|
Refresh your knowledge regarding the use of these commonplace inspection tools Weld gauges are an everyday tool for Certified Weld Inspectors. Gauges are available for checking alignment, checking dimensions before welding, verifying weld dimensions, and for measuring the size of porosity, among other items. Gauges can be single- or multipurpose. Following are descriptions and tips for using seven types of weld gauges. The gauges featured in this article are manufactured by G.A.L. Gage Co., Stevensville, Mich., and distributed by Newman Tools, Inc. ![]() Fig. 1 — Uses for a pipe internal alignment gauge.
This type of gauge measures internal
alignment of pipe after fitup — Fig. 1. It can be used to measure
internal misalignmentof pipe both before and after tacking. Not only
does the gauge measure internal mismatch of pipe wall, but it also
measures scribe lines, weld fillet size, and crown height. One side
measures in inches, the other side in metric units. Use of this type of
gauge helps to reduce the number of radiographic rejects. It satisfies
fitup requirements in the ASME, ANSI, API, and military standards.
![]() Fig. 2 — Two
types of single-purpose weld gauges. The gauge at left measures
internal misalignment; the gauge at right measures the size of the weld root. Single-Purpose Weld Gauges Following are the steps needed to quickly check internal alignment using the single-purpose gauge shown at left in Fig. 2. 1) Unlock the retaining screws. Press the gauge legs beyond the barrel. 2) Insert the legs (wires ) into the root opening between the two pieces of pipe to be fitted. Turn the gauge 90 deg, being careful to apply a constant back pressure to the barrel. 3) Hold the gauge as square as possible with the fitting to obtain an accurate reading. Lock the retaining screw. Reverse the 90-deg turn and remove the gauge. You're now ready to read the increment opposite the red line. 4) When the red line aligns with the 1/32 increment, you have achieved good internal alignment and fitup. Misalignment can be determined from the zero line by increment markings of 1/16 in. Following are the steps needed to determine weld root spacing using the single-purpose gauge shown at right in Fig. 2. 1) Unlock the retaining screw and insert the gauge interior alignment stops between the two pieces of pipe to be fitted. 2) Insert the leg with the long taper into the root opening until it makes contact with both sides. 3) Relock the retaining screw, remove the
gauge, and read it. The scale is calibrated in fractional dimensions
from 1/32 to 3/16 in. The readout represents the size of the weld root.
Fig. 3 — How to use an adjustable fillet
weld gauge.
Adjustable
Fillet Weld Gauge with Unequal Leg Measurement Feature The adjustable fillet weld gauge uses an offset arm that slides at a 45-deg angle to make fillet weld length measurements. You simply adjust the arm until it touches the toe of the vertical leg. The gauge is calibrated to 1/32 in. Four screws hold the offset arm in position for future adjustments. The gauge
also measures weld throat thickness to 1/16 in. by adjusting a pointer
in position for future reference. If the weld is concave, more filler
material can be added to build the weld throat up to standard. The
adjustable fillet weld gauge measures both leg lengths and weld throat
fillet weld thickness.
Fig.
4 — A bridge cam gauge can provide a variety of measurements.
Bridge Cam Gauge
It displays measurements in both inches and millimeters (linear measurements up to 60 mm or 2 in.). The gauge is easy to use. It is comprised of one rotating dial and one sliding pointer. You simply move the dial or pointer until it makes the appropriate contact and then read the result. ![]() Fig. 5 — A
single gauge checks the four
measurements required for
Visual
Weld Acceptance Criteria Gaugecompliance with the NRC visual weld acceptance criteria. This type of gauge is used to determine if fillet welds meet U.S. Nuclear Regulatory Commission (NRC) visual weld acceptance criteria for structural weldments — Fig. 5. It easily and quickly checks the four essential measurements required for compliance with the NRC visual weld acceptance criteria: undercut depth, porosity comparison, amount of porosity per linear inch, and crown height. The undercut
depth or crown height scale can be read to 1/32 in. Porosity
comparisions are in terms of 1/8 and 1/16 in. The linear gauge is in
1/16-in. increments. The gauge is easy to set and a locking screw holds
it in position for later reference. All four required measurements are
made with one gauge.
![]() Fig. 6 — Directions for using an automatic weld size gauge to determine fillet weld size; permissable tolerance of convexity, concavity, and underfill; and permissible tolerance of reinforcment. Automatic Weld Size Gauge An automatic weld size gauge provides accurate calibrations of butt-joint and fillet welds. The diagrams in Fig. 6 illustrate how welders and inspectors can accurately check sizes of convex or concave fillets as well as butt-joint weld reinforcements. The convexity and concavity sizes have automatically been determined in accordance with AWS D1.1, Structural Welding Code — Steel, paragraph 3.6. THOMAS NEUMANN (tom@newmantools.com) is President of Newman Tools, Inc., Ottawa, Canada.) is Manager, NDE Strategic Solutions, Framatome ANP, Inc., an AREVA and Siemens Company, Charlotte, N.C. |





