Dye penetrant testing is just one of the many added-value services we are able to offer, mostly conducted by our in-house team of inspectors and experts. By bringing more of your activity together into one place we can greatly simplify your procurement process.
Langley Alloys has been undertaking an increased level of dye penetrant inspection for our customers in recent months. Dye penetrant testing is a relatively low-cost method to check for surface defects in items, in our case a selection of forged components, pipes and fittings.
Also known as liquid penetrate inspection due to the use of a liquid dye to highlight surface features, ‘dye pen’ inspection exploits capillary action. A liquid is drawn in to small breaks or cracks that may exist in the surface. Firstly, the dye is applied to the clean surface of the item, by brush, spray or immersion. It is allowed to sit for a period of time, typically up to 30 minutes, before excess dye is removed. A second solution, called the developer, is then applied in our case by aerosol spray. Again, it is left to ‘develop’ as it absorbs the liquid dye that has been held in any surface breaks and thereby highlights their location and approximate size. Visual inspection is carried out in a well-lit space, although UV light may be used for certain dyes to increase the resolution.
The most common specification for (stainless) steel forgings is BS EN 10228-2, which builds upon the basic principles defined in BS EN ISO 3452-1. The demand here is has typically been for duplex and super duplex stainless steel fittings and flanges produced on our behalf. They are installed in pipe runs in the as-is condition, so confirming the absence of any surface defects is helpful for the most critical of applications.
Perhaps more unusually, we have also ‘dye pen’ inspected a number of batches of super duplex stainless steel seamless pipe. The relative size of these pipes makes them a little harder to handle, and they would have already received a level of inspection at the producing mill. Seamless pipes produced by extrusion will generally have very good product integrity, but for very demanding end uses we are seeing more exacting inspection plans.
Langley Alloys has been closely associated with the supply of copper-based alloys to Naval applications since its very inception, we also inspect such components to the relevant specifications. The Ministry of Defence’s DEF STAN 02-729 covers the general inspection procedures. This covers the requirements of DEF STAN 02-879, DEF STAN 02-835 (NES835) and DEF STAN 02-833, with copper alloys (Hiduron 130), high-strength copper nickel manganese (Hiduron 191) and nickel aluminium bronze (NAB) alloys respectively.
All ‘dye pen’ testing is undertaken in-house, offering a responsive and more cost-competitive service than using third-party inspectors. Our own inspectors meet the PCN Level 2 qualification demanded, with many years’ experience of both dye pen and ultrasonic testing.
If you would like to know more about our range of value-added inspection, testing and processing services, please contact us today.