Low-yield-ratio high-strength hot-rolled Q&P steel and manufacturing method thereof

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

Active Publication Date: 2013-08-07
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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  • Low-yield-ratio high-strength hot-rolled Q&P steel and manufacturing method thereof
  • Low-yield-ratio high-strength hot-rolled Q&P steel and manufacturing method thereof

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Embodiment

[0051] The manufacture of the low yield ratio high-strength hot-rolled Q&P steel of embodiment 1-9 specifically comprises the steps:

[0052] 1) Smelting, secondary refining, casting:

[0053] According to the chemical composition of each steel in Table 1, adopt converter or electric furnace smelting, vacuum furnace secondary refining, and casting to form billets or ingots; the thickness of billets is 120mm;

[0054] 2) Heating and hot rolling:

[0055] Heating the slab or ingot obtained in step 1) to 1100-1200°C and holding it for 1-2 hours, the starting temperature of rolling is 1000-1100°C, 5-7 passes of hot rolling and the cumulative deformation under high pressure is ≥50% , and then when the temperature of the intermediate billet drops to 900-950°C, rolling is carried out for 3-5 passes 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 ...

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Abstract

The invention relates to low-yield-ratio high-strength hot-rolled Q&P steel and a manufacturing method thereof. The steel comprises the chemical components of 0.20-0.40% of C, 1.0-2.0% of Si, 1.5-3.0% of Mn, no more than 0.015% of P, no more than 0.005% of S, 0.02-0.08% of Al, no more than 0.006% of N, 0.005-0.015% of Ti, and balance of Fe and unavoidable impurities. According to the invention, through low-cost component design, on a basis of common C-Mn steel, Si content is increased such that cementite precipitation is inhibited, and austenite grains are micronized through micro-Ti treatment. Also, with a combination of hot continuous rolling process and sectioned cooling process, a structure comprising proeutectoid ferrite, martensite, and residual austenite is obtained. The yield strength is lower than 700MPa, a tensile strength is higher than 1000MPa, a yield ratio is 0.50-0.60, and alloy cost is greatly reduced.

Description

technical field [0001] The invention belongs to the field of wear-resistant steel, and relates to a low-yield ratio high-strength hot-rolled Q&P steel and a manufacturing method thereof. The hot-rolled Q&P steel has a yield strength below 700MPa, a tensile strength above 1000MPa, and a yield ratio of 0.50 to 0.60 . 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 a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/14C21D8/00
Inventor 王焕荣李自刚王巍张建苏
Owner BAOSHAN IRON & STEEL CO LTD
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