Hydraulic Cylinder Chroming Explained: Definition, Benefits, Types, and Guide

Ever heard of hydraulic cylinder chroming? A form of electroplating, hard chrome plating has been made popular as a surface coating. With this form of cylinder replating, hydraulic cylinders chrome plating is touted for its hardness, corrosion protection, ability to minimize sliding wear, and extending the life expectancy of metal parts. For this reason, this process is used in many different applications with hydraulic and pneumatic cylinders, as well as pump shafts, rotors, swivel posts, and downhole tools.

To better understand the benefits of chroming, we are sharing more on the benefits, as well as a step-by-step guide to the process.

Benefits of the Hydraulic Cylinder Chroming

There’s a reason hydraulic cylinder chrome repair jobs have become so popular. With a host of benefits, and with a unique process to achieve, many are opting for this improvement to their hydraulic cylinders. Here’s why this hydraulic cylinder repair is so popular.

• Increased Hardness: Electro-deposited chrome offers an extremely hard surface. With the process of chrome plating, your components gain hardness, without actually changing their properties.
• Low Friction: As compared to steel, hard chrome has a super low coefficient of friction, allowing a component to operate at a lower temperature. With this lower temperature during operation, you extend the life of your equipment.
• Wear Resistance: With both the hardness and low friction of hard chrome, the hydraulic cylinder is now incredibly resilient to abrasion and mechanical contact.
• Corrosion Resistance: With hard chrome, hydraulic cylinders get an added resistance to atmospheric oxidation and better resistance to oxidizing and reducing agents.
• Sacrificial Wear Layer: Hard chrome deposits can be removed conveniently with chemical strippers, all without affecting the base material. This allows the plating to be stripped and re-plated as it wears, without harming the structure beneath.
• Lubricant Retention: The microcrack properties of hard chrome promote oil retention, allowing for better lubricity of the plated areas.

Cylinder Chrome Plating: Step-by-Step Process

Now that we know all the benefits of chrome cylinder plating, it’s time to understand the process. A hydraulic cylinder chrome rod repair with plating takes time and care, and it’s critical that you understand the process to achieve the desired finish. To assist, we are sharing a step-by-step guide to chrome plating.

#1. Initial Cylinder Inspection

At the initial inspection, the rod is evaluated to determine its condition before chrome plating. This is where an inspector should look for any signs of corrosion, pitting, marring, damage, or cracking. The presence of this damage will affect future steps of the re-chroming process.

#2. Stripping and Grinding the Old Plating

Before the new chrome application, the old surface must be removed. However, in order to preserve the material beneath without reducing the diameter of the rod itself, this process must be done very carefully. To do this, there are two different approaches: grinding and stripping.

• Electrolytic Stripping: During the stripping process, the rod is put in a reverse-electrolysis tank. As part of this, a negative current is applied to the solution, allowing chrome molecules to separate the surface. This strips the old chrome off the rod, revealing a clean, stripped surface.
• Stone Grinding: To do this, the rod is centered on a large grinding machine and rotated at a consistent rate as it’s brought in contact with the spinning stone. With this friction, the old material is sanded away.

#3. Cleaning the Cylinder

Now that the old chrome has been removed from the metal parts, it’s time to clean the surfaces. The rod should be cleaned and all debris and contaminants should be removed. If you don’t clean the rod first, anomalies may take place in the plating process, causing pitting or flaking, and ultimately limiting the lifespan of the newly plated chrome cylinder rod.

#4. Chrome Plating

To plate the cylinder, it must be placed in a bath containing a solution of dissolved metal molecules. During this, electrodes are attached to the rod and a positive current is applied to the solution. This allows the metal particles in the solution to attract to the surface and adhere to it.

With heightened technical needs, a precise amount of current must be delivered at a steady rate, while the bath chemistry and temperature must remain the same throughout the entire plating process. Any interruptions or errors in the power and temperature will result in a poor chroming job, causing the chrome cylinder rod to require more refinishing repair.

#5. Post Grinding and Linishing

Now that a fresh layer of chrome is on the rod, it’s time to finish it up. This involves two steps: post-grinding and linishing.

• Post-Grinding: For this, we go back to the same stone grinding technique used to remove the old layer of chrome before. However, we must be even more delicate at this stage, ensuring the surface is measured in fractions of millimeters to get it to the exact correct thickness.
• Linishing: After the post-grinding is linishing. This is the careful process of sanding the cylinder to the thickness required and the right surface finish. To do this, we use a purpose-made belt sanding machine. For this, a rod is centered in the linishing machine, which spins at a contact rate while different grades of linishing belts are applied to finely sand the surface. This will help achieve the ideal thickness and consistency.

#6. Post Plating Cylinder Inspection

Before wrapping up the cylinder, it’s time for an inspection. With the experience of a trained eye of a professional, the thickness and roughness of the rod must be carefully accounted for to determine the quality.

#7. Wrapping the Plated Cylinder

The final step of the hydraulic cylinder rod chrome plating process is wrapping. During this step, the rod is securely wrapped in cardboard and protective plastic to safeguard the chrome while it’s transported back to where it belongs.

Common Types of Chroming

A few different types of chrome plating can be used on hydraulic cylinders, depending on the application and required durability.

Engineering Chrome Plating

The attractive, reflective finish of engineering chrome plating makes it popular. Still, its use goes beyond simply providing an aesthetically pleasing look. Chrome plating also serves a practical purpose as a protective layer; thus, it is often employed in cylinder rods, piston rings, gun bores, and railers.

Decorative Chrome Plating

Decorative chrome is a combination of nickel and copper beneath a thin chromium coating, which creates a glossy and reflective surface and provides protection against corrosion. It is not as strong and durable as engineering chrome and therefore is often used on car wheels and truck bumpers.

Flash Chrome Plating

Flash chrome plating is ideal for applications exposed to light wear, as it offers good corrosion resistance despite its thin layer. This type of plating is employed as a decorative finish and for parts that require rust and corrosion resistance.

Thin Dense Chrome Plating

Thin dense chrome plating improves metal surfaces' corrosion and wear resistance. Its electrolyte solution is made of chromium and sulfuric acid and an anode of pure chromium metal, which creates a very thin, dense coating of chromium on the surface of the metal that is highly resistant to corrosion and wear.

Hard Chrome Plating

Hard chrome plating is a process that coats metal parts with a hard, wear-resistant layer. It is commonly used in the aerospace, automotive, and engineering industries to protect components from corrosion, wear, and abrasion. It can also increase the surface hardness of other metals, such as stainless steel.

How Often Should I Rechrome Hydraulic Cylinder Rod?

The longevity of your equipment's chrome plating largely depends on its condition and the environment in which you use it. Rechroming services should be performed every couple of decades in non-wear situations.

The need for re-chroming services is usually decided by the thickness of the chrome layer, how often maintenance and care are provided, and the quality of the chrome plating materials. 

Chrome plating provides a nice finish and protects your equipment from wear, impact, and corrosion. If you see any signs of damage or rust, you may need re-chroming services sooner rather than later.

Conclusion

The process of hydraulic cylinder chroming is one that takes special attention and care, ensuring that the newly-plated chrome cylinder is the correct thickness and roughness for it to function properly in your machinery. While this takes special care and attention, it is well worth the effort to extend the lifetime of your chrome cylinder rod.

To have an expert team handle your hydraulic cylinder chrome repair, Cylinders, Inc. is here to assist. As an expert hydraulic cylinder re-chroming company, we will ensure your cylinder rod is expertly repaired for years of use ahead. To begin the process, contact us online today.