Stainless Steel Forged Steel Internal Thread Socket Welding Swing Check Valves

Stainless Steel Forged Steel Internal Thread Socket Welding Swing Check Valves are automatic check valves specially designed for small and medium-bore, high-pressure and corrosive working conditions. Manufactured from forged stainless steel, they feature both internal thread and socket weld connections, which can be flexibly selected according to on-site installation conditions.

The valve opens and closes automatically relying on the pressure of the medium: the disc rotates around the hinge to open during forward flow, allowing smooth passage of the medium; in case of backflow, the disc closes rapidly under its own weight and reverse pressure to cut off backflow and protect pumps, compressors and downstream pipeline equipment.

Thanks to forged steel material and hard alloy sealing, the valve features high strength, erosion resistance, high temperature resistance and corrosion resistance, enabling long-term stable operation in harsh environments such as chemical, power, pharmaceutical and precision processing industries.

Stainless Steel Forged Steel Internal Thread Socket Welding Swing Check Valves are especially suitable for medium-low to medium-high pressure piping systems with limited installation space and high requirements for sealing reliability and structural strength.

Core Technical Parameters

Structure & Component Materials

All key components of Stainless Steel Forged Steel Internal Thread Socket Welding Swing Check Valves are made of forged stainless steel with strengthened sealing surfaces, and the overall performance far exceeds that of ordinary cast valves.

● Body/Bonnet: Forged 304/316/316L stainless steel, high density and strength

● Disc: Forged steel of the same material + Stellite hard alloy overlay

● Seat: Forged steel base + hard alloy overlay, wear and erosion resistant

● Hinge mechanism: Forged stainless steel; shaft made of 17-4PH precipitation-hardening stainless steel

● Thread seal: PTFE gasket

● Socket weld seal: Stainless steel welding material matching body

● Bonnet seal: 316L spiral wound gasket

● Bolts/Nuts: 304/316 stainless steel, consistent overall anti-corrosion

Design & Manufacturing Standards

The design, materials, processing and inspection of this valve series comply with national standards to ensure interchangeability and safety.

● Swing check valve: GB/T 12236

● Pressure-temperature rating: GB/T 12224

● Face-to-face dimension: GB/T 12221

● Thread standard: GB/T 7306

● Socket weld standard: GB/T 12224

● Forging standard: GB/T 13401

● Material standard: GB/T 1220

● Overlay welding process: GB/T 17491

● Pressure and seal test: GB/T 13927

● Installation specification: GB 50235

Core Product Advantages

Forged steel material, dual guarantee of strength and corrosion resistance

Adopting forged stainless steel, it is more resistant to high pressure, impact and corrosion than ordinary cast steel valves, suitable for long-term operation under severe working conditions.

Dual connection structure for flexible installation

Internal thread allows quick assembly and disassembly; socket weld is suitable for high-pressure, vibration and high-sealing scenarios.Stainless Steel Forged Steel Internal Thread Socket Welding Swing Check Valves can meet different users’ installation habits.

Swing structure, low flow resistance and sensitive action

The disc rotates around the shaft to open, providing smooth flow passage, low pressure loss and fast opening/closing response, effectively suppressing water hammer and backflow impact.

Metal hard seal, high temperature and wear resistance

Sealing surface overlaid with hard alloy, applicable to steam, high-temperature oil and corrosive media, with long service life and low leakage risk.

Compact size, ideal for limited spaces

The compact structure is especially suitable for instruments, small-bore process pipelines, unit matching, skid-mounted equipment and other space-restricted locations.

Selection Guidelines

Selection by Pressure & Model

● PN16: Low-pressure water supply, drainage and circulating water systems

● PN25: General oil and chemical process pipelines

● PN40/PN63: Medium-high pressure, high temperature and impact conditions

Model interpretation:1 = Internal thread, 6 = Socket weld, 4 = Swing type, P = Stainless steel.

Selection by Medium Corrosion

● Conventional water, air, weak corrosion → 304

● Chlorine-containing, weak acid/alkali, mild chemical → 316

● Strong corrosion, high temperature, high salt → 316L

Selection by On-site Conditions

● Frequent maintenance & disassembly → Internal thread

● High pressure, vibration, fixed installation → Socket weld

Installation Direction

● Horizontal pipeline: Universal structure applicable

● Vertical pipeline: Medium must flow upward

Installation & Maintenance

Installation Notes

● Verify model, pressure, diameter, material and connection match the pipeline before installation

● Clean pipeline impurities to avoid disc jamming

● Use PTFE tape or gaskets for threaded installation, tighten evenly

● Perform standard beveling, welding and inspection for socket weld to ensure no leakage

● Install in the flow direction marked by the arrow on the valve body

Routine Maintenance

● Regularly inspect threads, welds and bonnet for leakage

● Clean impurities in the valve cavity regularly to prevent hinge jamming

● Apply high-temperature grease to hinge shaft to reduce wear

● Worn sealing surfaces can be repaired by re-overlaying to extend service life

Troubleshooting

● Improper closing: Check for impurities or damage on disc, hinge and sealing surfaces

● External leakage: Retighten threads or replace gaskets; repair welds

● Stuck action: Disassemble and clean foreign matters, correct hinge mechanism

Typical Applications

With high strength, high corrosion resistance and high sealing performance, Stainless Steel Forged Steel Internal Thread Socket Welding Swing Check Valves are widely used in:

● Petrochemical and fine chemical process pipelines

● Power and power station auxiliary systems

● Pharmaceutical, food and beverage clean medium systems

● Instrument and small-bore high-pressure fluid control

● Corrosive medium pipelines such as seawater and chlorine-containing sewage