High-toughness spring steel and preparation method thereof

A technology with high strength and toughness and a manufacturing method, applied in the field of new materials for industrial steel, can solve the problems of low carbon content, waste of boron resources, low hardenability, etc. The effect of temperature saving

Inactive Publication Date: 2013-10-23
TANGSHAN QIANJIN IRON & STEEL GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in practical applications, 28mMnSiB still cannot meet the performance requirements of spring steel
First of all, the lower limit carbon content of 28mMnSiB is 0.23%, the carbon content is too low, the hardenability is low, and it cannot meet the performance requirements of the leaf spring
28MnSiB flat steel can be quenched when the thickness reaches 30mm, but the thickness of a large number of leaf springs is less than 13mm, and the addition of boron will cause waste of resources

Method used

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  • High-toughness spring steel and preparation method thereof
  • High-toughness spring steel and preparation method thereof
  • High-toughness spring steel and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] A high-strength and toughness spring steel, the alloy components and weight percentages are: C: 0.27%; Si: 0.30%; Mn: 0.80%; Cr: 0.30%; Ni: 0.25%; Cu: 0.30%; S: 0.035%; P: 0.035%; the rest is Fe and unavoidable impurities; the steel number of this spring steel is 30MnCr, and its manufacturing method includes:

[0042] a. Collect, screen and classify steel scrap,

[0043] Select the high-quality carbon structural steel processing return material as the raw material of scrap steel, and classify it according to the content of C element;

[0044] b. According to the requirements of the primary refining composition of the steel type, the ingredients are loaded into the furnace,

[0045] When selecting ingredients, control the content of harmful elements P and S in steel scrap to less than 0.03%, and control other harmful residual elements within the standard; adopt the bottom-making slag covering process in the initial smelting; use negative pressure cover equipment at the ...

Embodiment 2

[0063] A high-strength and toughness spring steel, the alloy components and weight percentages are: C: 0.32%; Si: 0.20%; Mn: 1.20%; Cr: 0.50%; Ni: 0.20%; Cu: 0.: 10% ; S: 0.015%; P: 0.03: 0%; B: 0.0030%; the rest is Fe and unavoidable impurities; the steel grade of this spring steel is 30MnCrB, and its manufacturing method is different from the embodiment in that the step h It also includes: adding ferroboron 4 to 5 minutes before feeding silicon-calcium wire in the later stage of refining.

[0064] 30MnCr B in the above-mentioned embodiment 1 and 30MnCr B in the embodiment 2 are carried out performance test analysis:

[0065] 1. The mechanical performance requirements after heat treatment are:

[0066] Yield strength ≥ 1180MPa, tensile strength ≥ 1280MPa, elongation ≥ 5%, reduction of area ≥ 25%.

[0067] 2. Hardenability requires that the hardness at 9mm is not less than:

[0068] 30MnCrB is HRC≥40.

[0069] 30MnCr is HRC≥30. (It can be hardened below 13mm.)

[0070] 3...

Embodiment 3～ Embodiment 6

[0113] The manufacturing method of the spring steel of the following embodiment 3 and embodiment 4 is the same as that of embodiment 1, and the manufacturing method of the spring steel of embodiment 5 and embodiment 6 is the same as that of embodiment 2. The basic performance test analysis, rolling, and spring production were carried out on Examples 3 to 6, and the results were found to be similar to those of Examples 1 and 2, having the same performance and meeting the performance requirements of spring steel.

[0114]

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Abstract

The invention discloses a high-toughness spring steel and a preparation method thereof. The spring steel comprises the following alloy components by weight percent: 0.27-0.32% of C, less than or equal to 0.30% of Si, 0.80-1.20% of Mn, 0.30-0.50% of Cr, less than or equal to 0.25% of Ni, less than or equal to 0.30% of Cu, less than or equal to 0.035% of S, less than or equal to 0.035% of P, the balance of Fe, and inevitable impurities, and the alloy component of the spring steel also comprises B being less than or equal to 0.0035%. The preparation method comprises the following steps of a. collecting, screening and sorting waste steel; b. proportioning materials and feeding the materials into a furnace according to component requirement of the primary refining of the type of the steel; c. smelting in an intermediate frequency furnace; d. melting down, slagging off and sampling; e. alloying through partial deoxygenation in the intermediate frequency furnace; f. slag-free tapping; g. deoxidizing in a ladle, and manufacturing ladle refining slag; h. refining in a finery; i. staying the ladle and soft blowing; j. pouring molten steel under the full protection of a conticaster; k. collecting the finished product; l. pile cooling, and slowly cooling for 24 hours; and m. coating color codes of the type of the steel. The high-toughness spring steel has better toughness and hardenability, the lower limit carbon content is improved to 0.27% so that the hardenability of the steel is guaranteed, and the property of a leaf spring is guaranteed.

Description

technical field [0001] The invention relates to a new material of industrial steel, in particular to a high-strength toughness spring steel and a manufacturing method thereof. Background technique [0002] Since the advent of low-carbon martensitic steel 28MnSiB in the 1980s, the use of low-carbon martensitic steel has become more and more extensive. Low-carbon martensitic steel is now used in leaf spring industry, coulter industry, chain industry, and high-strength finish-rolled rebar in the construction industry. [0003] The development of low carbon martensitic steel is in the ascendant in our country. However, there are too few steel grades of low-carbon martensitic steel, and the selection range of the user unit is very small. 28MnSiB has been included in GB / T1222 (2007 Spring Steel National Standard) in 2007. However, in practical applications, 28mMnSiB still cannot meet the performance requirements of spring steel very well. First of all, the lower limit carbon c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/18C22C33/06
Inventor 薛宝松蒋爱民唐建会
Owner TANGSHAN QIANJIN IRON & STEEL GRP CO LTD
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