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Prevention of Laser Welding Defect in Cobalt-Chromium Alloy for Dental Use

牙科用钴铬合金激光焊接缺陷的预防

基本信息

批准号：
13672068
负责人：
KAKIMOTO Kazutoshi
金额：
$ 1.98万
依托单位：
Osaka Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13672068/
关键词：
Laser Welding Cobalt-Chromium alloy Weld Defect

项目摘要

We elucidated the cause of weld defects in cobalt-chromium alloy by pulsed Nd: YAG laser such as the crack and the porosity. We investigated alloy composition, which did not cause crack, and welding methods of preventing generation of weld defects.The following results were obtained.There were no crack in weld of the alloy, which was composed of only cobalt, chromium and molybdenum. Therefore the cause of the crack was thought to be silicon and carbon.The crack generated easily so that there ware composition elements of investment into the cast.The casting cobalt-chromium alloy for dental use melted from the grain boundary. In the alloy, which generated easily the crack, it began to melt from small spots of the grain boundary. The densities of silicon, oxygen and phosphorus were high melted beginning part. In the alloy, which generated cracks easily, the melt began from the entire grain boundary and melted boundary with the matrix was not clear.In Nd: YAG laser welding with the rectangular pulse wave, if thickness was 1.7 mm or less for pure titanium, the welding without porosity was possible. But, it was very difficult to obtain a deep penetration weld without porosity at the cobalt-chromium alloy.We examined the prevention of porosity generated in the laser weld of the casting cobalt-chromium alloy for dental use by the wave control. But it was difficult to prevent porosity generation completely. In addition, it will be necessary to investigate it in the future. In pure titanium, porosity generation was prevented by wave control though it was not complete.

分析了脉冲Nd：YAG激光焊接钴铬合金时产生裂纹、气孔等焊接缺陷的原因。研究了不产生裂纹的合金成分和防止焊接缺陷产生的焊接方法，结果表明：仅由钴、铬、钼组成的合金焊缝无裂纹;因此认为裂纹产生的原因是硅和碳，裂纹的产生是由于包埋料中的成分成分混入铸件中，导致牙科用铸造钴铬合金从晶界处熔化。在容易产生裂纹的合金中，它从晶界的小斑点开始熔化。硅、氧、磷的密度在熔化初期较高。在容易产生裂纹的合金中，熔化从整个晶界开始，与基体的熔化边界不清楚，在矩形脉冲波的Nd：YAG激光焊接中，如果纯钛的厚度为1.7mm以下，则可以进行无气孔的焊接。但是，在钴铬合金上获得无气孔的深熔焊接是非常困难的。我们研究了通过波控制防止牙科用铸造钴铬合金的激光焊接中产生气孔。但很难完全防止孔隙的产生。此外，今后也有必要对此进行调查。在纯钛中，通过波控制防止了孔隙的产生，尽管波控制并不完全。