Cold-rolled steel plate and preparation method thereof

A technology for cold-rolled steel plates and slabs, applied in the field of cold-rolled steel plates and their preparation, can solve the problems of large temperature difference and difficult process control, and achieve the effects of low cost, low process implementation difficulty and excellent market prospects.

Inactive Publication Date: 2014-09-24
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the process is double-step annealing, the temperature difference between the two stages is large, and the process control is difficult.

Method used

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  • Cold-rolled steel plate and preparation method thereof

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preparation example Construction

[0012] The invention provides a method for preparing a cold-rolled steel plate. The method comprises: hot-rolling, coiling, cold-rolling, annealing and smoothing of the slab in sequence, wherein the temperature of the hot-rolling is 1100-1300°C, and the The finishing temperature of the hot rolling is 900-1000°C, and the thickness of the intermediate slab obtained after the hot rolling is 2.8-4.5 mm; after the hot rolling and before coiling, the intermediate slab obtained after the hot rolling is cooled to 700-850°C, the cooling rate of the cooling is 55-75°C / s; the coiling temperature is 730-770°C; the reduction rate of the cold rolling is 70-90%; the annealing temperature 800-900°C respectively, the annealing time is 50-70s; the flat elongation of the flat is 0.2-1%.

[0013] In the present invention, the slab can be selected according to production needs, for example, the slab can be a continuous casting slab. Preferably, the weight percent of the components of the slab is:...

Embodiment 1

[0030] This example is used to illustrate the preparation method of the cold-rolled steel plate provided by the present invention.

[0031] The slab is hot-rolled at 1199°C into a 4.0mm-thick intermediate slab, and the final rolling temperature of the hot rolling is 915°C; then cooled to 790°C at a cooling rate of 55°C / s, and then air-cooled for 14s; The coiling machine is coiled into coils, and the coiling temperature is 760°C; then cooled to room temperature (25°C), pickled with hydrochloric acid, and rolled into a cold-rolled sheet of 0.8mm at a reduction rate of 80% on a cold tandem rolling mill; and then Annealed on the continuous annealing unit, the annealing temperature is 850 ℃, the time is 65s; then it is flattened, and the flattened elongation is 0.49%. The mechanical property of the final cold-rolled steel plate is the yield strength R eL 135MPa, tensile strength R m 274MPa, elongation after break A 80 is 49.0%, the plastic strain ratio r 90 2.9, work hardening ...

Embodiment 2

[0034] This example is used to illustrate the preparation method of the cold-rolled steel plate provided by the present invention.

[0035] The slab is hot-rolled at 1100°C into a 3.0mm-thick intermediate slab, and the final rolling temperature of the hot rolling is 925°C; then cooled to 750°C at a cooling rate of 65°C / s, and then air-cooled for 12s; The coiling machine is coiled into coils, and the coiling temperature is 732°C; then cooled to room temperature (25°C), pickled with hydrochloric acid, and rolled into 0.8mm cold-rolled sheets at a reduction rate of 73% on a cold tandem rolling mill; and then Annealed on the continuous annealing unit, the annealing temperature is 868 ℃, the time is 55s; then it is flattened, and the flattened elongation is 0.68%. The mechanical property of the final cold-rolled steel plate is the yield strength R eL 143MPa, tensile strength Rm 285MPa, elongation after break A 80 is 47.5%, the plastic strain ratio r 90 2.8, work hardening expone...

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Abstract

The invention provides a preparation method of a cold-rolled steel plate. The method includes the steps: a plate blank is successively subjected to hot rolling, coiling, cold rolling, annealing and temper rolling, wherein the hot rolling temperature is 1100-1300 DEG C, the final rolling temperature of the hot rolling is 900-1000 DEG C, and the thickness of an intermediate plate blank obtained after the hot rolling is 2.8-4.5 mm; after the hot rolling and before the coiling, the intermediate plate blank obtained after the hot rolling is cooled to 700-850 DEG C, wherein the cooling rate of the cooling is 55-75 DEG C/s; the coiling temperature is 730-770 DEG C; the reduction rate of the cold rolling is 70-90%; the annealing temperature is 800-900 DEG C, and the annealing time is 50-70 s; and the temper rolling elongation rate of the temper rolling is 0.2-1%. The cold-rolled steel plate prepared by the preparation method enables the finished product mechanical property to reach the yield strength ReL of 135-143 MPa; and the cold-rolled steel sheet has the tensile strength Rm of 274-285 MPa, the elongation rate A80 after fracture of more than or equal to 44.0%, the plastic strain ratio r90 of more than or equal to 2.5 and the processing hardening index n90 of more than or equal to 0.25, and has excellent market prospects.

Description

technical field [0001] The invention relates to a cold-rolled steel plate and a preparation method thereof. Background technique [0002] With the continuous development of the automobile industry, the market's requirements for automobile plates continue to increase. In order to meet the market's deep drawing forming requirements, the demand for ultra-ultra-deep drawn cold-rolled steel sheets is becoming more and more urgent. [0003] Currently, CN101514392A discloses a continuous annealing process for deep-drawn and ultra-deep-drawn steel sheets as a method for preparing extra-ultra-deep-drawn cold-rolled steel sheets. The process includes: the steel plate is cleaned before annealing, enters the continuous annealing furnace at a speed of 150-350m / min, sprays the surface of the steel plate with nitrogen-hydrogen mixed gas, protects the steel plate and prevents oxidation, and heats the temperature of the steel plate to 120-180 ℃; heat the steel plate again to 750-780 ℃, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/02
Inventor 王敏莉郑之旺张功庭梁英刘勇王平利张林王海云谢勇
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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