Hardness tester for dry molds and cores 04421A

The 04421 hardness tester is designed for measuring the surface hardness of dry molds and cores in molding and core-making areas, by the quality control departments of foundries, in express laboratories, shop and factory molding material laboratories and in research organizations.

Composition

The model 04421 hardness tester for dry molds and cores consists of:

• a housing, an indenter,
• a spring mechanism,
• a base and an indicator.

The indenter of the tester is brought into contact with the surface of the mold, core or specimen under test, and the tester is pressed until its support surface fully touches the test surface. The indenter, overcoming the spring force, moves into the housing by an amount determined by the hardness of the test surface. The indenter movement is transmitted by a lever to the indicator stem, which turns the pointer; the pointer is held in the position corresponding to the hardness of the test surface.

Design and operation

The 04421 hardness tester works by increasing the force applied to the specimen by the indenter and recording the maximum force on the indicator.

Hardness is assessed by the resistance to penetration of a knife-edge tip (indenter) into the specimen to a depth of 0...2.5 mm under a load of 1.1...2.0 kgf (10.8... 19.6 N). A standard "figure-eight" specimen is used. The surface tested is the one that faced the lower plate of the box when the specimen was made. During testing, the tester is placed with its support surface on the specimen so that the knife is to the left of the specimen edge. The tester is then moved evenly from left to right along the specimen, pressing it firmly against the specimen surface. The red drag pointer records the maximum reading of the tester.

Specifications

Indication range, hardness units: Indication range, N	0-100 0-19.62
Measuring range, hardness units: Measuring range, N	30-100 12.753-19.62
Scale division value, hardness units: Scale division value, N	1.0 0.981
Indicator:	Shape - wedge-shaped segment Segment radius, mm - 16±0.2 Segment wedge angle, deg - 60°±40´ Projection from support surface - 2.5±0.1 Tester reading in this case < 0.294
Initial spring force on the indenter, N:	12.753 (at 30 hardness units)
Spring force at maximum indenter travel, N (kgf):	19.62 (at 100 hardness units)
Reduced measurement error in the range 30-100 hardness units:	by force on the indenter ±5% by indenter travel ±3%
Tester service life, years:	6
Mean time between failures, number of measurements	5000
Tester weight, kg:	0.2
Tester dimensions (H*W*D), mm:	70*45*28

• Hardness tester for green molds and cores 04412A, complete
• Plastic case
• Calibration certificate