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Method for preparing surface coating of high chrome steel

A high-chromium steel and coating technology, applied in the field of electrodeposition, can solve the problems such as the inability to guarantee the quality of the surface coating, achieve the effect of ensuring the performance of use and improving the anti-adhesion performance

Active Publication Date: 2009-09-30
BAOSHAN IRON & STEEL CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, with the development of sour oil and gas fields, the requirements for corrosion resistance of materials are getting higher and higher. High-chromium steel oil casing products suitable for high corrosion resistance have begun to be widely used. Because the chromium content is greater than 10%, the alloy content has reached About 20%, the use of traditional coating methods can no longer guarantee the quality of the surface coating, and a new coating process must be used for surface treatment to ensure the anti-adhesion performance requirements of high-chromium steel oil casing products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Degreasing: Degrease the high chromium steel coupling in an alkaline degreasing agent composed of 40g / L trisodium phosphate, 40g / L sodium carbonate and 30g / L sodium hydroxide. The degreasing temperature is 60°C and the time is until it is clean;

[0019] Weak corrosion: Activated in hydrochloric acid to pre-remove the passivation film on the surface of high-chromium steel, the concentration of hydrochloric acid is 25%, the time is 60sec, and the temperature is 30°C;

[0020] Weak corrosion, nickel plating: at 40°C, activate and cathode electrodeposit nickel in a solution containing hydrochloric acid and nickel chloride, the content of nickel chloride is 150g / L, 25% concentration of hydrochloric acid makes the nickel solution PH ≤ 1, current density 3A / dm 2 , the time is 3 minutes;

[0021] Copper-tin alloy plating layer: Electrodeposited copper-tin alloy plating solution is prepared from sodium cyanide 15g / L, cuprous cyanide 12g / L, sodium hydroxide 20g / L, and sodium st...

Embodiment 2

[0025] Degreasing: Put the high chromium steel coupling into the alkaline degreasing agent composed of trisodium phosphate 26g / L, sodium carbonate 27g / L, and sodium hydroxide 25g / L to degrease. The degreasing temperature is 60°C and the time is as long as it is clean;

[0026] Weak corrosion: Activated in hydrochloric acid to pre-remove the passivation film on the surface of high-chromium steel, the concentration of hydrochloric acid is 25%, the time is 42sec, and the temperature is 30°C;

[0027] Weak corrosion, nickel plating: at 40°C, activate and cathode electrodeposit nickel in a solution containing hydrochloric acid and nickel chloride. The content of nickel chloride is 120g / L, 25% concentration of hydrochloric acid makes the nickel solution PH≤1, and the current density is 3A / dm 2 , the time is 3 minutes;

[0028] Copper-tin alloy plating layer: Electrodeposited copper-tin alloy plating solution is prepared by sodium cyanide 12g / L, cuprous cyanide 8g / L, sodium hydroxid...

Embodiment 3

[0032] Degreasing: Put the high chromium steel coupling into the alkaline degreasing agent composed of trisodium phosphate 32g / L, sodium carbonate 33g / L and sodium hydroxide 35g / L to degrease. The degreasing temperature is 60°C and the time is as long as it is clean;

[0033] Weak corrosion: Activated in hydrochloric acid to pre-remove the passivation film on the surface of high-chromium steel, the concentration of hydrochloric acid is 25%, the time is 50sec, and the temperature is 30°C;

[0034] Weak corrosion, nickel plating: at 40°C, activate and cathode electrodeposit nickel in a solution containing hydrochloric acid and nickel chloride. The content of nickel chloride is 250g / L, 25% concentration of hydrochloric acid makes the nickel solution PH ≤ 1, and the current density is 3A / dm 2 , the time is 3 minutes;

[0035] Copper-tin alloy plating layer: Electrodeposited copper-tin alloy plating solution is prepared by sodium cyanide 20g / L, cuprous cyanide 15g / L, sodium hydrox...

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Abstract

The invention discloses a method for preparing surface coating of high chrome steel. The method comprises the following steps: degreasing, cold washing, weak corrosion, weak corrosion plus nickel plating, cold washing, copper-tin alloy plating, cold washing, passivation, cold-hot washing and molybdenum soaking. Nickel is pre-plated on the high chrome steel, and the copper-tin alloy is plated on the nickel plated surface. Compared with the prior art, the method has the advantages of improving the anti-bonding property of an oil casing connector, realizing the whole shackle of the oil casing connector, and ensuring the service performance of the oil casing in high chrome steel.

Description

technical field [0001] The present invention relates to electrodeposition technology, especially relates to the preparation of copper-tin alloy coating on the surface of high chromium steel oil casing coupling by electrodeposition method, which is a preparation technology for the surface coating of high chromium steel oil casing thread and sealing surface. Improve the anti-adhesion performance of the oil-casing joint. Background technique [0002] Oil casing is a product that must be used in the exploration and development of oil and gas fields. A single oil casing is connected by threads into a pipe string that can withstand various loads of several thousand meters. One of the quality indicators of the connection thread is to ensure repeated loading and unloading. There is no adhesive failure in buckle thread. The oil-casing joint is composed of internal thread and external thread. During use, the thread is tightened and loosened by make-up and breakout. The threaded joint...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/12C25D5/36C25D5/48
Inventor 王琍唐豪清许顺华曹世荣
Owner BAOSHAN IRON & STEEL CO LTD
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