High-strength steel for 750 to 880 MPa-level vehicles and production method thereof

A production method, 880mpa technology, applied in the field of vehicle steel production, to achieve the effect of improving strength level, good low temperature impact toughness and improving product quality

Inactive Publication Date: 2012-02-29
SHOUGANG CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] (3) In addition to the high strengthening of the girder to realize the lightweight of the vehicle, the steel for the compartment of heavy trucks and refitted vehicles can also use high-strength m

Method used

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  • High-strength steel for 750 to 880 MPa-level vehicles and production method thereof
  • High-strength steel for 750 to 880 MPa-level vehicles and production method thereof
  • High-strength steel for 750 to 880 MPa-level vehicles and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0039] Example 1:

[0040] The molten steel smelted in a 220-ton converter and refined outside the furnace is continuously cast into a slab, and its weight percentage is C: 0.077%, Si: 0.20%, Mn: 1.50%, P: 0.012%, S: 0.003%, Al: 0.041%, Nb: 0.047%, Ti: 0.10%, N: 0.004%, and the rest are Fe and unavoidable impurities. The thickness of the slab is 230mm.

[0041] Rolling is carried out in the 2250 hot continuous rolling production line, the heating temperature is 1200°C, the finish rolling entrance temperature is 1000°C, the thickness of the intermediate billet is 54mm, the final rolling temperature is 820°C, the target thickness is 10mm, after rolling, it is cooled to The target coiling temperature is 590°C, and air-cooled to room temperature after coiling.

[0042] The yield strength Rel of the high-strength steel produced according to the above method is 745MPa, the tensile strength is 820MPa, the elongation is 20%, the cold bending D=2a has no cracks on the surface, the im...

Example Embodiment

[0043] Example 2:

[0044] The molten steel smelted in a 220-ton converter and refined outside the furnace was continuously cast into a slab, and its weight percentage was the same as in Example 1. The thickness of the slab is 230mm.

[0045] Rolling is carried out in the 2250 hot continuous rolling production line, the heating temperature is 1220°C, the finish rolling entrance temperature is 1020°C, the thickness of the intermediate billet is 42mm, the final rolling temperature is 830°C, the target thickness is 8mm, after rolling, it is cooled to The target coiling temperature is 580°C, and air-cooled to room temperature after coiling.

[0046] The yield strength Rel of the high-strength steel produced according to the above method is 735MPa, the tensile strength is 800MPa, the elongation is 19%, the cold bending D=2a has no cracks on the surface, the impact energy at -20°C is 64J, and the impact energy at -40°C is 51J (impact test The sample size is 5mm×10mm×55mm).

Example Embodiment

[0047] Example 3:

[0048] The molten steel smelted in a 220-ton converter and refined outside the furnace was continuously cast into a slab, and its weight percentage was the same as in Example 1. The thickness of the slab is 230mm.

[0049] Rolling is carried out in the 2250 hot continuous rolling production line, the heating temperature is 1250°C, the finish rolling entrance temperature is 1060°C, the thickness of the intermediate billet is 34mm, the final rolling temperature is 850°C, the target thickness is 4mm, and after rolling, it is cooled to The target coiling temperature is 570°C. After coiling, the steel coil enters the slow cooling pit, and the temperature is lower than 150°C, leaving the pit to be air-cooled to room temperature.

[0050] The yield strength Rel of the high-strength steel produced according to the above method is 750MPa, the tensile strength is 805MPa, the elongation is 20.5%, and there is no crack on the surface of the cold-formed D=2a.

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Abstract

The invention relates to high-strength steel for 750 to 880 MPa-level vehicles and a production method thereof. The high-strength steel comprises the following chemical ingredients in percentage by weight: 0.07 to 0.09 percent of C, 0.15 to 0.25 percent of Si, 1.4 to 1.9 percent of Mn, 0.04 to 0.06 percent of Nb, 0 to 0.15 percent of Mo, 0 to 0.04 percent of V, 0.07 to 0.14 percent of Ti, 0.01 to 0.06 percent of Al, less than or equal to 0.02 percent of P, less than or equal to 0.01 percent of S, less than or equal to 0.008 percent of N and the balance of Fe and inevitable impurities. The production method comprises the following steps of: smelting; casting to form a casting blank; heating to the temperature of between 1,180 and 1,250 DEG C; performing final rolling at the temperature of between 820 and 850 DEG C; performing final cooling at the temperature of between 560 and 600 DEG C; and after a steel coil rolls off a production line, cooling slowly. By the production method, the strength of the material is between 750 and 880 MPa, and the steel has high low-temperature impact toughness and cold forming performance.

Description

technical field [0001] The invention belongs to the technical field of vehicle steel production, and relates to a 750MPa-880MPa high-strength steel for vehicles and a production method thereof. Low-cost component design is adopted to give full play to the strengthening effects of fine-grain strengthening and precipitation strengthening to produce 750MPa-880MPa grade vehicle steel hot-rolled coils. Background technique [0002] The lightweight of the car is to reduce the curb weight of the car as much as possible on the premise of ensuring the strength and safety performance of the car, thereby improving the power of the car, reducing fuel consumption and reducing exhaust pollution. Experiments have proved that if the weight of the vehicle is reduced by 10%, the fuel efficiency can be increased by 6%-8%, and the fuel consumption can be reduced by about 7%. Looking at the current situation of my country's energy shortage, road overloading and low transportation efficiency, du...

Claims

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Application Information

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IPC IPC(8): C22C38/14C21D8/02
Inventor 潘辉张鹏程李飞朱国森武军宽牛涛孟宪堂
Owner SHOUGANG CORPORATION
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