对用来加工手表盖的Gr2纯钛棒材生产过程中发现的端面点状缺陷进行了分析，通过对典型缺陷的显微组织及硬度进行检测，发现缺陷处晶粒更加细小，呈条带状，且显微硬度高于基体；对缺陷区域进行能谱分析，未发现明显的成分差异；最后对缺陷区域进行电子探针显微分析，发现其N元素含量远高于基体，属于N富集造成的局部冶金缺陷。通过对纯钛铸锭的真空电弧熔炼过程进行分析，得出产生该问题的原因为：一是海绵钛里混入TiN颗粒，熔炼时未剔除干净；二是在电极焊接时未采取有效的保护措施，焊接时有大气介质导致N元素含量增加。后期针对上述问题进行改善，有效避免了Gr2纯钛棒材出现此类冶金缺陷。
There are point-like defects on the surface of Gr 2 pure titanium rods which are used for producing watch covers.The defects were analyzed by testing microstructure and hardness .The results show that the grains of the defects are strip-like and the size is smaller than that in matrix , and the microhardness is higher than that of matrix . No obvious difference is found between chemical composition of defects and matrix after tested by Energy Dispersive Spectrometer .However , it is found that N element content in defect region is much higher than that in matrix after tested by Electron Probe Micro-analyzer , which means the local metallurgical defects are caused by N enrichment . After analyzing VAR melting process of pure titanium ingot , the reasons of these defects should be as follows .Firstly, there are TiN particles in titanium sponge , which are not been removed before melting .Secondly , effective protection measures are not taken when electrodes welding , and air causes N content increases .Late improvements were taken , and such metallurgy defects of Gr 2 pure titanium rods were averted .
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