本文分析了钎焊焊缝强度下降的原因，并提出改进措施。
This paper analyses the cause of strength descent of brazing weld, and proposes improving measures.
钎焊焊缝的枝晶间显微疏松导致的应力集中与微裂纹效应以及近焊缝区母材晶粒长大是导管早期疲劳开裂的主要原因。
The results show that the crack initiates at the outer surface of the weld comer and propagates into the steel base material with a high cycle fatigue mode.
而定位格架的表面颜色、钎焊缝质量、外形尺寸、破断力和结合层厚度均达到钎焊技术要求。
The grids completely meet with the requirements for soldering on surface color , welds quality, overall dimension, rupture stress and joint thickness.
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