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Are you
getting the quality you need from your welding fabricator? Welding is a critical manufacturing process and it is susceptible to a variety of discrepancies or defects if not performed by knowledgeable, skilled and certified personnel. All welds should be visually inspected for: |
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| Proper size and profile | ||||
| Cracks | ||||
| Porosity | ||||
| Slag Inclusions | ||||
| Undercut and/or Cold Lap | ||||
| Removal of all slag and weld spatter | ||||
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All fabricated
components/weldments should be inspected for: |
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| Dimensional accuracy and compliance to all contract drawing/specifications | ||||
| Overall straightness | ||||
| Missing welds | ||||
| Overall appearance | ||||
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How good are the welds you are buying? The quality and soundness of welds can be easily verified by using Certified, Independent Inspection Companies, who are able to perform various types of non-destructive tests to check the welds. |
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Visual Inspection | ||
| This type of
inspection can be done during fit-up, during the actual welding
process (if necessary), as well as after the welding has been
completed. Visual Inspection, although simple, can recognize several
types of discontinuities or defects such as: poor or improper
fit-up, improper weld size or shape, cracks, porosity, slag
inclusions, undercut and cold lap. |
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Magnetic Particle Inspection | |||
| This type of
inspection is limited to ferro magnetic materials and is used for
portable inspection utilizing an electromagnetic yoke. The legs of
the yoke are placed over the area to be inspected and the magnet is
energized while fine colored iron powder is sprinkled on the
inspection surface. Discontinuities will create a small secondary
magnetic field to which the iron particles will adhere. This method
is excellent for detecting surface and slightly sub-surface defects
that would normally be too small to be seen with the naked eye. |
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Liquid Dye Penetrant | |||
| This type of
inspection can be performed on both magnetic and non-magnetic
materials. Liquid Dye Penetrant Inspection involves using a cleaner
on the surface to be inspected and applying either a visible or a
fluorescent type dye. The dye is allowed to penetrate for a specific
time, then the excess material is removed and a developer is
applied. Any dye that has penetrated into discontinuities that are
open to the surface will then be drawn out by the developer. This
method is also excellent for detecting surface defects in welds that
would normally be too small to be seen with the naked eye. |
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Ultrasonic Inspection | |||
| This method
involves passing a high-frequency sound beam through the weld. A
piezoelectric crystal, which both generates and detects sound, is
placed onto the surface to be inspected. The frequency and angle of
the sound are determined by the material thickness and code
requirements. The sound received by the transducer is displayed on a
cathode ray tube, and the operator is then able to interpret the
length and depth of any discontinuities present in the material.
This method is used to detect, locate and measure both surface and
sub-surface defects in welds. |
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Radiography | |||
| This method uses x-rays or gamma rays to detect discontinuities in the interior of welds. The rays are passed through the material, with the film placed on the opposite side; the film is sensitive to radiation. Discontinuities present in the material will be more dense material (tungsten) or less dense (porosity) and therefore these areas will transmit more or less radiation respectively. The film is developed and the discontinuities will show as darker or lighter areas and can be interpreted by a trained radiographer. | ||||
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Weld-Tech Manufacturing Ltd. is a custom metal fabricator, which
specializes in high quality, certified welding and fabricating. Our
company is certified by the Canadian Welding Bureau (C.W.B.) to CSA
W47.1-03 and CSA W47.2-M1987. Our weld procedures are also A.S.M.E.
Section IX approved and certified for pressure pipe welding (B31.1
and B31.3). Our quality system is registered to the world recognized
ISO 9001:2000 Quality Standard. At Weld-Tech Manufacturing we are always ready to quote your requirement. |
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Weld-Tech Manufacturing Ltd. 563 Queensway East, Unit D Mississauga, ON. Canada, L5A 3X6 Tel: (905) 366-1302 Fax: (905) 366-1305 |
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All Rights Reserved
Website Design & Maintenance by:
Bliss Technologies
This page was last updated
on October 19, 2009