A Singer Car Crankshaft Showing A Hairline Crack While Undergoing A Magnaflux Test
Crack Testing & Magnaflux NDT
South Cerney Engineering carries out crack testing on a wide range of components. Based at Ashton Keynes near Swindon, Wiltshire, a short drive from Cirencester, we offer Magnaflux and dye penetrant NDT.
Fatigue is the most common cause of component failure. Repeated loading and unloading, from heat cycles or mechanical forces, allow a crack to grow from a small material flaw. These cracks usually start on or just below the surface, so they can go unnoticed until a part fails. Crack testing finds them before a component is refitted or rebuilt.
Crack Testing Methods: Magnaflux, Dye Penetrant & X-ray
Magnaflux testing is our primary method for detecting initial cracks on ferrous parts. We spray the cleaned component with a test solution, place it in a strong magnetic field, and inspect any flaws under UV light.
For non-ferrous (non-magnetic) materials, we use dye penetrant testing. The part is cleaned, a penetrant is applied and left to work into any flaws, then the surface is cleaned again and dried. A developer is then applied, drawing the penetrant back out to show the exact location of a crack.
X-ray inspection checks the whole component, including internal flaws and welds, and suits safety-critical parts. It is more costly and limited by part size, so for many jobs Magnaflux or dye penetrant testing gives the reassurance needed. We can advise on which method suits your component.
A helicoil gear being checked after suffering an impact
A con Rod passes crack testing checks
Components We Crack Test
Most metal components can be tested. We regularly Magnaflux or dye-test the following, and have tested many other parts too:
-
Crankshafts
-
Gears
-
Con-rods
-
Springs
-
Engine blocks
-
Pins
-
Suspension components
-
Wishbones
-
Uprights
For rare or expensive parts, crack testing offers useful reassurance before you spend more on machining or a rebuild. For cylinder heads, we also offer cylinder head pressure testing to check for leaks.
“With rare or expensive parts,
it’s a good way of having some reassurance”
Options Once a Crack Is Found
-
If testing reveals a crack, the right repair depends on its size, location, and cost.
-
Replacing the component is often simplest, but not always realistic, for example, with a vintage engine block of historical value.
-
Depending on how far the crack has progressed, you can dress back the area to remove a surface crack, provided it is not too deep.
-
Depending on the part and material, you can dress back the affected area and rebuild it with weld.
-
You can arrest the crack by drilling each end and pinning the holes to stop it from spreading.
-
Metal stitching, also known as metalocking, can arrest a crack. We have used metal stitch repairs successfully on vintage engine blocks for many years, and we also carry out cylinder head repairs and crankshaft grinding and polishing.
Get in touch
Our team of time-served engineers can advise on the most suitable test method for your parts and on repair options if a flaw is found.