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CN-121755563-B - Stainless steel online solid solution acid-free descaling method capable of adjusting roughness

CN121755563BCN 121755563 BCN121755563 BCN 121755563BCN-121755563-B

Abstract

The invention discloses an online solid solution acid-free descaling method for stainless steel with adjustable roughness, which comprises the steps of raw material preparation, steelmaking, continuous casting, hot rolling and solid solution treatment, wherein the process enters the acid-free descaling process after the solid solution treatment, the specific process comprises the steps of treating the stainless steel strip after the solid solution treatment by an S roller and descaling, wherein the surface temperature of a steel coil is not higher than 50 ℃, the stainless steel strip after the descaling is subjected to surface descaling by EPS treatment, the EPS treatment is variable-pass treatment, the variable-pass treatment is one of one pass, two passes and more than three passes, the stainless steel strip after the EPS treatment is brushed by a roller brush containing silicon carbide abrasive, the brushing is regulated by adopting a light brush mode, a medium brush mode and a heavy brush mode, the stainless steel strip after the brushing is rinsed, the stainless steel strip after the rinsing treatment is subjected to drying treatment, and the stainless steel strip after the rinsing treatment is coiled into a finished steel coil by a coiling machine.

Inventors

  • WANG SHAOFENG
  • SUN HONGJUN
  • SUN SHUHONG
  • YUAN LIJUN
  • HE LONG

Assignees

  • 杭州泰恩智达装备科技有限公司

Dates

Publication Date
20260508
Application Date
20260305

Claims (9)

  1. 1. The online stainless steel solid solution acid-free descaling method with adjustable roughness comprises raw material preparation, steelmaking, continuous casting, hot rolling and solid solution processes, and is characterized in that the solid solution process is an online solid solution process by utilizing the surface waste heat of a steel coil, and the online solid solution process enters the acid-free descaling process after the solid solution process, and the specific process comprises the following steps: (1) The stainless steel strip after the solid solution process is treated by an S roller and is subjected to scale breaking treatment; (2) Surface descaling is carried out on the stainless steel strip subjected to the descaling treatment through EPS treatment, wherein the EPS treatment adopts an abrasive slurry injection technology, the EPS treatment is variable-pass treatment, and the variable pass is one of one pass, two passes and three passes; (3) Brushing the stainless steel strip subjected to EPS treatment by adopting a roller brush, wherein the brushing is regulated by adopting a light brushing mode, a medium brushing mode and a heavy brushing mode; (4) Rinsing the stainless steel strip after the brushing treatment; (5) Drying the rinsed stainless steel strip, and then coiling the stainless steel strip into a finished steel coil by a coiling machine; In the step (2), when EPS treatment is carried out for one pass, a light brushing mode is selected, and the surface roughness of the stainless steel strip is reduced by 0.1-0.5 mu m; Selecting a middle brushing mode when EPS treatment is carried out for two passes, wherein the surface roughness of the stainless steel strip is reduced by 0.5-1.0 mu m; When EPS is processed for three times, a re-brushing mode is selected, and the surface roughness of the stainless steel strip is reduced by more than 1.0 mu m.
  2. 2. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 1, wherein the temperature of the waste heat on the surface of the steel coil after the hot rolling process is 800-900 ℃, the steel coil is connected with a heating furnace, the heating furnace is provided with different target heating temperatures and heat preservation time according to different materials, and after the heating furnace is heated and heat preserved, the steel coil is rapidly cooled, and the cooling speed is more than 30 ℃ per second, so that online solid solution is realized.
  3. 3. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 1, wherein in the step (3), a roller brush containing silicon carbide abrasive is adopted, the strip steel speed of the stainless steel is 20-150 m/min, and the proportion of the silicon carbide abrasive in the brush hair is 15-35%.
  4. 4. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 1, wherein the granularity of the silicon carbide abrasive adopting a light brush mode is 500-1500 meshes, the diameter of the brush hair is 0.3-0.5 mm, or the diameter of the brush hair adopts superfine brush hair, and the diameter of the superfine brush hair is 0.02-0.2 mm; the granularity of the silicon carbide abrasive in the middle brush mode is 180-320 meshes, and the diameter of the brush hair is 0.5-0.7 mm; The granularity of the silicon carbide abrasive in the heavy brushing mode is 60-150 meshes, and the diameter of the brush hair is 0.8-1.0 mm.
  5. 5. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 1, wherein the motor speed in a light brush mode is 500-800 RPM, the brush roll rolling reduction is 0-2 mm, the load power of a single bristle is 20-50 kW, and the water spray quantity of the single bristle is 80-120L/min, wherein the water pressure of the single bristle is 2-4 bar; The motor speed in the middle brush mode is 800-1100 RPM, the brush roll rolling reduction is 2-3 mm, the load power of the single bristle is 50-90 kW, single bristle with water pressure of 2-4 bar the water spraying amount is 120-250L/min; The motor speed in the heavy brush mode is 1100-1300 RPM, the brush roll rolling reduction is more than 3mm, the load power of the single bristle is 90-160 kW, single water pressure of 2-4 bar the water spraying quantity of the brush hair is 250-400L/min.
  6. 6. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 3, wherein the brush bristles of the roller brush containing silicon carbide abrasive are made of nylon materials, the S roller and the EPS roller are rubber rollers, and the casting slurry for EPS treatment comprises solid particles and working fluid, wherein the working fluid comprises water and an antirust agent.
  7. 7. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 1, wherein the grain size of the steel grit treated by EPS is 0.1-1.0 mm, and the casting speed is 25-110 m/s.
  8. 8. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 7, wherein during the first pass of EPS treatment, the grain size of the steel grit is 0.5-1.0 mm, and the casting speed is 50-110 m/s; during the second pass of EPS treatment, the grain size of the steel sand is 0.3-0.5 mm, and the casting speed is 35-60 m/s; during the third pass of EPS treatment, the grain size of the steel sand is 0.1-0.4 mm, and the casting speed is 25-40 m/s.
  9. 9. The method for online solid solution acid-free descaling of stainless steel with adjustable roughness according to claim 1, wherein the roughness of rollers in the solid solution process and the descaling treatment process is 0.6-0.8 mu m, and the roughness of S rollers and EPS rollers is 1-7 mu m.

Description

Stainless steel online solid solution acid-free descaling method capable of adjusting roughness Technical Field The invention belongs to the field of stainless steel acid-free descaling production technology, and particularly relates to a roughness-adjustable stainless steel online solid solution acid-free descaling method. Background The traditional stainless steel descaling process mainly comprises the following steps of uncoiling, welding, straightening and descaling, shot blasting, sulfuric acid pre-pickling, scrubbing, nitric acid and hydrofluoric acid mixed acid pickling, multi-stage water spray flushing, hot water rinsing, drying, oiling and coiling. The traditional dry shot blasting is used in the shot blasting process, the diameter of the used shot is generally 1-3 mm, and different shapes such as shot, steel wire cutting and the like can be used to improve the shot blasting descaling efficiency. The shot blasting motor used is 7.5, 15, 22 and 30kW, the shot blasting motor is usually used in a 15-30 kW interval according to different working conditions and requirements, the motor rotating speed is 2000-3000 RPM), the higher the throwing speed is, the larger the impact force is, the better the descaling effect is, but the roughness is obviously influenced, the throwing speed is generally 60-80 m/s, the surface descaling effect is optimally Sa2.5, and in order to improve the descaling speed, the residual oxide skin can only reach Sa2.0 generally and is jointly treated by pickling. Dry blasting is essentially a surface bombardment process by impacting a surface with a high-speed shot. The size, material, shape, velocity and throw of the projectile directly determine the surface roughness. The larger the shot, the faster the speed, and the higher the hardness, the larger the surface roughness values (Ra, rz) obtained, and the rougher the surface becomes. Conversely, a relatively smooth but matte surface can be achieved with fine pellets. The shot-blasted surface can form uniform and nondirectional pitted/rough surfaces, the surface is favorable for the adhesion of subsequent coatings, but the stainless steel surface does not need a coating, so that the dry shot-blasting is unfavorable for the roughness control of the stainless steel surface, the roughness is often larger, and the stainless steel surface needs to be treated together with pickling. At present, the surface of stainless steel is descaled by pre-pickling with sulfuric acid, mainly preheating and preliminary pickling of steel strip, and stripping most of oxide scale, especially FeO and Fe 3O4. The descaling of the stainless steel surface uses mixed acid pickling of nitric acid and hydrofluoric acid, which becomes a core link of stainless steel pickling. The 304 stainless steel scale contains chromium oxides (e.g., cr 2O3) that are difficult to remove, and must be mixed with acid having strong oxidizing and complexing capabilities. Nitric acid (HNO 3) is used for oxidation in the descaling of the stainless steel surface to promote passivation of the stainless steel, so that a compact passivation film is formed on the stainless steel surface, the glossiness is ensured, and excessive corrosion is prevented. However, in the prior art, the use of strong acids has the effect of descaling the stainless steel surface, and the stainless steel surface roughness is such that the strong acid generally acts as a "smoothing" or "finishing" of the stainless steel surface, and the strong acid pickling is a chemical etching process that preferentially dissolves the protrusions, microcracks, and areas damaged and activated by machining of the stainless steel surface. Thus, sharp peaks and valleys caused by shot blasting can be reduced, the stainless steel surface profile becomes relatively smooth, the sharpness of the surface is reduced, and finally the stainless steel is formed into a silvery white matte surface. However, the acid mist generated in the pickling and descaling process seriously affects the operating environment of workers, the waste acid treatment cost is high, the treatment is improper and the environment is easily polluted, in addition, the stainless steel can absorb hydrogen atoms in the pickling process, particularly high-strength or sensitized steel, hydrogen embrittlement is easy to generate, and cracks or stress corrosion cracking are caused. The existing acid-free descaling process (such as EPS) solves the environmental protection problem, but generally has the defects of insufficient control capability on the surface roughness of the steel plate and difficulty in flexibly adjusting the surface state according to the requirements of the final product. Disclosure of Invention The invention provides a stainless steel online solid solution acid-free descaling method with adjustable roughness, which adopts an online solid solution process and performs acid-free descaling on the upper surface and the lower surface of a steel belt. In order