工程机械液压缸拉杆多采用图1的焊接结构,经常处在重载、冲击、甚至弯扭载荷等恶劣工况下。用户反映,拉杆和叉头焊接处多有断裂。拉杆叉头和拉杆的材质多为中碳钢或合金钢,如45、45Mn、42CrMo等。焊缝为圆周V形对接焊缝,裂纹多源于焊接接头热影响区,断口呈光亮脆断特征,在焊 Construction machinery hydraulic cylinder rod more welding structure shown in Figure 1, often in heavy load, impact, and even bending and torsional load and other harsh conditions. Users reflect, pull rod and fork weld more broken. Trusses and lever rod material mostly carbon steel or alloy steel, such as 45,45 Mn, 42 CrMo and so on. The weld is a circumferential V-shaped butt weld with cracks originating from the heat-affected zone of the welded joint. The fracture is bright and fragile. In the weld