加热工艺对重轨钢奥氏体晶粒尺寸与脱碳层深度的影响  

Effect of Reheating Process on Austenite Grain Size and Decarburization Depth of Heavy Rail

作　　者：张旭峰[1] 张江玲[2] 肖金福[2] 

机构地区：[1]河北钢铁集团邯钢公司,河北邯郸056015 [2]中国钢研科技集团有限公司钢铁研究总院冶金工艺研究所,北京100081

出　　处：《轧钢》2013年第4期27-31,共5页Steel Rolling

摘　　要：热轧高强度重轨钢的珠光体团块尺寸和层片间距以及钢轨表面脱碳层深度对钢轨在磨损和滚动接触疲劳条件下的使用性能具有重要影响。在邯钢采用SMS Meer万能机组轧制100m定尺超长轨的设备工艺条件下,为了制定合理的U71Mn钢坯加热制度、细化珠光体组织和控制表面脱碳层深度,在实验室进行了加热工艺参数对U71Mn钢轨钢奥氏体晶粒尺寸和脱碳层深度的影响规律的实验研究。实验结果表明:U71Mn钢坯在加热温度升至1050～1150℃而均热时间为35min时,奥氏体晶粒尺寸和脱碳层深度开始有明显增长的趋势,奥氏体晶粒尺寸在120～160μm但比较均匀,有效脱碳层深度增加到0.42～0.61mm;当加热温度升高到1200～1250℃时,奥氏体晶粒尺寸超过180μm并随着保温时间的延长出现显著的不均匀长大,有效脱碳层深度增加到0.81～0.90mm。根据上述实验数据,对邯钢U71Mn钢加热工艺规程提出了优化参数,使热轧钢轨的珠光体组织、力学性能和脱碳层深度满足了国家标准和铁道部标准的要求。The pearlite-colony size and lamellar-spacing as well as the decarburization depth of hot-rolled high-strength heavy rail steel exert important influence on the rail performance under the condition of wear and rolling contact fatigue. In order to make reasonable reheating schedule for U71Mn billet on the 100 meter rail rolling line with SMS-Meer Universal-Mill in Handan Steel Company, the laboratory experiments have been carried out to investigate the effects of reheating parameters on austenite grain size and decarburization depth for pearl- ire refining and decarburization control. The results show that when reheating temperature was reached 1050- 1150℃ and soaking time was 35 min, the austenite grain size and the decarburization depth were dramatically increased. The austenite grain size reached 120-160;m but approximately uniform, the functional decarburization depth increased to 0.42-0.61 mm. When the reheating temperature was increased to 1200-1250℃ the austenite grain size exceeded 180;m and got an significantly uneven-growth with the prolongation of holding time. The functional deearburization depth increased to 0.81;0.90 mm. According to above experimental data, the modified reheating schedule was proposed and applied to the production of U71Mn rail steel; As a result, the microstructure of pearlite and the decarhurization depth in hot-rolled rail of U71Mn steel were controlled and qualified for the National Technical Standard and Railway Ministry Standards.

关 键 词：U71Mn重轨 奥氏体晶粒 脱碳层 加热温度 保温时间 

分 类 号：TG156.1[金属学及工艺—热处理]