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Continuous pickling production method of hot-rolled duplex stainless steel strip

A technology of duplex stainless steel and production method, which is used in grinding machines, grinding/polishing equipment, manufacturing tools, etc., can solve the problems of slow pickling speed, not very good, and the surface quality of strip steel is not very good, so as to improve the output , Improve the effect of pickling speed

Active Publication Date: 2016-06-01
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 duplex stainless steel are relatively strong, which will reduce the damage degree of scale on the surface of hot-rolled duplex stainless steel strip during mechanical descaling, and the effect of mechanical descaling is poor, resulting in The pickling speed 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 duplex stainless steel is: use hot-rolled duplex stainless steel as raw material, and then go through annealing + mechanical scale breaking + sulfuric acid pre-pickling + mixed acid pickling, which is improved by patent 200910227930.X. Add catalysts NaCl and H to the sulfuric acid pre-pickling solution 2 o 2 , the main function of the catalyst is to destroy the oxide scale structure. At the same time, by increasing the concentration of sulfuric acid and mixed acid pickling, the pickling speed is increased to 10-13m / 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 and descaling shot blasting machine has a projection rate of 975-1025 kg / min, and a shot blasting machine rotation speed of 2075-2125 rpm.

[0038] More optimally, step 2) H in electrolytic pickling pre-pickling 2 SO 4 The concentration is 280-320g / L, the pickling temperature is 78-82°C, the metal ion concentration is 40-60g / L, and catalyst H is added to the solution 2 o 2, the concentration is 20-30g / L, the current is 1400-1600A, and the pickling speed is 18-22m / min.

[0039] More optimally, step 3) the rotation speed of the grinding and scrubbing motor is 900-1100 rpm, and the motor current is 315-325A.

[0040] More optimally, step 4) H in the sulfuric acid pickling tank 2 SO 4 The concentration is 240-260g / L, the pickling temperature is 83-87°C, the metal ion concentration is 45-55g / L, and the pickling speed is ...

Embodiment 1

[0044] The annealed steel strip is subjected to shot blasting and descaling. The shot blasting machine throws 975kg / min, and the shot blasting machine rotates at 2075rpm.

[0045] After shot blasting and descaling, the strip is pre-pickled with sulfuric acid electrolytic pickling, where H 2 SO 4 The concentration is 280g / L, the pickling temperature is 78°C, the metal ion concentration is 40g / L, and catalyst H is added to the solution 2 o 2 , the concentration is 20g / L, the current size is 1400A, and the pickling speed is 18m / min.

[0046] After sulfuric acid electrolytic pickling, then grind and scrub, the motor speed is 900rpm, and the motor current is 315A.

[0047] After grinding and scrubbing, the strip passes through a sulfuric acid pickling tank, in which H 2 SO 4 The concentration is 240g / L, the pickling temperature is 83°C, the metal ion concentration is 45g / L, and the pickling speed is 18m / min.

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

Embodiment 2

[0052] The annealed steel strip is subjected to shot blasting and descaling. The shot blasting machine throws 1025kg / min, and the shot blasting machine rotates at 2125rpm.

[0053] After shot blasting and descaling, the strip is pre-pickled with sulfuric acid electrolytic pickling, where H 2 SO 4 The concentration is 320g / L, the pickling temperature is 82°C, the metal ion concentration is 60g / L, and catalyst H is added to the solution 2 o 2 , the concentration is 30g / L, the current size is 1600A, and the pickling speed is 22m / min.

[0054] After sulfuric acid electrolytic pickling, then grind and scrub, the motor speed is 1100rpm, and the motor current is 325A.

[0055] After grinding and scrubbing, the strip passes through a sulfuric acid pickling tank, in which H 2 SO 4 The concentration is 260g / L, the pickling temperature is 87°C, the metal ion concentration is 55g / L, and the pickling speed is 22m / min.

[0056] After pickling with sulfuric acid, the strip passes throu...

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Abstract

The invention discloses a production method for continuous pickling of hot rolled duplex stainless strip steel. The production method comprises the following steps: shot blasting and descaling after annealing; electrolytic pickling and pre-pickling 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 100-150g / l, the concentration of hydrofluoric acid in the bath is 35-55g / l, the concentration of metal ions in the bath is 5-20g / l, the acid liquor temperature is 45-65 DEG C and the pickling speed is 10-25m / 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 duplex 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 duplex stainless steel strip steel, a dense oxide layer 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. The scale machine and shot blasting machine remove most of the oxide scale on the surface of the strip steel. After general stainless steel such as austenitic stainless steel and ferritic stainless steel are mechanically broken by the scale breaker and shot blasting machine, about 90% of the surface of the strip steel is oxidized. The iron sheet was removed. However, the scale density and stability of hot-rolled duplex stainless steel are relatively strong, which will r...

Claims

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Application Information

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