Selecting the right rod for your hydraulic cylinder application
Here at Ramko we are committed to producing long lasting, high quality cylinders. There are various aspects of the cylinder we can look at to improve the life of our cylinders, but one of the most important parts in maintaining longevity is the corrosion resistance of the cylinder rod. Corrosion of the cylinder rod can cause several serious issues, the most common being leakages due to oil passing the seals or damage to the seals themselves.
The most commonly used form of corrosion protection on cylinder rods is hard chrome plating. Chrome plating is used to reduce friction, improve durability through abrasion tolerance and provide rust resistance. Chrome plating is a highly effective protection in normal, everyday environments and at Ramko we always use the highest grade of chrome plating available, however, there are limits to the amount of protection this type of surface treatment can provide.
Chromium has low tensile strength which leads to the development of micro cracks in the layer. In environments where there is high levels of corrosive elements or increased potential for mechanical damage these micro cracks can lead to the external environment penetrating the chromium layer resulting in corrosion. A solution to this is to combine the reduced friction of the chrome plating with other treatments or materials to provide the required level of protection.
Nickle Rod
One solution is to use a rod in which the hard chrome plating is combined with an underlying layer of nickel. The tensile strength of nickel is much higher than chromium so it is better able to maintain its anti-corrosion properties in harsher environments.
Chrome over stainless steel
In environments and applications where there is a very high-level exposure to corrosive elements, for example marine environments, the non-corrosive attributes of chrome plated stainless steel rod will provide the best protection. As stainless steel is alloyed with chromium & nickel it displays high tensile strength and superb anti-corrosion properties which makes it particularly suitable for highly corrosive environments.
The results of a 20 year corrosion study from a very corrosive environment – stainless steel has 9,000 times the life of carbon steel in this test.
Induction Hardened
If the cylinder is to be used in an application where the risk of mechanical damage is particularly high, the recommended rod treatment is induction hardening. The process of induction hardening involves the heating of steel using an electromagnetic field. This results in extremely high wear & fatigue resistance protecting the cylinder rod from external impact damage.
Care of Chrome
While these various types of rods provide different levels of corrosion and damage protection, they all have one thing in common – Hard chrome plating.
There are steps you can take to protect the integrity of the chrome on your cylinder rod. We strongly advise that all hydraulic cylinders with chrome which is exposed to the elements is regularly greased to protect against corrosion. This is particularly important during machine assembly, transportation and storage. We recommend the application of an adhesive water-resistant grease on all exposed chrome.
There may also be occasions were the chrome rod needs to be cleaned. If necessary, we recommend that nitric solvent, without chlorate, is used – the use of anything else has the potential to harm or reduce the protection of the chrome.
At Ramko Hydraulics Ltd, our cylinders are designed with the application firmly in mind. We will advise on the optimum rod type for your application while recognising the need to keep costs at a minimum. If you require a specialized hydraulic cylinder for any application, please contact our technical team to discuss your requirements.
Special Offers
We promised you more amazing special offers – and we are delivering. This October we will be offering fantastic discounts on our #1 selling cylinder online, the amazingly versatile 5030200.
– Order 1-4 cylinders get 15% off
– Order 5-9 cylinders get 20% off
– Order 10+ cylinders get 25% off
This offer is available from the 1st of October and will be running for 1 month only… so don’t miss out!
