Testing HAZ is tricky because the area is so small and the hardness can vary significantly over just a few millimeters. In my experience, a standard rebound tester won’t give you the resolution you need. Your best bet is to invest in a high-quality ultrasonic hardness tester The UCI method allows you to precisely place the probe exactly where you need it, which is perfect for narrow weld seams. I’ve been following the developments from Teqto lately, and their portable range is specifically designed for these kinds of industrial challenges. Their sensors are quite versatile and can handle different surface geometries much better than the old-school impact devices.
