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四十年代开始,时有发生的焊接金属结构低应力灾难性破坏,把抗断性问题提到了设计和冶金工作者的面前。本文就一种屈服强度为80kg/mm~2的不锈高强结构用钢焊缝金属,采用示波记录载荷——位移曲线的Charpy V冲击试验,落锤试验,动态撕裂(DT)试验以及COD断裂力学试验,对其抗断性进行初步探讨,并作出评价。试验表明,这类焊缝金属的Charpy V和DT吸收能平台值分别高达20kg-m/cm~2(>100呎-磅)和100kg-m,断裂总功中裂纹扩展功占主导地位。焊缝金属NDT低达-110℃。根据COD试验测定的δ_i值估算,K_(IC)可达600kg/mm~(3/2)左右。研究认为,这类焊缝金属在具有温度转变特征的金属中,其抗断性是较优秀的。同时,就强度转变特征而言,它也正处于具有最佳韧性的最高强度范围。参照现代抗断设计中采用的比值分析图,这类焊缝金属K_(IC)/σ_y≥1.5,就预示它的抗断性水平可与国內外同类高强母体金属相媲美。
Beginning in the forties, low-stress, catastrophic failure of welded metal structures sometimes occurred, posing the problem of resistance to design and metallurgical workers. In this paper, we use a Charpy V impact test, a drop weight test, a dynamic tearing (DT) test and an oscillograph record load-displacement curve for a stainless steel high strength structural weld metal with a yield strength of 80 kg / COD fracture mechanics test, preliminary study of its resistance to break, and make an assessment. Experiments show that the Charpy V and DT absorption plateau values of these weld metals are as high as 20 kg-m / cm 2 (> 100 ft-lb) and 100 kg-m, respectively, resulting in the dominant crack extension work. Weld metal NDT as low as -110 ℃. According to the δ_i value of COD test, K_ (IC) can reach about 600kg / mm ~ (3/2). Research suggests that such weld metal in the temperature transition characteristics of the metal, its resistance to break is better. At the same time, it is also in the highest strength range with the best toughness in terms of strength transitions. With reference to the ratio analysis diagram used in modern design, the weld metal K_ (IC) /σ_y≥1.5 indicates that the level of its resistance to fracture can be compared with the similar high-strength parent metal at home and abroad.