硅对中碳低合金铸钢组织和硬韧性的影响

采用硬度计、冲击试验机、显微镜、扫描电镜和X射线衍射仪,研究了经920℃水淬和250℃回火处理的含硅中碳低合金铸钢.结果表明,随着硅含量的增加,中碳低合金铸钢显微组织中出现了铁素体且其体积分数逐渐提高,铁素体渐呈内凹陷块状.硅含量在0.48％～1.73％范围内,硅含量对中碳低合金铸钢硬度作用不明显,硅含量大于1.73％时钢的硬度下降；硅含量在0.48％～2.43％范围内,随着硅含量的增加,中碳低合金铸钢冲击吸收功先升后降.硅含量为0.97％的中碳低合金铸钢V型缺口冲击吸收功为20.3 J,硬度HRC 53.9,硬韧性较好.

Effect of Si on Microstructures,Hardness and Toughness of the Medium-Carbon Low-Alloyed Cast Steel

The medium-carbon low-alloyed cast steel water-quenched at 920 ℃ and then tempered at 250 ℃,was investigated by durometer,impact testing machine,optical microscope,scanning electron microscopy(SEM) and X-ray diffraction(XRD).The results indicate that the ferrite appears in the microstructure and ferrite volume fraction increases gradually with the increase of silicon content,shape of the ferrite gradually turns to be concave massive phase.In the range of 0.48wt.% to 1.73wt.%,silicon has little effect on the hardness,but when silicon content is above 1.73wt.%,the hardness decreases with increase of silicon content.The impact absorbing energy of the medium-carbon low-alloyed cast steel firstly increased and then decreased with the increase of silicon content from 0.48% to 2.43%.The medium-carbon low-alloyed cast steel with 0.97% Si shows a better impact absorbing energy and hardness with V-notch impact absorbing energy 20.3 J and the hardness HRC 53.9.