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Fabrication and Processing of Grade 91 Material

May 10, 2014

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Fabrication and Processing of Grade 91 Material

Mechanical Engineering

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ASME Section IX - Weld Positions

Flat position (1G) The test plates are placed in an approximately horizontal plane and the weld metal deposited from the upper side Horizontal position (2G) The test plates are placed in an approximately vertical plane with the welding groove approximately horizontal Vertical position (3G) The test plates are placed in an approximately vertical plane with the welding groove approximately vertical Overhead position (4G) The test plates are placed in an approximately horizontal plane and the weld metal deposited from the underside Horizontal rolled (1G) The pipe is placed with its axis in an approximately horizontal plane with the welding groove in an approximately vertical plane and the pipe is rolled during welding Vertical (2G) The pipe is placed with its axis in an approximately vertical position with the welding groove in an approximately horizontal plane Horizontal fixed (5G) The pipe is placed with its axis in an appro...

AWS D1.1 - Visual Inspection Acceptance Criteria

Crack Prohibition Any Crack Shall be unacceptable, regardless of size or Location. Weld Base Metal Fusion Thorough fusion shall exit between adjacent layer of weld metal and between weld metal and base metal. Crater Cross Section All craters shall be filled to provide the specified weld size, except for the ends of intermittent fillet welds outside of their effective lengths. Weld Profiles Weld profiles shall be in conformance with AWS D1.1 Sub section 5.24 Time of Inspection Visual inspection of welds in all steel may begin immediately after the complete welds have cooled to ambient temperature. Acceptance criteria for ASTM A 514, ASTM A 514 and A 709 Grade 100 and 100 W steels shall be based on visual inspection performed not less than 48hours after completion of welds. Undersized Welds The size of fillet weld in any continuous weld may be less than the specified nominal size (L) without correction by the following amounts (U) Spec...

Welding Imperfection – Miscellaneous (Spatters, Stray Arc, Torn Surface)

STRAY ARC Local damage to the surface of the parent metal adjacent to the weld, resulting from arcing or striking the arc outside the weld groove, this results in random areas of fused metal where the electrode, holder, or current return clamp have accidentally touched the work. Causes Poor access to the work Missing insulation on electrode holder or torch Failure to provide an insulated resting place for the electrode holder or torch when not in use Loose current return clamp Adjusting wire feed (MAG welding) without isolating welding current Prevention Improve access (modify assembly sequence) Institute a regular inspection scheme for electrode holders and torches Provide an insulated resting place Regularly maintain current return clamps Retrain welder Comments An arc strike can produce a hard HAZ, which may contain cracks. These can lead to serious cracking in service. It is better to remove an arc strike by grinding than weld ...

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Fabrication and Processing of Grade 91 Material

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