摘要
采用室温拉伸、示波冲击、光学和扫描电镜组织分析、EBSD及断口分析等方法,研究了微观组织对一种高强度船板用钢低温冲击韧性的影响。结果表明,在相同合金成分条件下,由于压下率和冷却速率的差别,板厚1/2和1/4处的有效晶粒尺寸、大角度晶界比例及M/A岛的形态分布不同。有效晶粒尺寸、大角度晶界比例及第二相M/A岛的形态是影响低温冲击韧性的主要因素,其对低温冲击的裂纹形成功影响并不明显,但较大的有效晶粒尺寸、较低的大角度晶界比例及呈方向性分布的M/A岛却显著降低了裂纹扩展功,导致板厚1/2处的低温冲击韧性低于板厚1/4处。
The influence of microstructure on the low temperature Charpy impact toughness of a high strength microalloyed ship plate was investigated by means of the instrumented impact test and tensile test, optical metallographic microscopy, scanning electron microscopy and electron backscatter diffraction （EBSD）. The results showed that due to the difference in the reduction ratio and cooling rate, the effective grain size, ratio of high angle grain boundary and martensite/austenite （M/A） constituent in the center along the thickness direction of the experimental steel differed from those in the midway between the surface and the center along the thickness direction. Those factors had no obvious effect on the initiation energy of low temperature impact cracks. However, bigger effective grain size, lower ratio of high angle grain boundary and orientational M/A constituent greatly reduced the crack propagation energy, which resulted in lower Charpy impact toughness in the center along the thickness direction of the experimental steel at low temperature.
出处
《宝钢技术》
CAS
2012年第5期23-28,共6页
Baosteel Technology
关键词
微观组织
有效晶粒尺寸
船板
冲击韧性
microstructure
effective grain size
ship plate
impact toughness
