CN101109037A - Method of producing high undercooling control rolling fine grain high-strength C-Mn steel plate - Google Patents

Abstract

The invention is an undercooling controlled rolling fine grained high strength C-Mn steel plate production method, which relates to a steel plate rolling production process technology. The production technology comprises the steps that the C-Mn steel continuous casting steel billet with 50mm thickness is rolled for 6-pass in CSP production line under the temperature of 1150 DEG C. to 1000 DEG C., and the coarse microstructure of the casting billet is distorted and the microstructure generates recrystallization in deformation Austenite; The invention is capable of getting the higher strength; then, the C-Mn steel tape is cooled by the strong wind of the fan, and the big Austenite deformation is carried out; finally, the C-Mn steel tape is coiled on a roller machine as the finished product. The invention can get the higher strength through the crystallization of the steel with low C-Mn content; the alloy composite is simple and the price is lower; the invention is of good low temperature toughness and good cold bending forming; based on the composite regulation and base principle of application the technology, the invention is capable of getting the steel grade of good formablity of 400MPa level, 500MPa leve and 600MPa level from the C-Mn steel; the invention has the prevalent meaning of guidance to the fine grain high strength board's production.

Description

The high undercooling control rolling fine grain high-strength C-Mn steel plate production method

One, technical field

The present invention relates to the steel plate rolling production technology, especially a kind of high undercooling control rolling fine grain high-strength C-Mn steel plate production method

Two, background technology

The production technique of existing fine grain, high strength degree sheet material is to lead inferior rolling technology: comprise the rolling of two-phase region and the refinement of strain inducing ferrite crystal grain etc. more.Though this processing method can obtain thin crystal grain of tiny austenite and high intensity.But mixed crystal often takes place easily, especially the crystal grain generation gross distortion on top layer, be pie or strip, this tissue topography tends to produce detrimentally affect to the horizontal clod wash of sheet material, can cause producing the top layer tiny crack, vertical mechanical property and clod wash are not then had obvious influence, and this situation will have a strong impact on cold bending, limit the range of application of steel plate.

Three, summary of the invention

It is simple to the purpose of this invention is to provide a kind of production method, on continuous casting line, adopt short flow process steel strip production line (CSP), carry out gross distortion in early stage, controlled temperature, can make surface of steel plate avoid producing pie and along the rolling direction elongated grain, greatly reduce the mixed crystal in the tissue, improve cold bending, produce the C-Mn steel plate production method of tiny crack when avoiding horizontal clod wash.

Technical scheme that purpose of the present invention adopts is that its production method step is as follows:

A, lead inferior rolling: thickness is the C-Mn steel continuous casting steel billet of 50mm more, at 1150 ℃-1000 ℃, entering short flow process steel strip production line (CSP) is rolled, first passage is rolling, deflection is 45%-35%, it is rolling to carry out second passage, deflection is 50%-45%, and its temperature of steel strips is at 1050 ℃-950 ℃, then atomized water spray to steel band carry out strong cold after, carry out the empty mistake of the 3rd passage again, it is rolling to carry out four-pass again, and deflection is 35%-25%, 950 ℃-850 ℃ of its temperature of steel strips, it is rolling to carry out the 5th passage again, deflection is 35%-25%, and its temperature of steel strips is at 900 ℃-800 ℃, and it is rolling to carry out the 6th passage at last, deflection is 25%-15%, and its temperature of steel strips is at 850 ℃-750 ℃;

B, cooling fast: advanced rolling C-Mn steel band six times, and entered on the conveyer line of short flow process steel strip production line, and be subjected to electric fan and blow the high wind cooling, and made temperature fall 600 ℃-500 ℃;

C, roll bending: through high wind refrigerative C-Mn steel band, enter on the plate bending rolls of short flow process steel strip production line, be rolled into 60 tons-30 tons finished product.

The present invention adopts multi-pass rolling, and controlled temperature and rolling reduction make the thick tissue in the C-Mn steel continuous casting billet, after this distortion, make deformed austenite generation recrystallize, then cooling fast, carry out the austenitic gross distortion of high undercooling, be quickly cooled to then and coil about 560 ℃ of temperature.C-Mn steel with 0.16C-1.2Mn is an example, can obtain following performance: σ _s〉=350MPa, σ _b〉=450 MPa, δ ₅〉=30%, crystal grain even thickness, its size are about 6-8 μ m; Clod wash thickness is less than 8mm sheet material, d=0.5mm, and 180 ° are non-microcracked.

The present invention has following technical characterstic: the steel of common low C-Mn composition can obtain higher strength level by grain refining; Alloying constituent is simple, low price; Low-temperature flexibility is good, and cold bending is good; By adjusting composition and using the ultimate principle of present technique, can from the C-Mn steel, obtain the steel grade of the good plasticity of high strength of the various intensity ranks of 400MPa level, 500MPa level, 600MPa level; The present invention has the general guidance meaning to the production of fine grain, high strength degree plate.

Four, embodiment

Further specify the present invention below in conjunction with an embodiment.

Thickness is the 0.16C-1.2Mn steel continuous casting steel billet of 50mm, entering short flow process steel strip production line (CSP) under 1100 ℃ of temperature is rolled, the first passage rolling reduction is 40%, entering the second passage rolling reduction is 45%, its temperature of steel strips is at 1050 ℃, start waterworks, to the steel band atomized water spray carry out strong cold after, carry out the empty mistake of the 3rd passage, it is rolling to enter four-pass then, deflection is 30%, and its temperature of steel strips is at 900 ℃, and it is rolling to carry out the 5th passage again, deflection is 30%, its temperature of steel strips is at 850 ℃, and it is rolling to carry out the 6th passage at last, and deflection is 20%, its temperature of steel strips is being lacked C-Mn steel band on the flow process steel strip production line conveyer line then at 800 ℃, be subjected to electric fan and blow the high wind cooling, make the C-Mn temperature of steel strips drop to 550 ℃, on the plate bending rolls of short flow process steel strip production line, be rolled into 30 tons finished product at last.

Claims (1)

1. a high undercooling control rolling fine grain high-strength C-Mn steel plate production method is characterized in that production method, and its step is as follows:

A, lead inferior rolling: thickness is the C-Mn steel continuous casting steel billet of 50mm more, at 1150 ℃-1000 ℃, entering short flow process steel strip production line (CSP) is rolled, first passage is rolling, deflection is 45%-35%, it is rolling to carry out second passage, deflection is 50%-45%, and its temperature of steel strips is at 1050 ℃-950 ℃, then atomized water spray to steel band carry out strong cold after, carry out the empty mistake of the 3rd passage again, it is rolling to carry out four-pass again, and deflection is 35%-25%, 950 ℃-850 ℃ of its temperature of steel strips, it is rolling to carry out the 5th passage again, deflection is 35%-25%, and its temperature of steel strips is at 900 ℃-800 ℃, and it is rolling to carry out the 6th passage at last, deflection is 25%-15%, and its temperature of steel strips is at 850 ℃-750 ℃;

B, cooling fast: advanced rolling C-Mn steel band six times, and entered on the conveyer line of short flow process steel strip production line, and be subjected to electric fan and blow the high wind cooling, and made temperature fall 600 ℃-500 ℃;

C, roll bending: through high wind refrigerative C-Mn steel band, enter on the plate bending rolls of short flow process steel strip production line, be rolled into 60 tons-30 tons finished product.