高强度螺栓的应用研究

发布时间：2019-06-09 14:22

【摘要】：随着汽车、机械、能源、轻工、建筑等各个行业的发展,对制造各类螺栓的材料提出了更高的要求,在降低成本的同时,材料还要具有较轻的重量、超高的强度、可靠的韧性、较强的耐腐蚀性、较长的使用寿命和易加工等更优良的性能。因此,开展高强度螺栓钢的研究,开发性能更加优良的高强度螺栓具有重要意义。本课题采用电子探针能谱分析、XRD分析、硬度分析、SEM形貌分析、金相分析、拉伸试验分析、冲击试验分析以及断口分析等手段,对市场上常用的国内外8.8、10.9、12.9级螺栓以及自制的12.9级螺栓的成分、组织和性能进行了一系列对比研究分析。研究表明：国产螺栓一般采用中碳钢或中碳合金钢经调质处理制作而成；而部分进口螺栓采用了冷作强化非调质钢,同时调质钢中加入了更多的强碳化物合金元素,使得到的组织晶粒更细小,同时减少了晶界偏析,充分利用了合金碳化物的弥散强化作用,使得到的组织的强度、硬度、韧性、塑性等机械性能总体上要好于国产螺栓。国产螺栓在材质和制作工艺方面都与进口螺栓存在着差距。本论文还采用42CrMoVNb钢成功试制了12.9级高强度螺栓,测试其强度、硬度、韧性、塑性等性能都能满足国标对12.9级高强度螺栓的性能要求,并优于国产12.9级螺栓的性能。
[Abstract]:With the development of automobile, machinery, energy, light industry, construction and other industries, higher requirements have been put forward for the manufacture of all kinds of bolt materials. While reducing the cost, the materials also have lighter weight, super high strength, reliable toughness. Strong corrosion resistance, long service life and easy processing and other better properties. Therefore, it is of great significance to carry out the research of high strength bolt steel and develop high strength bolt with better performance. In this paper, electron probe energy spectrum analysis, XRD analysis, hardness analysis, SEM morphology analysis, metallographic analysis, tensile test analysis, impact test analysis and fracture analysis are used. A series of comparative studies and analysis were carried out on the composition, microstructure and properties of 8.8, 10.9, 12.9 and self-made 12.9 bolts commonly used in the market. The results show that the bolts made in China are generally made of medium carbon steel or medium carbon alloy steel by quenching and tempering treatment. Some imported bolts use cold work to strengthen non-quenched and tempered steel, at the same time, more strong carbide alloy elements are added to the quenched and tempered steel, which makes the microstructure grains smaller and reduces grain boundary segregation at the same time. By making full use of the dispersion strengthening effect of alloy carbides, the mechanical properties of the obtained microstructure, such as strength, hardness, toughness and plasticity, are better than those of domestic bolts as a whole. There is a gap between domestic bolts and imported bolts in material and manufacturing technology. In this paper, 12.9 grade high strength bolts have been successfully manufactured by using 42CrMoVNb steel. The strength, hardness, toughness and plasticity of 12.9 grade high strength bolts can meet the performance requirements of national standard for 12.9 high strength bolts, and are superior to those of domestic 12.9 grade bolts.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH131.3

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