ISO 15761 Manufacturing Process for Gate Valves

# ISO 15761 Manufacturing Process for Gate Valves

## Introduction to ISO 15761 Standard

The ISO 15761 standard specifies requirements for steel gate valves designed for petroleum, petrochemical, and related industries. This international standard ensures that gate valves meet strict quality and performance criteria for critical applications where reliability is paramount.

## Raw Material Selection

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

– Carbon steel or alloy steel forgings for valve bodies
– Stainless steel for trim components
– Appropriate gasket materials
– High-quality fasteners

## Forging Process

The primary manufacturing steps for ISO 15761 gate valves include:

### 1. Body and Bonnet Forging

Valve bodies and bonnets are typically manufactured through closed-die forging processes to ensure:

– Superior mechanical properties
– Dense grain structure
– Excellent resistance to pressure and temperature

### 2. Heat Treatment

All forged components undergo precise heat treatment to:

– Achieve required hardness
– Improve mechanical properties
– Relieve internal stresses

## Machining Operations

Precision machining transforms forged components into finished parts:

### Body Machining

– CNC turning of flow passages
– Flange face machining
– Seat pocket preparation
– Bolt hole drilling

### Gate and Stem Machining

– Precision grinding of sealing surfaces
– Thread cutting for stem operation
– Final dimensional verification

## Assembly Process

The assembly of ISO 15761 gate valves follows strict quality procedures:

1. Component cleaning and inspection
2. Seat ring installation
3. Gate and stem assembly
4. Packing installation
5. Bonnet attachment
6. Final torque verification

## Testing and Quality Control

ISO 15761 requires comprehensive testing:

### Pressure Testing

– Shell test at 1.5 times rated pressure
– Seat leakage test
– Backseat test (when applicable)

### Non-Destructive Examination

– Liquid penetrant testing
– Magnetic particle inspection
– Ultrasonic testing for critical areas

## Final Inspection and Certification

Before shipment, each valve undergoes:

– Dimensional verification
– Functional testing
– Surface finish inspection
– Marking verification
– Documentation review

## Conclusion

The ISO 15761 manufacturing process ensures gate valves meet the highest industry standards for performance and reliability in demanding applications. From material selection to final testing, each step is carefully controlled to produce valves that provide long service life and dependable operation in critical petroleum and petrochemical services.