铋对超低碳钢冷却过程中的固态相变与显微组织的影响  

Influence of bismuth on solid-state phase transformation and microstructure of ultra-low carbon steel during cooling

作　　者：汪杰[1] 彭红兵[1] 吴显辉 石红阳 朱明昌 汪晓勇 周超洋 Wang Jie;Peng Hongbing;Wu Xianhui;Shi Hongyang;Zhu Mingchang;Wang Xiaoyong;Zhou Chaoyang(School of Metallurgy Engineering,Jiangsu University of Science and Technology,Zhangjiagang Jiangsu 215600,China)

机构地区：[1]江苏科技大学冶金工程学院,江苏张家港215600

出　　处：《金属热处理》2024年第10期191-196,共6页Heat Treatment of Metals

基　　金：国家自然科学基金(51704127);张家港市科技计划(ZKYY2326);江苏省研究生科研与实践创新计划(SJCX24_2617)。

摘　　要：利用光学显微镜(OM)、扫描电镜(SEM-EDS)以及DSC热分析仪研究了冷却过程中铋(Bi)对超低碳钢固态相变与显微组织的影响。结果表明:超低碳钢中添加0.06%Bi能够推迟冷却过程中奥氏体向铁素体相变的发生,提高其相变激活能,不同冷速下相变开始与结束温度分别降低了0~16℃以及0~31℃,相变激活能提高了1364kJ/mol。在冷却过程中,铋能够偏聚于奥氏体与铁素体晶界,细化奥氏体与铁素体晶粒;随着冷速的增加,试验钢相变后铁素体晶粒尺寸逐渐减小,平均晶粒尺寸由10℃/min时的77.64μm减小至20℃/min的66.03μm;且与无铋钢相比,含0.06%铋的超低碳钢在相同冷速下,相变后铁素体晶粒尺寸更小,平均晶粒尺寸降幅在3.28~13.74μm。Influence of bismuth on solid-state phase transformation and microstructure of ultra-low carbon steel during cooling was studied by means of optical microscope(OM),scanning electron microscope(SEM-EDS)and differential scanning calorimetry(DSC).The results indicate that the addition of 0.06%bismuth to the tested ultra-low carbon steel delays the austenite-to-ferrite phase transformation during cooling and increases the activation energy of the transformation.The phase transformation start and end temperatures are decreased by O-16 C and 0-31 C,respectively,under different cooling rates,and the activation energy of the phase transformation is increasesd by 1364 kJ/mol.During cooling,bismuth tends to segregate at the austenite and ferrite grain boundaries,refining the austenite and ferrite grains.As the cooling rate increases,the ferrite grain size after transformation in the tested steel gradually decreases,with the average grain size reducing from 77.64μm at 10℃/min to 66.03μm at 20℃/min.Additionally,compared to the bismuth-free steel,the ultra-low carbon steel containing 0.06%bismuth has smaller ferrite grain size after transformation at the same cooling rates,with the average grain size reductions ranging from 3.28μm to 13.74μm.

关 键 词：铋 超低碳钢 固态相变 显微组织 冷却过程 

分 类 号：TG142.1*3[一般工业技术—材料科学与工程]