Hard chromium electroplating method

A technology for electroplating hard chromium and chromium layer, which is applied in the field of electroplating, can solve the problems of incomplete chromium layer, poor bonding force between chromium layer and substrate, etc., and achieve the effect of ensuring bonding force

Active Publication Date: 2013-02-13
CHINA HANGFA SOUTH IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention provides a method for electroplating hard chromium to solve the problems in the prior art that the bonding force between the chrom

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Cast superalloy parts are selected as parts to be plated. Dry-blow quartz sand on the surface of the parts to be plated, the particle size of the dry quartz sand is 70 mesh, and the compressed air pressure is 0.3MPa.

[0029] The electroplating system is set up, the lead plate electrode is used as the anode, the parts to be plated are used as the cathode, and the composition of the chromium-containing electroplating solution includes 225g / L of chromic anhydride CrO 3 and 2.25g / L sulfuric acid H 2 SO 4 .

[0030] at 70A / dm 2 Precharge the surface of the part to be plated with a current density of 2 minutes; then, at 20A / dm 2 Continue to chrome-plate the surface of the part to be plated at a current density of 180 minutes.

[0031] Heat the chrome-plated parts to 180°C and keep it warm for 3 hours to remove hydrogen.

Embodiment 2

[0033] Cast superalloy parts are selected as parts to be plated. Dry-blow quartz sand on the surface of the parts to be plated. The particle size of the dry quartz sand is 100 mesh, and the compressed air pressure is 0.4MPa.

[0034] The electroplating system is set up, the lead plate electrode is used as the anode, the parts to be plated are used as the cathode, and the composition of the chromium-containing electroplating solution includes 250g / L of chromic anhydride CrO 3 and 2.50g / L sulfuric acid H 2 SO 4 .

[0035] at 80A / dm 2 The current density of the surface of the part to be plated is pre-charged for 1 minute; then, at 40A / dm 2 Continue to chrome-plate the surface of the part to be plated at a current density of 180 minutes.

[0036] Heat the chrome-plated parts to 200°C and keep it warm for 3 hours to remove hydrogen.

Embodiment 3

[0038] Cast superalloy parts are selected as parts to be plated. Dry-blow quartz sand on the surface of the parts to be plated. The particle size of the dry quartz sand is 140 mesh, and the compressed air pressure is 0.5MPa.

[0039] The electroplating system is set up, the lead plate electrode is used as the anode, the parts to be plated are used as the cathode, and the composition of the chromium-containing electroplating solution includes 275g / L of chromic anhydride CrO 3 and 2.75g / L sulfuric acid H 2 SO 4 .

[0040] at 90A / dm 2 Precharge the surface of the part to be plated with a current density of 1 minute; then, at 60A / dm 2 Continue to chrome-plate the surface of the part to be plated at a current density of 180 minutes.

[0041] Heat the chrome-plated parts to 220°C and keep it warm for 3 hours to remove hydrogen.

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Abstract

The invention provides a hard chromium electroplating method. The method comprises the following steps: A, carrying out surface roughening treatment on a part to be plated; B, connecting the part to be plated to an electroplating system, and carrying out pre-charging on the surface of the part to be plated, so that an integral chromium layer is deposited on the whole surface of the part to be plated; and C, carrying out chromium plating on the surface of the part to be plated, so that the chromium layer achieves a specified thickness, wherein in the process of pre-charging in the step B, the current density is 30-50 A/dm<2> larger than the current density in the process of chromium plating in the step C. According to the hard chromium electroplating method provided by the invention, through plating a chromium layer on the surface of a part to be plated, the bonding force of the plated chromium layer and a substrate of the part to be plated is ensured, and the plated chromium layer can be uniform and complete.

Description

technical field [0001] The invention relates to the field of electroplating, in particular to a method for electroplating hard chrome. Background technique [0002] In the processing of engine parts, there are often various parts with different sizes, different parts, and different materials. If it is difficult to repair by other methods, hard chrome plating is generally used to remedy it. The main functions that hard chrome plating can play are: improving the wear resistance of parts and remedial dimensions for out-of-tolerance parts, especially in terms of remedial dimensions. [0003] The materials involved in the electroplating hard chrome process include steel, high chromium steel, stainless steel, superalloy, copper and copper alloy, etc. Among them, cast superalloy and cast stainless steel are common materials for ultra-tolerance parts. At present, the conventional method of electroplating hard chromium for cast superalloys is: first corrode the parts in hydrochloric...

Claims

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Application Information

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IPC IPC(8): C25D5/36C25D3/04
Inventor 曹荣华汪彬张正义卜小龙
Owner CHINA HANGFA SOUTH IND CO LTD
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