AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE-DIETERTGREEN HARDNESS TESTER ‘C’ SCALEIGENERAL PRINCIPLESThis instrument is designed for measuring the surface hardness of green sand mouldswhere the surface hardness values are in excess of 85 ‘B’ Scale, eg, moulds produced byhigh pressure moulding methods. Hardness values of 85 – 100 ‘B’ Scale are equivalent tovalues of 30 – 85 on the ‘C’ Scale tester making the instrument more sensitive in the higherranges of mould hardness.The test is similar to the Brinell Hardness Test – the softer the mould surface, the greater thepenetration of the probe into the mould surface.The hardness number indicated is the measurement of the depth of penetration of the probe,in thousandths of an inch. A mould offering no resistance to penetration has a zerohardness reading and one which completely resists penetration has a hardness of 100.IIDESCRIPTIONThe tester has a dial gauge, calibrated in thousandths of an inch, which is operated by aconical probe. The dial bezel can be rotated and the pointer held in any position by pressingthe locking button. This locking button is used when testing in blind positions of a mould.IIITEST PROCEDURE(a)(b)Press the Hardness Tester down on to a hard, flat surface until the anvil plate whichsurrounds the probe makes even contact with the surface. Slacken the clampingscrew and turn the milled bezel until the pointer reads 100. Re-clamp the bezel.Press the tester firmly down on to any flat surface of a mould until the anvil plate is incontact with the mould surface. The penetration of the probe into the mould surfaceis registered on the dial and is read direct as Green Hardness ‘C’ scale.123