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研究了正火工艺对35SiMnMo截齿钢组织和性能的影响。结果表明:900℃以下加热正火,35SiMnMo钢的强度和硬度随正火温度的升高而增大,加热温度高于900℃时,材料的强度和硬度随正火温度的升高呈下降趋势,900℃时出现最高值。加热温度超过880℃,冲击韧度有下降的趋势。900℃正火250℃以下回火,强度和硬度随回火温度的升高而增大,250℃回火强度和硬度出现峰值。300℃以下回火冲击韧度变化不大,超过300℃回火,冲击韧度下降,400℃出现了贝氏体回火脆性,超过400℃回火冲击韧度显著升高。出现回火脆性的原因与贝氏体铁素体板条之间的奥氏体发生分解有关。35SiMnMo钢900℃正火250℃回火可获得良好的强韧性。
The effect of normalizing process on microstructure and properties of 35SiMnMo pick steel was studied. The results show that the strength and hardness of 35SiMnMo steel increase with normalizing temperature when the temperature is below 900 ℃. When the heating temperature is higher than 900 ℃, the strength and hardness decrease with the increase of normalizing temperature , The highest value appears at 900 ℃. Heating temperature exceeds 880 ℃, impact toughness has a downward trend. 900 ℃ normalizing below 250 ℃ tempering, strength and hardness increased with the tempering temperature increases, 250 ℃ tempering strength and hardness peaks. The tempering impact toughness does not change much under 300 ℃. When the temperature exceeds 300 ℃, the impact toughness decreases, and the bainite temper brittleness occurs at 400 ℃. The tempering impact toughness increases remarkably at 400 ℃. The cause of temper brittleness is associated with the decomposition of austenite between the bainitic ferrite laths. 35SiMnMo steel 900 ℃ normalizing tempering 250 ℃ get good toughness.