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Production method for continuous pickling of hot rolled superaustenitic stainless strip steel

A technology of austenitic stainless steel and production method, applied in grinding machines, grinding/polishing equipment, manufacturing tools, etc., can solve the problems of poor mechanical descaling effect, poor surface quality of strip steel, slow pickling speed, etc.

Active Publication Date: 2014-05-28
WISDRI ENG & RES INC LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the scale density and stability of hot-rolled super austenitic stainless steel are relatively strong, which will reduce the degree of damage of scale on the surface of hot-rolled super austenitic stainless steel strip during mechanical descaling, and the effect of mechanical descaling is poor. As a result, the pickling speed in the pickling section is very slow, which limits the output, and the surface quality of the strip after pickling is not very good
[0003] At present, the production process of general NO.1 surface grade super austenitic stainless steel strip is: use hot-rolled super austenitic stainless steel strip as raw material, and then go through annealing + mechanical descaling + sulfuric acid pre-pickling + mixed acid pickling, Patent 201210335688.X improved it by adding catalysts NaCl and H to the sulfuric acid pre-pickling solution 2 o 2 , the main function of the catalyst is to destroy the scale structure. At the same time, by increasing the concentration of sulfuric acid and mixed acid pickling, the pickling speed is increased to 13-18m / min, but the pickling speed is still slow, and the acid pickling speed The surface quality of strip steel after washing can meet the requirements of NO.1 product
but not very good

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach

[0036] The technical scheme of the present invention has more optimized implementation mode as follows:

[0037] More optimally, in step 1) the shot blasting machine throws 1150-1250 kg / min, and the shot blasting machine rotates at 2200-2275 rpm.

[0038] More optimally, in step 2) the steel strip after shot blasting and descaling is pretreated by electrolytic pickling with sulfuric acid, wherein H 2 SO 4 The concentration is 340-360g / L, the pickling temperature is 78-82°C, the metal ion concentration is 45-55g / L, and catalyst H is added to the solution 2 o 2, the concentration is 25-35g / L, and the pickling speed is 24-26m / min.

[0039] More optimally, step 3) is subjected to sulfuric acid electrolytic pickling, and then to grinding and scrubbing, the motor speed is 1100-1200 rpm, and the motor current is 350-370A.

[0040] More optimally, in step 4) after grinding and scrubbing, the strip passes through a sulfuric acid pickling tank, wherein H 2 SO 4 The concentration i...

Embodiment 1

[0044] The annealed steel strip is subjected to shot blasting and descaling. The shot blasting machine throws 1150kg / min, and the shot blasting machine rotates at 2200rpm.

[0045] The steel strip after shot blasting and descaling is pretreated by electrolytic pickling with sulfuric acid, wherein H 2 SO 4 The concentration is 340g / L, the pickling temperature is 78°C, the metal ion concentration is 45g / L, and catalyst H is added to the solution 2 o 2 , the concentration is 25g / L, and the pickling speed is 24m / min.

[0046] After sulfuric acid electrolytic pickling, then grind and scrub, the motor speed is 1100rpm, and the motor current is 350A.

[0047] After grinding and scrubbing, the strip passes through a sulfuric acid pickling tank, in which H 2 SO 4 The concentration is 230g / L, the pickling temperature is 83°C, the metal ion concentration is 45g / L, and the pickling speed is 24m / min.

[0048] After pickling with sulfuric acid, the strip passes through a mixed acid pi...

Embodiment 2

[0052] The annealed steel strip is subjected to a shot blasting machine with a shot amount of 1250kg / min and a shot blasting machine speed of 2275rpm.

[0053] The steel strip after shot blasting and descaling is pretreated by electrolytic pickling with sulfuric acid, wherein H 2 SO 4 The concentration is 360g / L, the pickling temperature is 82°C, the metal ion concentration is 55g / L, and catalyst H is added to the solution 2 o 2 , the concentration is 35g / L, and the pickling speed is 26m / min.

[0054] After sulfuric acid electrolytic pickling, then grinding and scrubbing, the motor speed is 1200rpm, and the motor current is 370A.

[0055] After grinding and scrubbing, the strip passes through a sulfuric acid pickling tank, in which H 2 SO 4 The concentration is 270g / L, the pickling temperature is 87°C, the metal ion concentration is 55g / L, and the pickling speed is 26m / min.

[0056] After pickling with sulfuric acid, the strip passes through a mixed acid pickling tank, t...

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Abstract

The invention discloses a production method for continuous pickling of hot rolled superaustenitic stainless strip steel. The production method comprises the following steps: strip steel shot blasting and descaling after annealing; electrolytic pickling pretreatment with sulfuric acid; grinding and scrubbing; treatment in a sulfuric acid pickling bath; treatment in a mixed acid pickling bath; treatment in another mixed acid pickling bath, wherein the concentration of nitric acid in the bath is 150-250g / l, the concentration of hydrofluoric acid in the bath is 50-70g / l, the concentration of metal ions in the bath is 5-20g / l, the acid liquor temperature is 50-65 DEG C and the pickling speed is 22-28m / min. The production method has the beneficial effects that by adjusting the casting amount and rotating speed of a shot blasting machine, the pickling process, the acid liquor concentration, the acid liquor temperature and the acid liquor components, the strip steel pickling speed can be effectively increased, the yield can be increased and a good NO.1 surface can be obtained.

Description

technical field [0001] The invention relates to a continuous pickling production method for hot-rolled super austenitic stainless steel strips, belonging to the field of hot-rolled stainless steel annealing and pickling production. technical background [0002] During the finishing rolling process of hot-rolled super austenitic stainless steel strip, a layer of dense oxide scale will be formed on the surface of the strip steel. After annealing in a continuous annealing furnace, the thickness of the oxide layer will become thicker. After annealing, it is necessary Use a scale breaker and a shot blasting machine to remove most of the oxide scale on the surface of the strip steel. After the general hot-rolled stainless steel such as austenitic stainless steel and ferritic stainless steel is mechanically broken by the scale breaker and shot blasting machine, the surface of the strip steel is about 90% of the scale is removed. However, the scale density and stability of hot-roll...

Claims

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Application Information

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IPC IPC(8): C23G1/08C25F1/06B24B27/033B24C1/08
Inventor 李勇华
Owner WISDRI ENG & RES INC LTD
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