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研究了“零保温”淬火温度对27SiMn钢组织和力学性能的影响。探讨了“零保温”淬火条件下,奥氏体成分的不均匀性和马氏体转变的特点。实验表明,“零保温”淬火条件下,830～930℃范围内,随淬火温度升高,27SiMn钢的强、硬度和延伸率均增加;高于930℃后,逐步下降。该钢“零保温”淬火后得到细小的板条状马氏体组织,其原因与奥氏体晶粒细化和奥氏体中碳元素分布不均匀有关。27SiMn钢缸体采用(900±10)℃淬火,(630±10)℃回火的“零保温”调质处理工艺,力学性能完全满足技术要求。
The effect of “zero-holding” quenching temperature on microstructure and mechanical properties of 27SiMn steel was studied. The characteristics of austenite heterogeneity and martensite transformation under “zero insulation” quenching conditions were discussed. The experimental results show that the strength, hardness and elongation of 27SiMn steel increase with the increase of quenching temperature in the range of 830 ~ 930 ℃ under the condition of “zero - holding” quenching. When the temperature is higher than 930 ℃, the temperature decreases gradually. The steel “zero insulation” after quenching get small lath martensite, the reason and the austenite grain refinement and austenite uneven distribution of carbon related. The 27SiMn steel cylinder is quenched with (900 ± 10) ℃ and tempered with “zero heat preservation” (630 ± 10) ℃. The mechanical properties fully meet the technical requirements.