Manual Metal Arc Welding MMA

Solidified Molten weld Base metal weld metal metal 

Typical joint designs possible using MMA butt, lap, fillet and edge in heavier sections (see Appendix B - Weld Joint Configurations). 

Design joints using minimum amount of weld, i.e. intermittent runs and simple or straight contours 

Balance the welds around the fabrication s neutral axis. 

Distortion can be reduced by designing symmetry in parts to be welded along weld lines. 

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At this point in the fabrication process for the later RPVs, the welds were given a hot UT inspection to assure compliance with a pre-service examination. The shell course was then placed in a furnace and given a post-weld heat treatment (PWHT). The welds were then ground smooth on the external and internal surfaces. The ASME Code-required radiographic (RT) and MT inspections were then performed. Any required repairs of unacceptable indications were made at this point using manual metal arc (MMA) welding and a repeat of the preheat-post-weld heat treatment. 

Manual metal arc (MMA) or stick welding using a coated electrode manipulated manually... 

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