Yibeng Valve Z62Y-250 Fully Welded Gate Valve Welding Parameters and NDT
With a pressure rating of 25.0MPa (PN250) and temperature capability up to 540°C (with P57/170V materials up to 570°C), these valves provide reliable isolation where flange connections would pose leakage risks . This article provides essential welding parameters and non-destructive testing requirements for the Z62Y-250 fully welded gate valve.The main gate valve product names of China gate valve Network include:API Pneumatic Lug&wafer Knife-shaped Gate Valve,Electric Non-rising Stem Single Disc Wedge Gate Valve,Electric Slurry Valve,Electric Flange Gate Valve,Fire Special Signal Relisient Seat Seal Gate Valve,Manual Vacuum Isolated Wedge Gate Valve,Z41H Manual Flange Cast Iron Gate Valve,ZT9928 Manual Slurry Knife-shaped Gate Valve.
Welding Parameters for Z62Y-250
Weld Preparation: The welding bevel angle is typically 30 to 37.5 degrees, with a root gap of 2 to 3mm . The welding groove conforms to power industry standard 78DG or per customer specification .
Welding Process: Multi-layer, multi-pass welding is employed using TIG (argon arc) for the root pass, followed by filler welding and cap welding. Each layer undergoes dye penetrant inspection to verify no defects are present .
Post-Weld Heat Treatment: For alloy steel valve bodies, post-weld heat treatment at 600-650°C is performed to relieve residual stresses. Holding time is calculated at approximately 2 minutes per millimeter of wall thickness .
Connection Standard: Butt weld ends per ANSI B16.25 or DL/T531 standards, with welding end preparation designed to match the pipeline material for seamless integration .
Non-Destructive Testing Requirements
100% RT (Radiographic Testing): All circumferential and longitudinal welds must undergo 100% radiographic inspection to verify internal integrity before the valve is placed into service .
PT (Penetrant Testing): Each welding layer is inspected by dye penetrant testing after completion to confirm the absence of surface defects .
Ultrasonic Testing: Weld areas are inspected periodically using ultrasonic phased array technology to detect fatigue cracks during service life .
Material Verification: Positive Material Identification (PMI) is performed on all pressure-containing components. Hydrostatic shell testing at 37.5MPa and seal testing at 27.5MPa per the valve's performance specifications verify overall integrity .
Summary
The Yibeng Valve Z62Y-250 fully welded gate valve requires precision welding with 30-37.5° bevel angles, TIG root pass followed by multi-layer welding, and post-weld heat treatment at 600-650°C. Full compliance with NDT requirements including 100% RT, PT per layer, and UT monitoring is essential for reliable high-pressure steam service. Consulting with qualified valve manufacturers for certified welding procedure specifications and NDT documentation is strongly recommended for critical power plant applications.
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