Cast Steel Screw Fuel Oil Pump

I. Product Overview

Cast steel screw fuel oil pumps adopt high-strength cast steel materials and double-screw meshing structures, specifically designed for efficient transportation of fuel oils (crude oil, diesel, heavy oil, etc.), suitable for fuel supply and loading/unloading systems in industries such as shipping, petrochemicals, and power generation. The cast steel material system, combined with precision casting technology, offers excellent resistance to fuel scouring, wear, and high pressure, enabling stable operation under high-temperature and high-viscosity conditions to meet the safety and reliability requirements of fuel transportation.

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 corrosion intensifies in high-temperature (>200℃) or sulfur-containing fuel.

Applications: Suitable for manufacturing non-high-pressure components such as pump bodies and non-precision screws, commonly used in low-pressure fuel transportation scenarios (e.g., fuel supply for small diesel engines, fuel boiler refueling).

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, fuel scouring corrosion resistance is improved by 30%, and it can work stably under 3MPa high pressure, improving the transportation efficiency of fuel with viscosity ≤300cSt by 15%.

Applications: Used for key components such as screws and bearing seats of high-pressure fuel pumps, commonly found in marine main engine fuel systems and oil pipelines in petrochemical storage areas.

3.High-Alloy Cast Steel

Characteristics: Contains elements such as nickel, chromium, and molybdenum, with 5–8 times higher fuel corrosion resistance (especially to sulfur-containing fuel and ethanol gasoline) than carbon cast steel. It can operate in 300℃ high-temperature fuel, with screw surface hardness reaching HRC50–55, featuring outstanding anti-seizing and cavitation resistance, suitable for fuel media with fine particles (≤0.1%).

Applications: Suitable for special working conditions, such as sulfur-containing crude oil transportation in ocean-going tankers and fuel loading/unloading systems with corrosive additives in the chemical industry.

III. Technical Advantages

1. High-Viscosity Fuel Transportation Efficiency

Low-alloy cast steel screws achieve a transportation efficiency of 82%–88% in 200cSt heavy oil, 12% higher than cast iron screw pumps, with pressure pulsation ≤±0.08MPa to ensure stable fuel system supply.

The screw meshing clearance is controlled at 0.02–0.05mm, maintaining leakage ≤8mL/min in high-viscosity (≤500cSt) fuel, suitable for fuel injection systems requiring precise metering (e.g., gas turbine fuel supply).

2. Wear Resistance and Long Life

After surface hardening treatment, high-alloy cast steel screws have a wear rate of only 0.005mm per thousand hours in crude oil with 1.5% sulfur content, with a service life exceeding 28,000 hours—3.5 times longer than gray cast iron screw pumps.

The pump body uses wear-resistant alloy linings (such as tungsten carbide coatings) to resist scouring from fuel impurities (e.g., rust, sand), suitable for long-term continuous operation in tanker cargo oil loading/unloading systems.

3. Low Noise and Stability

Smooth screw meshing movement with operation noise ≤68dB, 7–10dB lower than gear fuel pumps, suitable for noise-sensitive port operation environments.

The cast steel pump body has good rigidity, with vibration amplitude ≤0.03mm, avoiding fuel leakage caused by vibration and complying with MARPOL anti-pollution standards.

IV. Application Scenarios

1. Marine Fuel Systems

Suitable for main engine fuel supply of ocean-going tankers and cargo ships, capable of transporting heavy oil (viscosity 380cSt), diesel, and other media, stably operating within the temperature range of -10℃–250℃, paired with heating systems for low-temperature start-up.

2. Petrochemical Fuel Transportation

Used for crude oil transportation in refineries and refined oil outbound pipelines, achieving long-distance fuel transportation under high pressure (≤2.8MPa), such as ship unloading pump groups for crude oil from terminals to tank farms.

3. Power Generation Equipment Fuel Supply

Provides fuel circulation for gas turbines and fuel generator sets. The low pulsation characteristics of screw pumps reduce fuel injector wear. High-alloy cast steel is recommended to cope with high-temperature fuel (≤300℃).

V. Precautions

1. Working Condition Limitations

Carbon cast steel pumps are unsuitable for fuels containing >10% ethanol or high sulfur (sulfur content >0.5%); high-alloy cast steel or corrosion-resistant linings must be selected (cost increases by 15%–20%).

When fuel viscosity >500cSt, a preheating device (such as steam tracing) should be paired to reduce viscosity; otherwise, pump efficiency drops by 10%–15%, and increased starting load may damage the screws.

2. Maintenance Recommendations

Regularly inspect screw meshing clearance; replace screw components when the clearance exceeds 0.08mm to avoid flow attenuation (allowable deviation ≤7%).

When fuel contains >0.2% moisture, separate the moisture 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 4%–6% lower than stainless steel pumps. Variable frequency speed regulation technology is recommended for large-flow scenarios (e.g., ≥100m³/h), reducing annual energy consumption by 10%–15%.

Casting carbon emissions are 38% higher than aluminum alloy. It is necessary to comply with current environmental policies and preferentially use low-alloy cast steel to reduce material consumption (12% less raw materials than carbon cast steel).