摘要
U75V 60kg/m重轨试样加热至900℃,模拟重轨万能轧制成品道次出口温度;随后,空冷25 s,模拟重轨从成品道次出口至冷床的温降;最后,将试样放入喷风通道对轨头表面和两个侧面进行欠速冷却.通过实验获得了U75V 60kg/m重轨最佳冷却工艺参数:喷嘴离轨头表面距离15mm,喷风压力0.26MPa,喷风时间80 s,风温28℃.在此欠速冷却条件下,轨头硬化层为对称帽形,轨头中心部位硬化层厚度大于24mm;组织为细珠光体,其平均片层间距比冷却前减小约50 nm;在轨头上圆角部位强度大于1 300 MPa,延伸率大于13%,分别比冷却前提高20%和60%以上.
The samples of U75V 60 kg/m heavy rail were heated to 900 ℃, simulating the temperature of heavy rail at the outlet of universal rolling, then the samples were cooled in open air for 25 s, simulating the temperature drop of heavy rail from the outlet to cooling bed; at last, the samples were put into air spraying channel to cool slackly on the top and both sides of rail head. The optimal cooling parameters were obtained after a lot of experiments： the distance between spraying nozzles and surface of rail head is 15 ram, the air pressure is 0.26 MPa, the spraying time is 80 s, and the air temperature is 28 ~C. Under this cooling condition, the hardened layer shows as ＂cap-shaped＂, the thickness of hardened layer at the center of rail head is more than 24 ram; the microstructure is fine pearlite, the average pearlite interlamellar spacing reduces about 50 nm than that before slack cooling; the tensile strength is more than 1 300 MPa at the top fillets and the percentage elongation is more than 13 %, increasing more than 20 % and 60 % than that before slack cooling, respectively.
出处
《东北大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2012年第9期1270-1273,1298,共5页
Journal of Northeastern University(Natural Science)
基金
国家科技攻关计划重点资助项目(2004BA317B-4-1)
关键词
U75V
重轨
欠速冷却
组织
性能
U75V
heavy rail
slack cooling
microstructure
properties
