Advantages and Process of Steel Castings in the Petroleum Fracturing Equipment Industry
Steel castings, relying on the advantage of near net forming, are widely used in complex structural components such as power end shells, gearbox bodies, fracturing head shells, pry racks, and integrated manifold bases. They are an important material solution for integrated design of fracturing equipment.
The application advantages of cast steel parts in hydraulic fracturing equipment
1. Advantages of integrated molding of complex structures
Many hydraulic fracturing equipment shells and frames have multiple installation benchmarks, irregular cavities, multiple interface branches, and staggered reinforcement structures. Steel castings can be cast into complex cavities and integrated structures in one go, without the need for extensive steel plate cutting or segmented welding.
-Reduce welding joints, avoid welding defects, welding deformation, and welding stress concentration issues;
-Good overall structural integrity, superior rigidity and anti vibration performance compared to welded structures, suitable for high-frequency impact vibration environments of fracturing pumps;
-Supporting modular integrated design, the support, lifting ears, oil passage, and installation boss are cast together to shorten the subsequent machining and assembly time.
2. The material allocation of cast steel parts is flexible and adaptable to diverse working conditions.
Cast steel can be matched with different oilfield conditions by adjusting the content of alloying elements such as C, Cr, Ni, Mo, V, etc
-Ordinary low-alloy cast steel: frame, base, protective cover shell, focusing on strength and impact toughness;
-Cr Mo series heat-resistant and hydrogen resistant cast steel, anti H ₂ S low-alloy cast steel: suitable for fracturing conditions in sulfur-containing oil and gas fields, meeting NACE sulfur resistance requirements;
-Martensitic stainless steel and duplex stainless steel cast steel: used for shells in contact with fracturing fluids and flowback fluids to enhance resistance to chloride ion corrosion and erosion.
Analysis of Steel Casting Process for Fracturing Equipment
1. Casting process: Adopting investment casting precision casting or resin sand casting, reasonably setting up sprues, cold iron, and eliminating shrinkage and looseness in thick and large parts; Ceramic sand cores are preferred for the inner cavity of the flow channel to reduce sand sticking.
2. Smelting control: Refine and remove gas, reduce oxygen content, harmful elements such as sulfur and phosphorus, and minimize inclusions.
3. Heat treatment: After casting, stress relief annealing is carried out first, followed by quenching and tempering (quenching+high-temperature tempering); Control the heating and cooling rate of castings with large wall thickness differences to avoid residual stress.
4. Post processing: channel polishing, rounded corner transition, eliminating stress concentration at sharp corners; The key overcurrent surface is welded with WC and cobalt based alloy wear-resistant layer.
5. Non destructive testing (NDT): Follow the API and SY/T petroleum equipment standards. High pressure pressure castings: MT+PT full coverage surface inspection, UT internal inspection, water pressure test and air tightness test for important parts.
6. Standard compliance: Petroleum fracturing castings often follow industry standards such as API 6A, API 7K, SY/T 5244, etc.
