碳含量对Si-Mn-B铸钢显微组织和抗磨性的影响

Influence of carbon content on microstructure and wear resistance of Si-Mn-B bainitic cast steel

研究了含1.5%Si-2.5%Mn-0.006%B和少量稀土、镍、铬、钛等合金的Si-Mn-B铸钢经900℃正火的显微组织和在销盘磨损和湿砂橡胶轮磨损条件下的抗磨损性能。钢中碳含量分别为0.17%、0.25%0、.34%、0.47%和0.53%。结果表明,碳含量较低时,主要形成粒状贝氏体,随着碳含量增加,钢的正火组织向针状贝氏体、上贝氏体和下贝氏体过渡,且组织变细。钢的硬度随碳含量增加而增大,冲击韧度随碳含量增加而下降。Si-Mn-B铸钢的耐磨性随碳含量的变化比较复杂。在销盘磨损条件下,使用低硬度玻璃砂磨料时,随着碳含量提高,磨损量减少,耐磨性增加,另外,材料的磨损量随着载荷的增加而增加,使用高硬度碳化硅磨料时,碳含量对磨损量的影响不明显。在湿砂橡胶轮磨损条件下,也呈现碳含量增加,磨损量减少的现象。

Influence of carbon content on microstructure and wear resistance of Si-Mn-B cast steel with different carbon content was studied. Abrasive wear performance of the Si-Mn-B cast steel normalized at 900℃ was examined by using a pin abrasion tester and a rubber wheel abrasive tester. The results show that the normalized microstructure of the Si-Mn-B cast steel is granular bainite mainly when the carbon content is low. The microstructure of the steel are changed gradually from granular bainite to needle-like bainite, upper bainite, lower bainite, and the microstructure are refined, when the carbon content increases. Hardness of the Si-Mn-B cast steel increases and impact toughness decreases with increasing carbon content. In pin abrasion test, the wear weight loss of Si-Mn-B cast steel decreases with the increase of carbon content and increases with increasing testing load, when glass paper is used as abrasive,however, when carborundum paper is used, no obvious change of the wear weight loss is observed with the increase of carbon content. In rubber wheel abrasive test, the wear weight loss decreases with the increase of carbon content.