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reedinstruments
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14
Pantone 534 Blue
Pantone 123 Yellow
Pantone 485 Red
Pantone 123 Yellow
Pantone 534 Blue
Black
Rich Black -
20/20/20/100
Blue - 100/80/30/5
Yellow - 0/27/100/0
Red - 10/100/100/5
Yellow - 0/27/100/0
Blue - 100/80/30/5
Only if you REALLY need them:
Pantone 534 Blue - 100/80/30/5
Pantone 485 Red - 10/100/100/5
Pantone 123 Yellow - 0/27/100/
INSTRUMENTS
Preventing Errors
Reference Test Pieces
To maintain high accuracy when taking measurements of different materi-
als it is important to use a standard test piece that resembles the material
and conditions being measured. The ideal reference test pieces should be
a group of test pieces with different thickness made of the same materials
that is going to be measured. The test pieces can provide calibrating fac-
tors for the meter (such as the microstructure of the material, heat-treating
condition, direction of particles, surface roughness, etc.). To meet the
highest requirements of accuracy a set of reference test pieces are critical.
Under most situations one can get satisfactory measuring accuracy with
only one reference test piece. This should be the same material and simi-
lar thickness with the object. Take an even-surfaced object, measure it by
using a micrometer, then use it as a test piece.
For thin material, when its thickness is near to the low limit of the probe’s
measuring range, one can use a test piece to determine the accurate low
limit. Never measure a material with a thickness lower than the low limit.
If the thickness range can be estimated, the thickness for the test piece
should select the high limit.
When the object is thick, especially an alloy with complex internal struc-
ture, select a test piece similar to the object from a group of test pieces,
giving you an idea of calibration.
For most casting and forging, their internal structures have some direc-
tion. In different directions, the sound velocity will experience some
change. To solve this problem the test piece should have an internal
structure with same direction as that of the object, and the transmitting
direction of sound wave in it should also be same as that for the object.
Under certain circumstances, referring to a material speed-of-sound
table can replace reference test pieces. The value in the speed-of-sound
table may have some difference from the actual measured values due to
difference in the material’s physical and chemical characteristics. This is
usually used for measuring low-carbon steel, and can only be taken as a
rough measurement.
REED Instruments
1-877-849-2127 | [email protected] | www.reedinstruments.com
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