船用低温钢的冲击断裂行为及韧脆转变温度曲线分析
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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(–97±5)℃;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(3.1±0.4)μm,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。
In order to compare the advantages and disadvantages of various methods for fitting the ductilebrittle 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 °C to-196 °C, 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) °C. 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.
In order to compare the advantages and disadvantages of various methods for fitting the ductilebrittle 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 °C to-196 °C, 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) °C. 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.
引文
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[12]薛宪营,刘奉家,秦军,等.HSLA Q345D中厚板韧脆转变温度测定与分析[J].钢铁,2011,46(10):94-98.
[13]罗晓蓉,陈晨枫,丁欲晓,等.基于Origin软件正确评定韧脆性转变温度[J].物理测试,2010,28(2):37-39,43.
[14]袁鹏斌,张毅,李建鹏.控轧钢不同取向冲击试验对形成“断口分离”的影响[J].焊管,1995,18(6):24-33.
[15]HWANG B,KIM Y M,LEE S,et al.Correlation of rolling condition,microstructure,and low-temperature toughness of X70 pipeline steels[J].Metall Mater Trans A,2005,36(7):1793-1805.
[2]ZHAO X Q,PAN T,WANG Q F,et al.Effect of inter-critical quenching on reversed austenite formation and eryogenic toughness in QLT-processed 9%Ni steel[J].Journal of Iron and Steel Research International,2007,14(5):240-244.
[3]杨跃辉,蔡庆伍,武会宾,等.两相区热处理过程中回转奥氏体的形成规律及其对9Ni钢低温韧性的影响[J].金属学报,2009,45(3):270-274.
[4]WIESNER C S.Predicting structural crack arrest behaviour using small-scale material characterization tests[J].Int J Pres Ves Piping,1996,69(2):185-196.
[5]邓伟,高秀华,秦小梅,等.X80管线钢的冲击断裂行为[J].金属学报,2010,46(5):533-540.
[6]周民,杜林秀,刘相华,等.不同温度下X100管线钢的冲击韧性[J].塑性工程学报,2010,17(5):108-113.
[7]苏增强.浅谈韧脆转变温度试验[J].理化检验-物理分册,2003,10(39):546-547.
[8]罗晓蓉,陈晨枫,丁欲晓,等.基于Origin软件正确评定韧脆性转变温度[J].物理测试,2010,2(28):37-39,43.
[9]王烽,廉晓洁.冲击韧脆转变曲线数学模型的选择[J].理化检验-物理分册,2009,45(10):617-620,632.
[10]兰亮云,邱春林,赵德文,等.低碳贝氏体钢焊接热影响区中不同亚区的组织特性与韧性[J].金属学报,2011,47(8):1046-1054.
[11]刘东升,程丙贵,罗咪.F460高强韧厚船板焊接热影响区的组织和冲击断裂行为[J].金属学报,2011,47(10):1233-1240.
[12]薛宪营,刘奉家,秦军,等.HSLA Q345D中厚板韧脆转变温度测定与分析[J].钢铁,2011,46(10):94-98.
[13]罗晓蓉,陈晨枫,丁欲晓,等.基于Origin软件正确评定韧脆性转变温度[J].物理测试,2010,28(2):37-39,43.
[14]袁鹏斌,张毅,李建鹏.控轧钢不同取向冲击试验对形成“断口分离”的影响[J].焊管,1995,18(6):24-33.
[15]HWANG B,KIM Y M,LEE S,et al.Correlation of rolling condition,microstructure,and low-temperature toughness of X70 pipeline steels[J].Metall Mater Trans A,2005,36(7):1793-1805.