【作者】 张夏平；

【导师】 高原；

【作者基本信息】 太原理工大学 ， 材料加工工程， 2003， 硕士

【摘要】 机用锯条有高速钢和双金属锯条两种，但存在消耗合金元素，碳化物分布不均匀，冶金困难和工艺复杂等问题。利用双层辉光渗金属技术形成的表面冶金高速钢可以解决上述问题。双辉离子渗金属技术可以在钢件表面形成不同含量的合金层，达到高速钢的成分。通过淬火回火热处理，使表面达到良好的综合机械性能。本研究用20Cr₂V₂机用锯条坯材作为试样进行渗金属后渗碳的热处理，再进行工艺和性能的研究，为表面高速钢机用锯条的工业化推广进行有益的探索。 研究选用6片同种工艺下的渗金属试样进行随后的渗碳和淬回火热处理。用三种碳势、两种淬火方式、三种淬火温度、五种回火温度得出不同含碳量、不同淬火工艺、不同淬火温度的回火曲线。比较不同组合工艺下的回火性能，包括不同含碳量同一淬火温度的回火硬度，相同含碳量不同淬火温度的回火硬度。用金相和XRD进行组织结构的分析；对纯铁、硬度粗糙度不同的机用锯条、高速钢试样进行1250N 2小时的磨损性能研究；对550℃回火后试样进行不同接触压力下耐磨性能研究。太原理工大学硕士论文 研究结果表明:利用双层辉光离子渗金属可在ZoCrZVZ机用锯条表面形成厚度30 pm一150 pm的W一Mo共渗层，表面合金含量约20%的扩散层，是一种结构性梯度材料。渗碳后的表层随碳势的不同而有不同的含碳量，高于定比碳一定浓度的碳势不会在表面形成网状碳化物。在不同碳势同一淬火温度的回火后硬度的影响中，硬度随碳势的增加而增加，分级淬火后的硬度由于淬火方式的影响使得在三种碳势下回火硬度较低。在不同淬火温度同一碳势的回火硬度的曲线中，0.70/0碳势下油淬的硬度随淬火温度升高而增加，有明显的二次硬化现象。随着碳势的增加，温度对淬火后硬度的影响更加明显，1200℃油淬后1.35t/0碳势的硬度达到最高，而且比1100℃、1150℃的硬度值高很多。 磨损试验显示硬度和表面粗糙度对磨损的影响是主要的，本实验中，硬度高，表面光滑，则磨损量小。磨损量由表面粗糙度和硬度综合决定。表面冶金高速钢与高速钢W6Mo5Cr4VZ相比，其硬度值越接近，磨损量越相似。硬度相同，表面粗糙度大的表面高速钢摩擦系数稍大。摩擦系数大的原因是由于润滑条件下的微切削造成的。硬度值越高，表面越粗糙，微切削越难，摩擦系数越大。磨痕表面形貌在高硬度时为分散的犁沟状，低硬度时由于微切削容易进行，犁沟连接在一起形成边缘连续 太原理工大学硕士论文的磨面。 结构决定性能，物质宏观的性能归根到底是由其微观结构决定的。合金价电子理论是材料研究的新方法，用其进行组织和结构的分析可以较好地解释微观结构的变化。更多还原

【Abstract】 Power hacksaw blade is made of high-speed steel and bi-metalic metals. However, the high-speed steel consumes a great deal of alloying elements and the bi-metalic saw has difficulties in alloying and complexities in the processes. The above problem can be solved by surface alloying high-speed steel which is made from Double Glow Plasma Surface Alloying Technique. By using DGPSAT, the alloy layer with special physical, chemical and mechanical performance can be obtained on the surface of metallic materials. Moreover,the content of alloying metals in the surface can approach that of high-speed steel. After quenching and tempering, a good comprehensive mechanical properties can be achieved. In these experiments, power hacksaw blade 20Cr2V2 actes as the sample to have heat treatment after metal alloying and carborizing. Then engage in the research of technologies and performance. All these work are expected to explore the industrializing application of the surface high-speed steel power hacksaw blade.Six blocks in the same metal-alloying process are treated in different carbon potentials, different quenching temperatures and different tempering temperatures. Three carbon potentials, two quenching methods, three quenching temperatures, five tempering temperatures can finally lead to different tempering curves. From these curves, we cancompare the different tempering performance to each other. The comparative involved the different carbon content’s tempering hardness on the same quenching temperature process and the different quenching temperature process on the same carbon contents. The metallograph and X-raydiffraction method were used to analyze structures. Then wear testing are used to compare the different samples after quenching and tempering in 550 ℃ and the sample of high-speed steel during 2 hours and under 1250N.The results indicate that the depth of alloying layer are between 30μ m and 150μm on the surface of blade 20Cr2V2.f he surface material’s alloying content is between 10% and 40% by DGPSAT. The carborizing surface has different carbon contents with different Carbon potentials. The carbon potential which is higher than the balance carbon principle is not easy to come into being network carbide. The different influences in the different carbon potentials of a fixed quenching temperature are that the higher is the quenching temperature ,the higher is the quench’s tempering hardness. The interrupted quenching’s hardness curves are a little lowerthan the oil quenching’s hardness in three carbon potentials. The different influences in the different quenching temperatures of a fixed carbon potential is that, the hardness of oil quench in 0.7% carbon potential is rising with temperature, there is obvious secondary hardening in 0.7%carbon poential. With the carbon potential’s rising, the temperature’s influence is more crutial, so the hardness after 1200 ℃ oil quench in the 1.35% potential is highest The gap between oil quench and interrupted quenching is obvious. The influence of quenching method on hardness after tempering is due to alloying carbide’s amount. The amount in interrupted quenching is big, so it can delay Martensite’s transformation.The wear and tear test shows that the material hardness and surface condition have a crucial influence on the wear performance. In this wear experiment, the higher is the hardness and the more smooth is the surface , the smaller is the wear quantity. Wear quantity is decided by the surface and the hardness. Comparing the surface alloy’s high-speed steel to WeMo5Cr4V21 the more similar is the hardness, themore similar is the wear quantity. In the same hardness, the more rougher is the surface, the biger is the cof The biger cof is owing to the micro cutting under the condition of oiling. The higher hardness and rougher surface lead to a hard microcutting , so the cof is big. The surface in the higher hardnessis separate cut, but the surface in the lower hardness is an area owing to a lot of cuts gather更多还原