高精度SH-CCT曲线绘制方法探索

Study of methods for drawing high-quality SH-CCT curves

钢铁材料SH-CCT曲线是焊接工艺制定的重要依据。如何根据膨胀曲线获得准确的相转变点和相转变量,是精确绘制SH-CCT曲线的基础。根据测得的实际膨胀曲线,针对其相转变拐点不明显,以及转变量较少,无法直接确定的情况,提出了采用膨胀曲线、杠杆法和金相法相结合进行相转变点测定;针对转变量和转变组织不明显,采用组织观测和显微硬度相结合来测定组织分布。经过对几个钢种的实际应用,取得了良好的效果,实现了SH-CCT曲线的高精度绘制。

Welding process of steel is on the basis of SH-CCT curves.In order to draw a high-quality SH-CCT curve,the basic works are to get the accurate phase transition points on the dilatometric curves and the real amount of phase transformation.The authors,according to the analyses of many experimental dilatometric curves,used lever method combined with metallographic test to obtain accurate phase transition points which didn＇t appear obviously on the dilatometric curves and method of microstructure analysis combined with microhardness examinations to determine phases distribution and content.These methods were successfully applied in a few steels and high-quality SH-CCT curves were achieved.