不同氟化物对钛合金A-TIG焊成形和组织的影响

Effect of Different Fluoride on Weld Formation and Organization with A-TIG Welding of Titanium Alloy

摘要:

采用9种氟化物进行TC4钛合金A-TIG焊接试验，并利用高速摄像机和汉诺威焊接质量分析仪采集焊接过程中的电弧形态和电压信号，焊后对焊接接头的成形参数和宏观组织进行了对比分析。结果表明：9种氟化物中MgF2活性剂增加焊缝熔深效果最显著，达到无活性剂时的2倍，KF居次，LiF可降低焊缝熔深；相比MgF2活性剂，KF活性剂的熔宽小，热影响区宽度窄，接头总宽度小；NaF活性剂获得了最小的热影响区宽度；NaF、KF、MgF2、AlF3活性剂焊缝的β柱晶生长方向与焊缝中心轴线的倾角比其它活性剂大，柱晶长度由熔深大小决定，柱晶宽度尺寸排序：AlF3＞KF＞MgF2＞NaF；热影响区粗晶区晶粒大小排序：MgF2＞NaF＞AlF3＞KF。

Abstract:

Nine kinds of fluoride were used for A-TIG welding of titanium alloy. Welding arc shape and electrical signals were collected by the high-speed cameras and Hannover analyser in the process. After welding, organization of welded joint was observed and analysised. The results show that: MgF₂ had the apparent effect in increasing the weld penetration, it was 2 times the depth of weld without flux. KF was in the second place. LiF could decrease the weld penetration; Compared with MgF₂, KF had a small weld width , narrow HAZ width and total joint width. NaF obtained the minimum HAZ width; The angle of NaF, KF, MgF₂ and AlF₃ between columnar crystal growth direction and weld center axis was bigger than the other fluoride. The length of the column crystal size was determined by the size of penetration, the width variation law was for AlF₃＞KF＞MgF₂＞NaF; the grain size of coarse grain area in HAZ was for MgF₂ > NaF > AlF₃ > KF.