Heat treatment process method for EA1N-material urban rail car axle

Abstract

The invention discloses a heat treatment process method for an EA1N-material urban rail car axle; the heat treatment process method includes the steps of two times of normalizing and one time of tempering, wherein the heat preservation temperature of first normalizing is 850-880 DEG C, and the heat preservation time is 3-4 h; the temperature of second normalizing is 810-820 DEG C, and the heat preservation time is 3-4 h; the content of C in the steel type is 0.32-0.40%, the upper limits of the contents of Si, Mn, P, S, Cr, Cu, Mo, Ni and V are respectively 0.50, 1.20, 0.020, 0.020, 0.30, 0.30, 0.08, 0.30 and 0.06, and the balance is Fe and inevitable impurities. By the first normalizing, the car axle austenite is homogenized, the material organization and composition segregation is eliminated, and uniform organization morphology is obtained; and through the second normalizing, the car axle is austenitized at the temperature, fine austenite crystal grains are formed, after the car axle is cooled, fine ferrite and pearlite organizations are obtained, so as to achieve relatively high strength and toughness.

Description

technical field [0001] The invention belongs to the technical field of iron and steel heat treatment, and specifically refers to a heat treatment method for an urban rail axle made of EA1N material. Background technique [0002] With the advancement of urbanization in my country, urban rail transit has also been vigorously developed. According to the data of the "2012 China Urban Rail Transit High Level Forum", from 2006 to 2010, the annual increase in urban rail transit operating mileage was 177 kilometers. In 2011 In 2019, the operating mileage of rail transit in Mainland China cities increased by 283 kilometers. At present, 14 cities across the country have opened and operated rail transit, and the operating mileage of urban rail transit in mainland China was 1,630 kilometers by the end of 2011. After more than ten years of development, urban rail transit in Mainland China has entered a stage of rapid development. [0003] On September 6, 2012, the National Development a...

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Problems solved by technology

After the EA1N axle is treated, its mechanical properties, metallographic structure, grain size and fatigue strength can basically meet the requirements of the EN13261 standard, but the yield strength of most axles is 340N / mm 2 Left and right, the grain size is 5 to 6, the value is low, and sometimes it does not meet the standard, and it needs to be re-heated, resulting in waste of electric energy, increased cost, and reduced efficiency. If the axle is re-heated three times and fails, it will be scrapped. The scrapping of furnace axles caused a loss of about 600,000 yuan. For this reason, research on the heat treatment process of urban rail axles made of EA1N was carried out

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