Red Color Portable Hardness Tester User Calibration Function With Large Screen LCD MH-320

Preparation of Sample Surface

Preparation for sample surface should conform to the relative requirement in the Appendix Table 3.

• In the preparation processing for sample surface, the hardness effect of being heated or cold processing on the surface of sample should be avoided.
• Too big roughness of the being measured surface could cause measure error. So, the surface of the sample to be measured must appear metallic luster, smoothing and polish, without oil stain.
• Support of test sample. Support is no necessary for heavy sample. Medium-weight parts must be set on the smoothing and stable plane. The sample must set absolutely equability and without any wobble.
• Curved surface: The best testing surface of sample is flat. When the curvature radius R of the surface to be tested is smaller than 30mm (D, DC, D+15,C, E and DL type of impact device) and smaller than 50mm (G type of impact device), the small support ring or the shaped support rings should be chosen.

• The sample should have enough thickness, minimum thickness of sample should conform to Table 3.
• For the sample with hardened layer on surface, the depth of hardened layer should conform to Table 3.
• Coupling. Light-weight sample must be firmly coupled with a heavy base plate. Both coupled surface must be flat and smooth, and there is no redundant coupling agent existing. The impact direction must be vertical to the coupled surface. When the sample is a big plate, long rod or bending piece, it can be deformed and become unstable, even though its weight and thickness is big enough, and accordingly, the test value may not be accurate. So the sample should be reinforced or supported at its back.

• Magnetism of the sample itself should be avoided.

Operating Method and Attentions

1 Start-Up

----Insert the plug of the impact device into the socket of impact device on the instrument.

----Press the power key,now power is on. The instrument is in working mode.

2 Loading

Pushing the loading-tube downwards until contact is felt. Then allow it to slowly return to the starting position or using other method locking the impact body.

3 Localization

Press the impact device supporting ring firmly on the surface of the sample, the impact direction should be vertical to the testing surface.

4 Testing

Press the release button on the upside of the impact device to test. The sample and the impact device as well as the operator are all required to be stable now. The action direction should pass the axis of the impact device.

Testing

• Press the release button on the upside of the impact device to test. The sample and the impact device as well as the operator are all required to be stable now. The action direction should pass the axis of the impact device.
• Each measure area of the sample usually need 5 times of testing operation. The result data dispersion should not more than mean value±15HL.
• The distance between any two impact points or from the center of any impact point to the edge of testing sample should conform to the regulation of Table 4-1.
• If want accurate conversion from the Leeb hardness value to other hardness value, contrastive test is needed to get conversion relations for the special material. Use inspection qualified Leeb hardness tester and corresponding hardness tester to test at the same sample respectively. For each hardness value, each measure homogeneously 5 points of Leeb hardness value in the surrounding of more than three indentations which need conversion hardness, using Leeb hardness arithmetic average value and corresponding hardness average value as correlative value respectively, make individual hardness contrastive curve. Contrastive curve at least should include three group of correlative data.

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Red Color Portable Hardness Tester User Calibration Function With Large Screen LCD MH-320 Images