Steel for microalloying lorry axle and technique for producing the same

A technology of steel for railway freight cars and axles, applied in the field of alloy steel, can solve the problems of low crack resistance, segregation of material components, low grain size, etc., and achieve high toughness, toughness and low temperature impact resistance. The effect of cleanliness

Inactive Publication Date: 2009-08-05
JIANGSU SHAGANG GROUP HUAIGANG SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, ordinary 50 steel is used as the material for domestic axles. After overall heat treatment, ordinary 50 steel has defects such as low strength, low grain size level, and low crack resistance sensitivity. In addition, ordinary 50 steel billets are produced by die-casting technology. , the mat

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Prepared by the following production process:

[0038] (1) Converter smelting, smelting in an 80-ton converter top-bottom combined blowing converter, adding molten iron and scrap steel, and adding NiFe and MoFe into the converter along with the scrap steel to achieve pre-de-P and initial composition adjustment and converter smelting of higher alloy steel;

[0039] (2) LF refining, desulfurization and composition fine-tuning in an 80-ton LF furnace;

[0040] (3) RH refining, using 80 tons of RH to achieve vacuum degassing and further removal of inclusions without mixing steel slag, ensuring [H]≤0.00015% and high cleanliness of molten steel;

[0041] (4) Continuous casting, using the R14m 6-machine 6-strand continuous casting machine produced by Danieli, Italy, to cast a round billet of φ500mm;

[0042] (5) Continuous rolling, using a blanking machine to roll into axle shaft blanks.

[0043] The chemical composition of the resulting steel:

[0044] C 0.54%, Si 0.34%, M...

Embodiment 2

[0048] The chemical composition of the resulting steel:

[0049] C 0.51%, Si 0.30%, Mn 0.78%, Cr 0.23%, Ni 0.21%, Mo 0.10%, Al 0.029%, S 0.0040%, P 0.011%, Cu 0.02%, Sb 0.003%, Sn 0.0015%, As 0.006%, [0] 0.0012%, [N] 0.0040%, V 0.090%, Ti 0.029%, the rest is Fe.

[0050] All the other implementations are as in Example 1.

[0051] The 250mm billet was sampled after overall normalizing (830°C), and the obtained mechanical properties are as follows:

[0052] Tensile strength R m =425MPa, yield strength R el =780MPa, elongation A 5 =21.5%, reduction of area Z=42%, -20°C, V-notch impact energy AKv=43J. The austenite grain size of the steel is 6.5.

Embodiment 3

[0054] The chemical composition of the resulting steel:

[0055] C 0.53%, Si 0.33%, Mn 0.76%, Cr 0.22%, Ni 0.19%, Mo 0.10%, Al 0.030%, S 0.0030%, P 0.010%, Cu 0.01%, Sb 0.003%, Sn 0.0015%, As 0.006%, [0] 0.0013%, [N] 0.0044%, V 0.094%, Ti 0.031%, the remainder is Fe.

[0056] All the other implementations are as in Example 1.

[0057] The 230mm billet was sampled after overall normalizing (830°C), and the obtained mechanical properties are as follows:

[0058] Tensile strength R m =435MPa, yield strength R el =790MPa, Elongation A 5 =21.%, reduction of area Z=39%, -20°C, V-notch impact energy AKv=44.5J. The austenite grain size of the steel is 7.0.

[0059] The steel of the present invention has been inspected by Qiqihar Rail Fittings Co., Ltd., Changjiang Axle Factory, and Jinxi Axle Factory, and has good performance. The above-mentioned mechanical performance data are actual measurement data of the three axle factories.

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Abstract

The invention discloses microalloyed steel used for an axle of a railway freight car, wherein the microalloyed steel contains the following chemical components by weight: 0.50-0.57 percent of C, 0.17-0.40 percent of Si, 0.60-1.00 percent of Mn, 0.20-0.35 percent of Cr, 0.18-0.40 percent of Ni, 0.08-0.18 percent of Mo, 0.02-0.06 percent of Al, 0.020-0.060 percent of Ti, 0.030-0.10 percent of V, less than or equal to 0.010 percent of S, less than or equal to 0.020 percent of P, less than or equal to 0.005 percent of B, less than or equal to 0. 20 percent of Cu, less than or equal to 0.010 percent of Sb, less than or equal to 0.03 percent of Sn, less than or equal to 0.04 percent of As, less than or equal to 0.0015 percent of [O] and less than or equal to 0.0060 percent of [N], and the rest is Fe. The invention has high strength, good plasticity, good low-temperature impact property and good crack-resistance sensitivity.

Description

Technical field: [0001] The invention relates to alloy steel in the iron and steel industry, in particular to the design of high-strength, crack-resistant and high-toughness micro-alloyed steel for axles of railway wagons and its production process. Background technique: [0002] With the sustained and stable development of my country's economy, the railway transportation capacity has become a bottleneck seriously restricting the development of the national economy (the per capita railway mileage in my country is 7cm). For this reason, in 2008, the state proposed a railway construction plan with an investment of 2 trillion yuan. In order to ensure the completion of the construction plan issued by the state, at the same time, learn the lessons of the "5.29" and "7.21" two accidents in 2008, which occurred in "5.29" and "7.21", to curb the failure of axle cracks, completely reverse the passive situation of safe transportation of freight cars, and realize railway transportation...

Claims

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Application Information

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IPC IPC(8): C22C38/50C22C38/54C22C38/60C22C33/04C21C5/28C21C7/06C21C7/064C21C7/10C21C7/072C21D8/00B22D11/00
Inventor 王忠英尹修刚张小华
Owner JIANGSU SHAGANG GROUP HUAIGANG SPECIAL STEEL CO LTD
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