West Cerchar abrasiveness index tester ASTM D7625-10 Reservoir geomechanics Instruments

The apparatus accurately determines the rock abrasivity index (CAI) employed for the classification of rock materials in terms of abrasivity. The CAI is a dimensionless unit obtained from measuring the wear on a HRC55 Rockwell Hardness steel stylus tip after it has been used to abrade a specimen with a 70 N normal force.

The apparatus comprises a stationary stylus, a deadweight (70 N) placed on top of the stylus, a stiff load frame, a rigid vice to firmly clamp the rock sample and a cross table with two adjustable axes for specimen alignment along the two horizontal axes. The device comes with a graduated knob for 0.01 mm accurate scratch distance control.

Options include an indenter visualization system, spare indenters and a sharpening tool. The former encompasses a digital camera with indenter support and inspection software to reveal the wear amount which is then correlated to the abrasiveness index (CAI). The sharpening tool rapidly sharpens a worn stylus for subsequent scratch tests.

Standard :

• ASTM D7625-10

Load :

• 70 N

Maximum specimen height :

• 150 mm (6 inches)

Maximum specimen diameter :

• 76 mm (3.0 inches)

Scratch distance precision :

• 0.01 mm

Steel stylus :

• Rockwell Hardness HRC 54/56

Weight :

• 25 kg

Dimensions (W × L × H) :

• 330 × 500 × 500 mm

• ASTM-compliant, West model
• Easy manual handling
• Features precision slide for smooth movement of the rock specimen over the required scratch distance
• Easy adjustment of the daylight for different specimen heights