新型水基淬火介质的制备及冷却特性研究

发布时间：2019-04-13 17:17

【摘要】：淬火就是将钢加热到临界点温度以上,保温一定时间使其奥氏体化,继而以大于临界冷却速度冷却,从而获得介稳状态的马氏体组织的金属热处理工艺过程。淬火的主要目的是使钢的硬度以及耐磨性提高,获得机械性能优良的加工零件。在热处理工艺中,淬火相对来说是最为重要的一种工序,而冷却是淬火成功与否的关键因素。因此,淬火工序中一个十分重要的问题是冷却性能优良的淬火介质的选取。目前,聚烷撑乙二醇淬火介质(PAG)是聚合物淬火介质作为一种新型淬火介质的代表,以其突出的特点有逐渐取代淬火油的趋势,已经成为了往后新型淬火介质发展的主要方向之一。聚烷撑乙二醇淬火介质通常是由聚烷撑乙二醇、冷速调整添加剂、防锈剂、防腐剂、消泡剂和水组成。本文主要通过Labview温度采集系统测定三种不同平均分子量的聚烷撑乙二醇的冷却特性,筛选出冷却特性最符合要求的聚烷撑乙二醇。通过测定冷却特性方法确定两种不同平均分子量的冷速调整添加剂聚乙烯吡咯烷酮的最佳配比。参考标准《合成切削液》中防锈腐蚀性试验筛选出几种防锈性能合格的防锈剂,再结合Labview温度采集系统测定添加不同防锈剂对研制的淬火介质冷却特性的影响,筛选出综合性能最好的防锈剂。然后添加适量合适的防腐剂和消泡剂。最后确定的新型水基淬火介质的成分为3%～12%的聚烷撑乙二醇C,0.45%复合冷速调整添加剂(0.375%聚乙烯基吡咯烷酮A+0.075%聚乙烯基吡咯烷酮B),0.1%复合防锈剂(0.05%硼砂+0.05%磷酸钠),0.35%o防腐剂(水杨酸),0.1‰消泡剂(聚乙二醇),余量为水。对研制出的新型淬火介质进行冷却性能的研究,通过设计单因素实验研究自制淬火介质浓度、温度的变化规律以及搅拌对其冷却性能的影响。结果表明：随着聚烷撑乙二醇浓度的增大,自制淬火介质的冷却速度逐渐降低,高温区降低明显,低温区降低的相对不明显；随着淬火介质的温度升高,自制淬火介质的冷却速度降低,最大冷却速度降低得比较明显,低温区冷却速度几乎没有变化；淬火介质在搅拌情况下能够提高介质高温区域的冷却速度,对介质低温区域的冷却速度几乎没有影响。将自制淬火介质与水、淬火油和国外陶氏UCONE淬火介质产品进行冷却性能对比。试验结果表明：自制淬火介质的冷却性能处于水和淬火油的冷却性能之间,与UCONE淬火介质的冷却性能相当。选取低碳钢20CrMnTi、中碳钢42CrMo、高碳钢GCr15进行淬火试验,采用自制淬火介质与水和油进行对比,测定三种钢淬火后硬度分布曲线。结果表明：20CrMhTi经3%自制淬火介质淬火后表面硬度达到51.1HRC,经水淬火后表面硬度达到51.3HRC;42CrMo经12%自制淬火介质淬火后表面硬度达到62.2HRC,经油淬火后表面硬度达到60.2HRC;GCrl5经8%自制淬火介质淬火后表面硬度达到67.7HRC,经油淬火后表面硬度达到58.1HRC。自制淬火介质能够适用碳含量不同的钢的淬火,其应用范围广泛。
[Abstract]:The quenching is to heat the steel to above the critical point temperature, keep the temperature for a certain time to austenitize the steel, and then cool the steel at a greater than the critical cooling speed, so as to obtain the metal heat treatment process of the martensite structure with the metastable state. The main purpose of the quenching is to improve the hardness and the wear resistance of the steel, and to obtain a machined part having excellent mechanical properties. In the process of heat treatment, quenching is the most important one, and cooling is the key factor in the success of quenching. Therefore, one of the most important problems in the quenching process is the selection of the quenching medium with excellent cooling performance. At present, the poly (ethylene glycol) quenching medium (PAG) is a kind of new quenching medium, and its outstanding characteristics have the tendency of gradually replacing the quenching oil, which has become one of the main directions for the development of the new quenching medium. The polyalkylene glycol quenching medium is usually composed of a polyalkylene glycol, a cold-speed adjusting additive, an anti-rust agent, a preservative, a defoaming agent and water. In this paper, the cooling characteristics of three kinds of polyalkylene glycol with different average molecular weights were measured by Labview temperature acquisition system, and the most satisfactory polyalkylene glycol was selected. The optimum ratio of the two different average molecular weight cold-rate adjustment additives, such as the polyoxyalkylene ketone, was determined by the determination of the cooling characteristics. In reference to the rust-proof corrosion test in the standard , several anti-rust agents qualified for rust-proof performance are selected, and the influence of different anti-rust agents on the cooling characteristics of the quenching medium developed by adding different anti-rust agents is determined by the Labview temperature acquisition system, and the best anti-rust agent can be selected. And then a proper amount of a preservative and a defoaming agent are added. finally, the component of the novel water-based quenching medium is 3-12% of the polyalkylene glycol C, 0.45% of the composite cold-speed adjusting additive (0.375% of the polyethylene-based polydioxanone A and 0.075% of the polyethylene-based polydioxanone B), and 0.1% of the composite anti-rust agent (0.05% of the borax + 0.05% sodium phosphate), 0.35% o preservative (salicylic acid), 0.1% anti-foaming agent (polyethylene glycol) and the balance of water. The research on the cooling performance of the newly developed quenching medium is carried out. The influence of the concentration and temperature of the self-made quenching medium and the effect of the stirring on the cooling performance of the newly developed quenching medium is studied. The results show that with the increase of the concentration of the polyalkylene glycol, the cooling rate of the self-made quenching medium is gradually reduced, the high temperature area is reduced, and the low temperature area is less obvious; with the increasing of the temperature of the quenching medium, the cooling speed of the self-made quenching medium is reduced, And the cooling speed of the medium high-temperature region can be improved under the condition of stirring, and the cooling speed of the medium-low-temperature region is hardly affected. The cooling performance of the self-made quenching medium was compared with that of the water, the quenching oil and the foreign ceramic UCONE quenching medium. The results show that the cooling performance of the self-made quenching medium is between the cooling performance of the water and the quenching oil, and the cooling performance of the quenching medium is comparable to that of the UCONE quenching medium. The steel 20CrMnTi, the medium carbon steel 42CrMo and the high-carbon steel GCr15 were selected for quenching test, and the hardness distribution curve after quenching was determined by comparing the self-made quenching medium with water and oil. The results show that the surface hardness of 20CrMohTi after quenching with 3% self-made quenching medium reaches 51.1 HRC, the surface hardness after water quenching is 51.3 HRC, and the surface hardness of 42CrMo after quenching with 12% self-made quenching medium reaches 62.2 HRC, and the hardness of the surface after oil quenching reaches 60.2 HRC; The surface hardness of GCrl5 after quenching with 8% self-made quenching medium reached 67.7 HRC, and the surface hardness after oil quenching reached 58.1 HRC. Self-made quenching medium can be used for quenching steel with different carbon content, and its application range is wide.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG154.4

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