Most service failures begin at the surface. A fatigue crack starts at a weld toe, a sharp corner, or a machining mark, then grows inward under load until the component gives way. Magnetic particle and dye penetrant testing exist to catch those cracks while they are still small — including many that are far too fine to see with the naked eye.
Magnetic Particle Testing (MT)
MT applies to ferromagnetic materials — carbon steel, most structural steels, and many alloy steels. The component is magnetised, and fine magnetic particles are applied to the surface. Where a crack interrupts the magnetic field, the particles gather along it and make it visible.
- Detects surface and slightly subsurface flaws
- Fast enough for large areas and long weld runs
- Works through thin coatings in many cases
- Effective on irregular shapes where other methods struggle
Dye Penetrant Testing (PT)
PT works on any non-porous material — including stainless steel, aluminium, copper alloys, and other non-magnetic metals where MT cannot be used. A penetrating liquid is drawn into surface-breaking flaws by capillary action; after the excess is removed, a developer draws it back out, revealing the flaw as a clear indication against the developer background.
- Applicable to non-magnetic materials
- Detects surface-breaking cracks, porosity, and laps
- No electrical supply or magnetising equipment required
- Suitable for remote locations and confined spaces
The choice between them is usually straightforward: if the material is ferromagnetic, MT is faster and can find flaws just below the surface. If it is not, PT is the method. Both are limited to flaws that reach or nearly reach the surface — for anything buried deeper, ultrasonic or radiographic testing is required.
Where We Apply Them
- Weld inspection — toe cracks, root cracks, and surface porosity
- Structural connections — fatigue-prone joints and bracket welds
- Castings and forgings — surface defects before machining or acceptance
- Lifting equipment and padeyes — periodic in-service crack detection
- Shafts, hooks, and rotating components — fatigue crack screening
- Repair verification — confirming a ground-out defect has been fully removed
Why Work With Us
- Personnel qualified and certified in accordance with ASNT SNT-TC-1A and ISO 9712
- Approved service supplier for ABS, BKI, BV, RINA, ClassNK, KR, DNV, IRS and LR
- IRATA-certified rope access technicians who also hold NDT qualifications
- Consumables and procedures selected to suit the material and acceptance standard
- Based in Batam, close to the yards and facilities we serve
Request a Quote
Phone / WhatsApp: +62 813 7202 1412
Email: info@htmarineinspection.com
Office hours: Monday – Friday 08.00 – 17.00, Saturday 08.00 – 14.00