HT-7
Hardness Tester

• Six hardness scales plus strength of material
• Conversion from one scale to another
• Compensated for direction of measurement
• Automatic error detection
• Prints results on mPRINT
• Measures on many materials

APPLICATION AREA:

1. In situ Hardness measurement on dies and moulds, large and heavy work pieces, shafts, bearings, etc.
2. Laboratory measurement on special forms.
3. Identification of materials by measuring strength of material.

TECHNICAL DATA:

PRINCIPLE OF OPERATION:
Energy Quotient-(LEEB's Method) An Impact body with a tungsten carbide tip is impelled by a spring onto the metal surface. The ratio of rebound velocity to the impact velocity is proportional to the hardness of the sample. The microprocessor converts this into a hardness value in various scales.

OPERATION:
The impact body is loaded into a probe. The direction of impact is selected. The probe is positioned over the sample and the impact body is released. The OPTEL HT-7 displays the hardness value giving a beep. Attachments for positioning the probe in recessed areas and on cylindrical jobs are provided.
As in the conventional hardness tester measurement, the sample surface should be bright and smoothly ground (RT< 8-10 microns). Minimum 3-5 readings should be taken and the average reading recorded. The Optel HT-7 is factory calibrated. A surface area of 10 mm sq. is sufficient for measurement. (Radius of curvature more than 30 mm).
Work pieces weighing more than 5 kgs (thickness more than 8mm) can be directly measured. Lighter work pieces can be supported firmly to a heavy back mass (or front mass) using couplant like oil, glycerin, etc. The back mass/ front mass should have matching geometry. Improperly coupled jobs will tend to vibrate resulting in inconsistent results.

DISPLAY AREA:
The special Liquid Crystal Display and the Keyboard of the HT-7 organized in various zones makes the operation simple and fast. The keyboard and other operations are confirmed by sound beeps. An elaborated Operation Manual gives further details and instructions.

RANGE & MATERIALS:
Impact device - Measuring range LD: 200-900

Table I

STRENGTH OF MATERIAL:

Table 2