最近几年来,特别是1943至1947年,在美国发生了许多焊接船的破坏事件,其中不少船只完全折断成两个部分,但是断裂时船只并未经受特殊的载荷,在破坏的地方也没有明显的塑性变形,因此证实是脆性破坏。这些事故的发生认为有下列几个原因:在焊缝中存在显著的应力集中,如裂缝、未焊透、气孔、夹渣、咬肉等缺陷;不合理的焊接结构和高的残余应力;在低的温度下;基本金属、焊缝金属和近焊缝区域的金属具有高的缺口敏感性。鉴定钢材脆性破坏的方法很多,总的说来不外乎试验不同缺口形状、应力集中、试样大小和在不同负荷情况下(如冲击、抗拉、弯曲)测定材料抵抗裂缝伸张的 In recent years, especially from 1943 to 1947, many welding vessel sabotage occurred in the United States, many of which were completely broken into two parts, but at break the vessel was not subjected to any special loads nor was it destroyed Clear plastic deformation, and therefore prove to be brittle failure. The occurrence of these accidents is considered for several reasons: There are significant stress concentrations in the weld, such as cracks, imperfections, pores, slag inclusions, biting and other defects; irrational welding structure and high residual stress; Low temperatures; metals in base metals, weld metals and near weld areas have high notch sensitivity. Identification of brittle failure of steel in many ways, in general, no more than test different notch shape, stress concentration, sample size and under different load conditions (such as impact, tensile, bending) to determine the material to resist crack extension