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Cold annealing and pickling technique for 204 Cu stainless steel with thickness of 1.5-2.0 mm

A stainless steel, cold-rolled annealing technology, applied in the direction of manufacturing tools, furnace types, furnaces, etc., can solve the problems of uneven surface oxide scale, residual oxide scale, and uneven oxide scale on the surface of strip steel, so as to improve the surface quality of products , Improve the effect of brush roller mode and reduce the reference temperature

Inactive Publication Date: 2019-02-22
ZHANGJIAGANG POHANG STAINLESS STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Due to the existing technology of 204Cu steel grade stainless steel after cold rolling and rolling, the steel plate comes out of the continuous annealing furnace during annealing, and the full width of the upper and lower surfaces of the strip steel is irregular, and black oxide scales are piled up, and after electrolysis of sodium sulfate (Na 2 SO 4 solution electrolysis), mixed acid (HF solution + HNO 3 solution) after pickling, the surface of the steel plate does not have agglomerated black scale, but there are agglomerated white spot defects on the upper and lower sides of the strip steel, which cannot be eliminated by grinding with sandpaper, which seriously affects the quality of the stainless steel plate and cannot be used for surface purposes, thereby affecting product sales.
[0013] After a lot of research and analysis, it is concluded that after the horizontal continuous annealing of 204Cu stainless steel, the surface oxide skin of the steel plate is thicker, and the furnace temperature plays a decisive role in the thickness of the oxide skin, so the above defects are mainly caused by the surface oxide skin during furnace annealing. Uneven generation leads to
The reasons: 1. The annealing temperature benchmark is too broad. At present, the thickness of 204Cu stainless steel after cold rolling and rolling is 0-2.0mm, and the width is not limited. The annealing temperature benchmark in this thickness range only divides 2 temperature benchmark intervals; (2) The annealing temperature is too high , the current annealing reference temperature is too high, especially the Z1&Z2 temperature is too high, the steel plate absorbs too much heat to increase the thickness of the scale on the surface of the strip, and the high temperature increases the unevenness of the scale on the surface of the strip, and the scale remains after pickling There are group-shaped white spot defects; (3) The brush roller is not strong enough to destroy the oxide scale on the surface of the strip, resulting in residual oxide scale on the surface

Method used

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  • Cold annealing and pickling technique for 204 Cu stainless steel with thickness of 1.5-2.0 mm
  • Cold annealing and pickling technique for 204 Cu stainless steel with thickness of 1.5-2.0 mm
  • Cold annealing and pickling technique for 204 Cu stainless steel with thickness of 1.5-2.0 mm

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 1.5-2.0mm thick 204Cu stainless steel cold annealing and pickling process, including cold rolling annealing step and mixed pickling step, cold rolling annealing step Z1, Z2, Z3, Z4, Z5, Z6, There are 10 heating zones Z7, Z8, Z9, Z10 and different temperatures are set. The temperature reference (°C) is as follows:

[0033]

[0034] In the table: TV=thickness of strip steel×running speed of strip steel, Kvar—represents the increased temperature value for every increase of 1 TV value.

[0035] The setting of the brush roller in the mixed acid pickling step is as follows:

[0036] parameter

1# brush roller

2# brush roller

3# brush roller

4# brush roller

Current (A)

15.4

15.4

10.7

10.7

speed(rmp)

600

600

600

600

Load(mm)

2

2

2

2

[0037] The material of the brush roller in this embodiment is nylon.

[0038] The neutral salt electrolysis benchmark in the neutral salt electrolysis step...

Embodiment 2

[0044] 1.5-2.0mm thick 204Cu stainless steel cold annealing and pickling process, including cold rolling annealing step and mixed pickling step, cold rolling annealing step Z1, Z2, Z3, Z4, Z5, Z6, There are 10 heating zones Z7, Z8, Z9, Z10 and different temperatures are set. The temperature reference (°C) is as follows:

[0045]

[0046] In the table: TV=strip thickness×strip running speed, Kvar—represents the increased temperature value for every increase of 1 TV value;

[0047] The setting of the brush roller in the mixed acid pickling step is as follows:

[0048]

[0049] The material of the brush roller in this embodiment is nylon.

[0050] The neutral salt electrolysis benchmark in the neutral salt electrolysis step is as follows:

[0051]

[0052] The mixed acid standard in the mixed acid pickling step is as follows:

[0053]

[0054] The 204Cu stainless steel plate with a thickness of 1.5-2.0mm was obtained through the steps set in the above-mentioned Ex...

Embodiment 3

[0056] 1.5-2.0mm thick 204Cu stainless steel cold annealing and pickling process, including cold rolling annealing step and mixed pickling step, cold rolling annealing step Z1, Z2, Z3, Z4, Z5, Z6, There are 10 heating zones Z7, Z8, Z9, Z10 and different temperatures are set. The temperature reference (°C) is as follows:

[0057]

[0058] In the table: TV=thickness of strip steel×running speed of strip steel, Kvar—represents the increased temperature value for every increase of 1 TV value.

[0059] The setting of the brush roller in the mixed acid pickling step is as follows:

[0060]

[0061] The material of the brush roller in this embodiment is nylon.

[0062] The neutral salt electrolysis benchmark in the neutral salt electrolysis step is as follows:

[0063]

[0064] The mixed acid standard in the mixed acid pickling step is as follows:

[0065]

[0066] The 204Cu stainless steel plate with a thickness of 1.5-2.0 mm was obtained through the steps set in the...

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Abstract

The invention discloses a cold annealing and pickling technique for a 204 Cu stainless steel with thickness of 1.5-2.0 mm, which comprises a cold roll annealing step and a mixed-acid pickling step. The cold roll annealing step is used for setting different temperatures of heating zones from Z1 to Z10 in combustion chambers of an annealing furnace. Working intensity of the brush rolls is adjusted through the mixed-acid pickling step, wherein current of 1 # brush roll and 2 # brush roll is 15.4A to 26.8A, the rotating speed is 600rmp to 800rpm, and load is 2mm to 3mm; and current of 6 # brush roll and 4 # brush roll is 10.7A to 16.4A, the rotating speed is 600rmp to 800rpm, and load is 2mm to 3mm. The cold annealing and pickling technique for the 204 Cu stainless steel with thickness of 1.5-2.0 mm has the advantage of being suitable for preparing the 204 Cu stainless steel with thickness of 1.5-2.0 mm, and beneficial effects that annealing temperature benchmarks are refined according tothickness of the stainless steel, thickness of the oxide skin is reduced, uniformity of the oxide skin is improved, destructive power of the brush rolls to the oxide skin on surface is enhanced, upperand low surfaces of an obtain stainless steel plate has no white spots over full width, and the product surface quality is improved.

Description

technical field [0001] The invention belongs to the technical field of stainless steel production, and in particular relates to a cold annealing process for white spots on the surface of stainless steel. Background technique [0002] According to its metal structure, stainless steel is divided into five categories: austenitic stainless steel, ferritic stainless steel, austenitic-ferritic (duplex) stainless steel, martensitic stainless steel and precipitation hardening stainless steel. At present, the commonly used stainless steel is mainly austenitic Stainless steel accounts for about 80% of the market share, among which 304 stainless steel is more popular. According to its chemical composition, austenitic stainless steel is divided into two series of chromium-nickel series (300 series in the United States) austenitic stainless steel and chromium-manganese series (200 series in the United States) austenitic stainless steel. Chromium-manganese (200 series) austenitic stainle...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/26C21D9/56C21D11/00C25F1/06C25F7/00
CPCC21D1/26C21D9/56C21D11/00C25F1/06C25F7/00
Inventor 白伟伟刘奇毅
Owner ZHANGJIAGANG POHANG STAINLESS STEEL
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