Type 1 DFT Instruments

Question 1

Type 1 DFT gauges are described as?

Answer 1

Magnetic pull of DFT Gauges.

Question 2

Type 1 DFT gauges are associated with what specification(s).

Answer 2

SSPC-PA 2

ASTM D7091

Question 3

Type 1 gauges work by means of a 1___ ___, a ___ ___, and a ____ ___.

Answer 3

Permanent magnet, a calibrated spring, and a graduated scale.

Question 4

The attraction between the 1____ and the ___ ___ pulls the two together. As the 2___ ___ increases it becomes easier to pull the magnet away.

Answer 4

1. Magnet and the steel substrate.

2. Coating thickness.

Question 5

Type 1 gauges measure coating thickness by measuring?

Answer 5

Pull off force.

Question 6

Thinner coatings have a 1___ magnetic attraction while thicker films have a 2. ___ magnetic attraction.

Answer 6

1. Higher

2. Lower

Question 7

The dial type magnetic pull off gauge is commonly referred to as?

Answer 7

A banana gauge or mechanical gauge.

Question 8

Magnetic pull off gauges are rugged, simple, inexpensive, portable and usually do not require?

Answer 8

Calibration.

Question 9

Magnetic pull off gauges work well in areas where ___ gauges might cause problems.

Answer 9

Electronic.

Question 10

To properly use a magnetic pull off gauge: Place the gauge on a clean dry 1___ surface. Rotate the dial beyond the 2___ ___. Move the 3___ down to the surface. Slowly rotate the 4___ back (which is increasing spring tension) at a constant speed until the magnet pops up from the 5___ ___ substrate. Where possible the dial should be stabilized by pressure from the inspectors hands.

Answer 10

1. Cured.
2. Expected thickness.
3. Probe
4. Dial.
5. Coated Ferrous

Question 11

Keep magnetic probes free of ___ particles and other residues.

Answer 11

Magnetic particles.

Question 12

Do not use the dial type gauge within 1__ ___ of an edge, or near 2___ equipment, or on metal being 3___ as it may become magnatized.

Answer 12

1. One inch.
2. Vibrating equipment.
3. welded.

Question 13

Magnetic pull off gauges should only be calibrated the manufacturer or approved laboratory. The calibrator should be able to issue a certificate of calibration showing?

Answer 13

Its calibration is traceable to a national metrology institute.

Question 14

Do not use ___ or ___ ___ shims to verify the accuracy of Type 1 gauges. Such shims are fairly rigid and curved. Tey do not lie perfect flat, even on a smooth surface,

Answer 14

Plastic or non-magnetic shims.

Question 15

Type 1 gauges have non-linear (___) scales and adjusting features are linear in nature.

Answer 15

Logarithmic.

Question 16

Type 1 gauges have 1___ (Logarithmic) scales and adjusting features are 2___ in nature. Therefore, any mathematical adjustment made of readings from these gauges limits the DFT range for which the gauge will provide accurate readings.

Answer 16

1. Non-linear

2. Linear

Question 17

Magnetic gauges measure the distance from the probe tip to what is termed the 1___ ___ ___ of the steel. When the steel surface is smooth and even, its 2___ ___ is the 1___ ___ ___.

Answer 17

1. Effective magnetic surface.

2. Surface plane.

Question 18

If the steel is roughened the effective magnetic surface is an imaginary place located somewhere between the highest peaks and lowest valleys of the surface profile. This effective magnetic surface is also called a?

Answer 18

Base metal reading.

Question 19

Once the DFT readings are taken, deduct the ___ ___ ___ from the DFT.

Answer 19

Base Metal Reading.

Question 20

Because scales are logarithmic, these instruments are most accurate at the __ of their range with an atypical tolerance of -/+ 5 percent.

Answer 20

Bottom.

Question 21

Common errors that may produce inaccurate readings with a dial type magnetic pull off gauge are:

1. Failure to obtain ___.
2. Rotating the dial ___ ___.
3. Taking measurements too ___ to the ___ or on ___ surfaces.
4. Measuring ___, ___ or __ films.

Answer 21

1. Failure to obtain BMR.
2. Rotating the dial too fast.
3. Taking measurements too close to the edge or on vibrating surfaces.
4. Measuring dirty, tacky or soft films.

Question 22

The pencil pull off gauge, type 1, is another type of magnetic pull off gauge. The instrument is a ___ ___, similar in size to a large pencil, with an internal magnet and spring.

Answer 22

Hollow tube.

Question 23

Most pencil-type pull off gauges have large magnets and are designed to work in only one position (Vertical or horizontal. ) to avoid the effects of ___. Some versions have scales to compensate for this effect, regardless of orientation.

Answer 23

Gravity

Question 24

Hold the pencil gauge ___ to the surface and place the magnet in contact with the surface. As the gauge body pulls away from the coated surface, the magnet remains attached. Keep a close watch on the indicator and note the reading when the probe is pulled away from the surface.

Answer 24

Perpendicular.

Personal Question: What possible use could this stupid thing have?