Special anode of plating chromium on cavity of slender pipe and chromium plating method thereof

Abstract

The invention discloses a special anode of plating chromium on a cavity of a slender pipe and a chromium plating method thereof. The special anode is obtained by adopting a 20# steel wire as an inner core, plating copper on the surface of the steel wire, plating a lead-tin alloy and then carrying out heat treatment on the steel wire. According to the chromium plating method, the electroplating iscarried out by using a chromium plating solution; the solution temperature is 62-66 DEG C; the power is supplied at a current intensity which is 30-35 A / dm<2> in the plating area of an inner hole piece; and the electroplating time is 160-180 minutes; therefore, the thickness of an electroplated chromium layer on the single side can be not less than 0.035 mm. According to the special anode and thechromium plating method provided by the invention, the chromium plating standard rate can be increased by 2-3 times and the chromium plating workload and the production cost are largely reduced.

Description

technical field [0001] The invention relates to the field of electroplating, in particular to a special anode for chrome-plating the inner cavity of a slender pipe fitting and a chrome-plating method thereof. Background technique [0002] Electroplating is a process for surface treatment of workpieces. Due to the excellent performance of the chrome plating layer, chromium plating is a commonly used method in the electroplating process. [0003] When chrome-plating the inner holes of some slender pipe fittings, lead anodes are generally inserted into the slender pipe fittings for electroplating. Due to the softness of the lead anode and the limited size of the inner holes of the parts, this anode is easily too large, resulting in a low plating pass rate. Therefore, in the prior art, hard chromium plating on the inner cavity of the slender tube currently has the following defects: [0004] 1) The inner bore of the slender tube is chrome-plated due to the small diameter, which...

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Problems solved by technology

[0004] 1) The inner bore of the slender tube is chrome-plated, due to the small diameter, it is difficult to make pictographic anodes, and it is almost impossible to make pictographic anodes, so the chromium speeds on the Yin and Yang lines in the slender tube holes are inconsistent, resulting in poor uniformity of the chromium layer

[0005] 2) Due to the small diameter, it is difficult to control the concentricity of the anode in the inner cavity and the slender tube, so it will also cause one-sided chromium layer and poor uniformity of chromium layer

[0006] 3) Due to the small caliber, the fluidity of the inner cavity solution is poor. At present, the forced flow is mainly driven by the bubbles generated in the electroplating process to supplement the consumption of the inner cavity solution, which leads to many defects.

[0007] 4) Due to the small caliber, the diameter or area of ​​the selected anode is small, the ratio of cathode and anode is out of balance during the electroplating process, and the voltage drop loss at the upper and lower ends of the slender tube is relatively large, about 3V, resulting in a large chrome-plated cone difference in the inner cavity

[0008] 5) In the chromium plating solution, due to the imbalance of the ratio of the cathode and anode areas, the content of trivalent chromium increases, and it needs to be treated to reduce trivalent chromium. At present, it needs to be treated in the attached tank, but the separation of impurities has not been achieved.