Frequently Asked Questions
What are examples of parts that usually require Hard Chrome plating and on what materials can Hard Chrome be applied?
Prime examples would be hydraulic cylinder rods, rollers, piston rings, mold surfaces, thread guides, etc. Chromium can be deposited on a wide variety of metals. Steels, Stainless steels, Copper and Brass are the most receptive metals for an adherent deposit. The more exotic metals, such as Inconell, Hastalloy and Titanium are more difficult to plate, but with the proper pre-treatment methods an adherent deposit can be achieved. Aluminum, in many cases, can receive a "direct" deposit of Hard Chrome. This depends on several factors; the Aluminum alloy itself, the geometry of the part, the area to be plated and the thickness of the deposit. In some cases it is necessary to deposit a layer of copper or nickel prior to Chrome.
What Tolerances can be acheived after Chrome Plating?
The more plating thickness required and the closer the tolerance, the more difficult it is to satisfy the tolerance. At RNJ Hard Chrome we will utilize every possible technique available and do our utmost to satisfy your dimensional requirements. We do our best to meet all reasonable and difficult tolerance requirements however it is difficult to say just what tolerances can be met. As a reasonable guideline the less plating required and the wider the tolerance, the easier it is to acheive the tolerance.
How thick can Chrome deposit be applied?
Deposit thicknesses range from "flash" (very thin deposits .000010") to "heavy buildups" (up to .050 in some cases). The final application of the part usually determines the thickness of the deposit. Some of these applications and the related thicknesses would be the degree of corrosion resistance required, the amount of anti-galling on stainless steel required, the amount of hardness required and the degree of wear and repair required.
What is the hardness of the Chrome deposit?
Chromium is ultra hard, 850-1000 Hv (68-72 Rc) harder than most industrial abrasives. These hardness factors are achieved at about an .002" deposit thickness. That does not mean that a "thinner" deposit will not significantly improve the "wear" on a surface. Due to its very low "coefficient of friction" it has ultra high metal-to-metal sliding wear resistance, a characteristic often confused with hardness. This benefit can be achieved at a thickness well below .0005".
What thickness of Chrome should I specify?
Robin Groeschke, owner of RNJ Hardchrome will be happy to discuss your particular application and determine a plating thickness that will meet your requirements.
Can additional Chrome be applied over and existing Chrome Surface?
In most cases chrome can be applied to an existing layer of chrome. Upon receipt of the parts, we will evaluate the existing deposit as to its integrity, i.e. general condition, thickness and adhesion. Bear in mind that this existing layer of chrome will now be the "foundation" for the ultimate adhesion of the new chrome deposit. If we determine that the existing chrome deposit is not satisfactory we will recommend stripping the deposit and re-plating an additional thickness.
What is your average turnaround?
At RNJ Hardchrome we do our best to meet all reasonable, and in most cases, urgent delivery requirements. At RNJ Hardchrome we know that by the time your product reaches us it is already due, or in many cases, already late. Be assured that we will do our utmost to get your product back to you on time.
Can existing Chrome be removed?
In most cases an existing Chrome deposit can be removed either by chemical stripping or by mechanically grinding. In many cases we recommend chemical stripping, return to customer for repair, re-plating oversize, and return to customer for final grind.
What kind of adhesion to the base metal should I expect?
It gives superb substrate adhesion, greater than 10,000 psi.