Canadian Frigates. Ship Weld Problems.
MIG
and flux cored weld Issues:
During
the nineteen nineties, I was invited to provide a weld evaluation for an East
Coast, Canadian Ship Yard. The yard was building Frigates for the Canadian
Navy and in case some forget the ships of course were paid for by the Canadian
tax payers.
During my evaluation of the ship yard practices, I was astounded
to find that welding was beyond chaos, it could easily be described as Disney
Land turned inside out. The weld engineers at the yard had enabled poor weld practices
effecting both the weld quality and productivity and I met no one that appeared
to fully grasp the fundamentals of either the MIG and flux cored weld processes
utilized.
It was also interesting to note, that as a result of apathetic
management at this ship yard, the engineers were placed in a position that they
could not tell the welders what to do. Welding supervisors with less expertise
were allowed to give weld instructions . However the bottom line at this yard
is the majority of weld personnel including the weld engineers, supervisors, QA
personnel and welders, all had a minimal understanding of the widely used MIG
and flux cored processes.
Note
from Ed: This will tell you something about the general management / engineering
apathy and lack of process ownership too often found in the welding industry.
The ratio of weld engineers to global welding facilities is extremely
low, yet when weld engineers are hired perhaps 1 in 10 are given the full responsibility
for the weld personnel that impact the daily weld quality and productivity. If
someone wants to hire me, I refuse to look at any job as the "plant weld
engineer". I tell the company or employment agency, I am only interested
in a position in which I have the full responsibility for the weld quality and
productivity attained, therefore I need to be the "weld manager". This
shocks many in management who are not used to ownership, responsibility or accountability
for the products they build. If you want to know how few companies are looking
for weld managers, go to the world's largest job site www.monster.com and in the
keyword box, type in two words, "weld manager".
ONE
WELD SETTING FOR THE CANADIAN FRIGATES. 
To
make the common 6mm, carbon steel fillet welds on the frigates, the ship yard
welders for some strange reason would use two processes, MIG and flux cored. For
the first weld pass they would use MIG with short circuit weld parameters. The
short circuit weld parameter were better suited to welding thin gauge sheet metal.
The first short circuit pass had to result in cold welds with lack of fusion.
Then using the same wire feed and voltage settings, cold flux cored welds were
made over the top of the cold short circuit welds leaving lack of weld fusion
with slag entrapment. Each day hundreds of welders would use this poor weld practice
put down thousands of fillet welds.
It
was difficult for me to believe, that the ship yard managers allowed the welders
to use both MIG and flux cored with unsuitable parameters for the same fillet
welds. It was also incredible, that the welders had not been taught to use the
superior penetrating MIG spray transfer mode.
It
may come as no surprise to learn that I quickly discovered that few in the yard
knew what short circuit and spray transfer was, and even fewer understood the
working weld parameter range of the E71T-1 flux cored wires.
To
produce the common, 1/4 - (6 mm), carbon steel fillet welds on the Navy frigates,
the 200 plus ship yard welders would first use the MIG "short circuit transfer"
on the flat / horizontal welds on steel parts that ranged from 3 to 25 mm thick.
In case anyone in the Navy ever reads this site, for their belated information,
the short circuit weld transfer settings used to weld the important structural
parts of their ships, would normally be used to weld thin sheet metal in the range
of 14 to 10 gauge.
When
I questioned the ship yard's weld engineers why the welders were using the MIG
Short Circuit and globular weld transfer mode, I simply got that confused weld
look that I normally get when discussing welding with my wife. The short circuit
and globular parameters were used with an 0.045 (1.2mm) wire, set at a wire feed
rate of 200 to 300 ipm, 180 to 240 amps and 20 to 23 volts.
Without question these welds would result in extensive lack of weld fusion, on
carbon steel
parts > 4 mm.
To
add to the horizontal
fillet weld problems at the yard, the short circuit welds were then followed by
a second cold weld pass made with an 0.045 (1.2 mm), gas shielded "all position"
E71T-1 flux cored wire using the same wire feed settings of 200 to 300 inch/min.
The flux cored wire feed settings used for the horizontal fillet welds, were low
settings you would use for vertical up welds. For the horizontal fillet welds,
a wire feed rate of approx. 500 inch/min and 28 volts would be typical with an
0.045 wire. The fast freeze E71T-1 wires used at low settings had to ensure a
massive amount of lack of weld fusion with the horizontal fillet welds.
Its
a simple fact, that the
MIG and flux cored wire feed settings used in this yard were poorly suited to
attain consistent weld fusion on most of the >
4 mm carbon steel
welds made in the flat and horizontal weld positions. Most fillet welds on ships
are only subject to a surface weld examination and without question, too many
of the welds on the Canadian frigates had to have extensive lack of weld fusion,
slag and porosity. Of course whenever you see weld issues of this scope, it would
also place a large question mark about the weld integrity in the frigate's critical
welds.
To
put salt in the frigates welding wounds, every weld produced at the yard with
the low wire feed settings, took 50 to 80% longer than it should have, which likely
was not an issue for the ship yard management as the Canadian tax payers paid
the welding bills. This
Canadian yard spent over a million dollars annually on welder training, again
a ridiculous waste of tax payers money as it was certainly not effective MIG or
flux cored process control training.
I delivered my report which provided the required data for the yard to get it's
welds to the quality they should be and also provided them with an opportunity
for approx. 3 million dollars annually in weld cost savings. The savings would
be generated from the reduction in weld cost rework and dramatically increasing
all the weld deposition rates.
I
was later informed that the report never got as far as the first manager who reviewed
it. My guess was the manager was too embarrassed to present it to his executive
team, or possibly the manager did not want the navy to be aware of the weld quality
and over costs of it's frigates.
As
the following data shows, poor work man ship and lack of process expertise in
ship yards, may do more damage to Canada's and the US navy vessels, than the elusive
weapons of mass destruction.
For
retirement, some have bigger dreams than others.
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