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研究了不同热处理条件下,19MnSiAlCr钢中加入Al部分替代Si后的贝氏体转变。选区衍射分析显示,在780、800、820℃加热后于460℃等温,组织中出现条状Fe3C。在780、800、820℃加热和425、400℃等温处理后,都得到BF+M/A岛或BF+残留奥氏体的贝氏体组织。研究表明,渗碳体的析出是因为等温温度过高。粒状贝氏体的出现是由于奥氏体中Si、Al原子没有完全扩散而阻止了碳化物的析出,形成了BF+(M/A、RA)的无碳化物贝氏体。在425℃以下等温,由于Si、Al元素的扩散能力减弱阻止了碳化物的析出,因而只得到无碳化物贝氏体,而且随着等温温度的降低,贝氏体含量增加。
The bainite transformation of 19MnSiAlCr steel with partial substitution of Si for Si under different heat treatment conditions was studied. Constituency diffraction analysis showed that strip Fe3C appeared in the microstructure at isothermal temperatures of 780, 800 and 820 ° C at 460 ° C. After heating at 780, 800 and 820 ℃ and isothermal treatment at 425 and 400 ℃, the bainitic structure of BF + M / A island or BF + retained austenite was obtained. Research shows that the precipitation of cementite is due to isothermal temperature is too high. The occurrence of granular bainite is due to the incomplete diffusion of Si and Al atoms in austenite and the precipitation of carbides, and the formation of carbide-free bainite of BF + (M / A, RA). At temperatures below 425 ° C, carbide-free bainite is prevented due to the diminished diffusion capacity of Si and Al, and carbide-free bainite is obtained. As the isothermal temperature decreases, the bainite content increases.