Cast Steel Gear Cargo Oil Pump

I. Product Overview

Cast steel gear cargo oil pumps use high-strength cast steel as the core material and adopt the gear meshing principle to achieve efficient transportation of liquid media such as fuel oil and lubricating oil. They are suitable for cargo oil loading/unloading and circulation systems in industries such as shipping, ports, and petrochemicals. The cast steel material system, combined with precision casting technology, integrates high strength, wear resistance, and fuel corrosion resistance, enabling stable operation under high-pressure and high-temperature conditions to meet the safety and reliability requirements of cargo oil 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 its strength declines significantly at high temperatures (>200℃).

Applications: Suitable for manufacturing non-high-pressure components such as pump bodies and non-precision gears, commonly used in low-pressure cargo oil transportation scenarios (e.g., fuel transfer in small tanker cargo tanks).

(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.

Applications: Used for key components such as gears and bearing seats of high-pressure cargo oil pumps, commonly found in cargo oil loading/unloading systems of large tankers and oil pipelines in petrochemical storage areas.

(3) High-Alloy Cast Steel

Characteristics: Contains elements such as nickel, chromium, and molybdenum, fuel corrosion resistance (especially for sulfur-containing fuel and ethanol gasoline) is 5–8 times higher than carbon cast steel, can operate in 300℃ high-temperature cargo oil, gear surface hardness reaches HRC50–55, with excellent anti-seizing and cavitation resistance.

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

III. Technical Advantages

1. High Strength and Wear Resistance

Under 4MPa high-pressure cargo oil scouring, the wear rate of low-alloy cast steel gears is only 0.01mm per thousand hours (medium impurity content ≤0.2%), with a service life exceeding 25,000 hours—3 times longer than gray cast iron pumps—suitable for long-term continuous operation in cargo oil terminals.

After carburizing and quenching treatment, the surface hardness of gears is high, resisting wear from rust, sand, and other particulate impurities in cargo oil, reducing maintenance frequency.

2. High-Temperature Resistance and Sealing Reliability

High-alloy cast steel pump bodies can operate in 280℃ high-temperature cargo oil, with thermal deformation rate <0.3%, avoiding pump body expansion and leakage caused by rising oil temperature to meet crude oil heating and transportation needs.

The fit clearance between the pump body and gears is controlled at 0.02–0.05mm. Combined with fluororubber seals, cargo oil leakage is ≤5mL/h, complying with the MARPOL anti-pollution sealing standard.

3. Balance of Cost and Applicability

The cost of cast steel materials is 1/3–1/2 that of stainless steel, and single-piece production cost is 40% lower than forged alloy steel, suitable for mass application in large cargo oil loading/unloading systems.

Gear pumps have a simple structure, with maintenance costs 60% lower than screw pumps—only requiring regular replacement of seals and filter cleaning, reducing port equipment operation and maintenance pressure.

IV. Application Scenarios

1. Marine Cargo Oil Systems

Suitable for loading/unloading and transfer operations in tanker cargo tanks, capable of transporting media such as crude oil, diesel, and heavy oil. It coordinates with deck cargo oil pipelines for efficient loading/unloading, such as cargo oil pump groups of 300,000-ton tankers.

2. Petrochemical Storage Transportation

Used for cargo oil transfer in petrochemical storage areas, achieving long-distance pipeline transportation under high pressure (≤3MPa), such as crude oil intake pumps in refineries and refined oil outbound pumps.

3. Special Media Transportation

High-alloy cast steel pumps can resist corrosion from sulfur-containing crude oil (sulfur content >2%) and ethanol gasoline (ethanol content ≤15%), suitable for media transportation in chemical tankers and special oil depots.

V. Precautions

1. Working Condition Limitations

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

When the working temperature exceeds 200℃, high-alloy cast steel pumps should be used, and pressure should be controlled ≤2MPa to avoid stress cracking.

2. Maintenance Recommendations

Regularly inspect gear wear; replace gears when tooth surface wear >0.5mm to prevent flow decline due to increased meshing clearance (allowable deviation ≤5%).

When cargo oil contains >0.3% impurities, install a filter with precision ≤50μm at the pump inlet to prevent particle wear on the sealing surface.

3. Environmental Protection and Energy Efficiency

The hydraulic efficiency of cast steel pumps is 5%–8% lower than stainless steel pumps. In large-flow scenarios (e.g., ≥200m³/h), variable-frequency motors are recommended for energy saving, reducing annual energy consumption by 10%–15%.

Casting carbon emissions are 45% higher than aluminum alloy, meeting current industry standards, but attention should be paid to green upgrading needs under the "dual-carbon" policy.