Valve

Types of Valves

Surface Treatment, Painting & Coating of Valve

To ensure long-term durability and resistance to harsh environmental conditions, our valves undergo strict surface preparation and coating processes.

1. Surface Preparation

Sand Blasting / Shot Blasting: The valve body is thoroughly blasted to remove rust, mill scale, and oil, achieving a near-white metal finish (Sa2.5) for optimal coating adhesion.

2. Standard Coatings (For Carbon & Alloy Steel)

Anti-Rust Primer: A base layer of epoxy primer is applied to prevent oxidation.

Topcoat Painting: Available in standard colors (e.g., Black, Blue, Red) or customized colors. The paint is highly resistant to salt spray, UV rays, and chemical corrosion.

Epoxy Coating: For severe corrosive environments (such as marine or chemical plants), heavy-duty epoxy coatings (e.g., Fusion Bonded Epoxy - FBE) are applied both internally and externally.

3. Specialized Treatments

Hot-Dip Galvanizing: Available for carbon steel valves used in outdoor or underground water systems, providing a thick, sacrificial zinc layer.

Stainless Steel Valves: Typically undergo Pickling & Passivation to maximize the chromium oxide passive layer, removing welding scale and enhancing corrosion resistance.

4. Stem & Trim Protection

Valve stems and internal trims (disc, seat) are precision machined and may be treated with hard chrome plating or nitriding to improve wear and corrosion resistance.

5. Marking & Identification

Each valve is clearly marked with the size, pressure class, material, and flow direction arrow according to API/ASME standards for safe installation.

Q1: How do I choose between a Gate Valve and a Ball Valve?
A: Gate valves are ideal for fully open or fully closed isolation, offering minimal flow resistance, making them perfect for main pipelines. Ball valves offer quick quarter-turn operation and a tighter, bubble-tight seal. They are preferred for applications requiring frequent operation or fast emergency shut-off, such as in natural gas or chemical processing.

Q2: What is the difference between WCB and CF8M valve materials?
A: WCB is cast carbon steel, suitable for general service with non-corrosive fluids (water, oil, gas) at moderate temperatures. CF8M is cast 316 stainless steel, offering excellent corrosion resistance in aggressive environments (chemicals, seawater, acidic fluids). We also supply Duplex valves for extreme chloride environments.

Q3: How do you ensure the valves will not leak in the field?
A: We maintain Strict Quality Control and perform 100% Pressure Testing on every valve according to API 598 standards. This includes a shell test (for body integrity) and a seat leakage test (for sealing performance). We also conduct NDT (RT/PT/MT) upon request and fully accept third-party inspections (SGS, BV).

Q4: Can you supply valves suitable for extreme temperatures?
A: Yes. We offer valves designed for a wide temperature range from -196°C (cryogenic LNG service) to 600°C (high-temperature steam service). We use specialized materials and extended bonnets to ensure reliable sealing and operation under these extreme conditions.

Q5: Do you provide valves with actuators for automation?
A: Yes. We offer Integrated Customized Services. Our valves can be equipped with manual handwheels, gearboxes, pneumatic actuators, or electric actuators. We can also provide actuated valve assemblies (with brackets and couplings) ready for immediate installation.

Q6: What are your payment terms and lead times?
A: We offer Flexible Payment plans, including L/C (Letter of Credit) and open account. Standard lead times are typically 20–35 days after receipt of the advance payment, depending on the valve type, sizes, materials, and whether custom actuators or coatings are required.