GMAW[PULSED ARC]

Date 10-01-2002 18:04

I work for the US NAVY as a QA SPECIALIST in a private ship yard that builts destroyers.The deck house and other bulkheads are 1/4 thick at most and the contractor uses GMAW[FLUX CORE].The weld size is 1/8 but there is much over sized welding that causes bulk head distortion and a huge amount of time is spent on flame straightening.The other shipyard working on the same contract uses GMAW[PULSED ARC] and there is very little distortion and hence very little flame straightening. I noticed from technical info that pulsed arc is good on thickness up to 3/8of an inch.The material is high tensile strength steel.Anyone with a technical background,etc. have an opinion on the use of GMAW pulse arc vs. GMAW-FLUX CORE in this situation? DON KUMPUNEN

By Niekie3 (***)

Date 10-01-2002 19:41

GMAW-Pulsed generally has a lower heat input than spray transfer GMAW, while being able to be welded in all positions. With a reduction in heat input, distortion generally reduces. FCAW can also be a low heat input process, as long as the welders are welding fast enough. There are however two general issues:

1) With the slag around, it is easier to over-weld with FCAW than GMAW with solid wire.
2) FCAW is generally a deeply penetrating process. While this is great for ensuring that the materials stick together, it tends to increase distortion on assymetrical weldments.

Hope this helps

Regards
Niekie Jooste