碳含量对690合金组织和力学性能的影响及强化机制

 研究了不同碳含量对脱敏态690合金显微组织和力学性能的影响，并对合金的强化机制进行了分析。研究结果表明：碳质量分数在0.011%～0.033%的范围内时，随着其含量的增加，脱敏态690合金的晶界析出物形貌由细小半连续的颗粒逐渐转变为粗大分散的颗粒；主要析出物为M23C6富铬碳化物，M23C6析出物的质量分数从0.181%增加到0.541%。同时，随碳含量的增加,脱敏态690合金的平均晶粒尺寸从23μm减少到10μm；室温抗拉强度从702.5MPa增加到810MPa；屈服强度从300MPa增加到402.5MPa。细晶强化是690合金的主要强化方式。

Effect of Carbon Content on Microstructure, Mechanical Properties of 690 Alloy Steel and Analysis of Strengthening Mechanisms

The effect of carbon content on the microstructure and mechanical properties of 690 alloy steel was investigated.The results are as follows: in the range of 0.011%-0.033%,with the increase of carbon content,topography of precipitate on grain boundary of the desensitization 690 alloy gradually transforms into bulky scattered particles from tiny semi-continuous particles;the content of Cr-rich M23C6 which are the main precipitates increases from 0.181% to 0.541%;the grain size of the desensitization 690 alloy steel decreases from 23 μm to 10 μm;the tensile strength increases from 702.5 MPa to 810 MPa and the yield strength increases from 300 MPa to 402.5 MPa at room temperature.The main strengthening mechanisms of 690 alloy steel are fine grained strengthening and the second phase strengthening.