Macrography testing is the most common destructive test to verify the goodness of welding; in addition to being the most common it is also the easiest to accomplish. Even in the workshop or on site, after performing the heel. To make a good macrography it is necessary to follow the following simple steps:
Macro examination carried out directly in the workshop.
- Wait for the time necessary for the joint to cool down. It must be possible to touch it with your bare hands.
- Cut the weld across the desired point by means of a belt saw with liquid cooling. A cross-cut sawing machine or a grinding wheel with a cutting disc may also be used, provided that care is taken not to overheat the cutting surface afterwards.
- Polish the melted area using the polishing machine to replace the abrasive paper from the coarsest to the finest, until it reaches the desired roughness. In the field you can also use a grinding wheel with say abrasive, possibly used to obtain a more shiny surface.
- Proceed with the chemical attack used the appropriate reagent according to the type of material. The most common are 10/20% nitric acid in alcoholic solution for ferrous alloys. Direct water (50% nitric acid 50% hydrochloric acid) for stainless steels.Place under the hood, pour a thin layer on the glossy area and wait for the time necessary to obtain the desired surface corrosion. This time can change depending on the type of alloy.
- Wash away the chemical reagent with alcohol to dry with care.
JJ Lab, the laboratory of Solving Uni.On, is equipped with all the tools and equipment to obtain any type of macrographic sample in terms of size and type of material using cutting-edge technology.
JJ Lab Macrographic Station
Graphic processing program