低合金钢断裂韧性J_(Ic)韧脆转变机理的研究

Study of Low Alloy Steel Fracture Toughness J_(Ic)Ductile-Brittle Transition Mechanism

试验研究了球形容器用低合金钢 36mm和 4 0 mm 1 6Mn R钢板屈服强度σs、启裂断裂韧性 Ji 韧脆转变区的变化规律 ,使用试验数据 ,利用裂尖向观断裂机制 ,建立了低合金刚的弹塑性断裂韧性 JIC 在韧脆转变区的转变模型 ,该模型预测的韧脆转变规律与 1 6Mn R钢母材和焊缝以及 A50 8- 钢焊缝的低温断裂力学的试验结果一致 ,研究表明低合金钢断裂韧性的韧脆转变机制是断裂应力 σ′f 控制的脆性解理断裂和断裂应变ε*f 控制的塑性韧窝断裂相互竞争机制作用的结果。图 5表 3参 1

Initiation fracture toughness J i and yield stress σ s of 36mm and 40mm 16MnR sphericity vessel low alloy steel was investigated in ductile brittle transition region. The elastoplastic fracture toughness J i transition model of the low alloy steel has been established by the appropriate microstructural failure criterion near the crack tip and test data. The J Ic rule that predicted by the transition model is consistent with the results of fracture mechanical test in low temperature for 16MnR steel, 16MnR metal weld, and A508 Ⅲ. The conclusion of this research is that the ductile brittle transition mechanism of elasto plastic fracture toughness J Ic of the low alloy is the mechanism of competition between the brittle cleavage fracture mecanism by fracture stress σ  f takes over and the ductile void growth mechanism by fracture strain ε  f takes over. Figs5, tables3 and refs11.