How do you choose between “normal” and “high-pressure” hydraulic oil?

发布时间：2022年03月14日 14:49

Those familiar with hydraulic oils know that they come in two main types: “standard” and “high-pressure.” Let me briefly explain the difference: L-HM hydraulic oil, commonly referred to as anti-wear hydraulic oil, is developed by enhancing and improving the anti-wear performance of the standard HL-type hydraulic oil. This makes it suitable for hydraulic systems with anti-wear requirements. However, for hydraulic systems operating under different pressure levels, it’s important to select the appropriate product. When the system pressure ranges from 7.0 to 14 MPa and the system temperature is between 50 and 80°C, the system is considered medium-to-high pressure, and standard anti-wear hydraulic oil can be used. When the system pressure exceeds 14 MPa and the system temperature is above 80°C...

As those familiar with hydraulic oil know, hydraulic oil is divided into two types: “standard” and “high-pressure.” Let’s briefly explain them below:

L-HM hydraulic oil, commonly known as anti-wear hydraulic oil, is developed by enhancing and improving the anti-wear performance of the standard HL-type hydraulic oil. This makes it suitable for hydraulic systems with anti-wear requirements. However, for hydraulic systems operating under different pressure levels, it’s important to select the appropriate product accordingly.

When the system pressure is between 7.0 and 14 MPa and the system temperature is between 50 and 80℃, the system is considered medium-to-high pressure, and a standard anti-wear hydraulic oil can be used.

When the system pressure exceeds 14 MPa and the system temperature is between 80 and 100°C, a high-pressure anti-wear hydraulic oil should be used. Of course, a high-pressure oil can completely replace a standard oil, but it’s not recommended to substitute a standard oil with a high-pressure one, as this would shorten the oil’s service life.

In addition, there’s also a type of anti-wear hydraulic oil known as “ashless.” What makes it special? The additive systems used in anti-wear hydraulic oils fall into two categories: ash-containing formulations and ashless formulations.

Gray hydraulic oil

Ash-containing hydraulic oils refer to those in which the proportion of zinc (Zn)-based additives exceeds 0.03%; conversely, hydraulic oils with a zinc additive content below 0.03% are classified as ashless hydraulic oils.

Ash-free hydraulic oil

The advantage of ash-free hydraulic fluids is that they do not contain zinc, so they won't react with silver-containing components. Many components—such as valves—use silver-plated materials; if zinc is present, it can undergo an electroplating reaction with silver, displacing the silver and damaging the component. Ash-free hydraulic oils do not corrode copper components, making them particularly suitable for piston pumps equipped with copper or copper-alloy parts. They also exhibit excellent antioxidant and anti-rust properties, significantly reducing the formation of sludge and acidic substances, thereby keeping the system clean, minimizing failures, and extending the service life of the oil. During use, these oils produce no ash and do not react with silver components. Ash-free hydraulic oils are also referred to as anti-silver hydraulic fluids.

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