摘要
采用热模拟试验方法对新研制的CrNb低合金高强轨钢热处理工艺参数的最佳选择以及可焊性进行研究。研究结果表明 :CrNb轨钢重新奥氏体化、加热温度为 80 0℃～ 850℃时 ,U型缺口冲击值达到 70J以上 ,为热轧状态的 5倍多 ;当冷却速度为 1 0℃·s- 1 ～ 1 75℃·s- 1 时 ,为细片状珠光体组织 ,其硬度为 362HV～ 391HV ;焊接CCT曲线的测定结果表明 ,当冷却速度小于 0 5℃·s- 1 时 ,组织为全珠光体。采用加热温度为轨头踏面 940℃ ,冷却速度约 1 0℃·s- 1 的工艺参数对实物钢轨进行全长热处理后 ,其σb,σ0 2 ,δ5,Ψ ,ak 分别比热轧轨提高 2 7 6 % ,1 8 8% ,38 1 % ,1 55 6 %和 2 5 7% ,奥氏体晶粒度和珠光体片间距得到了明显的细化。
The paper studied the heat treatment techn iq ue parameters of CrNb high strength low alloy rail steel and its weldability. Th e study results indicate when CrNb rail steel was reheated to 800℃—850℃, the impact toughness was 70 J, five times the value of heat-rolling condition. When the cooling rate reached 1 0℃·s -1 —1 75℃·s -1 , fine pearlite st ructure was achieved, the hardness of rail was about 362 HV—391 HV. Measurement of welding CCT curve indicates at a cooling rate of below 0 5℃·s -1 pea rlite structure was achieved. The temperature of heating at the rail tread surfa ce was 940℃ and the cooling rate was 10℃·s -1 . After the full length hea t treatment CrNb rail steel is higher in σ b, σ 0 2 , δ 5, Ψ and a k by 27 6%, 18 8%, 38 1%, 155 6%, and 25 7% respectivel y. A nd the size of austenite grain and pearlite inter-lamellar space are distinctly refined. This proves that this new steel ahs good heat treatment technique and weldability.
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2002年第5期121-125,共5页
China Railway Science
基金
铁道部科技发展计划项目 ( 99G4 2 )
