Hardness tester WPM

Principles:

- Measuring spot is made from ball-shaped tip

- Load: < 3000 kg

- Check the measuring tip with the optical system

Brinell scale with factors:

Different L/D²

Ball Diam (mm)                      Load (Kp)

-  Used for large, not-too-accurate parts,  such as castings and forgings

-  Not used for tough materials, thin sheets, curved surfaces

Advantages:

- Wide measuring range

- Comparable with other loads (with a fixed L/D² factor)

- Less sensitive to test the surface quality

- Relative to tensile strength

Disadvantages:

- Measurement marks change the material's hardness

- Not suitable for too thin, too hard, plated material, curved surface

- Influenced by the operator

Principals:

- Various types of probes with different materials and shapes

- Measuring load: < 150 kg

- Check the depth of the measuring mark

- Including 15 regular Rockwell scales & 15 surface Rockwell scales

Applications:

For many parts with different materials, sizes, and shapes

Advantages:

- Optical system is not necessary

- Quick and easy

- Not affected by the operator

Disadvantages:

Various scales with different gauges and internal loads

KNOOP HARDNESS TEST (HK)

Principles:

- Measuring tip is designed to measure with low loads, shallow and long measuring marks

- Measuring load: < 1 kg

Applications:

- Small, precise details

- Thin sheet material

- Coating material

Advantages:

- A method for all materials

- Can test small area and individual phase

- Coated material and measured near the edge of the specimen

- Directional properties of materials

Disadvantages:

- Can't compare between loads

- Must prepare samples carefully

Principals:

- One tip / one scale for all materials

- Measuring load: 1 – 120 kg (Macro); < 1 kg (Micro)

Applications:

- Small, precise details

- Thin sheet material

- Coating material

Advantages:

- Comparable with multiple loads

- One method for all materials

- Able to test a small area and phase individually

Disadvantages:

Requires to prepare the sample well