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介绍了衡阳华菱钢管有限公司利用Gleeble 1500热模拟试验机研究X70QS无缝管线钢管在不同冷却条件下组织及显微硬度的变化规律,绘制了试验条件下X70QS无缝管线钢管的CCT曲线。试验结果表明,随着冷却速度的提高,X70QS无缝管线钢的微观组织由多边形铁素体(PF)逐渐向针状铁素体(AF)转变。实验室条件下,X70QS无缝管线钢以40~60℃/s冷却后能得到以细小均匀的针状铁素体为主的理想组织,并且针状铁素体晶粒内弥散分布一定数量的细小M/A岛状组织。这种AF+M/A的混合组织结构能有效地提高材料的强度和韧性。
In this paper, Hengyang Valin Steel Pipe Co., Ltd. Was used to study the variation of microstructure and microhardness of X70QS seamless pipe under different cooling conditions by Gleeble 1500 thermal simulation test machine. The CCT curves of X70QS seamless pipe were drawn under the experimental conditions. The experimental results show that with the increase of cooling rate, the microstructure of X70QS seamless line steel gradually changes from polygonal ferrite (PF) to acicular ferrite (AF). Under laboratory conditions, X70QS seamless line steel with 40 ~ 60 ℃ / s after cooling can be fine uniform acicular ferrite-based ideal organization, and acicular ferrite grain dispersed within a certain number of Small M / A island tissue. The mixed structure of AF + M / A can effectively improve the strength and toughness of the material.