Nondestructive Testing - NDT Lab

Frequently Asked Questions

What is Nondestructive Testing?

Nondestructive testing (NDT) is a group of inspection methods used to evaluate the condition and integrity of a material, component, or structure without causing damage. NDT techniques detect surface and internal defects, measure material properties, and verify part quality—ensuring safety and performance while allowing the item to remain in service.

Common NDT methods include ultrasonic testing, magnetic particle inspection, liquid penetrant inspection, radiographic testing, and visual inspection. These processes are widely used in industries such as aerospace, manufacturing, construction, energy, and transportation to maintain quality standards and prevent costly failures.

By using NDT, companies can identify flaws early, extend equipment life, meet regulatory requirements, and improve overall reliability—all without sacrificing the tested component. We also offer remote NDT services.

What are Nondestructive Examination Methods?

Nondestructive examination (NDE) methods—also referred to as nondestructive testing (NDT)—are techniques used to inspect and evaluate materials, components, or assemblies without causing damage. These methods help identify surface and internal defects, verify dimensions, and assess material properties while allowing the part to remain in service.

Common NDE methods include:

• Ultrasonic Testing (UT) – Uses high-frequency sound waves to detect internal flaws.

• Magnetic Particle Inspection (MPI) – Identifies surface and near-surface defects in ferromagnetic materials.

• Liquid Penetrant Inspection (LPI) – Reveals cracks, porosity, and other surface flaws.

• Radiographic Testing (RT) – Uses X-rays or gamma rays to view internal structures.

• Visual Inspection (VT) – The most basic method, often used as a first-line quality check.

These methods are essential in industries such as aerospace, oil and gas, power generation, manufacturing, and transportation to ensure safety, meet regulatory requirements, and prevent costly failures—without destroying the tested item.

Sub Source specializes in Liquid Penetrant Inspection (LPI), Magnetic Particle Inspection (MPI), and Nital Etch (also known as Temper Etch).

What are the Advantages of NDT?

Nondestructive testing (NDT) offers significant benefits for quality control, safety, and cost efficiency in industries that rely on high-performance materials and components. Key advantages include:

• No Damage to Components – Parts can be inspected without altering or destroying them, allowing continued use.

• Early Detection of Flaws – Identifies surface and internal defects before they cause failures or costly downtime.

• Cost Savings – Reduces scrap, rework, and unplanned outages by catching problems early.

• Increased Safety – Prevents accidents by ensuring materials and structures meet safety standards.

• Versatility – Applicable to metals, composites, welds, coatings, and more across multiple industries.

• Regulatory Compliance – Helps meet industry codes, certifications, and legal requirements.

• Quality Assurance – Verifies manufacturing processes and maintenance work meet specifications.

By integrating NDT into production and maintenance programs, companies can improve reliability, extend service life, and protect both people and assets—all without sacrificing the tested component.  In-house and remote NDT services are available.

What is the difference between NDT and NDE?

Nondestructive Testing (NDT) and Nondestructive Examination (NDE) are closely related terms often used interchangeably, but there is a subtle difference:

• Nondestructive Testing (NDT) – Refers to the process of applying specific methods (such as ultrasonic, magnetic particle, or radiographic testing) to detect flaws, measure properties, or verify the integrity of a material or component without causing damage.

• Nondestructive Examination (NDE) – Encompasses not only the testing process, but also the analysis, interpretation, and evaluation of the results to determine whether the material meets required standards.

In short, NDT is the testing action, while NDE includes both testing and the subsequent evaluation. Both play a critical role in quality assurance, safety compliance, and reliability across industries like aerospace, manufacturing, energy, and transportation.

What is Magnetic Particle Inspection?

Magnetic Particle Inspection (MPI) is a nondestructive testing (NDT) method used to detect surface and near-surface defects in ferromagnetic materials such as iron, nickel, cobalt, and their alloys. The process involves magnetizing the part and applying fine magnetic particles—either dry or suspended in liquid—that gather at areas where magnetic flux is interrupted by a flaw, making cracks, seams, or inclusions visible.

Key Advantages of MPI:

• Highly Sensitive – Detects even small or subtle surface defects.

• Quick and Efficient – Ideal for production environments and field inspections.

• Versatile Applications – Used in manufacturing, welding, aerospace, automotive, and structural steel industries.

MPI is widely valued for its speed, accuracy, and cost-effectiveness, making it a go-to method for ensuring the safety, quality, and reliability of critical components without causing damage.