Cast Steel Screw Lubricating Oil Pump

I. Product Overview

Cast steel screw lubricating oil pumps adopt high-strength cast steel materials and double-screw meshing design, specializing in efficient transportation of viscous media such as lubricating oil and hydraulic oil. They are suitable for lubrication systems of construction machinery, metallurgical equipment, and industrial gearboxes. The cast steel material system, combined with precision casting technology, offers excellent wear resistance and high-pressure resistance, enabling stable operation under high-viscosity and high-load conditions to meet the long-life and reliability requirements of industrial lubrication systems.

II. Core Materials and Characteristics

(1) Carbon Cast Steel (ZG)

Characteristics: Carbon content 0.15%–0.60%, tensile strength 400–700MPa, compressive strength 500–850MPa. With mature casting technology and good weldability, it can withstand impact vibration under medium loads, but wear intensifies in high-temperature (>200℃) or high-viscosity media.

Applications: Suitable for manufacturing non-high-pressure components such as pump bodies and non-precision screws, commonly used in low-pressure lubricating oil transportation scenarios (e.g., small machine tool lubrication systems, ordinary gearbox oil supply).

(2) Low-Alloy Cast Steel

Characteristics: Added with alloy elements like manganese, silicon, and chromium, tensile strength increases to 500–900MPa, yield strength is 20%–30% higher than carbon cast steel, with significantly enhanced wear and fatigue resistance. It can work stably under 3MPa high pressure and improves the transportation efficiency of lubricating oil with viscosity ≤460cSt by 20%.

Applications: Used for key components such as screws and bearing seats of high-pressure lubricating oil pumps, commonly found in forced lubrication systems of construction machinery (e.g., excavator hydraulic systems) and heavy machinery gearboxes.

(3) High-Alloy Cast Steel

Characteristics: Contains elements such as nickel, chromium, and molybdenum, with 5–8 times higher corrosion resistance to extreme pressure additives in lubricating oil than carbon cast steel. It can operate in 250℃ high-temperature lubricating oil, with screw surface hardness reaching HRC50–55, featuring outstanding anti-seizing and wear resistance, suitable for lubricating oil media with solid particles (≤0.1%).

Applications: Suitable for special working conditions, such as high-temperature rolling mill bearing lubrication in the metallurgical industry and lubricating oil transportation systems with corrosive additives in chemical equipment.

III. Technical Advantages

1. High-Viscosity Media Transportation Efficiency

Low-alloy cast steel screws achieve a transportation efficiency of 85%–90% in 320cSt lubricating oil, 15% higher than cast iron screw pumps, with pressure pulsation ≤±0.1MPa to ensure stable oil supply in lubrication systems.

The screw meshing clearance is controlled at 0.03–0.06mm, still maintaining low leakage (≤10mL/min) in high-viscosity (≤680cSt) media, suitable for equipment requiring precise oil supply such as injection molding machines and die-casting machines.

2. Wear Resistance and Long Life

After nitriding treatment, high-alloy cast steel screws have a surface hardness of HV900–1000, with a wear rate of only 0.008mm per thousand hours in lubricating oil containing extreme pressure additives (such as sulfur and phosphorus compounds), with a service life exceeding 30,000 hours—4 times longer than gray cast iron screw pumps.

The pump body adopts a double-layer structure design: the outer cast steel provides high-strength support, and the inner wear-resistant alloy coating (such as Stellite) further reduces wear, suitable for 24-hour continuous industrial scenarios.

3. Low Noise and Stability

Smooth screw meshing movement with operation noise ≤70dB, 5–8dB lower than gear lubricating oil pumps, suitable for noise-sensitive workshop environments (e.g., precision machine tool lubrication).

The cast steel pump body has good rigidity, with vibration amplitude ≤0.04mm, avoiding seal failure or pipeline loosening caused by vibration and improving system reliability.

IV. Application Scenarios

1. Construction Machinery Lubrication Systems

Suitable for oil supply to hydraulic tanks of excavators and loaders, capable of transporting anti-wear hydraulic oil (viscosity 46–68cSt), stably operating within the temperature range of -20℃–120℃ to meet field operation needs.

2. Metallurgical Equipment Forced Lubrication

Used for circulating lubrication of rolling mill bearings and gearboxes, achieving continuous transportation of high-temperature lubricating oil (150℃–200℃) under high pressure (≤2.5MPa), such as the bearing lubrication system of continuous casting machine segment sectors.

3. Industrial Gearbox Oil Supply

Provides lubricating oil circulation for large wind power gearboxes and marine gearboxes. The low pulsation characteristics of screw pumps can reduce gear impact and extend the life of transmission components. High-alloy cast steel is recommended to cope with extreme pressure additives in gear oil.

V. Precautions

1. Working Condition Limitations

Carbon cast steel pumps are unsuitable for lubricating oil with extreme pressure additive concentration >5%; low-alloy or high-alloy cast steel materials must be selected to avoid tooth surface electrochemical corrosion.

When lubricating oil viscosity >680cSt, a preheating system (such as an electric heating jacket) should be paired to reduce viscosity; otherwise, pump efficiency drops by 10%–15%, and surging starting current may damage the motor.

2. Maintenance Recommendations

Regularly inspect screw meshing clearance; replace screw components when the clearance exceeds 0.1mm to avoid flow attenuation (allowable deviation ≤8%).

When lubricating oil contains >0.1% moisture, replace the oil in a timely manner and clean the pump cavity to prevent corrosion of cast steel components (especially carbon cast steel materials).

3. Energy Efficiency and Environmental Protection

The hydraulic efficiency of cast steel screw pumps is 3%–5% lower than stainless steel pumps. Variable frequency speed regulation technology is recommended for large-flow scenarios (e.g., ≥50m³/h), reducing annual energy consumption by 8%–12%.

Casting carbon emissions are 35% higher than aluminum alloy. Attention should be paid to environmental policy requirements, and low-alloy cast steel is preferred to reduce material consumption (15% less raw materials than carbon cast steel).