作者：褚峰, 张靖, 陆春洁, 岑风

作者单位：江苏省（沙钢）钢铁研究院, 江苏 张家港 215625

关键词：低温钢;冲击韧性;韧脆转变温度;Boltzmann函数;有效晶粒尺寸

摘要：

为比较拟合韧脆转变温度曲线各方法的优劣，确定船用低温钢韧脆转变温度，研究其冲击断裂行为，在20 ℃至-196 ℃系列温度下对试验钢进行Charpy冲击试验，并对其金相组织和断口进行分析。结果表明：使用Boltzmann函数拟合韧脆转变温度曲线的物理意义明确；船用低温钢韧脆转变温度为（-975）℃；试验温度高于韧脆转变温度时，裂纹形核功及延性裂纹扩展阻力变化不明显，但裂纹脆性扩展的阻力和裂纹失稳后的止裂能力随温度下降有较明显的降低；试验温度低于韧脆转变温度后，裂纹形核功及延性裂纹扩展阻力随温度降低迅速减小；试验钢的有效晶粒为（3.10.4）m，细小的有效晶粒尺寸，是保证其低温韧性良好，韧脆转变温度低的主要原因。

Analysis of impact fracture behavior and ductile-brittle transition temperature curve of the low temperature ship steel

CHU Feng, ZHANG Jing, LU Chunjie, CEN Feng

Institute of Research of Iron and Steel, Sha-steel, Zhangjiagang 215625, China

Abstract: In order to compare the advantages and disadvantages of various methods for fitting the ductile-brittle transition temperature curves, determine the ductile-brittle transition temperature of ship steel and research the impact fracture behavior, Charpy impact tests were performed for the tested steels at a series of temperatures from 20℃ to -196℃, and then the microstructures and fractures were analyzed. The results show that the physical significance for fitting the ductility-brittle transition temperature curve with Boltzmann function is clear. The ductility-brittle transition temperature of low temperature ship steel is (-97±5)℃. When the test temperature is higher than the ductile-brittle transition temperature, the crack nucleation energy and ductile crack expansion resistance is not obvious change, but the brittle crack expansion resistance and crack arrest ability after losing stability have a significant decrease along with temperature dropping. After the test temperature is lower than the ductile-brittle transition temperature, the crack nucleation energy and ductile crack expansion resistance rapidly decrease with along temperature decreasing. The effective grain size of test steel is (3.1±0.4) μm, and small effective grains size is the main reason for ensuring good low-temperature ductility and lower ductile-brittle transition temperature.

Keywords: low temperature steel;impact ductility;ductile-brittle transition temperature;Boltzmann function;effective grain size

2018, 44(9): 136-140  收稿日期: 2018-03-18;收到修改稿日期: 2018-04-21

基金项目: 

作者简介: 褚峰(1991-),男,江苏张家港市人,技术员,主要从事金属材料检测工作

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