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CN-121992280-A - Production process of SPA-H plate strip for thin hot-rolled container

CN121992280ACN 121992280 ACN121992280 ACN 121992280ACN-121992280-A

Abstract

The invention discloses a production process of an SPA-H plate strip for a thin hot-rolled container, which belongs to the field of steel material processing and is used for solving the technical problems that the plate shape quality, thickness precision control and corrosion resistance uniformity of the thin hot-rolled SPA-H plate strip in the prior art are required to be further improved, and the whole quality and production efficiency of the product are required to be further improved. The invention further improves the plate shape quality, thickness precision control, corrosion resistance uniformity and production efficiency of the SPA-H plate and strip through molten iron pretreatment, rough smelting, refining, rolling and cooling.

Inventors

  • GUO LIHE
  • YU WENLONG
  • ZHAO DONGHUI
  • WANG LUNING
  • LI ZHENZHONG
  • WANG HUIBIN
  • XU BO
  • YIN WEI
  • WANG HAO

Assignees

  • 本溪北方轧钢有限公司
  • 本溪北营钢铁（集团）股份有限公司

Dates

Publication Date
20260508
Application Date
20260120

Claims (9)

  1. 1. The production process of the SPA-H plate strip for the thin hot-rolled container is characterized by comprising the following steps of: S1, melting iron at 1400-1600 ℃, and then removing sulfur and phosphorus by adopting a blowing method and a top-bottom combined blown converter to obtain pretreated molten iron; s2, adding the pretreated molten iron, scrap steel, a slag former and alloy elements into a converter, smelting for 20-30min at 1620-1680 ℃, transferring into an LF refining furnace for refining, and adding a deoxidizer and alloy micro-adjustment to obtain refined steel; and S3, carrying out continuous casting, rough rolling and finish rolling on the refined steel, and cooling and coiling to obtain the SPA-H plate strip for the thin hot rolling container.
  2. 2. The process for producing SPA-H slab for thin hot rolled container according to claim 1, wherein in step S1, the blowing method comprises the steps of taking argon as a carrier, injecting desulfurizing agent into molten iron at a speed of 8-10kg/min through a spray gun inserted into the molten iron at a depth of 1.0-1.5m, so that the sulfur content in the molten iron is reduced to 0.004%, and the operation of the top-bottom combined blown converter comprises the steps of blowing oxygen at a flow rate of 1.2-1.5Nm 3 /(t.min) at the top of the top-bottom combined blown converter, simultaneously adding dephosphorizing agent into a feed hopper above the mouth of the converter, and blowing argon at a volume flow rate of 0.03-0.15Nm 3 /(t.min) at the bottom, so that the phosphorus content in the molten iron is reduced to 0.01%.
  3. 3. The process for producing the SPA-H plate strip for the thin hot-rolled container according to claim 2, wherein the desulfurizing agent is magnesium particles with the particle size of 0.5-1mm, the dephosphorizing agent is obtained by mixing lime and dolomite according to the mass ratio of 4:1, the concentration of the argon is 99.99%, and the concentration of the oxygen is 99.5%.
  4. 4. The process for producing SPA-H strip for thin hot rolled containers according to claim 1, wherein in step S2, the refining operation in the LF refining furnace comprises transferring molten steel into the LF refining furnace, adding deoxidizer and alloy micro-regulator, blowing argon gas with a concentration of 99.99% from the bottom at a flow rate of 140-160L/min for 15-30min, and stabilizing the temperature of molten steel at 1580-1620 ℃ after refining.
  5. 5. The production process of the SPA-H plate strip for the thin hot rolled container according to claim 1, wherein in the step S2, the mass ratio of the pretreated molten iron to the scrap steel is 9:1-2, the slag former consists of lime and dolomite according to the mass ratio of 5:1, the addition amount of the slag former is adjusted according to the slag alkalinity to ensure the slag alkalinity to be 2.5-3.5, the alloy elements are obtained by mixing copper, chromium and nickel according to the mass ratio of 5:8:1, the deoxidizer is aluminum wires, the alloy micro-adjustment consists of titanium wires and ferrosilicon according to the mass ratio of 1:10, and the addition amount of the alloy elements, the deoxidizer and the alloy micro-adjustment is used for ensuring that the element content in refined steel accords with the following range ,C:0.05-0.12%、Si:0.20-0.50%、Mn:0.20-0.50%、P:0.005-0.065%、S:0.01-0.02%、Cu:0.25-0.55%、Cr:0.30-1.25%、Ni:0.05-0.12%、Ti:0.02-0.05%.
  6. 6. The process for producing SPA-H plate strip for thin hot rolled container according to claim 1, wherein in step S3, the continuous casting operation comprises adding refined steel into a continuous casting machine, and controlling the continuous casting drawing speed to be 1.0-1.3m/min by adopting a crystallizer and terminal electromagnetic stirring technology to obtain a continuous casting blank with the thickness of 230+/-5 mm.
  7. 7. The process for producing SPA-H strip for thin hot rolled containers according to claim 1, wherein in step S3, the rough rolling operation comprises feeding a continuous casting billet into a heating furnace, preserving heat for 3-4 hours at a heating speed of 6-12 ℃ per minute at 1250-1280 ℃, then feeding into a roughing mill, pressing at a total reduction of 70-80% by using a 6-pass rolling mill, and controlling the side pressure of the vertical roll to be 30-50mm by using a vertical roll mill, thereby obtaining a billet with a thickness of 35-50 mm.
  8. 8. The process for producing SPA-H plate strip for thin hot rolled container according to claim 1, wherein in step S3, the finish rolling operation comprises rolling a billet into a roll shape, placing the roll shape into a hot rolling box, after heat preservation for 20-30min at 1020-1050 ℃, spraying hot rolling lubricating oil on the surface of the billet and the rolling surface of a finishing mill group, transferring the billet into the finishing mill group, wherein the pressing groups control the rolling reduction rate of the front 3 frames of the group to be 40-50%, the rolling reduction rate of the rear 4 frames to be gradually reduced to be 15%, and the threading speed to be 10-11m/S, thus obtaining the plate strip with the thickness of 1.8-3.0 mm.
  9. 9. The process for producing SPA-H plate strip for thin hot rolled container according to claim 1, wherein in step S3, the cooling coiling operation comprises the steps of placing the plate strip after finish rolling into a laminar flow cooling device, controlling the cooling speed to be 25-35 ℃ per second, when the final cooling temperature of the plate strip reaches 580-600 ℃, then entering a coiling machine, coiling the plate strip with constant tension of 70-100kN, and after coiling, conveying the plate strip into a creep pit for heat preservation for 2-4 hours, thus finally obtaining the SPA-H plate strip for thin hot rolled container.

Description

Production process of SPA-H plate strip for thin hot-rolled container Technical Field The invention relates to the field of steel material processing, in particular to a production process of an SPA-H plate strip for a thin hot-rolled container. Background SPA-H steel has excellent atmospheric corrosion resistance, so that the SPA-H steel becomes a core steel in the field of container manufacturing, along with the development of the container industry to the light weight and low cost direction, the requirements of thin-specification hot-rolled SPA-H plate strips are increasingly increased, the self weight of the container can be effectively reduced, the logistics transportation cost is reduced, the space utilization rate of the container body can be improved, but the manufacturing process of the plate strips still faces a plurality of technical bottlenecks, and the conventional production process is difficult to meet the high quality requirements. At present, the manufacturing method of the thin hot rolled SPA-H plate strip needs to be further optimized, in the molten iron pretreatment stage, the desulfurization and dephosphorization process is low in efficiency, harmful impurities are not thoroughly removed, residual impurities are easy to influence the purity and mechanical properties of the subsequent steel, in the smelting process, the adding proportion precision of alloy elements is insufficient, and an efficient stirring and dispersing means is lacked, so that the elements are unevenly distributed in molten steel, the corrosion resistance difference of different parts of the plate strip is directly caused, the service life of a container is shortened, if no effective tissue regulation and control measures are adopted in the continuous casting stage, casting blanks with uneven components segregation or grains are easily formed, hidden dangers are buried for the subsequent rolling defects, the heating temperature of the casting blanks is uneven during rough rolling, the soaking time is insufficient, the rolling reduction rate distribution is unreasonable in the finish rolling stage, and the head-tail temperature difference of the plate strip is not optimized, the problems of poor plate shape and over-thickness precision are often caused, and the stress elimination treatment is further omitted after cooling and coiling, and the corrosion resistance stability is further weakened. In view of the technical drawbacks of this aspect, a solution is now proposed. Disclosure of Invention The invention aims to provide a production process of an SPA-H plate strip for a thin hot-rolled container, which is used for solving the technical problems of plate shape quality, thickness precision control, corrosion resistance uniformity, and product overall quality and production efficiency to be further improved in the manufacturing process of the thin hot-rolled SPA-H plate strip in the prior art. The invention aims at realizing the following technical scheme that the production process of the SPA-H plate strip for the thin hot-rolled container comprises the following steps of: S1, melting iron at 1400-1600 ℃, and then removing sulfur and phosphorus by adopting a blowing method and a top-bottom combined blown converter to obtain pretreated molten iron; s2, adding the pretreated molten iron, scrap steel, a slag former and alloy elements into a converter, smelting for 20-30min at 1620-1680 ℃, transferring into an LF refining furnace for refining, and adding a deoxidizer and alloy micro-adjustment to obtain refined steel; and S3, carrying out continuous casting, rough rolling and finish rolling on the refined steel, and cooling and coiling to obtain the SPA-H plate strip for the thin hot rolling container. Further, in the step S1, the blowing method comprises the steps of taking argon as a carrier, spraying desulfurizing agent at the speed of 8-10kg/min through a spray gun inserted into molten iron with the depth of 1.0-1.5m, so that the sulfur content in the molten iron is reduced to 0.004%, and the operation of the top-bottom combined blown converter comprises the steps of blowing oxygen at the top of the top-bottom combined blown converter at the flow rate of 1.2-1.5Nm 3/(t.min), simultaneously adding the dephosphorizing agent into a charging hopper above the mouth of the converter, and blowing argon at the volume flow rate of 0.03-0.15Nm 3/(t.min) at the bottom, so that the phosphorus content in the molten iron is reduced to 0.01%. Further, the desulfurizing agent is magnesium particles with the particle size of 0.5-1mm, the dephosphorizing agent is obtained by mixing lime and dolomite according to the mass ratio of 4:1, the concentration of the argon is 99.99%, and the concentration of the oxygen is 99.5%. Further, in the step S2, the refining operation in the LF refining furnace comprises the steps of transferring molten steel into the LF refining furnace, adding deoxidizer and alloy micro-adjusting agent, blowing argo