难变形金属热强旋成形方法研究

发布时间：2018-04-25 16:21

本文选题：难变形金属 + 热强旋　；参考：《华南理工大学》2015年硕士论文

【摘要】：难变形金属化学成分复杂、合金元素含量高、冷加工变形抗力大、成形性能差,其中镍基高温合金因具有较高的高温强度、良好的耐腐蚀、抗氧化性等综合性能,广泛应用于航空航天、船舶、燃气轮机、能源、化工和电工电子等复杂恶劣环境中。对于应用于飞机发动机、燃气轮机燃烧室的镍基高温合金Haynes230合金筒形件的成形加工,现在采用的制造方法非常保守,一般采用板料卷制后焊接的方法加工Haynes230合金筒形件。近年来,随着热强旋成形技术在钛合金、镁合金等难变形金属材料成形方面的应用研究越来越多,成形工艺和加工技术得到不断发展。利用热强旋来加工难变形金属已表现出极大的优势,对推动高端核心装备先进成形技术的发展具有重要的科学意义和广阔的应用前景。本文主要以热强旋成形方法加工难变形金属Haynes230合金筒形件为研究内容,制定了合理的热强旋成形工艺方案,利用有限元仿真分析软件ABAQUS对热强旋成形过程进行了模拟,并对热强旋成形后的工件进行了成形精度分析和组织性能分析。本文主要研究内容和结论如下:1、根据材料的管坯尺寸、力学性能特性和强力旋压成形原理,制定了难变形金属Haynes230合金筒形件的热强旋成形工艺参数,包括道次减薄率、进给比和旋压温度等。针对热加工过程中常用的加热形式:火焰加热和感应加热,通过对比分析两种加热方式在温度均匀性、加热速度、温度可控性等方面的优缺点,选择高频感应加热方式对管坯进行加热,采用温控仪对加热温度进行控制。同时,旋前对芯模进行有效的预热,大大减少了坯料对芯模的传热,使坯料温度分布较均匀。2、根据强力旋压成形原理,考虑温度对成形过程的影响,设计出热强旋所需的工装,对HGQX-LS立式热强旋旋压机床进行了适当的改造,配置了测温仪、温控仪和高频感应加热设备,为热强旋试验的顺利进行奠定了基础。3、利用课题组获得的材料高温本构模型,借助有限元数值模拟软件ABAQUS对热强旋成形过程进行了有限元数值模拟,得到了热强旋温度和进给比对旋压成形过程的影响规律,为后续试验提供了重要的参考依据。4、对旋压件壁厚偏差、直线度、椭圆度进行了分析,由于材料的热胀冷缩、材料的回弹和机床的退让,热强旋后的工件精度变差;原始坯料的表面质量对热旋后工件的表面质量影响较大;同时,合适的进给比是获得良好表面质量工件的重要条件。5、对热强旋工件进行了力学性能试验,热强旋后工件的强度大大增加,加工硬化非常明显。分析了不同温度下旋压件的显微组织,与冷旋一样,旋压件的显微组织为纤维组织,且随旋压温度的升高,显微组织中的再结晶晶粒越来越多,旋压件的强度随旋压温度的升高呈现出下降的趋势。
[Abstract]:The chemical composition of refractory metals is complex, the content of alloy elements is high, the deformation resistance of cold working is large, and the formability is poor. Among them, nickel-based superalloys have high high temperature strength, good corrosion resistance, oxidation resistance and other comprehensive properties. Widely used in aerospace, ship, gas turbine, energy, chemical and electrical and other complex adverse environment. For the forming process of nickel-base superalloy Haynes230 alloy cylinder used in aircraft engine and gas turbine combustion chamber, the manufacturing method is very conservative. Generally speaking, the Haynes230 alloy cylinder is fabricated by welding after sheet metal rolling. In recent years, more and more research has been done on the application of hot strong spin forming technology in the forming of difficult metal materials such as titanium alloy, magnesium alloy and so on, and the forming process and processing technology have been continuously developed. It has shown great advantages to use thermal strong rotation to process hard metal, which is of great scientific significance and broad application prospect to promote the development of advanced forming technology of high-end core equipment. In this paper, a reasonable hot strength rotary forming process is developed, and the thermal strength spin forming process is simulated by the finite element simulation software ABAQUS, which is mainly based on the hot strong spin forming method for the cylinder parts of metal Haynes230 alloy which is difficult to be deformed by means of the thermal strength spin forming method. The forming accuracy and microstructure and properties of the workpiece formed by hot spinning are analyzed. The main contents and conclusions of this paper are as follows: 1. According to the size of tube billet, mechanical properties of material and the principle of strong spinning forming, the technical parameters of thermal strength spinning forming of the hard deformed metal Haynes230 alloy cylindrical parts, including the pass thinning rate, are worked out. Feed ratio and spinning temperature etc. In view of the common heating forms in the process of hot working: flame heating and induction heating, the advantages and disadvantages of the two heating methods in temperature uniformity, heating speed, temperature controllability and so on are compared and analyzed. The tube billet is heated by high frequency induction heating, and the heating temperature is controlled by temperature controller. At the same time, the effective preheating of the core die before spinning greatly reduces the heat transfer between the billet and the core die, and makes the temperature distribution of the blank more uniform. According to the principle of strong spinning forming and considering the influence of temperature on the forming process, the equipment required for heat intensity spinning is designed. In this paper, the HGQX-LS vertical heat strength spinning machine has been modified properly, and the thermometer, temperature control instrument and high frequency induction heating equipment have been equipped, which has laid the foundation for the successful thermal strength spin test. The material constitutive model of high temperature obtained by the research group has been used. The finite element numerical simulation software ABAQUS is used to simulate the thermal strength spinning process, and the influence of the heat intensity rotation temperature and feed ratio on the forming process is obtained. This paper provides an important reference basis for further test. The wall thickness deviation, straightness and ellipticity of spinning parts are analyzed. Due to the thermal expansion and shrinkage of materials, the springback of materials and the retreat of machine tools, the precision of workpiece with heat strength rotation becomes worse. The surface quality of the original billet has a great influence on the surface quality of the workpiece after hot spinning, at the same time, the suitable feed ratio is the important condition to obtain the workpiece with good surface quality. The strength of the workpiece is greatly increased, and the work hardening is very obvious. The microstructure of spinning parts at different temperatures is analyzed. The microstructure of spinning parts is fibrous, and with the increase of spinning temperature, the recrystallization grains in the microstructure become more and more. The strength of spinning parts decreases with the increase of spinning temperature.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

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