In modern industrial hydraulic systems, hydraulic fluid not only performs power transmission, lubrication, protection, and cooling functions, but also must maintain long-term stable operation under complex operating conditions such as high temperature, high pressure, and high humidity. Hydrolytic stability is a key indicator of hydraulic oil quality. When hydraulic systems inevitably come into contact with moisture (such as condensate, cooler leaks, or ambient moisture intrusion), the oil can easily undergo hydrolysis, leading to increased acidity, additive decomposition, and sludge formation, which in turn can cause equipment corrosion, valve sticking, and system failure. Therefore, ashless anti-wear hydraulic oil, a representative of the new generation of high-performance hydraulic fluids, possesses excellent hydrolytic stability.
1. The Essential Advantage of Ashless Formulas: Avoiding Metal-Catalyzed Hydrolysis
Traditional anti-wear hydraulic oils often utilize zinc-containing anti-wear additives (such as ZDDP, zinc dialkyl dithiophosphate). While these additives provide excellent anti-wear performance, the metallic zinc and phosphate bonds in their molecular structure are susceptible to hydrolysis in the presence of moisture, forming acidic substances and precipitates. More seriously, zinc ions themselves have a catalytic effect, accelerating the oil's oxidation and hydrolysis process, creating a vicious cycle. Ashless anti-wear hydraulic oil, on the other hand, does not contain metal additives. Its anti-wear performance relies on "ashless" extreme pressure anti-wear agents such as organophosphorus, phosphate esters, amides, or borates. These organic additives have a stable molecular structure and lack easily hydrolyzed metal-sulfur-phosphorus bonds, fundamentally avoiding the problem of metal ion-catalyzed hydrolysis and significantly improving the oil's hydrolytic stability.
2. Selected Base Oils and Additives Synergistically Enhance Stability
Ashless anti-wear hydraulic oil typically uses highly refined mineral oil or synthetic base oils (such as PAO and esters). These base oils inherently possess excellent chemical inertness and low impurity content, making them less reactive with water. Furthermore, specialized hydrolysis stabilizers and demulsifiers are incorporated into the formula to further enhance its hydrolysis resistance. Hydrolysis stabilizers neutralize trace acidic substances and suppress the rise in acid value; demulsifiers promote rapid oil-water separation, preventing the long-term presence of emulsions and reducing the time and area of contact between water and oil. This synergistic design of "base oil + ashless additives + functional additives" enables ashless hydraulic oil to demonstrate extended stability and reduced acid value growth in simulated wet heat tests.
3. Practical Application Verification: Excellent Performance in Humid and High-Temperature Environments
In humid or temperature-severe industrial environments such as metallurgy, shipbuilding, papermaking, and wind power, hydraulic systems are highly susceptible to moisture absorption. Actual operational data shows that systems using ashless anti-wear hydraulic oil exhibit a slower acid value increase, lower filter clogging rates, and significantly reduced failure rates of hydraulic valves and servo mechanisms. Especially in closed-circuit systems, ashless oil maintains cleanliness over time, reduces varnish and sludge deposition caused by hydrolysis products, and extends oil change intervals and equipment life.
4. Dual Guarantee of Environmental Protection and System Cleanliness
Ashless anti-wear hydraulic oil not only exhibits excellent hydrolytic stability, but also exhibits good biodegradability and low toxicity, complying with modern environmental regulations. Hydrolysis does not produce metal salt precipitation, reducing the burden on the environment and wastewater treatment systems. Furthermore, high hydrolytic stability means a cleaner system, reducing maintenance costs and downtime risks.
This ashless anti-wear hydraulic oil not only exhibits excellent hydrolytic stability but also demonstrates superior overall performance compared to traditional zinc-containing hydraulic oils under demanding operating conditions such as humidity, high temperatures, and high loads. Its metal-free formula, stable molecular structure, and advanced additive technology effectively inhibit hydrolysis, ensuring long-term reliable operation of hydraulic systems.
