Model 04421

The mold hardness tester for dry molds and cores, model 04421, is intended for surface hardness determination at mold and core sections of foundry workshops, molding materials workshops and factory laboratories as well as research institutes.

Component parts and operation principle of the unit

This unit consists of a housing which is designed to assemble all parts. The indicator recording the readings is mounted on top of the housing. The indenter, and then the bearing surface of the bush is brought into contact with the tested surface of a mold or a core. In this case, the indenter moves relative to the housing by a quantity determined by the tested surface hardness. Using a lever, the movement of the indenter is transmitted to the indicator rod in the specified ratio (1:2.5). As a result, the arrow rotates. After removing the hardness tester from the test surface, the spring returns the indenter to its initial position, while the hardness tester fixes the obtained hardness value. Movement of the indenter by 2.5 mm corresponds to the rotation of the arrow by 360˚. The indenter’s sump force is provided by a spring. The readings can be reset by pressing the reset button on the indicator. Before starting the measurement, it is necessary to turn the upper ring of the indicator associated with the scale in order to align the arrow with the zero mark of the scale.

Brochure

**Technical specifications:**
Readings range, hardness units	0-100
Measurement range, hardness units	30-100
Indenter shape	Wedge-shaped segment
Indenter segment radius, mm	16±0.2
Wedge angle of the indenter segment, degrees	45˚±40’
Indenter spread relative to the bearing surface, mm	2.5±0.1
Service life of the hardness tester, min. years	6
Mean time between failures, measurements	5*10³
Hardness tester overall dimensions, mm
Length	45±3
Width	28±3
Height	70±3
Unit weight, kg	0.2±0.05