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Pickling method for hot rolled double-phase stainless steel plates

A stainless steel plate, pickling technology, applied in the field of stainless steel pickling, can solve the problems of low metal ion content, high pickling temperature, slow pickling speed, etc., to reduce production costs, improve production efficiency, and meet the pickling surface quality Effect

Inactive Publication Date: 2012-02-01
BAOSTEEL SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Use H 2 SO 4 Pre-pickling can also reduce NO x generation, reduce gas pollution, but require the use of new acid in the pre-pickling stage, high pickling temperature, and require low metal ion content in the pickling solution, which is difficult to control
Pickling with this process, the pickling speed is slow, the steel plate needs to swing back and forth on the roller table, and the online pickling rhythm time of each plate needs to be pickled for about 25 minutes

Method used

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  • Pickling method for hot rolled double-phase stainless steel plates
  • Pickling method for hot rolled double-phase stainless steel plates
  • Pickling method for hot rolled double-phase stainless steel plates

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Embodiment 1: Pickling of S31803 duplex stainless steel hot-rolled steel plate

[0027] The thickness of the steel plate is 10mm, the width is 2000mm, and the length is 8000mm.

[0028] After the surface of the steel plate is shot blasted, it is sent into the pre-washing cover (section) by the roller table, and then enters the pre-pickling cover (section) for pre-pickling. The composition of the pre-pickling liquid is: HNO 3 140g / l, HF 80g / l, metal ion content 25g / l, temperature 45°C. After pre-pickling, the steel plate enters the water washing section, and after the water washing section, the steel plate enters the final pickling cover (section) for pickling. The acid composition is: HNO 3 200g / l, HF 55g / l, metal ion content in acid 25g / l, temperature 45°C, final water washing, air curtain blowing, and drying after final pickling. The steel plate advances continuously on the roller table at a speed of 1m / min, and the online pickling rhythm time of each plate is 10m...

Embodiment 2

[0029] Embodiment 2: Pickling of S31803 duplex stainless steel hot-rolled steel plate

[0030] The thickness of the steel plate is 10mm, the width is 2000mm, and the length is 8000mm.

[0031] After the surface of the steel plate is shot blasted, it is sent into the pre-washing cover (section) by the roller table, and then enters the pre-pickling cover (section) for pre-pickling. The composition of the pre-pickling liquid is: HNO 3 180g / l, HF 100g / l, metal ion content 40g / l, temperature 50°C. After pre-pickling, the steel plate enters the water washing section, and after the water washing section, the steel plate enters the final pickling cover (section) for pickling. The acid composition is: HNO 3 280g / l, HF 75g / l, metal ion content in acid 40g / l, temperature 50°C, final water washing, air curtain blowing, and drying after final pickling. The steel plate advances continuously on the roller table at a speed of 2m / min, and the online pickling rhythm time of each plate is 5m...

Embodiment 3

[0032] Embodiment 3: Pickling of S32304 duplex stainless steel hot-rolled steel plate

[0033] The thickness of the steel plate is 10mm, the width is 2000mm, and the length is 8000mm.

[0034]After the surface of the steel plate is shot blasted, it is sent into the pre-washing cover (section) by the roller table, and then enters the pre-pickling cover (section) for pre-pickling. The composition of the pre-pickling liquid is: HNO 3 165g / l, HF 85g / l, metal ion content 30g / l, temperature 40°C. After pre-pickling, the steel plate enters the water washing section, and after the water washing section, the steel plate enters the final pickling cover (section) for pickling. The acid composition is: HNO 3 220g / l, HF 60g / l, metal ion content in acid 30g / l, temperature 40°C, final water washing, air curtain blowing, and drying after final pickling. The steel plate advances continuously on the roller table at a speed of 2.5m / min, and the online pickling rhythm time of each plate is 4m...

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Abstract

Provided is a pickling method for hot rolled double-phase stainless steel plates. According to the invention, pickling with two mixed acids is utilized; a mixed solution of HNO3 and HF is used for pickling both in a prepickling stage and a final pickling stage, wherein, in the prepickling stage, a prepickling solution comprises 140 to 180 g / l of HNO3 and 80 to 100 g / l of HF, the content of metal ions in acids is 5 to 40 g / l, in the final pickling stage, a final pickling solution comprises 200 to 280 g / l of HNO3 and 55 to 75 g / l of HF, and the content of metal ions in acids is 5 to 40 g / l; thesteel plates are subjected to the steps of prepickling and final pickling for 11.3 to 34 minutes. The invention enables on-line pickling time for each steel plate to be shortened to no more than 10 minutes, production efficiency to be greatly improved and pickling surface quality to meet on-site requirements and requirements of users; in the invention, steel plates continuously move forward on a roller way and do not need to swing to and fro, and the special process of passivation treatment is left out, thereby substantially reducing production cost.

Description

technical field [0001] The invention relates to the technical field of stainless steel pickling, in particular to a pickling method for a hot-rolled duplex stainless steel plate. Background technique [0002] Pickling of stainless steel is to use acid solution to carry out acid chemical treatment on the surface of stainless steel with oxide skin on the surface, remove the oxide layer and chromium-poor layer formed on the surface of stainless steel during high temperature thermal processing, and simultaneously passivate to form no oxide layer residue, And bright white surface state. [0003] Among stainless steel products, pickling of 300 series stainless steel such as 304, 316 and 321 is the most representative. The 300 series stainless steels are all single-phase austenitic stainless steels. Because they contain more alloying elements such as Cr, Ni, Mo, Ti, etc., the composition and structure of the scale formed during thermal processing are obviously different from those...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23G1/08
Inventor 王国富周庆军齐慧滨徐松乾
Owner BAOSTEEL SPECIAL STEEL CO LTD
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