半导体激光-TIG电弧复合热源表面熔覆工艺及性能研究

发布时间：2018-03-06 02:18

本文选题：激光熔覆　切入点：激光-TIG电弧复合热源熔覆　出处：《兰州理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：在抽油泵、矿山支架、核阀、航空发动机叶片等高附加值工件表面对于表面熔覆方法的要求越来越高。特殊性能的高附加值工件表面工作环境苛刻,对质量和性能要求高,需要达到冶金结合,主要采用堆焊热源;激光、等离子弧、TIG都是常用的堆焊热源,但单一热源具有热源特性调控范围窄、熔覆效率低、稀释率大、裂纹倾向明显等问题。为了解决这一问题提出一种矩形大光斑半导体激光-TIG电弧复合热源表面熔覆方法。首先,建立激光-TIG电弧复合热源熔覆实验系统原型,分析了激光-TIG电弧复合热源特性,以Q235钢为基体材料,采用预置粉末法进行单TIG热源、大光斑半导体激光热源、激光-TIG电弧复合热源表面熔覆Ni60A合金粉末单道熔覆试验;分析了不同热源工艺参数(激光功率、扫描速度、离焦量、TIG电流)对单道熔覆层宏观形貌、熔宽、熔高、稀释率、高宽比、浸润角等成形特征参数的影响。其次,根据不同热源模式的作用和单层单道熔覆层横截面的形貌特征,将单道熔覆层成形分成了六种模式。通过对不同热源模式、母材和粉末熔化、传热与成形特征关系的分析,揭示了六种熔覆层成形模式的形成机理。对比不同外加热源的作用,可知激光-TIG电弧复合热源可以增大获得理想熔覆层的工艺范围。最后,分析不同热源表面熔覆方法的工艺参数与熔覆层质量两者间的联系:采用扫描电镜、XRD、EDS(能谱分析)、显微硬度计等检测手段分析单激光、单TIG、半导体激光-TIG电弧复合不同热源参数对熔覆层质量的影响。结合不同热源表面熔覆方法的工艺参数、熔覆层性能、熔覆层成形三者间的联系,得到最优的单道熔覆工艺参数;并通过优化单层多道搭接工艺参数,获得质量、性能良好的单层多道熔覆层,并在工程实际中得到了应用。
[Abstract]:On the surface of high value-added workpiece such as sucker pump, mine support, nuclear valve, aeroengine blade and so on, the surface cladding method is more and more demanding. Laser and plasma arc TIG are common heat sources for surfacing welding, but single heat source has narrow control range of heat source characteristics, low cladding efficiency and high dilution rate. In order to solve this problem, a surface cladding method of semiconductor laser TIG arc composite heat source with rectangular large spot is proposed. First, the prototype of laser TIG arc composite heat source cladding experiment system is established. The characteristics of laser TIG arc composite heat source were analyzed. The single TIG heat source, large spot semiconductor laser heat source and laser TIG arc composite heat source surface cladding Ni60A alloy powder on the surface of Q235 steel were tested by preset powder method. The effects of different heat source process parameters (laser power, scanning speed, defocus and TIG current) on the macroscopic morphology, width, melting height, dilution rate, aspect ratio and infiltration angle of single pass cladding layer are analyzed. According to the effect of different heat source modes and the morphology of cross section of single pass cladding layer, the single pass cladding layer forming is divided into six modes. The relationship between heat transfer and forming characteristic is analyzed by analyzing different heat source mode, base metal and powder melting, heat transfer and forming characteristic. The forming mechanism of six kinds of cladding forming modes is revealed. Compared with different external heat sources, the laser TIG arc composite heat source can increase the technological range of obtaining the ideal cladding layer. The relationship between process parameters and cladding quality of different heat source surface cladding methods is analyzed. Single laser is analyzed by means of scanning electron microscope (SEM) XRDX EDS (Energy Spectrum Analysis, Microhardness Meter), etc. The influence of different heat source parameters on the quality of the cladding layer by single TIGand semiconductor laser TIG arc compounding, combining with the technological parameters of the surface cladding method of different heat sources, the properties of the cladding layer, and the relationship among the three factors, the forming of the cladding layer, The optimum single pass cladding process parameters are obtained, and the single layer multipass cladding layer with good quality and good performance is obtained by optimizing the single layer multi-pass lap process parameters, and it is applied in engineering practice.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG174.4

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