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为了探讨高锰含量对微合金钢性能的影响及其夹杂物存在形态,采用低碳+钒铁微合金化工艺生产一种高强度热轧型钢,锰质量分数为1.50%~1.60%。结果表明:产品屈服强度为440~460 MPa,抗拉强度为600~620 MPa,金相组织为铁素体+团状珠光体,带状组织3~4级,晶粒度为7~8.5级,但是锰提高了团状珠光体的相对量,削弱了钢材的低温冲击韧性。锰除固溶于铁基体中外,多以含锰夹杂物的形式存在,主要包括片状硫化锰、球形复合型夹杂物和纺锤体形复合型夹杂物。

Effect of manganese on micro-alloyed steel and its inclusion morphology

In order to discuss the effect of high content Mn on micro-alloyed steel and its inclusion morphology, a low carbon and vanadium micro alloying process was applied for high strength hot-rolled section steel with mass fraction 1.5%-1.6% Mn. The result shows that the products tensile strength is 440-460 MPa and yield strength is 600-620 MPa, the microstructure is ferrite and coarse pearlite cluster with band structure in level 3-4 and grain size in level 7-8.5, but the high content of Mn increases the proportion of pearlite which worsens the low-temperature impact toughness. Beside dissolved in the iron matrix, Mn exists as inclusions including flaky MnS, spherical composite inclusion and spindle shaped composite inclusion.