Surface enhanced rare earth high-carbon chrome steel for high-speed rails, and production technology thereof

A high-carbon chromium steel, surface strengthening technology, applied in the direction of metal material coating process, coating, solid diffusion coating, etc., can solve the problems of uneven thickness of the surface carbide layer, poor comprehensive performance, etc., to achieve high surface hardness and Reasonable matching of high toughness, improving wear resistance and reducing energy consumption

Inactive Publication Date: 2017-06-16
HENAN UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to overcome technical defects such as uneven thickness of carbonized layer on the surface of alloy steel for high-speed rail bearings and poor comprehensive performance in the prior art, the present invention provides a surface-strengthened rare-earth high-carbon chromium steel for high-speed rail and its preparation process. The composition, proportion and preparation process of the rare earth high carbon chromium steel achieve a reasonable match of high strength, high surface hardness and high toughness

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  • Surface enhanced rare earth high-carbon chrome steel for high-speed rails, and production technology thereof
  • Surface enhanced rare earth high-carbon chrome steel for high-speed rails, and production technology thereof

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preparation example Construction

[0022] A preparation process for surface-strengthened rare earth high-carbon chromium steel for high-speed iron, including placing GCr15 steel parts in a closed salt bath furnace containing rare earth and aluminum powder in a neutral molten salt, passing metal atoms in the molten salt and steel parts matrix The carbon and nitrogen atoms in the steel react chemically and diffuse on the surface of the steel substrate to form a metal carbide layer containing rare earth elements. The rare earth elements described in the present invention are yttrium and neodymium, which can be added as a single element, or two kinds can be mixed and added at the same time. In the form of chlorides of yttrium and neodymium.

[0023] A salt bath process for preparing rare earth high-carbon chromium steel of the present invention, the process comprises the following steps:

[0024] (1) Substrate pretreatment: put the GCr15 steel parts into methanol or gasoline for cleaning, and then polish the surfa...

Embodiment 1

[0034] The surface-strengthened rare-earth high-carbon chromium steel described in this embodiment is infiltrated with yttrium and neodymium metals on the surface of the GCr15 steel substrate through a molten salt bath to form a metallic carbon layer containing yttrium and neodymium. Its salt bath process is:

[0035] (1) Substrate pretreatment: Put the GCr15 steel parts into methanol for cleaning, and then polish the surface of the cleaned GCr15 steel parts to obtain the pretreated substrate for later use;

[0036] (2) Preparation of molten salt: the distribution ratio of the molten salt is Al-BaCl 2 -NaCl-NaF-YCl 3 -NdCl 3 , wherein the mass fraction of Al powder is 3%, the mass fraction of NaF is 7%, the mass fraction of NaCl is 6.875%, and the mass fraction of BaCl 2 The mass fraction of YCl is 48.125%. After the molten salt is melted at 830°C, YCl with a mass fraction of 15% is added respectively. 3 and NdCl with a mass fraction of 20% 3 , keep warm for 3h, get molte...

Embodiment 2

[0041] The surface-strengthened rare-earth high-carbon chromium steel described in this embodiment is infiltrated with yttrium and neodymium metals on the surface of the GCr15 steel substrate through a molten salt bath to form a metallic carbon layer containing yttrium and neodymium. Its salt bath process is:

[0042] (1) Substrate pretreatment: Put the GCr15 steel parts into gasoline for cleaning, and then polish the surface of the cleaned GCr15 steel parts to obtain the pretreated substrate for later use;

[0043] (2) Preparation of molten salt: the distribution ratio of the molten salt is Al-BaCl 2 -NaCl-NaF-YCl 3 -NdCl 3 , wherein, the mass fraction of Al powder is 4%, the mass fraction of NaF is 8%, the mass fraction of NaCl is 5.34%, the mass fraction of BaCl 2 The mass fraction of YCl is 42.66%. After the molten salt is melted at 830°C, YCl with a mass fraction of 17.5% is added 3 and NdCl with a mass fraction of 22.5% 3 , keep warm for 2h, get molten salt, and set...

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Abstract

A production technology of surface reinforced rare earth high-carbon chrome steel for high-speed rails includes the following steps: placing a GCr15 steel part in a closed salt bath furnace containing neutral molten salts of rare earth and aluminum powder, and carrying out a chemical reaction on metal atoms in the molten metals and carbon and nitrogen atoms in the steel part substrate to carry out diffusion in order to form a rare earth element-containing metal carbide layer on the surface of the steel substrate. The rare earth element is yttrium and neodymium, can be added as a single element, and also can be added after two elements are mixed, and when the two rare earth elements are simultaneously added, a mass ratio of yttrium to neodymium is 1:1 to 1:4, yttrium is added in a yttrium chloride form, and neodymium is added in a neodymium chloride form. The invention also provides the surface reinforced rare earth high-carbon chrome steel for high-speed rails. The components, the ratio and the preparation method of the molten salts are adjusted to realize reasonable coupling of the high strength, the high surface hardness and the high toughness of the rare earth high-carbon chrome steel. The technical defects of uneven thickness and poor comprehensive performances of the carbide layer on the surface of the alloy steel for high-speed rail bearings in the prior art are overcome in the invention.

Description

technical field [0001] The invention relates to the technical field of surface strengthening treatment of steel parts, in particular to a rare-earth high-carbon chromium steel used for high-speed railway bearings and a salt bath infiltration process thereof. Background technique [0002] High-speed rail bearings are one of the key running components of high-speed train mechanical transmission systems, and their performance, life and reliability have become the limiting factors for the stability and safety of the entire vehicle. Taking the CRH5 axle box bearing with a marshalling mass of 451t as an example, based on the average value, the load of each set of bearings is about 68.7kN, the maximum rolling body load is about 7.6kN, and the contact stress between the inner ring raceway and the roller is about 810MPa. At present, the domestic steel types used for train bearings include high-carbon chromium bearing steels (GCr15, GCr15SiMn, GCr15SiMo, GCr18Mo, etc.) and carburized ...

Claims

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Application Information

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IPC IPC(8): C23C8/46C23C8/80
CPCC23C8/46C23C8/80
Inventor 张毅李丽华国秀花王悔改安俊超王智勇孙慧丽柴哲宋克兴田保红刘勇任凤章贾淑果
Owner HENAN UNIV OF SCI & TECH
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