Bright electrochromism method for cold-rolled steel strip

A technology of bright electroplating and cold-rolled steel strip, which is applied in the direction of anodic oxidation, etc., which can solve the problems of insufficient brightness of the coating, serious corrosion of equipment, yellow spots on chrome-plated plates, etc., and achieve the effect of wide application range, light corrosion of equipment, and bright coating

Inactive Publication Date: 2011-04-20
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most widely used in the two-step chromium plating process is the chromium plating electrolyte with chromium anhydride plus sulfuric acid. Most of this chromium plating electrolyte is chromium plating under high concentration chromium anhydride, which seriously corrodes the equipment and has a high temperature (48±2℃ ), high energy consumption
In addition, the chrome-plated plate has problems such as easy to produce macula and insufficient brightness of the coating.

Method used

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  • Bright electrochromism method for cold-rolled steel strip
  • Bright electrochromism method for cold-rolled steel strip
  • Bright electrochromism method for cold-rolled steel strip

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] The cold-rolled steel strip after electrolytic degreasing, water washing and drying is electroplated under the following conditions, and the chrome plating process is as follows:

[0019] In the first step of electroplating the chromium layer, the concentration of chromic anhydride in the bath composition is 120g / L, NH 4 The concentration of F is 1.7g / L, the concentration of mixed rare earth additives (including lanthanum nitrate and cerium nitrate) is 0.7g / L; the temperature of the plating solution is 28°C; the current density is 30A / dm 2 ;The electroplating time is 15s; the second step is electroplating chromium oxide, the concentration of chromic anhydride in the bath composition is 50g / L, NH 4 F concentration is 1.0g / L, NaOH concentration is 6g / L; bath temperature is 20°C; current density is 10A / dm 2 ; Plating time 4s.

[0020] The running speed of the steel belt is 450m / min.

[0021] Measured chrome plating amount: 76mg / m 2 , the amount of chromium oxide: 13mg / ...

Embodiment 2

[0024] The cold-rolled steel strip after electrolytic degreasing, water washing and drying is electroplated under the following conditions, and the chrome plating process is as follows:

[0025] In the first step of electroplating the chromium layer, the concentration of chromic anhydride in the bath composition is 140g / L, NH 4 The concentration of F is 2.0g / L, the concentration of mixed rare earth additives (including lanthanum nitrate, europium nitrate, and praseodymium nitrate) is 1.0g / L; the temperature of the plating solution is 35°C; the current density is 50A / dm 2 ;Electroplating time 13s; The second step is electroplating chromium oxide, the concentration of chromic anhydride in the plating solution is 60g / L, NH 4 F concentration is 1.5g / L, NaOH concentration is 8g / L; bath temperature is 20°C; current density is 14A / dm 2 ; Plating time 5s.

[0026] The running speed of the steel belt is 450m / min.

[0027] Measured chrome plating amount: 100mg / m 2 , the amount of ch...

Embodiment 3

[0030] The cold-rolled steel strip after electrolytic degreasing, water washing and drying is electroplated under the following conditions, and the chrome plating process is as follows:

[0031] In the first step of electroplating the chromium layer, the concentration of chromic anhydride in the bath composition is 150g / L, NH 4 The concentration of F is 2.5g / L, the concentration of mixed rare earth additives (including europium nitrate, praseodymium nitrate, and neodymium nitrate) is 1.2g / L; the temperature of the plating solution is 40°C; the current density is 50A / dm 2 ;Electroplating time 17s; The second step is electroplating chromium oxide, the concentration of chromic anhydride in the plating solution is 68g / L, NH 4 F concentration is 1.7g / L, NaOH concentration is 10g / L; bath temperature is 25°C; current density is 16A / dm 2 ; Plating time 4s.

[0032] The running speed of the steel belt is 450m / min.

[0033] Measured chrome plating amount: 120mg / m 2 , the amount of c...

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Abstract

The invention discloses a bright electrochromism technique for a cold-rolled steel strip. The technique is characterized by comprising the following steps: (1) electroplating a chromium layer, wherein the plating solution comprises the following components: 100-160 g/L of chromic anhydride, 1.5-3.0 g/L of NH4F, and 0.5-1.5 g/L of mixed rare-earth additive; the temperature of the plating solution is between 25 and 40 DEG C; the current density is between 25 and 70 A/dm<2>; and the electroplating time is between 10 and 20 s; and (2) electroplating and oxidizing the chromic layer, wherein the plating solution comprises the following components: 50-75 g/L of chromic anhydride, 0.8-2.5 g/L of NH4F, and 5-15 g/L of NaOH; the temperature of the plating solution is between 15 and 30 DEG C; the current density is between 8 and 20 A/dm<2>; and the electroplating time is between 2 and 6 s. In the invention, the performance advantages of the plating solution are fully used to obtain a uniform chromium-plated plate with bright plating layer and good quality, thus further improving the surface quality of the chromium-plated plate. Meanwhile, the method has the advantages of low corrosion to equipment, low temperature and effective reduction of energy consumption.

Description

technical field [0001] The invention relates to a treatment method for chrome plating on the surface of a cold-rolled steel strip, which belongs to the chrome plating process in the electroplating technology. Background technique [0002] At present, tin-plated steel strips are generally used as packaging materials at home and abroad, but tin resources are scarce and the price is high. Chrome-plated steel strips are gradually replacing tin-plated steel strips. Practice has proved that compared with tin plate, chrome plate is more suitable for packaging exposed to outdoor, salt spray and other fields, such as crown caps used in a large number of beer bottles. In the packaging of alkaline medicines such as sodium hydroxide, the performance of chrome-plated plates is also better than that of tin-plated plates. In addition, when used to make canned meat and canned vegetables containing sulfide, tinplate will produce black sulfide, and chrome plate is suitable for the packaging ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D7/06C25D3/04C25D11/34
Inventor 高发明于升学侯莉刘玉文白振华
Owner YANSHAN UNIV
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