What is NDT?

NDT is short for non-destructive testing and is the only tool available today that can, without destroying the weld/material, verify whether the weld/material is homogeneous or not or if the detected imperfections in the weld/materials are acceptable in accordance with the relevant acceptance criterias.

NDT consists of many different test-methods that combined with each other, will ensure 100% quality assurance of the object being tested. For more information, please contact us.

Test-Methods

The extent of required NDT and choice of NDT-method varies depending on the test object (geometry and material of the test object), the applicable standards and specifications. Here are some basic information regarding the different test-methods we use. Please contact us if you have questions regarding NDT, or if you need help to determine the extent/method of testing your project requires.

VT (visual testing) – By visually inspecting the surface of an object, we are able to detect surface imperfections such as cracks, pores, insufficient or excessive throat thickness, slag, root/cap concavity and convexity, as well as asymmetric leg length, undercut and more.

PT (penetrant testing) – By using a penetrating liquid on the surface of an object, we detect surface imperfections as well as imperfections located just underneath the surface of the object. Mostly used on non-ferritic materials.

MT (magnetic testing) – Also known as MPI (magnetic particle testing). By applying magnetic powder to a ferritic material while creating a magnetic field using a hand held magnet, we are able to detect surface imperfections and imperfections located just underneath the surface of an object. This test-method is limited to ferritic materials.

UT (ultrasonic testing) – By using ultrasonic testing we are able to detect volumetric, internal imperfections in an object. Using probes that send out sound waves, we are able to work out the exact depth and length of any internal imperfections. In addition, ultrasonic testing is often used for thickness measurement on vessels, boilers, castings and pipes. Ultrasonic testing can normally only be performed on materials where thickness > 8mm.

RT (radiographic testing) – By using a radioactive source (isotope) or an x-ray tube, we detect surface imperfections as well as internal imperfections of an object. A film is placed on the backside of the object that is to be tested, the object and film is then exposed to radiation before the film is developed and analyzed. This test-method has no limitations regarding material, thickness or diameter.

ET (eddy current testing) – Eddy current testing use the electromagnetism principle. Conventional eddy current testing utilises electromagnetic induction to detect imperfections in the surface, or just below the surface of conductive materials. A coil energised with alternating current is placed in proximity to the test surface generating an alternating magnetic field, which interacts with the object tested producing eddy current in the vicinity. The electrical conductivity variations or magnetic permeability of the object, or the presence of any imperfections, will cause a change in eddy current and a corresponding change in phases and amplitude of the measured current. The changes are shown on a screen, and interpreted.

PMI (positive material identification) – PMI is used for verification of materials and to measure the alloy content in materials. A portable handheld device “scans” the material, and information regarding type of material along with alloy content is displayed on the screen of the device. The device we use is NITON XL3t 980 GOLDD+

Features and benefits of using NITON XL3t 980 GOLDD+:

  • Light element detection (Mg, Al, Si, P, S) without helium or vacuum purging
  • High count rate for lower detection limits, and faster analysis

HT (hardness testing) – Quality Welding uses portable hardness testing equipment to test the hardness of any given material. The equipment we use is the MIC 10 UCI Hardness Tester.
GE’s MIC 10 enables quick and convenient on-site hardness testing according to the UCI method (Ultrasonic Contact Impedance – standardized according to ASTM A1038 and DIN 50159). The diamond indent in the material’s surface is electronically measured and instantly displayed without using the cumbersome optical evaluation normally associated with conventional hardness testers.

Features and benefits of using MIC 10 UCI Hardness Tester:

  • Automatic conversion into different hardness scales and tensile strength
  • Fast and effective
  • Suitable for on-site hardness testing because of size and weight
  • Possible to measure in any direction (overhead positions, horizontal…)
  • The narrow size of the probe enables us to take measurements on locations with difficult accessibility, such as tooth flanks or roots of gears.