# ISO 15761 Standard Manufacturing Process for Gate Valves
## Introduction to ISO 15761 Standard
The ISO 15761 standard specifies the requirements for the manufacturing process of steel gate valves designed for petroleum, petrochemical, and related industries. This international standard ensures that gate valves meet stringent quality, performance, and safety criteria for critical applications.
## Key Stages in the Manufacturing Process
### 1. Material Selection and Preparation
The manufacturing process begins with selecting appropriate materials that comply with ISO 15761 specifications. Common materials include:
- Carbon steel
- Stainless steel
- Alloy steel
Raw materials undergo rigorous testing for chemical composition and mechanical properties before being approved for production.
### 2. Casting or Forging of Valve Components
Gate valve bodies and bonnets are typically produced through either casting or forging processes:
- Casting: Suitable for complex shapes and large quantities
- Forging: Provides superior mechanical properties for high-pressure applications
### 3. Machining and Finishing
Precision machining operations ensure proper dimensions and surface finishes:
- CNC turning and milling
- Drilling and tapping
- Grinding and lapping of sealing surfaces
## Quality Control Measures
### Non-Destructive Testing (NDT)
ISO 15761 requires various NDT methods to detect potential defects:
- Radiographic testing (RT)
- Ultrasonic testing (UT)
- Magnetic particle inspection (MPI)
- Liquid penetrant testing (PT)
### Pressure Testing
All gate valves undergo rigorous pressure testing:
- Shell test at 1.5 times the design pressure
- Seat leakage test
- Backseat test (when applicable)
## Final Assembly and Inspection
The assembly process includes:
- Installation of stem, gate, and sealing components
- Proper lubrication of moving parts
- Final operational testing
Completed valves receive comprehensive documentation including material certificates, test reports, and compliance statements with ISO 15761 requirements.
## Benefits of ISO 15761 Compliance
Manufacturing gate valves according to ISO 15761 offers several advantages:
- Ensured reliability in critical applications
- International recognition and acceptance
- Standardized performance requirements
- Improved safety in petroleum and petrochemical operations
