Are the hardness blocks supplied with a calibration certificate?
You can choose the factory calibration certificate or the FSUE "VNIIFTRI" calibration certificate. This certificate is issued by the main hardness center of Russia - a metrological institute FSUE "VNIIFTRI" which is a delegate from Russia during international comparisons (http://vniiftri.ru/index.php/en/).
How to quickly determine the type of hardness tester?
It depends on the size of the measurement object. If the mass is less than 3 kg or the wall thickness is less than 10 mm, then you need to choose UCI - MET-U1A. If the weight is more than 3kg and the thickness is more than 10mm, then you can use the dynamic MET-D1A. If you have different details, it is better to take the combined MET UDA.
Does the surface to be measured need to be cleaned?
Yes, but it is enough to grind the part with a portable grinder to remove scale, paint, rust.