Barge hull repair?

[willard]

Carrying out welded repairs to the hull of a 100yr old steel barge, and having major problems with the weld gassing, if I try to weld using anything other than 2inch back step technique (in some areas this doesnt work either). I am using a 376amp, mig set, with 1mm wire and Ar/Co2 gas.

I feel the problems are being caused by corrosion being present in the rivetted joint adjacent to the weld joint, and anything other than short welds is causing problems. I would be very grateful if anyone could offer any advice, on how this problem might be eased a little.

Willard

 

[mats758]

WILLARD
YOU ARE ENCOUNTERING A VERY COMMON PROBLEM WHEN WORKING WITH THE MIG PROCESS ON ANY TYPE OF CORRODED STEEL. IT WOULD BE TO YOUR ADVANTAGE TO UTILIZE THE SMAW (STICK) PROCESS WITH A LOW HYDROGEN ELECTRODE SUCH AS ER7018.THE COMBINATION OF THE CLEANSERS IN THE FLUX AND THE LOW HYDROGEN CHARACTERISTIC WILL BE A BIG BENEFIT.

 

[evelrod]

Willard, you can use 'flux core' in your MIG as easily as using E-7018. Not much difference. However, having worked on a 60+ year old Navy barge I can say E-6010/11 or E-6013 will be a lot simpler unless you can bead blast to clean metal. I had to replate several deck sections where rust was almost total. Bead blasting just made BIGGER holes so wire brushing and chipping was what it got. The mild steel electrodes worked ok, even looked good. Very time consuming though.

Rod

 

[evelrod]

thread725-36505


Rod

 

[mcprofusion]

I agree with EVELROD.

You should be employing the FCAW process. Although SMAW is perfectly acceptable as well, you need a high deposition process that will cut through the mill scale.

FCAW - E70T-1 is an all position wire, designed to give give you superior mechanical properties with X-ray quality. It employs a 100% CO2 shielding gas. It gives low spatter , with a soft arc.