Combined portable hardness testing solution to increase the efficiency of inspection quality control processes

摘要

Successful quality control by avoiding test samples, dismantling, sectioning and/or preparation can be achieved in a timely manner when taking advantage of portable hardness testing solutions. Test principles such as Leeb Rebound, Portable Rockwell and Ultrasonic Contact Impedance (UCI) provide modern, quick and easy tools that can supplement or potentially replace traditional test methods. Portability is a key aspect for all of the above methods despite the test principles being significantly different to one another. The decision making process of which instrument to utilise is directly related to geometrical and mechanical properties of the test sample and it is firmly recommended to consider and understand the limitations prior to testing. Since there is no direct mathematical relationship between different test methods it is a common practice to correlate them to one another. As an example the existing default hardness conversions in Leeb or UCI devices are based on certain minimal sample geometries unlike Portable Rockwell instruments which have almost no restrictions in regard to thickness and mass, as well as being far more material independent. A new approach is to create a simple custom correlation for exotic materials and for samples that do not meet the geometrical requirements based on the Portable Rockwell measurements. This would allow the user to broaden the capabilities into difficult to reach areas. This paper will advance into this principle by highlighting examples such as weld inspection where testing is required on the base material, HAZ (Heat Affected Zone) and the weld. Additionally, independent guidelines (ASME, Nordtest, DGZfP) and standards (ASTM, ISO, DIN) are covered in order to help select the most suitable test method for each specific application.