或集体已经发表的研究成果，也不包含其他已申请学 位或其他用途使用过的成果。与我一同工作的同志对本研究所做的贡献均 已在论文中做了明确的说明并表示了谢意。 若有不实之处，本人愿意承担相关法律责任。 学位论文题目 作 者 签 名 日期 年 月 日 万方数据 大连理工大学专业学位硕士学位论文 - I - 摘 要 采煤机截齿作为采煤机的刀具，是采煤过程中消耗最大的零件之一，截齿的提前失 效不但降低了生产效率， 还造成了材料的浪费。 本文选用金属型镶铸法制备采煤机截齿， 齿头选用耐磨性能优异的高铬白口铸铁，齿体选用兼具韧性和硬度的低合金钢。将齿体 金属液浇入预先放置齿头的镶铸模具中，机械加工后进行分段热处理，制成金属型镶铸 截齿。镶铸法使得齿头与齿体间能够产生冶金结合，再结合齿头圆台形结构的设计，使 得齿头能够牢牢固定在齿体中。 本文对金属型镶铸截齿的材料成分、模具、热处理工艺进行了设计，保证制造工艺 简单、两种材料的镶铸效果好、热处理后截齿的组织与性能均满足设计要求。对不同热 处理态的金属型镶铸截齿的微观组织、物相组成、物理性能和力学性能进行了测试与分 析，对金属型镶铸截齿进行了采煤现场测试。得到以下结果 金属型齿头的共晶碳化物尺寸远小于砂型齿头。齿头材料在淬火后，组织由奥氏体 马氏体共晶碳化物转变为马氏体共晶碳化物二次碳化物， 经过淬火后， 齿头材料的 硬度为 6568HRC。从 930℃升高到 950℃，随着淬火温度的升高，材料的硬度增加，但 增幅不大。相较于不含钨元素的齿头材料，含钨齿头由于钨元素溶入基体和形成碳化物 的原因，经过 930℃淬火后，含钨齿头中的奥氏体全部转变为马氏体，含钨齿头的硬度 更高、耐磨性更好。但是通过分析可知，钨和钼的碳化物会偏聚在基体的晶界处，导致 材料部分偏析，并且难以消除。 金属型齿体铸态组织为铁素体珠光体魏氏组织，淬火组织为马氏体，正火组织为 铁素体珠光体。由于铸钢在铸造时冷速过快，导致铸态组织存在大量魏氏组织，降低 材料性能，通过淬火和正火处理后，能够消除魏氏组织，经过回火后，淬火组织转变为 回火马氏体，正火组织没有变化，是为了消除截齿的内应力，保证材料性能。齿体材料 淬火态的硬度为 55HRC，淬火回火的硬度下降较小，正火态的硬度为 45.6HRC，回火 后硬度基本没有变化，齿体材料的铸态冲击韧性为 143，正火态冲击韧性为 172，齿体 的硬度、冲击韧性均高于MT/T 246-2006 采掘机械用截齿的要求，能够保证截齿耐 磨的同时不发生弯曲或断裂。 金属型镶铸采煤机截齿结合区的分析表明结合区处发生了冶金结合，使得结合处 有宽度约为 17.5μm 的融合区，镶铸区域平均剪切强度为 188.83MPa。通过热膨胀系数 和应力分析表明齿头材料内应力较小，齿体材料受到压应力。通过对齿头与齿体距端 部不同距离的组织分析，齿头材料和齿体材料均呈现出缓慢变化的组织形貌，齿头越靠 万方数据 金属型镶铸采煤机截齿的组织与性能研究 - II - 近端部，其基体、碳化物越细小，组织越均匀；靠近端部齿体出现马氏体组织，距端部 越远，马氏体组织越少，直到马氏体组织全部消失，组织位铁素体珠光体。 经过黑龙江省双鸭山市和鹤岗市的采煤现场测试表明 金属型镶铸采煤机截齿的齿 头不发生脱落，齿头随齿体一同磨损，截齿使用寿命直到齿头全部磨损为止，并且齿体 没有发生断裂，仅有少数截齿发生了弯曲。金属型镶铸截齿在高硬度的煤矿中，使用寿 命与奥德截齿接近，但制造成本大大降低，在普通硬度的煤矿在，使用寿命优于传统钎 焊截齿。 关键词采煤机截齿；金属型；镶铸；高铬铸铁；低合金钢 万方数据 大连理工大学专业学位硕士学位论文 - III - Research on Structure and Properties of Metal Mold Cast-in Shearer Cutting Pick Abstract Shearer cutting pick, as the cutter of shearer, is one of the most consumed parts in the process of coal mining. The premature failure of cutting pick not only reduces the production efficiency, but also increases the waste of materials. In this paper, the cutting picks were prepared by metal mold cast-in process. Cutting pick head selected high chromium white cast iron with excellent abrasion resistance. Cutting pick body selected low alloy steel with both toughness and hardness. The cutting pick head metal liquid Poured into the cast-in mold in which the head is placed in advance. Subsection heat treatment is carried out after machining. Finally, we got the metal mold cast-in cutting pick. Between the head and the body can produce the metallurgical bonding, and combined with the design of the cutting pick head conical structure. These make the cutting pick head firmly fixed in the body. In this paper, the material composition, mold and heat treatment technology of metal mold cast-in cutting picks were designed. To ensure that the manufacturing process is simple, the cast-in process effect of the two materials is prefect and the microstructure and properties of the metal mold cast-in cutting pick after heat treatment meet the design requirements. The microstructure, phase composition, physical properties and mechanical properties of metal mold cast-in cutting pick with different heat treatment states were tested and analyzed. The field test of metal cast-in cutting picks were carried out. Get the following results The eutectic carbide structure of the metal mold cutting pick head is much smaller than that of the sand mold cutting pick head. After quenching, the structure of the head material changes from austenite martensite eutectic carbide to martensite eutectic carbide secondary carbide, the Rockwell hardness of the cutting pick head material is 6568HRC. From 930 ℃ to 950 ℃, with the increase of quenching temperature, the hardness of material increased, but not much. Compared with the cutting pick head materials without tungsten, the head with tungsten because of tungsten into matrix and the carbide ed, after 930 ℃ quenching, the austenite in the head with tungsten is all transed into martensite. The hardness and wear resistance of the cutting pick head with tungsten are better. However, it can be seen from the analysis that the carbide of tungsten and molybdenum will polarize at the grain boundary of the matrix, that causes partial segregation of the material and difficult to eliminate. The as-cast microstructure of the metal mold cutting pick body is composed of ferrite pearlite widmannstatten structure. The quenching microstructure is martensite. And the 万方数据 金属型镶铸采煤机截齿的组织与性能研究 - IV - normalizing microstructure is ferrite pearlite. Due to cast steel cools too fast in casting, there are a large number of widmannstatten microstructures in the as-cast microstructure. widmannstatten reduce the material perance. After quenching and normalizing treatment can eliminate the widmanstatten structure. After tempering, the quenching structure changes into tempered martensite. And normalizing group did not change. These treatments mainly eliminate the internal stress of cutting pick and guarantee the material perance. The hardness of the cutting pick body material in quenching state is 55HRC. The hardness of quenching and tempering decreases little. The normal hardness is 45.6HRC. There is no change in hardness after tempering. The impact toughness of the cutting pick body material is 143 J/cm2. The impact toughness of normal state is 172 J/cm2. The hardness and impact toughness of the cutting pick body are all higher than the national standard requirements of shearer cutting pick. It can ensure that the cutting pick wear without bending or fracture. The analysis of the joint zone of the metal mold cast-in cutting pick showed that Metallurgical bonding occurred at the bimetallic bond zone. The junction has a fusion zone with a width of about 17.5 μm. The average shear strength was 188.83MPa. Analysis by thermal expansion coefficient and stress showed that The internal stress of the cutting pick head material was small. Cutting pick body material subjected to compressive stress. Through the analysis of the microstructure at different distances from the end of the head and the body, it can be seen that both the head and the body exhibit a slowly changing microstructure. The closer to the end of the head, matrix and carbide are finer and the more uni the structure; martensite appears near the end of the body, the farther from the end, the martensite have reduced. Until the martensite disappears completely, the structure is ferrite pearlite. Through the coal mining field test in Shuangyashan city and Hegang city, Heilongjiang province, it was shown that the head of the metal mold cast-in cutting pick does not fall off. The head wore away with the body. The service life of the cutting pick was up to the end of the head. And the body does not break. Only a few picks have been bent. In the coal mines with high hardness, the service life of the metal mold cast-in cutting pick is close to that of the Aude cutting pick. But the manufacturing cost is greatly reduced. In the coal mines with ordinary hardness. The service life is better than that of the traditional brazing cutting pick. Key WordsShearer Cutting Pick; Metal Mold; Cast-in Process; High Chromium Cast Iron; Low Alloy Steel 万方数据 大连理工大学专业学位硕士学位论文 - V - 目 录 摘 要 ............................................................................................................................. I Abstract ............................................................................................................................ III 1 绪论 .............................................................................................................................. 1 1.1 采煤机截齿的研究现状及发展 ....................................................................... 1 1.2 镶铸技术的研究现状 ....................................................................................... 2 1.3 铬系白口铸铁概述 ........................................................................................... 3 1.3.1 铬系白口铸铁的分类 ............................................................................ 3 1.3.2 高铬白口铸铁中合金元素的作用 ........................................................ 4 1.3.3 高铬白口铸铁的凝固组织 .................................................................... 6 1.3.4 高铬白口铸铁的热处理工艺 ................................................................ 7 1.1.4 低合金钢概述 ................................................................................................ 8 1.4.1 低合金钢的分类 .................................................................................... 8 1.4.2 低合金钢的热处理工艺 ........................................................................ 8 1.5 本文研究背景、目的及主要内容 ................................................................... 9 1.5.1 研究背景和目的 .................................................................................... 9 1.5.2 研究主要内容 ...................................................................................... 10 1.5.3 技术路线 .............................................................................................. 10 2 实验材料及方法 ........................................................................................................ 11 2.1 实验材料 ......................................................................................................... 11 2.1.1 截齿齿头材料 ...................................................................................... 11 2.1.2 截齿齿体材料 ...................................................................................... 11 2.2 金属型镶铸模具设计 ..................................................................................... 12 2.2.1 齿头金属型模具的设计 ...................................................................... 12 2.2.2 金属型镶铸模具的设计 ...................................................................... 14 2.3 金属型镶铸采煤机截齿的设备及铸造工艺 ................................................. 16 2.3.1 截齿齿头的设备及铸造工艺 .............................................................. 16 2.3.2 金属型镶铸采煤机截齿的设备及铸造工艺 ...................................... 16 2.3.3 热处理工艺 .......................................................................................... 16 2.4 成分分析及组织观察 ..................................................................................... 18 2.4.1 成分分析 .............................................................................................. 18 2.4.2 显微组织观察 ...................................................................................... 18 万方数据 金属型镶铸采煤机截齿的组织与性能研究 - VI - 2.4.3 SEM 及 EDS 分析 ............................................................................... 19 2.4.4 电子探针分析 ...................................................................................... 19 2.4.5 X 射线衍射分析 .................................................................................. 19 2.4.6 热膨胀系数分析 .................................................................................. 19 2.5 力学性能测试及采煤现场测试 ..................................................................... 19 2.5.1 硬度测试 .............................................................................................. 19 2.5.2 冲击韧性测试 ...................................................................................... 20 2.5.3 剪切强度测试 ...................................................................................... 20 2.5.4 采煤现场测试 ...................................................................................... 21 3 金属型铸造截齿齿头成分、组织及力学性能 ........................................................ 22 3.1 齿头耐磨合金成分分析 ................................................................................. 22 3.2 显微组织分析 ................................................................................................. 22 3.2.1 砂型齿头与金属型齿头显微组织分析 .............................................. 22 3.2.2 不含钨金属型齿头显微组织分析 ...................................................... 23 3.2.3 含钨金属型齿头显微组织分析 .......................................................... 24 3.3 物相分析 ......................................................................................................... 27 3.3.1 不含钨高铬耐磨合金齿头物相分析 .................................................. 27 3.3.2 含钨高铬耐磨合金齿头物相分析 ...................................................... 28 3.4 SEM 及 EDS 分析 .......................................................................................... 29 3.4.1 不含钨金属型齿头 SEM 及 EDS 分析 .............................................. 29 3.4.2 含钨金属型齿头 SEM 及 EDS 分析 .................................................. 30 3.5 电子探针分析 ................................................................................................. 32 3.6 洛氏硬度分析 ................................................................................................. 33 3.6 本章小结 ......................................................................................................... 33 4 金属型铸造截齿齿体成分、组织及力学性能 ........................................................ 35 4.1 齿体低合金钢成分分析 ................................................................................. 35 4.2 显微组织分析 ................................................................................................. 35 4.2.1 砂型齿体与金属型齿体显微组织分析 .............................................. 35 4.2.2 金属型齿体显微组织分析 .................................................................. 36 4.3 物相分析 ......................................................................................................... 37 4.4 力学性能分析 ................................................................................................. 38 万方数据 大连理工大学专业学位硕士学位论文 - VII - 4.4.1 洛氏硬度分析 ...................................................................................... 38 4.4.2 冲击韧性分析 ...................................................................................... 39 4.5 本章小结 ......................................................................................................... 39 5 金属型镶铸截齿结合部位的成分、组织及力学性能分析 .................................... 40 5.1 显微组织分析 ................................................................................................. 40 5.1.1 不含钨齿头截齿的结合部位显微组织分析 ...................................... 40 5.1.2 含钨齿头截齿的结合部位显微组织分析 .......................................... 41 5.1.3 镶铸截齿淬火回火处理后齿头显微组织分析 ................................ 42 5.1.4 镶铸截齿淬火回火处理后齿体显微组织分析 ................................ 43 5.2 SEM 分析 ........................................................................................................ 44 5.3 电子探针分析 .................................