Low-cost low-yield-strength anti-knock steel and production method thereof

A low-yield strength and production method technology, applied in low-cost low-yield strength earthquake-resistant steel and its production field, can solve the problems of small thickness specifications of produced products, increased production costs, and high prices of niobium elements, and achieve low production costs, Improved welding performance and simple composition

Inactive Publication Date: 2016-04-13

WUYANG IRON & STEEL

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AI-Extracted Technical Summary

Problems solved by technology

However, the relative price of niobium element is high, which increases the production cost, and the thickness specification of the produced product is not large

[0005] The patent with the publication number CN104561777A discloses 225-grade low-yield-strength steel used in low-temperature harsh environments and its production method. It is based on low C and low Mn, adding various microalloying elements such as Ni, Nb, a...

Method used

[0067] The microstructure of the thickness 1/4 (100X) of the steel plate obtained in Examples 1-4 is shown in Figures 1-4. As shown in Figures 1 to 4, its metallographic structure is a uniform polygonal ferrite structure, the molten steel has high purity, fine grains, and the grain size reaches 7.0 grades. Since...

Abstract

The invention discloses low-cost low-yield-strength anti-knock steel and a production method thereof. The low-cost low-yield-strength anti-knock steel comprises, by weight percentage, not larger than 0.05% of C, not larger than 0.05% of Si, not larger than 0.60% of Mn, not larger than 0.010% of P, not larger than 0.005% of S, 0.015%-0.035% of Ti, 0.020%-0.050% of Alt and the balance Fe and inevitable impurities. The production method includes the steps of smelting, continuous casting, heating, controlled-rolling and controlled-cooling rolling and thermal treatment. By the adoption of composition design that only Ti is added based on low C and low Mn, in combination with the special controlled-rolling and controlled-cooling process and the thermal treatment process, the low-temperature flexible low-yield-strength anti-knock steel with the thickness reaching 80 mm is produced successfully, wherein the yield strength ranges from 205 MPa to 245 MPa, the tensile strength ranges from 300 MPa to 400 MPa, the yield ratio is smaller than or equal to 0.70, the specific elongation is larger than or equal to 50%, and -40 DEG C impact power is larger than or equal to 200 J. By the adoption of the method, the production cost is low, the process is simple, the product performance is excellent, and the comprehensive mechanical performance of products is stable.

Technology Topic

Lower yieldThermal treatment +3

Image

Examples

Experimental program(5)

Example Embodiment

[0026] Example 1

[0027] A low-cost, low-yield-strength earthquake-resistant steel with a thickness of 20mm. The chemical composition is shown in Table 1. The balance is Fe and inevitable impurities.

[0028] The above-mentioned seismic steel production methods include: smelting, continuous casting, heating, controlled rolling and controlled cold rolling, and heat treatment processes to obtain low-cost and low-yield strength seismic steel. The specific process is as follows:

[0029] The molten steel is smelted according to the predetermined composition and continuously cast to obtain a continuous casting billet with a thickness of 350mm.

[0030] The cooled continuous casting slab is heated, the heating temperature is 1250℃, the heating coefficient is 10min/cm, and the soaking section is in the furnace for 30min.

[0031] Controlled rolling and controlled cold rolling process: adopting stage II rolling: stage I rolling temperature is 1200℃, single pass reduction rate is ≥15%, cumulative reduction rate is 88%, intermediate temperature waiting thickness (opening steel thickness) 40mm; the start rolling temperature of the second stage is 870℃, the final rolling temperature is 822℃, and the single pass reduction ratio is ≥9%; the total rolling passes of the two stages are controlled at 10 passes.

[0032] After rolling, it adopts ACC cooling, the cooling rate is 7℃/s, the water ratio is controlled at 1:1.2, and the redness temperature of the steel plate is 700℃.

[0033] In the heat treatment process, the heating temperature is controlled at 890℃, and the heating time is kept for 30 minutes according to the thickness of the steel plate.

[0034] The results of the mechanical properties of the obtained steel plates are shown in Table 2.

Example Embodiment

[0035] Example 2

[0036] A low-cost, low-yield-strength anti-seismic steel with a thickness of 40mm. The chemical composition is shown in Table 1. The balance is Fe and unavoidable impurities.

[0037] The above-mentioned seismic steel production methods include: smelting, continuous casting, heating, controlled rolling and controlled cold rolling, and heat treatment processes to obtain low-cost and low-yield strength seismic steel. The specific process is as follows:

[0038] The molten steel is smelted according to the predetermined composition and continuously cast to obtain a continuous casting billet with a thickness of 350mm.

[0039] The cooled continuous casting slab is heated, the heating temperature is 1200℃, the heating coefficient is 10min/cm, and the soaking section is in the furnace for 50min.

[0040] Controlled rolling and controlled cold rolling process: adopting stage II rolling: stage I rolling temperature is 1050℃, single pass reduction rate is ≥18%, cumulative reduction rate is 77%, and the intermediate thickness (thickness of open steel) 80mm; the start-rolling temperature of stage II is 880℃, the final rolling temperature is 840℃, and the single-pass reduction rate is ≥10%; the total rolling passes of the two stages are controlled at 10 passes.

[0041] After rolling, ACC cooling is adopted, the cooling rate is 7°C/s, the water ratio is controlled at 1:1.9, and the redness temperature of the steel plate is 690°C.

[0042] In the heat treatment process, the heating temperature is controlled at 900°C, and the heating time is kept for 60 minutes according to the thickness of the steel plate.

[0043] The results of the mechanical properties of the obtained steel plates are shown in Table 2.

Example Embodiment

[0044] Example 3

[0045] A low-cost, low-yield-strength anti-seismic steel with a thickness of 60mm. The chemical composition is shown in Table 1. The balance is Fe and inevitable impurities.

[0046] The above-mentioned seismic steel production methods include: smelting, continuous casting, heating, controlled rolling and controlled cold rolling, and heat treatment processes to obtain low-cost and low-yield strength seismic steel. The specific process is as follows:

[0047] The molten steel is smelted according to the predetermined composition and continuously cast to obtain a continuous casting billet with a thickness of 350mm.

[0048] The cooled continuous casting slab is heated, the heating temperature is 1250℃, the heating coefficient is 11min/cm, and the soaking section is in the furnace for 65min.

[0049] Controlled rolling and controlled cold rolling process: adopting stage Ⅱ rolling: stage Ⅰ rolling temperature is 1100℃, single pass reduction rate is ≥17%, cumulative reduction rate is 66%, intermediate thickness (thickness of open steel) 120mm; the start rolling temperature of stage II is 856℃, the final rolling temperature is 790℃, and the single-pass reduction ratio is ≥12%; the total rolling passes of the two stages are controlled at 12 passes.

[0050] After rolling, it adopts ACC cooling, the cooling rate is 5℃/s, the water ratio is controlled at 1:1.5, and the steel plate redness temperature is 670℃.

[0051] In the heat treatment process, the heating temperature is controlled at 910°C, and the heating time is kept for 130 minutes according to the thickness of the steel plate.

[0052] The results of the mechanical properties of the obtained steel plates are shown in Table 2.

PUM

Property	Measurement	Unit
Yield strength	205.0 ~ 245.0	MPa
Tensile strength	300.0 ~ 400.0	MPa
Impact energy	>= 200.0	J

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Improve welding performance

Production method of low-temperature steel plate capable of being welded by high heat input

ActiveCN102766748AImprove welding performance

Owner:INST OF RES OF IRON & STEEL JIANGSU PROVINCE

Low-temperature and high-toughness hot rolled H-shaped steel with yield strength of 550 MPa and preparation method thereof

ActiveCN107794450AImprove welding performanceReduce smelting cost

Owner:SHANDONG IRON & STEEL CO LTD

Low-cost low-yield-strength anti-knock steel and production method thereof

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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