挡座圈焊缝开裂失效分析

Failure analysis of weld cracking of retaining ring

针对起重机挡座圈在正常行驶中突然开裂失效,采用化学成分分析、维氏硬度检测、断口分析、金相组织分析及断面能谱分析等手段,对挡座圈开裂的原因进行了分析。结果表明:化学成分、维氏硬度、裂纹附近金属中的夹杂物、金相组织等检测结果均符合标准要求,但焊缝凸起处表面发现存在较多的折叠缺陷,表面处发现氧化物、硫化物等。根据裂纹的特点判断焊缝产生的裂纹属于脆性断裂,产生原因为焊接不良导致焊缝处存在大量O、S、P等元素,导致焊缝裂纹的产生。

In addressing the issue of sudden cracking in the crane block ring during normal operation.This study employs a comprehensive array of analytical techniques including chemical composition testing,Vickers hardness testing,fracture analysis,metallurgical organization analysis,and cross-section energy spectrum analysis.The objective is to ascertain the root causes behind the cracking phenomenon.Analysis of the results reveals that while the chemical composition,Vickers hardness,and presence of inclusions near the crack conform to standard requirements.Significant folding defects are observed on the surface of the weld bulge,along with the presence of oxides and sulfides.Based on the crack characteristics,it is determined that the weld fracture is of brittle nature.That attributed to subpar welding quality resulting in an abundance of oxygen(O),sulfur(S),phosphorus(P),and other elements at the weld site,consequently facilitating the formation of weld cracks.