- Core Design Standards
1. ASME B16.34
Position: General specification for valve design and manufacturing, covering pressure-temperature ratings, material requirements and test methods for flanged, threaded and welded end stop valves.
Technical Points: Pressure Rating: Covering Class 150 to Class 2500, up to PN420 (about 42MPa); Material Specification: The shell commonly uses castings and forgings such as ASTM A216 WCB (carbon steel) and A351 CF8M (stainless steel), which must meet the ASTM Material Test Report (MTR) certification; Test Requirements: The valve body must pass an overpressure test of 1.5 times the nominal pressure, and the valve seat sealing verification pressure is 1.1 times the nominal pressure.
2. API 602
Position: Supplementary specification for small-diameter (DN≤100mm) steel stop valves, suitable for high-pressure conditions in the oil and gas industry.
Features:
Structural design: Supports threaded, socket welding or flange connection, and the valve stem adopts an anti-blowout structure;
Manufacturing process: Forged, surface hardening treatment improves wear resistance.
- Supporting standards
1. ASME B16.10 Content: Specifies the structural length (face-to-face dimension) of the stop valve to ensure the installation compatibility of valves of different brands.
Example:
The structural length of the long series of DN50 (2-inch) valves is 216mm, and the short series is 178mm.
2. ASME B16.5 Content: Defines the connection dimensions, sealing surface types (such as RF convex face, RTJ ring connection) and pressure-temperature curves of flange-end stop valves.
Applicable range: Class 150~2500 flanges, diameters DN15~DN600.
- Test and inspection standards
1. API 598
Content: General method for valve sealing and strength test, used in conjunction with ASME B16.34.
Test process:
Shell test: 1.5 times the nominal pressure for ≥3 minutes, no visible leakage;
Seal test: Use air or nitrogen, leakage rate ≤ISO 5208 Class IV (liquid medium) or Class VI (gas medium).
- Typical application adaptation
1. High temperature and high pressure scenario
Adaptive structure: Bellows sealed stop valve adopts ASME B16.34 to ensure zero leakage under 550℃ working conditions.
Material optimization: Valve seat is welded with Stellite 6 to improve erosion resistance.
2. Special medium control
Corrosion-resistant design: Lined stop valve (such as PTFE lining) follows ASME B16.34 and is suitable for strong acid and strong alkali media.
Summary: The ASME standard for stop valves is based on ASME B16.34, with B16.10 (structural length), B16.5 (flange) and API 598 (testing) as supporting standards, forming a full-process specification system covering design, manufacturing and acceptance, which is widely used in high-parameter working conditions in the fields of petroleum, chemical industry and energy.
