I. Main Standards for Stainless Steel Flanged Gate Valves
Stainless steel flanged gate valves comply with international, national, and industry-specific standards, selected based on application scenarios:
1. International Standards
API 600: American Petroleum Institute standard for oil/gas industries, requiring valve bodies in cast steel/stainless steel with pressure ratings of 150LB~2500LB (API official data).
ANSI B16.34: Specifies flange dimensions and pressure-temperature ratings (e.g., Class 150 valves withstand 19.6 bar at ambient temperature per ASME).
2. Chinese National Standards
GB/T 12234: General technical requirements for flanged gate valves, mandating seal test pressures at 1.1× nominal pressure (e.g., 17.6 bar for PN16 valves).
HG/T 20592: Chemical industry flange standard aligned with EN 1092-1 (e.g., DN50 flange outer diameter: 165 mm per HG/T 20592-2009).
3. Special Industry Standards
ISO 10434: Covers high-pressure valves for oil/gas, requiring -46℃ low-temperature impact tests (ISO 2023 edition).
II. Key Parameters & Selection Criteria
1. Pressure Rating Selection
Low-pressure (PN10~PN16): Prioritize GB/T 12234.
High-pressure (Class 600+): Require API 600 compliance with 20%~30% thicker valve bodies (ASME B16.34 calculations).
2. Sealing Performance
Soft-seal valves: Leakage ≤0.01×DN mm³/s (GB/T 13927-2008).
Metal seals: Must pass API 598 high-pressure gas tightness tests.
3. Material & Corrosion Resistance
304 stainless steel: Temperature range -196℃~800℃.
316L: Superior for chloride environments (ASTM A351).
III. Standard Comparison & Engineering Recommendations
1. API vs. GB Differences
API emphasizes high-pressure durability (e.g., 10,000+ cycles), while GB focuses on general use (5,000 cycles).
2. Selection Workflow
Step 1: Identify medium (corrosive/non-corrosive).
Step 2: Match pressure-temperature curves (ANSI B16.34 Appendix).
Step 3: Verify flange compatibility (e.g., ANSI B16.5 vs. HG/T 20592).
