Pipe bending machines utilize hydraulic systems for power. Movements such as the positioning of the intermediate slide, the return of the rotary unit, and the operation of the main drive and other components require power. Using electric motors for the intermediate slide and rocker arm rotary unit would result in excessive equipment size and structural constraints. In contrast, a hydraulic system offers high driving force and reliability. Notably, it enables stepless adjustment of the feed rate, allowing for precise selection of the optimal speed and enhancing the machine's operability. It also simplifies the design, reduces manufacturing costs, and facilitates easier maintenance.

So, what kind of hydraulic oil is best suited for pipe bending machines? Experts from Huameng Machinery highlight the importance of good viscosity-temperature characteristics. During operation, hydraulic oil temperatures rise due to pressure losses; if the oil has poor viscosity-temperature stability, its viscosity drops significantly, leading to inadequate lubrication, increased leakage, and compromised operational precision. Conversely, excessive viscosity at low temperatures can hinder startup in winter. Therefore, the oil must maintain a stable viscosity across the operating temperature range; a viscosity index of 90 or higher is generally required.

As the hydraulic system operates and oil temperatures rise, the oil becomes increasingly prone to oxidation and deterioration. Oxidation occurs rapidly at high temperatures, producing sludge and deposits that contaminate the system and impair its normal function.

Good Demulsibility
If water mixes with the hydraulic oil, unstable components within the oil can form hydrophilic organic acids and soaps. Agitation by the pump causes emulsification, which reduces lubricity and adversely affects the performance of pumps and valves.

Good Foam Resistance
The presence of foam in the hydraulic oil can cause "stick-slip" (erratic movement) and noise within the hydraulic system.

Good Lubricity
The clearance between moving parts in hydraulic components is very tight—typically ranging from a few microns to around 100 microns. To extend component lifespan, the oil must form a strong film on moving surfaces, establishing fluid lubrication to minimize wear. Pour point: The pour point of the hydraulic fluid should be at least 10°C lower than the minimum ambient temperature; otherwise, excessively low temperatures would increase the fluid's viscosity, hindering startup or even rendering the system inoperable.

Good compatibility:
The fluid should exhibit minimal or no chemical interaction with various materials to prevent deterioration or loss of effectiveness.