Abstract: Heavy rail of steel U75 V is rolled by 14 passes rough-rolling (BD1) - intermediate rolling (BD2) and 6 passes CCS finishing rolling ( UR₁ , ER, UR2, UR₃ , EF and UF) from 280 mm x 380 mm cast bloom. The structure in deformed sample of heavy rail of steel U75V at different pass was observed by using metallographic microscope. Results show that with increasing pass reduction ratio of heavy rail steel at BD1 E, BD2B, UR] and UF, the ratings of pearlite grain size at head, waist and bottom of heavy rail increase respectively from 6.0〜6. 5,6. 0 ~ 6. 5 and 6. 0 ~ 6. 5 to 8. 0 ~ 8. 5 , 7. 5 〜 8. 0 and 8. 0 ~ 8. 5 , at that the spaces between lamellae of pearlite decrease respectively from 0. 51 |±m, 0. 41 μm and 0. 49 to 0. 29 μm, 0. 27 μm and 0. 25 μm, that are available to increase the mechanical properties of heavy rail.

Key words: Heavy Rail Steel, Reduction Ratio, Structure

摘要： U75V钢重轨由280 mm×380 mm铸坯经14道次粗轧(BD1)-中轧(BD2)和CCS 6道次精轧(UR₁、ER、UR₂、UR₃、EF、UF)而成。用金相显微镜观察U75V重轨钢不同道次轧制变形试样的组织。结果表明,随重轨钢BD1E、BD2B、UR1和UF道次压缩比的增加,重轨头部、腰部和底部的珠光体晶粒度等级分别由6.0～6.5、6.0～6.5、6.0～6.5升至8.0～8.5、7.5～8.0、8.0～8.5,珠光体片层间距(μm)分别由0.51、0.41、0.49降至0.29、0.27、0.25,从而有利于提高重轨的力学性能。

关键词: 重轨钢, 压缩比, 组织