700MPa high strength hot rolling Q&P steel and manufacturing method thereof

A manufacturing method and high-strength technology, applied in the field of wear-resistant steel, can solve problems such as low strength and difficult realization of ferrite

Active Publication Date: 2013-07-24
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Chinese patent CN102226248A discloses a carbon-silicon-manganese hot-rolled Q&P steel, but micro-Ti treatment is not carried out in the design of the alloy composition; Chinese patent CN101775470A discloses a production process of complex-phase Q&P steel, which is actually a two-step production process The process of Q&P steel; Chinese patent CN101487096A discloses a kind of production of C-Mn-Al series Q&P steel with two-step heat treatment method, its main feature is that the elongation is very high, but the strength is low
Therefore, it is difficult to obtain a certain amount of ferrite by reducing the finishing temperature in the actual production of hot rolling.

Method used

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  • 700MPa high strength hot rolling Q&P steel and manufacturing method thereof
  • 700MPa high strength hot rolling Q&P steel and manufacturing method thereof
  • 700MPa high strength hot rolling Q&P steel and manufacturing method thereof

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Embodiment

[0050] The manufacture of the 700MPa grade high-strength hot-rolled Q&P steel of embodiment 1~5 specifically comprises the following steps:

[0051] 1) Smelting, secondary refining, casting:

[0052] According to the chemical composition of each steel in Table 1, adopt converter or electric furnace smelting, vacuum furnace secondary refining, casting to form billets or ingots;

[0053] 2) Heating and hot rolling:

[0054] Heating the cast slab or ingot obtained in step 1) to 1100-1200°C and keeping it warm for 1-2 hours, the starting rolling temperature is 1000-1100°C, rolling 5-7 times and the cumulative deformation is ≥50%; then the intermediate billet When the temperature drops to 900-950°C, 3-5 passes of rolling are carried out and the cumulative deformation is ≥70%; the hot rolling process is as follows: figure 2 Shown; The specific heating and hot rolling process parameters of each embodiment are as shown in table 2, and billet thickness 120mm;

[0055] 3) Sectional c...

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Abstract

The invention relates to 700MPa high strength hot rolling Q&P steel and a manufacturing method thereof. The steel has the following chemical components in percentage by weight: 0.15-0.40% of C, 1.0-2.0% of Si, 1.5-3.0% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.3-1.0% of Al, less than or equal to 0.0065% of N, 0.005-0.015% of Ti and the balance of Fe. The yield strength is greater than or equal to 70MPa, the strength of extension is greater than or equal to 1300MPa, and the ductility is greater than 10%. According to the invention, through a reasonable compound design, based on common C-Mn steel components, austenite crystal is refined by micro Ti treatment by improving the content of Si to inhibit separation of cementite, so that the austenite transformation kinetics in the air cooling process is accelerated by improving the content of Al. Meanwhile, a hot continuous rolling process is matched with a sectional cooling process, so that proeutectoid ferrite+martensite+retained austenite tissues are obtained. The cost of the alloy is greatly lowered.

Description

technical field [0001] The invention belongs to the field of wear-resistant steel, and relates to a 700MPa high-strength hot-rolled Q&P steel and a manufacturing method thereof. The yield strength of the hot-rolled Q&P steel is ≥700MPa, the tensile strength is ≥1300MPa, and the elongation is >10%. Background technique [0002] Quenching-partitioning steel, or Q&P steel, has been a research hotspot in the field of high-strength steel in the past ten years. Its main purpose is to improve the plasticity of steel while improving the strength of steel, that is, to increase the strength-plastic product of steel. At present, Q&P steel has been recognized as an important new steel type in the third generation of advanced high-strength steel in the field of automotive steel. [0003] The main process of Q&P steel is: heating the steel to the complete austenite zone or partial austenite zone, after a period of homogenization treatment, it is rapidly quenched to Ms and Mf (Ms and Mf...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/28C21D8/00
CPCC21D1/84C21D6/005C21D6/008C21D7/13C21D8/00C21D8/005C21D8/0226C21D8/0263C21D9/46C21D2211/001C21D2211/005C21D2211/008C22C33/04C22C38/001C22C38/002C22C38/02C22C38/04C22C38/06C22C38/14
Inventor 王焕荣李自刚王巍张建苏李建业
Owner BAOSHAN IRON & STEEL CO LTD
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