# ISO 15761 Gate Valve Manufacturing Process

## Introduction to ISO 15761 Gate Valves

The ISO 15761 standard specifies requirements for steel gate valves used in petroleum, petrochemical, and related industries. These valves are designed for on-off service and provide reliable shut-off capabilities in high-pressure and high-temperature applications.

## Raw Material Selection

The manufacturing process begins with careful selection of raw materials that meet ISO 15761 specifications:

– Carbon steel or alloy steel forgings for valve bodies
– Stainless steel for trim components
– Graphite or PTFE for sealing materials
– Bolting materials with appropriate strength ratings

## Manufacturing Process Steps

### 1. Forging and Casting

The primary components (body, bonnet, and gate) are created through either forging or casting processes:

– Forged components offer superior strength for high-pressure applications
– Cast components are suitable for complex geometries and larger sizes
– Both methods must meet ISO 15761 material and quality requirements

### 2. Machining Operations

Precision machining ensures proper fit and function:

– CNC turning and milling of valve bodies and bonnets
– Boring of seat areas to exact tolerances
– Gate profiling for optimal sealing performance
– Thread cutting for stem and bolting connections

### 3. Assembly Process

The assembly phase includes:

– Installation of seats and sealing components
– Gate and stem assembly with proper alignment
– Bonnet attachment with appropriate gasketing
– Packing installation for stem sealing

### 4. Testing and Inspection

ISO 15761 requires rigorous testing:

– Shell test at 1.5 times design pressure
– Seat leakage test per ISO 5208 standards
– Functional testing of operation mechanism
– Dimensional verification of critical features

## Quality Control Measures

Throughout the manufacturing process, multiple quality checks are implemented:

– Material certification verification
– Non-destructive testing (NDT) including:
– Liquid penetrant inspection
– Magnetic particle inspection
– Ultrasonic testing
– Radiographic examination for critical welds

– Hardness testing of critical components
– Final visual inspection before shipment

## Surface Treatment and Coating

To ensure longevity and corrosion resistance:

– Shot blasting for surface preparation
– Application of protective coatings:
– Epoxy coatings for general service
– Specialized coatings for corrosive environments
– High-temperature coatings for thermal applications

## Packaging and Shipping

Final steps include:

– Proper cleaning and preservation
– Protection of sealing surfaces
– Secure packaging to prevent damage
– Documentation including:
– Material certificates
– Test reports
– Operation and maintenance manuals

## Conclusion

The ISO 15761 gate valve manufacturing process combines precision engineering with rigorous quality control to produce reliable valves for critical applications. By adhering to the ISO standard, manufacturers ensure consistent performance and safety in demanding industrial environments.