Hot rolling wire rod of 1800 MPa level for low-alloy structure and manufacture method thereof

A manufacturing method and wire rod technology, applied in temperature control and other directions, can solve the problems of adding more alloying elements, increasing material cost, and complex metallurgical process, and achieving the effects of low production cost, loose process system, and simple metallurgical process.

Active Publication Date: 2009-11-25
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the disadvantages of alloying strengthening technology are: adding a large amount of alloying elements will increase the material cost and make the metallurgical process complicated
However, the microstructure of this spring steel is a mixed structure of lamellar martensite and ferrite, and its carbon content is relatively high, which belongs to medium-high carbon spring steel; the steel is quenched and cooled rapidly at 20-200 °C / s after rolling, Subsequent low-temperature tempering treatment below 200°C; the invention adds more alloy elements, and the cost is higher; the steel adopts rapid cooling and low-temperature tempering treatment, and the plasticity is poor; in addition, quenching and tempering treatment make the production process complicated

Method used

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  • Hot rolling wire rod of 1800 MPa level for low-alloy structure and manufacture method thereof
  • Hot rolling wire rod of 1800 MPa level for low-alloy structure and manufacture method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Smelt molten steel in a vacuum electromagnetic induction furnace according to the chemical composition shown in Table 1, and cast it into continuous casting slabs or steel ingots, heat the continuous casting slabs or steel ingots to 1220-1270 ° C, and keep it warm for 125 minutes; then rough rolling, rough rolling The starting temperature ranges from 1140 to 1180°C, and the temperature range after rolling is from 1130 to 1160°C, rolling into bars with a diameter of φ22±0.5mm. Then finish rolling, the temperature range of finish rolling is 1000~1050℃, and the wire rod of φ9±0.3mm is rolled on the continuous rolling mill. After rolling, it is controlled and cooled by the Stelmore line, and the cooling rate is 5°C / s.

Embodiment 2

[0035] The implementation is the same as in Example 1, wherein the heating temperature is 1220-1270° C., and the temperature is kept for 130 minutes; the rough rolling start temperature range is 1140-1180° C., and the bar is rolled into a φ22±0.5mm bar. The finishing rolling heating temperature is ≥1050°C, the rolling temperature range is 1000-1050°C, and the wire rod is rolled into a wire rod of φ9±0.3mm on a continuous rolling mill. After rolling, it is controlled and cooled by the Stelmore line, and the cooling rate is 4°C / s.

Embodiment 3

[0037] The implementation is the same as in Example 1, wherein the heating temperature is 1220°C-1270°C, and the temperature is kept for 140 minutes; the rough rolling start temperature range is 1140-1180°C, and the bar is rolled into a φ22±0.5mm bar. The finishing rolling heating temperature is ≥1050°C, the rolling temperature range is 1000-1050°C, and the wire rod is rolled into a wire rod of φ9±0.3mm on a continuous rolling mill. After rolling, it is controlled and cooled by the Stelmore line, and the cooling rate is 6°C / s.

[0038] The chemical composition (wt%) of the hot-rolled wire rod of table 1 comparative example of the present invention and embodiment 1-3

[0039] C

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Abstract

The invention provides a hot rolling wire rod of 1800 MPa level for a low-alloy structure and a manufacture method thereof. The hot rolling wire rod of 1800 MPa level for the low-alloy structure comprises the following chemical components by weight percentage: 0.30 to 0.40 percent of C, 2.0 to 3.0 percent of Si, 2.5 to 4.0 percent of Mn, 0.30 to 0.40 percent of Mo, and the balance of Fe and unavoidable impurities. The invention adopts Mn-Si-Mo line components, and produces a medium carbon hot rolling wire rod which takes fine acicular martensite structure as the characteristic through purification smelting, rough rolling, finish rolling and the controlled cooling technology. The hot rolling wire rod has the steel yield strength no less than 1600 Mpa, the tensile strength no less than 1800 Mpa, the yield ratio no less than 0.80 percent, the elongation no less than 9.0 percent and the reduction of area no less than 40 percent.

Description

technical field [0001] The present invention relates to high-strength steel and its manufacturing method, in particular, the present invention relates to 1800MPa level low-alloy structure hot-rolled wire rod and its manufacturing method. Background technique [0002] In recent years, with the rapid growth of industries such as bridges, automobiles, and machinery manufacturing, the demand for high-strength wire and bar steel has increased in order to achieve sustainable development that saves resources and protects the environment. The main techniques currently used to increase the strength of wire and bar steel are alloying and increasing the carbon content. [0003] Alloying technology is currently a commonly used method to improve the strength of steel. This method increases the strength and toughness of steel by adding alloy elements such as Ni, Cr, Mo, Si and Mn and microalloy elements such as Nb, V and Ti, and uses alloying strengthening to improve the strength and tou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/12B23P17/00B21B37/74
Inventor 刘俊亮王军艺
Owner BAOSHAN IRON & STEEL CO LTD
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