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| Experimental Study on the Mechanical Properties of Rail Steel at low Temperature |
| XI Wang, WANG Yuan-qing, SHI Yong-jiu |
| Tsinghua University, Beijing 100084, China |
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Abstract Research purposes: At a low temperature，the mechanical properties of rail steel get worse and brittle failures can happen more easily. This threatens the railway transportation seriously. It is necessary to find out the mechanical properties of rail steel at low temperature because there are more and more railway constructions at low temperature, such as Qinghai-Tibet railway. The study of this paper will provide a basis of the railway constructions in cold areas.
Research methods: This paper carries out a tension experiment with the U71Mn and U75V rail steels which are 60 kg/m at +20℃、0℃、-20℃ 、-40 ℃、-60℃ and gets the strength and plasticity index of the tow type of rail steels. The datum of the experiment is analyzed from the recent research results about steel.
Research results: The experiment of this paper gets the tensile strength, proof strength (non-proportional extension), percentage elongation after fracture and percentage reduction of area of U71 Mn and U75 V he echanical properties of rail steels at a series of low temperatures. Temperature sensitivity coefficients of the two types of rail steels are calculated and then the tensile strengths at low temperature can be forecasted. Which type of rail steel should be chosen at low temperature is proposed through the comparison of U71 Mn and U75 V.
Research conclusions: When the temperature drops, the strength of rail steels rises and the plasticity descends. The U71 Mn steel has a good plasticity at-60℃ while the U75 V steel get brittle seriously, so U71 Mn rail steel should be chosen when the temperature of the environment is low.
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Received: 04 July 2006
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2006, Vol. 23 
