Non-Destructive Testing (NDT) refers to a technical method for defect inspection, performance evaluation and structural analysis of raw materials, components, semi-finished products and finished products during equipment manufacturing, without damaging the material, structural integrity and service performance of tested equipment. Its core value lies in identifying hidden hazards in advance, guaranteeing product quality, lowering production costs and preventing safety accidents.

I. Core Application Stages of NDT in Equipment Manufacturing

NDT runs through the whole equipment manufacturing process and is mainly applied in the following key phases:

1. Raw Material Acceptance Stage: Inspect internal defects such as porosity, slag inclusion, cracks and lamination in base materials including steel, non-ferrous metals and composite materials, and prevent unqualified raw materials from entering production.

2. Component Machining Stage: Conduct inspection on machined parts, forgings, castings, weldments, etc., for example:

• Inspection of shrinkage cavities, gas pores and sand holes in castings;

• Inspection of laps, cracks and inclusions in forgings;

• Inspection of weld cracks, incomplete penetration, gas pores and slag inclusions in weldments.

3. Assembly & Commissioning Stage: Reinspect key positions of assembled equipment (such as welds, bolted connections and pressure-bearing components) to ensure no new defects are introduced during assembly and verify the structural stability of equipment.

4. Factory Acceptance Stage: As a core quality verification method before equipment delivery, perform comprehensive inspection on key components of complete equipment and issue inspection reports to meet customer acceptance requirements and industrial standards.

II. Common NDT Technologies for Equipment Manufacturing and Applicable Scenarios

III. Core Advantages of NDT in Equipment Manufacturing

1. Non-destructive: The equipment can be normally put into service after testing. No test samples need to be scrapped, reducing material loss.

2. Comprehensiveness: It covers the whole process from raw materials to finished products, enabling "early detection and early treatment" of defects.

3. Accuracy: Combined with digital testing equipment (such as phased array ultrasonic testing and DR digital radiography), it can accurately locate defect position and size and provide quantitative data for quality evaluation.

4. Compliance: It meets mandatory standard requirements of industries including special equipment (pressure vessels, hoisting machinery, etc.), military industry and aerospace, and helps enterprises pass system certification.

IV. Quality Control Key Points for NDT in Equipment Manufacturing

1. Personnel Qualification: Inspectors shall hold corresponding NDT qualification certificates (such as CNAS and ASNT certifications) and possess professional operation capabilities.

2. Equipment Calibration: Testing instruments shall be calibrated regularly to ensure testing accuracy meets standard requirements.

3. Standard Basis: Tests shall be carried out in strict accordance with national standards (GB/T series), industrial standards (e.g. GB 150 for pressure vessels) or international standards (e.g. ISO, ASME).

4. Report Specification: Test reports shall contain information including testing methods, equipment parameters, defect data and evaluation results to ensure traceability.

V. Industry Development Trends

With the upgrading of intelligent manufacturing technologies, NDT for equipment manufacturing is developing toward the direction of digitalization, intelligence and automation:

• Digital inspection: DR/CR digital radiography and phased array ultrasonic testing replace traditional film radiography to realize data storage and analysis;

• Automated inspection: Robots equipped with testing probes realize continuous on-line inspection for large-scale equipment and production lines;

• Intelligent evaluation: Combined with AI algorithms, automatically identify defect types and sizes to improve inspection efficiency and accuracy.