A production method of high-strength pipeline steel with low yield ratio

A high-strength pipeline steel and production method technology, applied in the field of metal rolling, can solve the problems of high strength and low yield ratio, and achieve good toughness, excellent yield ratio range, and huge social benefits

Active Publication Date: 2018-10-16
HBIS COMPANY LIMITED HANDAN BRANCH COMPANY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For the field of pipeline steel production, the problem that has long plagued steel companies is the contradiction between the performance of "high strength" and "low yield ratio"; the use of pipeline steel with a yield ratio exceeding the standard is strictly prohibited. cause great distress

Method used

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  • A production method of high-strength pipeline steel with low yield ratio
  • A production method of high-strength pipeline steel with low yield ratio
  • A production method of high-strength pipeline steel with low yield ratio

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Example 1: Purified molten steel is obtained through smelting, and then cast into slabs through continuous casting machines. The composition weight percentages are: C: 0.03%, Si: 0.025%, Mn: 1.50%, P: 0.0018%, S : 0.006%, Als: 0.015%, Nb: 0.055%, Ti: 0.030%, Cr: 0.20%; Pcm: 0.13%; heat the billet to 1100°C and keep it for 320min; The pressure is 22Mpa, and the furnace oxide scale on the surface is completely removed; then rolling in the austenite recrystallization zone in the first rolling process, the starting rolling temperature is 1020°C, after the slab widening rolling is completed, four passes are used for elongation rolling In the first rolling, the pass reduction rates are 16%, 18%, 18%, and 25%, respectively, and the cumulative effective reduction rate is 77%. The temperature range of the second rolling start rolling temperature is 780°C. The pass reduction rates are 13%, 15%, 17%, and 10% respectively; the cooling temperature is 670°C, the DQ cooling section co...

Embodiment 2

[0034] Example 2: Purified molten steel is obtained through smelting, and then continuously cast into a slab through a continuous casting machine. The composition weight percentages are: C: 0.05%, Si: 0.06%, Mn: 1.61%, P: 0.013%, S : 0.005%, Als: 0.025%, Nb: 0.059, Ti: 0.020%, Cr: 0.26%; Pcm: 0.15%; heat the billet to 1130°C and keep it for 340min; to 26Mpa, thoroughly remove the furnace oxide scale on the surface; then carry out rolling in the austenite recrystallization zone in the first rolling process, the starting rolling temperature is 1050°C, and after the slab widening rolling is completed, four passes are used for elongation rolling Rolling, the pass reduction rate is 16%, 17%, 19%, 20% respectively, the cumulative effective reduction rate is 72%, the starting temperature of the austenite non-recrystallized zone in the second rolling pass is 795 ° C, four passes are adopted rolling, the pass reduction rate is 12%, 14%, 16%, 10% respectively. The starting cooling temp...

Embodiment 3

[0036] Example 3: Purified molten steel is obtained by smelting, and then cast into slabs through continuous casting machines. The composition weight percentages are: C: 0.07%, Si: 0.08%, Mn: 1.70%, P: 0.025%, S : ≤0.007%, Als: 0.045%, Nb: 0.070%, Ti: 0.010%, Cr: 0.30%; Pcm: 0.18%; heat the slab to 1150°C and keep it for 360min; turn on all the high-pressure water for descaling and descaling The water pressure is 30Mpa, and the surface furnace scale is completely removed; then the rolling in the austenite recrystallization zone in the first rolling process is carried out, and the starting rolling temperature is 1080°C. Pass rolling, the pass reduction rate is 17%, 18%, 19%, 22%, the cumulative effective reduction rate is 76%, and the rolling temperature range of the austenite non-recrystallized zone in the second rolling pass is 810°C , using four-pass rolling, the pass reduction rate is 12%, 15%, 15%, 10%, respectively, the cooling temperature is 690 °C, and the DQ cooling se...

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Abstract

The invention relates to a low-yield-ratio high-strength pipeline steel production method. The method includes the working processes of steelmaking-continuous casting, casting blank heating, casting blank control rolling, steel plate control cooling and straightening through a straightening machine; in the working process of rolling, during austenite crystalline region elongation rolling, the single track reduction rate is not lower than 16%, the accumulated valid reduction rate is not lower than 70%, and the austenite crystalline region single track reduction rate is not higher than 18%; and in the working process of control cooling, the austenite crystalline region rolling starting temperature is lower than Ar3 temperature by 20 DEG C to 30 DEG C, the rolling temperature scope is located in an austenite and ferrite coexistence region, the cooling starting temperature is lower than the Ar1 temperature, and large phase change stress is prevented from being generated in the cooling process. A pipeline steel product produced through the process has the high strength, and meanwhile has the good tenacity and the excellent yield ratio scope; and the contradiction of high strength and low yield ratio of the iron and steel industry pipeline steel series products is solved, and the best level of similar enterprises in China is achieved.

Description

technical field [0001] The invention relates to a production method of high-strength pipeline steel with low yield ratio, belonging to the technical field of metal rolling. Background technique [0002] As a raw material for pipelines transporting oil and natural gas, pipeline steel is of paramount importance to safety, and the yield ratio is an indicator of the deformation ability of the material from the initial plastic deformation to the final fracture, so the yield ratio is an important mechanical performance index in pipeline steel. The smaller the yield ratio, the greater the deformation capacity of the material and the greater the strength margin; the larger the yield ratio, the smaller the plastic range of the material after yielding, and the easier it is to fracture. Before the steel pipe undergoes internal pressure deformation to rupture, there is a limit value for the circumferential deformation, which decreases with the increase of the yield ratio of the steel pi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21B1/22B21B37/74B21B37/76B21B37/48C21D8/10C22C38/38C22C38/02C22C38/06C22C38/26C22C38/28
CPCB21B1/222B21B37/48B21B37/74B21B37/76B21B2001/225C21D8/105C21D2211/001C21D2211/005C22C38/02C22C38/06C22C38/26C22C38/28C22C38/38
Inventor 朱坦华李玉谦杜琦铭刘红艳梅东贵姚宙成慧梅郝宾宾
Owner HBIS COMPANY LIMITED HANDAN BRANCH COMPANY
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