Low-alloy steel high in strength and toughness performance and preparing method of low-alloy steel

A low-alloy steel and high-performance technology, applied in the field of iron and steel metallurgy, can solve problems that affect the qualified rate of finished products and profit margins, high energy consumption in production and manufacturing, and long manufacturing processes for high-performance steel products.

Active Publication Date: 2016-08-24
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] When the above-mentioned common manufacturing method is used to produce this kind of high-performance micro-alloyed steel, if important technical measures such as light pressing of the slab and electromagnetic stirring are not taken to prevent the defects of the slab and improve the quality of the slab, the central area of ​​the slab will eventually solidify. Cause internal quality problems such as porosity, porosity, and component segregation, which affect the performance uniformity and quality level of the final product in the thickness direction
[0008] Moreover, in the process of continuous casting, molten steel solidification and cooling to room temperature, the C and N compounds in the steel will concentrate in the columnar grains or austenite grain boundaries and precipitate, easily forming brittle phases, and the billet will form the third brittle temperature zone; if the subsequent process For example, the control of billet reheating system, rolling system, etc. is not standardized, and these brittle phases are easily inherited and retained in the final steel plate product
When the stee

Method used

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  • Low-alloy steel high in strength and toughness performance and preparing method of low-alloy steel
  • Low-alloy steel high in strength and toughness performance and preparing method of low-alloy steel
  • Low-alloy steel high in strength and toughness performance and preparing method of low-alloy steel

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preparation example Construction

[0043] The present invention also provides a method for preparing the above-mentioned low alloy steel with high strength and toughness, which includes the following steps:

[0044] a) The smelted molten steel with the required composition is continuously cast into 200-300mm thick slabs through continuous casting equipment, the superheat is controlled at 15-30℃, the drawing speed is 0.8-1.2m / min, and the straightening section casting The surface temperature of the blank is controlled at 900-950℃, and the center temperature is 1300-1480℃;

[0045] b) After the billet is discharged, it is quickly descaled and cooled on-line, and then uses the high temperature of the core of the cast billet to achieve a uniform temperature return;

[0046] c) After the surface temperature of the slab rises to 1050~1100℃, the slab is sent to the subsequent rolling mill for direct rough rolling, and the thickness of the intermediate slab is controlled to be 3-4 times the thickness of the finished product; ...

Embodiment 1

[0058] The molten steel that has been smelted, the Nb+Ti addition in the steel is 0.032%, the gas element N content is 42ppm and the composition has reached the Q460E requirements is continuously cast into a 250mm billet through the continuous casting equipment, and the pouring temperature, the drawing speed and the second With the cold water distribution system, the surface temperature of the straightening section of the cast slab detected is 913℃ and the core temperature is 1308℃.

[0059] Then, when the surface temperature of the cast slab is at 825°C, descaling and cooling starts, and when the cooling stops, the surface temperature of the slab is detected to be 610°C.

[0060] Then the cast slab is cut to length and waits for the billet to return to red on the roller table. When the surface temperature rises to 1055°C, direct rolling begins. The final rolling temperature of the rough rolling stage is 965°C and the thickness of the intermediate billet is 135mm. After the rough ro...

Embodiment 2

[0063] The finished smelted steel with Nb+Ti addition amount of 0.051%, gas element N content detected as 25ppm, and the composition has reached X80M requirements, is continuously cast into 300mm steel billets through continuous casting equipment, and the pouring temperature, drawing speed and two With the cold water distribution system, the surface temperature of the straightening section of the cast slab detected is 906℃, and the core temperature is 1475℃.

[0064] Then, when the surface temperature of the cast slab is at 890°C, descaling and cooling starts, and when the cooling stops, the surface temperature of the slab is detected to be 570°C.

[0065] Then the cast slab is cut to length and waits for the billet to return to red on the roller table. When the surface temperature rises to 1098℃, direct rolling begins. The final rolling temperature of the rough rolling stage is 1000℃ and the thickness of the intermediate slab is 100mm. After rough rolling, the stand rolls are conti...

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Abstract

The invention discloses low-alloy steel high in strength and toughness performance and a preparing method of the low-alloy steel. The preparing method is a reasonable matching method for improving the strength and toughness performance in the manner that the aspects of component improvement, short-procedure design in which casting blank reheating is omitted, casting blank core part quality improvement, structure micronization control and rolling schedule optimization are taken into comprehensive consideration, the technical skill potential of modern material machining is fully reflected, and the actions of grain refinement, controlled rolling, rapid cooling and other technology means on steel strengthening and toughening are brought into play. It is ensured that brittle phase crack initiation of products of moderate-thickness plates is reduced and a new structure form is obtained so as to prevent crack expanding, and the breakthrough of the short-procedure technology of direct hot rolling of the ultrahigh strength and toughness steel casting blank is achieved.

Description

Technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a low-alloy steel with high strength and toughness and a preparation method thereof. Background technique [0002] High performance steel (HPS) is a new generation of steel with higher strength, better toughness, weldability, cold formability and corrosion resistance compared with traditional low carbon steels, and it is resistant to embrittlement during actual application. The breaking performance has been significantly improved and improved to meet the harsh operating environment and alternating load conditions of marine engineering, engineering machinery, bridge construction, pipeline construction and other high-end equipment for the high strength, high plasticity and toughness of the steel used, and easy welding Requirements for functional indicators such as performance and crack arrest. Under the background that the entire society is concerned about the safety ...

Claims

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Application Information

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IPC IPC(8): C22C38/08C22C38/12C22C38/14C22C38/16C22C38/18C22C38/02C22C38/04C21D8/02
CPCC21D8/0226C22C38/02C22C38/04C22C38/08C22C38/12C22C38/14C22C38/16C22C38/18
Inventor 孙卫华胡淑娥张爱民王勇徐霞
Owner SHANDONG IRON & STEEL CO LTD
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