What Is Hard Chrome Plating?

The Short Answer

Hard chrome plating — also called industrial chrome plating or engineering chrome — is an electroplating process that bonds a layer of chromium metal onto a component's surface. The purpose isn't appearance. It's performance: a hard chrome layer makes a part dramatically more resistant to wear, friction, and corrosion, and it can rebuild worn surfaces back to their original dimensions.

If a steel shaft, hydraulic rod, or mill roll has to slide, seal, rotate, or survive abuse for years, there's a good chance hard chrome is what makes that possible.

How the Process Actually Works

Electroplating is controlled chemistry. The part is submerged in a tank of chromium plating solution and connected to a DC power supply as the cathode (the negative side). Anodes in the tank complete the circuit. When current flows, dissolved chromium in the solution is reduced to chromium metal at the part's surface — atom by atom, layer by layer.

Think of it like rust in reverse. Corrosion strips metal away from a surface, ion by ion. Electroplating uses electrical current to do the opposite: it deposits metal onto the surface in a dense, bonded, uniform layer. The longer the part stays in the tank and the more current applied, the thicker the chromium deposit grows.

Because deposition happens gradually, thickness can be controlled precisely — and that control is what makes hard chrome an engineering process rather than a cosmetic one. Deposits are typically specified anywhere from 0.0001" for thin dense chrome up to 0.030" or more for heavy buildup and restoration work.

One thing chrome plating doesn't do is self-level. The deposit follows the surface beneath it and builds slightly unevenly on complex geometry. That's why hard chrome and precision grinding belong together: after plating, the part is ground to its final dimension and surface finish. The chrome provides the performance; the grind provides the precision.

Hard Chrome vs. Decorative Chrome

This is the single most common point of confusion — and the reason we turn away calls about bumpers and motorcycle parts every week. Both processes deposit chromium, but they are different products for different worlds:

	Hard (Industrial) Chrome	Decorative Chrome
Purpose	Wear resistance, corrosion protection, dimensional restoration	Appearance — bright, mirror-like shine
Typical thickness	0.0001" – 0.030"+	Measured in millionths of an inch
Applied over	Directly onto steel and other base metals	A nickel underlayer (chrome is just the top coat)
Typical parts	Hydraulic rods, shafts, rolls, molds, cylinders	Bumpers, wheels, faucets, trim
Who does it	Industrial job shops like Masterchrome	Decorative plating shops

Masterchrome does industrial hard chrome only. If you need decorative work on automotive or consumer items, a decorative plating shop is the right call — see our FAQ for details.

What Hard Chrome Does for a Part

Extreme surface hardness

As-deposited hard chrome typically measures around 65–70 HRC — harder than virtually any machined steel surface it protects. Practically, that means abrasive particles, metal-to-metal contact, and packing friction wear out much more slowly. Parts that previously wore out in months can run for years.

Low friction

Chromium has a naturally low coefficient of friction against steel and most seal materials. On a hydraulic rod or piston, that means less drag, less heat, less seal wear, and smoother operation over the component's life.

Corrosion resistance

Chromium forms a thin, stable oxide film on its surface — the same self-protecting behaviour that makes stainless steel "stainless." A hard chrome layer shields the base steel from moisture, process chemicals, and atmosphere in service.

Dimensional restoration

Because deposit thickness is controllable, hard chrome can rebuild a worn surface. A shaft journal worn 0.015" under size can be plated back up past nominal, then precision ground to the original drawing dimension. For large or long-lead-time components, restoration routinely costs a fraction of replacement — and turns scrap back into a serviceable part.

Where Hard Chrome Is Used

Almost every heavy industry relies on hard chrome somewhere in its equipment:

• Hydraulics — cylinder rods and plungers, where the chrome surface seals against packing millions of cycles
• Nuclear & power generation — valve stems, shafts, and critical components where reliability is non-negotiable
• Aerospace — landing gear, actuators, and components plated to AMS specifications
• Pulp & paper — press rolls and dryer components running continuously in wet, corrosive conditions
• Steel & metal processing — mill rolls and guides facing constant abrasion
• Plastics — molds, screws, and barrels where release, wear, and finish all matter
• Oil & gas, mining, marine, forestry — pumps, rams, pins, and shafts operating in the harshest environments in industry

See the full list of sectors we serve on our About page.

The Journey of a Part Through Our Shop

Here's what actually happens when your part arrives at Masterchrome:

1. Incoming inspection. We measure and document the part's condition — dimensions, existing wear, damage, and any old chrome that needs to come off.
2. Stripping (if required). Existing chrome is chemically removed in a controlled process that preserves the base metal.
3. Pre-machining or grinding. Damaged surfaces are trued up and undersized to make room for the specified chrome thickness.
4. Cleaning and masking. The part is cleaned, and areas that must stay chrome-free are masked off.
5. Plating. The part goes into the tank, and chromium is deposited to the calculated thickness under controlled current, temperature, and chemistry.
6. Finish grinding. The plated surface is precision ground (OD or ID) to final dimension and specified surface finish.
7. Polishing or superfinishing (when specified). For seal surfaces and low-Ra requirements, we take the finish further.
8. Final inspection. Dimensions and finish are verified against the drawing before the part ships back.

Details on each capability are on our Services page.

Common Specifications

Industrial chrome work is governed by published standards that define deposit quality, thickness, adhesion, and post-plate treatment. The specifications we plate to most often:

• AMS 2406 — the general aerospace specification for hard chromium plating
• AMS 2460 — chromium plating spec that superseded portions of older military standards
• AMS-QQ-C-320 — the aerospace adoption of the legacy federal QQ-C-320 chromium plating specification
• MIL-STD-1501 — military standard for chromium plating of steel parts
• EES 6.8-1 — engineering equipment specification used by industrial customers

If your drawing calls out a standard — including baking for hydrogen embrittlement relief on high-strength steels — include it with your quote request and we'll plate and document to it.

When Hard Chrome Is — and Isn't — the Right Choice

Hard chrome is usually the right answer when:

• A sliding, sealing, or rotating surface is wearing out faster than the rest of the component
• A worn part is expensive or slow to replace, and restoration can bring it back to print
• You need a hard, low-friction, corrosion-resistant surface with a precise final dimension
• A specification (AMS, MIL, or customer spec) explicitly calls for chromium plating

It's not the right fit when:

• The goal is cosmetic — that's decorative chrome, which we don't offer
• The part is a consumer or automotive item like wheels, bumpers, or trim

Not sure which side your part falls on? That's exactly what we're here for. Describe the part, the problem, and the environment it runs in, and we'll give you a straight answer — including telling you if chrome isn't the right solution.