ISO 15761 Standard Manufacturing Process for Gate Valves

# ISO 15761 Standard Manufacturing Process for Gate Valves

## Introduction to ISO 15761 Standard

The ISO 15761 standard specifies requirements for the design, manufacturing, and testing of steel gate valves used in petroleum, petrochemical, and related industries. This international standard ensures that gate valves meet stringent quality and performance criteria for critical applications.

## Key Stages in the Manufacturing Process

### 1. Material Selection and Preparation

Manufacturers must select materials that comply with ISO 15761 specifications, typically including carbon steel, stainless steel, or alloy steel. The standard defines:

– Chemical composition requirements
– Mechanical properties
– Heat treatment procedures
– Material certification standards

### 2. Casting or Forging Process

The valve body manufacturing begins with either:

Casting method: Molten metal is poured into molds to form the basic valve shape. ISO 15761 requires rigorous quality control of casting processes to prevent defects.

Forging method: Metal is shaped under high pressure while heated to improve mechanical properties. Forged valves typically offer better strength characteristics.

### 3. Machining Operations

Precision machining ensures proper fit and function of all components:

– CNC machining of valve bodies and bonnets
– Seat and seal surface finishing
– Stem machining and threading
– Gate wedge profiling

### 4. Assembly Process

The assembly phase includes:

Proper alignment of the gate between seats

Installation of stem, packing, and sealing components

Torque verification of all fasteners

Lubrication of moving parts as specified

## Quality Control and Testing

### Non-Destructive Testing (NDT)

ISO 15761 mandates several NDT methods:

– Radiographic testing (RT)
– Ultrasonic testing (UT)
– Magnetic particle inspection (MPI)
– Liquid penetrant testing (PT)

### Pressure Testing

All valves must undergo:

Shell test: 1.5 times the maximum working pressure

Seat test: 1.1 times the maximum working pressure

Backseat test: When applicable, per standard requirements

## Final Inspection and Certification

Before shipment, each valve undergoes:

– Dimensional verification
– Functional testing
– Surface finish inspection
– Marking and tagging per ISO 15761 requirements
– Documentation preparation including material certificates and test reports

## Benefits of ISO 15761 Compliance

Manufacturing gate valves to ISO 15761 standards provides:

Consistent quality across production batches

Reliable performance in demanding applications

Global acceptance in petroleum and petrochemical industries

Reduced risk of field failures and maintenance issues

## Conclusion

The ISO 15761 standard establishes a comprehensive framework for gate valve manufacturing that ensures safety, reliability, and performance. By following these standardized processes, manufacturers can produce gate valves that meet the rigorous demands of the oil and gas industry while providing customers with confidence in their critical infrastructure components.