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张成竹, 王东晔, 华程, 刘岳, 张骞, 朱振新. B950CF钢超窄间隙激光填丝焊接头疲劳性能[J]. 焊接学报, 2024, 45(9): 94-102. DOI: 10.12073/j.hjxb.20230920001
引用本文: 张成竹, 王东晔, 华程, 刘岳, 张骞, 朱振新. B950CF钢超窄间隙激光填丝焊接头疲劳性能[J]. 焊接学报, 2024, 45(9): 94-102. DOI: 10.12073/j.hjxb.20230920001
ZHANG Chengzhu, WANG Dongye, HUA Cheng, LIU Yue, ZHANG Qian, ZHU Zhenxin. Fatigue properties of B950CF steel ultra-narrow gap laser wire filler welding joint[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2024, 45(9): 94-102. DOI: 10.12073/j.hjxb.20230920001
Citation: ZHANG Chengzhu, WANG Dongye, HUA Cheng, LIU Yue, ZHANG Qian, ZHU Zhenxin. Fatigue properties of B950CF steel ultra-narrow gap laser wire filler welding joint[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2024, 45(9): 94-102. DOI: 10.12073/j.hjxb.20230920001

B950CF钢超窄间隙激光填丝焊接头疲劳性能

Fatigue properties of B950CF steel ultra-narrow gap laser wire filler welding joint

  • 摘要: 超窄间隙激光填丝焊(ultra-narrow gap laser welding,Ultra-NGLW)是一种先进的厚贝氏体钢焊接技术,具有热输入小,焊接接头低应力、变形小等优点. 通过对不同“激光填丝-激光打底”比例的Ultra-NGLW接头高频拉-拉疲劳试验,绘制了10 mm厚不同填丝深度Ultra-NGLW接头S-N曲线,并通过对比分析接头的S-N曲线和疲劳断口特征,得到影响Ultra-NGLW接头疲劳性能的主要原因. 试验结果表明,随着激光填丝深度的加深,接头的疲劳性能逐渐降低,填丝深度为0 mm时,接头疲劳强度为337.5 MPa,当填丝深度达到5 mm后,疲劳强度趋于稳定在270 MPa左右,Ultra-NGLW接头的疲劳源主要为焊缝粗晶区和熔合区的气孔、夹杂等焊接缺陷,在高频拉-拉疲劳循环载荷的作用下,粗晶区马氏体脆硬组织中形成较多裂纹,使其疲劳源裂纹快速扩展并连通脆硬组织中的裂纹直至接头失效.

     

    Abstract: Ultra-NGLW is an advanced welding technology for thick bainitic steel, which has the advantages of low heat input, low stress and deformation of welded joints.By conducting high-frequency tensile fatigue tests on Ultra-NGLW joints with different "filling-bottoming" ratios, S-N curves of 10 mm thick Ultra-NGLW joints with different wire filling depths were plotted, and by comparing and analyzing the S-N curve and fatigue fracture characteristics, the main factors affecting the fatigue performance of Ultra-NGLW joints were identified. The experimental results indicate that as the depth of laser wire filling increases, the fatigue performance of the joint gradually decreases. When the filling depth is 0 mm, the fatigue strength of the joint is 337.5 MPa, while the filling depth reaches 5 mm, the fatigue strength tends to stabilize at around 270 MPa. The fatigue source of Ultra-NGLW joints is mainly welding defects such as pores and inclusions in the coarse-grained and fusion zones of the weld. Under the action of high-frequency tensile fatigue cyclic loads, more cracks are formed in the martensitic brittle hard structure in the coarse-grained zone, causing the fatigue source cracks to rapidly expand and connect the cracks in the brittle hard structure until the joint fails.

     

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