Welding operating procedures

Joints may be made by welding in any material for which it is possible to qualify welding procedures, welders, and welding operators in conformance with the rules in para. IP-9.2. 

In an auto theft case, the vehicle information number tab (VIN) had been removed and a second one welded on to replace it. The VIN tab was examined in the SEM and the weld, the remaining fracture surfaces, the grinding marks and the swarf remnant from the grinding were easily identified and photographed. These features are shown in Figure 1. Metallographic procedures were also used after the SEM analysis to confirm the fact that a welding operation had been performed. 

Stacks are designed to vent exhaust gases from industrial processes. If the gases are combustible, flare stacks may be used to burn the exhaust gases before they are vented into the atmosphere. In the case of combustible gases, operational procedures should be used that prevent the infiltration of oxygen into the stack where it could mix with the exhaust gases and cause an explosion. Stacks should be built with welded seams rather than bolted joints. Bolted joints, especially joints... 

Everyone involved in welding operations must take necessary precautions to prevent fires, explosions, or personal injuries. Even for small or routine jobs, you should always follow established safety procedures and resist the temptation to take shortcuts. 

Toxic air emissions may be a by-product of a process or procedure in your facility. Areas that often get overlooked involve potentially toxic chemicals produced from welding operations, gasoline-powered forklift vehicles, power tools with internal combustion motors, and vehicle bay exhaust. Employee exposure to any air emissions that are being created in your facility must be accounted for. You may need to contact the supplier of your welding rods for help in tracking down the appropriate SDS. 

This issue is generally linked with the possibility of establishing of a two-phase state air/water or steam/water in lines connected to RCS with isolation valves. That diphasic state can induce corrosion attacks in the part of lines connected to RCS between the RCS and the first isolation valve. Up to now these attacks are limited to weld junctions and disk assembly of swing check valves. The studied solution consist to avoid these diphasic states with a sufficient pressure and operational procedures of air venting. 

Prevention can be accomplished by proper design and operating procedures. Nonabsorbant gasketting material should be used at flanged joints, while fully penetrated butt-welded joints are preferred to threaded joints. 

The basic guidelines for preventing cracking would seem to be to operate at minimum stress levels, at as low an HjS concentration as possible and to make sure that welding procedures are adequately specified and followed. Furthermore, extensive periods of operation at temperatures that might cause sigma phase formation should be avoided. 

All welding shall be performed using procedures and operators that are qualified in accordance with the requirements of para. GR-3.2.4. 

Operations such as gas or electric welding and cutting with cutting torches cannot be safely performed on hydrogen gas pipelines, mains, or auxiliary equipment, unless all possibility of leakage of hydrogen into the work area is eliminated. The following procedures are recommended ... 

All underground steel service lines shall be joined by threaded and coupled joints, compression-type fittings, or by qualified welding or brazing methods, procedures, and operators. 

Welding of piping, pressure containing parts, and wetted parts, as well as any weld repairs to such parts, shall be performed and inspected by operators and procedures qualified in accordance with Section VIII, Division 1, and Section IX of the ASME Code. 

To avoid brittle fracture during operation, maintenance, transportation, erection, and testing, good design practice shall be followed in the selection of fabrication methods, welding procedures, and materials for vendor furnished steel pressure retaining parts that may be subjected to temperature below the ductile-brittle transition point. 

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