# ISO 15761 Compliant Gate Valve Manufacturing Process
## Introduction to ISO 15761 Standard
The ISO 15761 standard specifies the requirements for steel gate valves used in petroleum, petrochemical, and related industries. Compliance with this standard ensures that gate valves meet stringent quality, safety, and performance criteria for critical applications.
## Raw Material Selection
The manufacturing process begins with careful selection of raw materials:
– Carbon steel or alloy steel forgings
– Stainless steel trim components
– High-quality sealing materials
– Corrosion-resistant coatings
All materials must meet the chemical composition and mechanical property requirements specified in ISO 15761.
## Forging and Casting Processes
### Body and Bonnet Formation
The valve body and bonnet are typically created through:
– Closed die forging for superior strength
– Investment casting for complex geometries
– Heat treatment to achieve desired mechanical properties
### Quality Control Measures
Each component undergoes:
– Dimensional inspection
– Non-destructive testing (NDT)
– Material certification verification
## Machining Operations
Precision machining ensures proper fit and function:
– CNC turning for accurate dimensions
– Milling of flange faces and sealing surfaces
– Drilling and tapping of bolt holes
– Grinding of critical sealing surfaces
All machining tolerances must comply with ISO 15761 specifications.
## Assembly Process
The assembly phase includes:
– Installation of stem and gate components
– Proper alignment of sealing surfaces
– Torque-controlled fastening of bolted connections
– Application of anti-seize compounds
## Testing and Inspection
### Pressure Testing
All valves undergo:
– Shell test at 1.5 times design pressure
– Seat leakage test per ISO 5208
– Backseat test when applicable
### Final Inspection
Before shipment, each valve receives:
– Visual inspection
– Dimensional verification
– Functional testing
– Marking and tagging per ISO 15761 requirements
## Surface Treatment and Coating
Final surface preparations include:
– Shot blasting for surface preparation
– Application of protective coatings
– Marking with required identification
– Packaging for corrosion protection during transit
## Certification and Documentation
Upon successful completion, manufacturers provide:
– Material test reports
– NDT reports
– Pressure test certificates
– Compliance declaration to ISO 15761
This comprehensive manufacturing process ensures that ISO 15761 compliant gate valves deliver reliable performance in demanding industrial applications.