Non-Destructive Testing

Inspection of welds and welded assemblies involves knowledge of many factors including dimensional inspection, non-destructive examination methods, welding processes, welding metallurgy, destructive testing, weld procedure and welder performance qualification requirements and the examination and test requirements of codes, standards, and specifications, and the acceptance standards to be employed.

At Si-Tech, extensive experience with all discontinuities associated with welding processes, has honed our ability to interpret and accurately judge the difference between minor discontinuities and rejectable defects. These are the critical elements of material evaluation at which we excel. Non-destructive examination methods are by far the fastest, cheapest, and most precise data gathering tools available to your company. After the data provided by NDE points the way for engineering to develop a course of action, repair work can begin. When work is completed, NDE will prove that all work was performed correctly.

EXAMPLES OF NON-DESTRUCTIVE EXAMINATION SERVICES:

• Gamma radiography and X-ray: Not unlike that picture the dentist took of your tooth. We can see all the way through a weld or metal base material up to six inches thick. If a crack, incomplete fusion, porosity, or any other unacceptable condition exists below the surface, we’ll give you a picture of it. We can place a mark right on your steel pipe, pressure vessel, or ship's hull plate so your welding supervisor will know exactly were to grind in order to remove the defect.

• Ultrasonic shear-wave and pulse-echo testing: We start by introducing high frequency sound into the material and observe the "echo" on the oscilloscope. This will reveal how much of your piping system has corroded away on the inside and how much wall thickness remains--without cutting open the pipe. We also can pinpoint weld defects below the surface with uncanny accuracy.

• Magnetic particle testing: First, induce a magnetic field on the item you want to inspect. Then introduce thousands of minute ferromagnetic materials and watch them run over the material surface and gather together at the defective area. Sorry stainless steel and aluminum--no magnetic testing for you; ferrous materials only.

• Liquid penetrant examination: Clean that surface and remove any extraneous material that may influence our results. Paint that penetrant onto the surface of the item we are inspecting. The penetrant seeps into the defects open to the surface. Highly visible bright red or fluorescent color, great wetting ability, low surface tension, and just check out that capillary action! Your vision wasn’t good enough to see those defects open to the surface, but look again after the emulsifier and developer stages have been completed. That surface has fatigue cracks all over it. At least now you know they exist.

Of course the actual inspections performed require much more than the simple scenarios given above. Procedures, discontinuity interpretations, defect evaluations, exploratory re-inspections, photographs, documentation . . . the list goes on. The list of other NDE methods not mentioned above such as eddy-current and boroscopic examinations is also extensive. The key is to remember that non-destructive examination methods are an excellent and cost effective way to obtain data in order to make a more informed decision regarding repair or replacement of your facilities. Call or e-mail us to discuss your individual needs. It won’t cost you a dime to talk to us about your situation, and it may just save you the heavy cost of replacing items unnecessarily, or failing to repair items that are about to fail.