【摘要】 考虑到北极寒冷的气候环境特点，采用夏比冲击试验和三点弯曲试验研究了名义屈服强度为690MPa的Q690高强钢的低温冲击韧性和断裂韧性，并基于试验结果建立了夏比冲击能与CTOD之间的非线性关系。基于CGM有限元方法研究了屈服强度、硬化指数、试样厚度和焊缝强度匹配系数对Q690高强钢母材和焊接试样CTOD阻力曲线的影响。结果表明，温度对夏比冲击能和CTOD的影响符合Boltzmann函数规律。低温使高强钢的韧性降低，脆性增强。根据Boltzmann函数，得到了Q690高强钢的韧脆转变温度，可作为寒冷地区工程材料选择的参考标准。硬化指数、试样厚度和焊缝强度匹配系数对高强钢母材和焊接试样的阻力曲线影响较大，而屈服强度影响相对较小，这对高强结构钢的选材具有重要的参考意义。更多还原

【Abstract】 With consideration of the feature of the cold weather environment in the Arctic, impact toughness and fracture toughness of Q690 high strength steel with nominal yield strength of 690 MPa were studied by Charpy’s impact test and three-point bending test. Based on test results, a nonlinear relationship between Charpy’s impact energy and CTOD was established. Effects of yield strength, hardening index, thickness and strength matching coefficient on CTOD resistance of base metal and welded specimen of the high strength steel were studied with applying complete Gurson’s model(CGM) and the finite element method.The results show that temperature has an effect on Charpy’s impact energy and CTOD. Low temperature will reduce the toughness and increase the brittleness of the high strength steel. According to the Boltzmann function, the ductile-brittle transition temperature of the high strength steel is obtained, which can be used as a reference for the selection of engineering materials in cold areas. Hardening index, thickness and strength matching coefficient have great influence on the resistance of the base metal and welding sample of the high strength steel, but have little influence on its yield strength, which has important reference value for the material selection of high strength structural steel.更多还原