Leading Professional Gate Vales Supplier in China

Raw Materials and Processing Techniques

Carbon Steel Gate Valve

• Raw Material Selection

ASTM A216 WCB carbon steel with controlled carbon content (0.25%–0.30%) ensures a balance between casting fluidity (pouring temperature: 1560°C ± 20°C) and mechanical performance. Chromium-vanadium micro-alloying improves intergranular corrosion resistance, enabling the material to meet or exceed the requirements of the ASTM G48 salt spray test (≥500 hours).

• Precision Forming Technology

Resin sand molding achieves a surface roughness of ≤Ra 12.5 μm and dimensional tolerances conforming to CT8 grade. An intelligent temperature control system, monitored via infrared, ensures a controlled cooling rate of ≤120°C/h, effectively preventing hot tearing.

• Post-Processing Enhancement

Multi-stage heat treatment, including normalizing (900°C × 2 hours) followed by tempering (650°C × 4 hours), results in a stabilized hardness range of HB 170–210. Automated shot blasting using 0.8 mm steel shot provides 100% surface coverage, effectively eliminating residual stresses.

Ductile Iron Gate Valve

1. Material Performance Breakthroughs

• High-Strength Ductile Iron Formula The product adopts QT450-10 material, which achieves a tensile strength of ≥485 MPa (8% higher than the national standard) and an elongation of 12%. The nodularity ratio reaches ≥95% (industry average: 90%), and the graphite sphere diameter is ≤0.05 mm.
• Corrosion Resistance Upgrade The valve inner cavity is coated with a 300 μm-thick epoxy resin layer, which has passed a 1000-hour salt spray test without rusting. The addition of a special 0.5% copper alloy enhances the resistance to chloride ion corrosion by 40%.

2. Casting Process Innovations

• Precision Forming Technology. The casting process combines resin sand molding with chill casting, achieving a dimensional accuracy of CT8 (compared to the traditional CT10). X-ray monitoring at thermal nodes ensures that porosity remains ≤0.005%.
• Heat Treatment Enhancement A dual annealing process (900℃ × 2h + 750℃ × 4h) results in a ferrite matrix content of ≥90%. Additionally, -40℃ cryogenic treatment increases impact toughness by 25%

Forged Steel Gate Valve

The performance of raw materials used in forged steel gate valves is significantly improved through forging processes. Key characteristics include: High Strength and Compactness: Raw materials such as carbon steel (carbon content: 0.2%–0.3%) and alloy steel (e.g., A105 forgings) acquire a high-density microstructure as a result of forging. This leads to enhanced compressive strength and sealing performance when compared to cast materials. The forging process effectively removes internal defects, ensuring stable and reliable operation under high-pressure and high-temperature conditions, such as those encountered in oil extraction or thermal power generation.