“Hayley and STW have been a great asset to our company and have assisted us with their knowledge and professionalism.”
Precision Magnetic Particle Inspection Services
ISO 9001 Certified More than 10 Years’ Industry Experience Same-Day Response to EnquiriesNeed An Inspection Quickly?
Speak with our team today for expert advice and responsive support.
Magnetic Particle Inspection (MPI) Services
Magnetic Particle Inspection is a highly sensitive non‑destructive testing method for ferromagnetic materials. It magnetises a component and applies iron particles to reveal fine cracks and irregularities on or just below the surface. Magnetic Particle Inspection can help you:
When Could You Need Magnetic Particle Inspection?
MPI is ideal when you need to find surface or near‑surface defects that could affect safety or performance. It is commonly used for quality control, maintenance, and compliance checks.
• Locate fine surface cracks and irregularities
• Inspect welds and ferromagnetic components after fabrication or in‑service
• Identify defects on or near the surface of a material
• Assess whether a component is suitable for continued use
• Support compliance with relevant industry standards
If you are unsure whether MPI is the right method for your application, our team will be happy to advise.
TO DISCUSS YOUR MAGNETIC PARTICLE INSPECTION REQUIREMENTS
Why Is Magnetic Particle Inspection Used?
MPI is widely chosen because it is fast, reliable, and can be performed on‑site with minimal preparation. It reveals defects that visual inspection alone would miss.
• Detects fine surface and near‑surface discontinuities
• Works on complex geometries and irregular shapes
• Delivers fast results – ideal for production or maintenance turnaround
• Both colour contrast and fluorescent (UV) methods are available for different surface conditions
• Portable equipment allows testing at your facility or on location
MPI Inspection or Liquid Penetrant Testing?
Choosing the correct surface inspection method depends on your material. MPI works only on ferromagnetic metals (iron, steel, nickel alloys). For non‑ferromagnetic materials like aluminium, copper, or stainless steel, Liquid Penetrant Testing (LPI) is required.
• MPI – best for ferromagnetic materials; detects surface and near‑surface flaws
• LPI – suitable for all non‑porous materials; detects surface flaws only
• Colour contrast and Fluorescent LPI can be used for varying component types, and different sensitivity level requirements.
• If the component is not ferritic or magnetizable then Liquid Penetrant Inspection can be used instead of Magnetic Particle Inspection.
TO DISCUSS YOUR MAGNETIC PARTICLE INSPECTION REQUIREMENTS
Why Choose S.T & W Inspections?
Choosing the right inspection partner ensures quality, compliance, and confidence throughout your project.
• More than a decade of industry experience
• Visible and fluorescent MPI methods available
• Short‑notice mobilisation where required
• Same‑day responses to enquiries
• ISO 9001 certified and Constructionline approved
• Experience across rail, structural steel, and other demanding sectors
• Access to a broad range of NDT expertise
• Support from experienced Responsible Welding Co‑Ordinators (RWCs)
Hear from our clients
“Great service, friendly, helpful and accommodating.”
“ST&W Inspections are a very reliable supplier of ours. They are quick to support us at with any inspections that we require sometimes on a short turnaround. This includes completing paperwork that we require to give to our clients and also if an inspection is required on site, they are always reliable to be able to meet our demands. Also, their knowledge of the industry is massive support to us when we require information when we might not have the answers.“
“It is genuinely a pleasure doing business with you and I look forward to continuing the relationship and using your services“
Supporting Welding Compliance & Qualification Requirements
Our Responsible Welding Co‑Ordinators ensure that welding procedures are followed and finished welds comply with British Standards and project specifications.
• Supervision of welding activities and procedure compliance
• Practical guidance on weld quality and defect prevention
• Support with new weld procedure development and qualification
• Confidence that welding meets safety and quality requirements
Additional Non-Destructive
Testing Services
Alongside Magnetic Particle Inspection, S.T & W Inspections provides a range of additional NDT services, including:
Visual Inspection
Ultrasonic Inspection
Liquid Penetrant Testing
Phased Array Ultrasonic Testing
Positive Material Identification
District Heating NDT
Our broad service offering enables clients to access multiple inspection methods through a single trusted provider.
Discuss Your Magnetic
Particle Inspection
Requirements
Whether you need weld inspection, crack detection, component assessment, or wider
NDT support, our team is ready to help.
Tell us about your project requirements, and we’ll recommend the most suitable
inspection approach.