Cored Welds, part 2.
Continued from part 1:
Flux Cored Data Pipe
SHIELDED FLUX CORED: Supporters
of pulsed MIG or metal cored wires for pipe fill passes often bring up concerns
about the gas shielded flux cored wires and "weld slag", however the
slag benefits usually outweigh the slag issues.
using the flux cored (FCAW) weld consumables recommended at this site, and those
weld consumables are correctly applied, the flux cored weld slag should fall off
during and after the weld. If the weld slag does not fall off, it should take
only a few seconds to remove. A positive point in pipe welding is the removal
of the weld slag gives the welder an opportunity to examine the weld between passes.
FLUX CORED WELD DEPOSITION: In
contrast to pulsed
MIG and metal cored wires for pipe welds, the flux cored slag that acts as a mold
and protects for the molten metal, enables higher wire feed (deposition) rates
increasing both manual and weld automation weld production potential. Depending on the flux cored wire manufacturer's
product, you can expect 8 to 12 lb/hr deposition rate for "all position"
steel pipe and fabrication welds.
flux cored pipe or plate groove weld, always look for lack of fusion
slag entrapment in the first two passes over the root.
FLUX CORED WELD QUALITY: From a weld quality
perspective, in contrast to pulsed MIG flux cored enables
superior side wall weld fusion. The issues with flux cored will be trapped slag
which can impare weld fusion, porosity and worm tracks.
FLUX CORED AND EASE OF USE: In contrast to
pulsed MIG, when the flux cored process is utilized for the pipe fill passes,
the flux cored process requires much less skills which reduces training time.
you use a "quality flux core wire" with the correct technique and
Ed's recommended parameters,
and also use 300F interpass temp control with multi-pass welds, that flux cored weld slag should almost peel off.
OIL (Canada). COLD LAKE, PIPE PROJECT.
On above left. Ed carrying out pipe root weld research comparing
MIG. STT - RMD and Short Circuit modes on a a 16 inch natural gas pipe root for Imperial
Oil. On right
Ed evaluating different gas shielded flux cored wires for the over head position
with the Cold Lake, Canadian pipe welders.
weld management is wise
their focus is on;
the pipe side wall weld fusion potential
of the weld process
or consumables utilized especially with the first and second
fill passes over the root,
 the weld personnel awareness of the optimum
process control, parameter ranges and technique requirements for weld defect prevention,
pipe, alignment dimensions, edge
preps and root gap dimensions to minimize the
opportunity for pipe root weld and side wall fusion problems,
 the weld deposition rate potential of the weld
process or consumables utilized,
 how easy it
is to utilize the process or consumables recommended,
how suitable and durable is the weld equipment selected
for the shop or field work. When welding with flux cored be aware that regular,
low cost CV MIG equipment will outperform inverters, multi-process power sources
and pulsed MIG equipment. The CV equipment will cost less, be more durable and
easier to repair.
suitability of the weld consumable selected especially for the
In this position check the weld fluidity, ease of use and the weld transfer. Take
note of the weld spatter generated in the over head position. The weld spatter
can end up in the nozzle blocking either the gas flow or the contact tip bore, causing
porous welds, or a wire burn back.
Sometimes in order
to use a "narrow pipe bevel", the weld inspection may require "shear
wave ultrasonic examination". This mode of inspection is necessary so the
NDT equipment can size the weld flaw, and determine
if the flaw is acceptable based on CTOD and fracture mechanic equations. Pipe
line companies are aware of this complex inspection criteria and the issues generated,
and therefore may only consider the narrow bevel welds or low fusion MIG modes
for small pipe line projects. Narrow gap and compound pipe joints require field
machining and the pipe roundness deviation is always a concern.
When using narrow, bevel pipe weld joints, or weld processes such as pulsed MIG
that provide minimum side wall weld fusion, extraordinary weld inspection methods
may be required. What you save on the narrow weld prep is often lost on the additional
weld inspection required and the consequences of that magnified inspection.
BACKING AND VEE GROOVE PLATE EDGE PREPS.
making all position flux cored welds on vee groove welds on carbon steel plate
with ceramic backing, two interesting questions would
be, what would the minimum vee groove angle and weld gap be?
In ship yards
where the typical steel thickness plate is 9 to 25 mm, when welding that vee groove
with ceramic backing, the optimum root weld gap size is 5-6 mm. The minimum,
"combined" vee groove angle should be 40 degrees.
TO POOR TRAINING, POOR MANAGEMENT AND LACK OF WELD PROCESS KNOWLEDGE,
FITTERS IN SHIP YARDS - CONSTRUCTION PROJECTS OFTEN DON'T DELIVERS WHAT WELDERS
a ship yard, poor edge preps, oversized gaps, excess weld and extra weld rework
and NDT costs can readily double the weld budget required per ship. Ed has developed
a ship yard Welder Training Program so that both welders and fitters can have a greater
understanding of the process requirements, the best weld practices and the weld cost and quality implications of their actions, See Ed's manual MIG and flux cored programs.
Ed, in our shop when welding carbon steels we have a choice of either MIG, pulsed
MIG, metal cored, self shielded flux cored, all position gas shielded or flat
position flux cored wires. I would appreciate guidelines on when or where to use
these processes and consumables. We weld thin gage to 1/2 (12mm).
For welding carbon steels, the following weld process logic guidelines
all welds made in the vertical, flat, and horizontal positions, on applications
less than 0.080, <2mm,
traditional MIG short circuit with an 0.035 (1 mm) weld wire is well suited. With
short circuit transfer (wire feed 200 to 350 ipm or 10 to 12 o'clock and voltage
in the 16 to 20 volt range), the low volts / amps and arc on / arc off characteristics,
provides low weld energy which reduces weld burn through potential and provides
low distortion potential. Best weld position "vertical down".
2006. After 20 even Miller and Lincoln have now figured out how to build decent, pulsed MIG equipment. I can now recommend
pulsed MIG for most thin gage applications.
welds on parts 0.080 to 0.150 thick,
the pulsed mode with an 0.045 (1.2 mm) MIG wire
can provide many benefits for all steels and especially sluggish applications
like stainless or nickel alloys. However in this application range, steels and
stainless are also readily welded with an 0.035 (1 mm) electrode and traditional
high short circuit settings. Controlled globular transfer or low spray transfer
settings with the 0.035 and 0.040 wires are also excellent.
applications > 4 mm. In contrast to spray the
pulsed process with an 0.045 wire can provide lower weld heat input for heat sensitive
applications. For greater weld fusion or improved arc consistency with automated
welds, consider spray.
the steel parts have mill scale or surface contaminates that effect the MIG weld
transfer, weld quality or the arc stability, it's time to consider gas
shielded flux cored. Do not use the all position flux cored wires if most
of the flux cored welds are made in the flat position. Use the E70T-1 wires.
pulsed MIG when consistent quality, vertical up welds are required for steel or
stainless >3/16, >4.8 mm, consider instead all position, E71T-1 gas shielded
flux cored wires with argon 15 to 25% CO2. FCAW electrode diameters 0.035 to
0.052 (1 to 1.4 mm) are recommended. From a weldability perspective, and its weld current range and deposition potential, my first
choice has always been the 0.045 (1.2 mm) E71T-1 wires.
NOTE WHEN MANUAL CODE WELDS AND ALLOY WELDS ARE REQUIRED TIP TIG SHOULD BE THE FIRST WELD PROCESS OF CHOICE. www.tiptigusa.com
To optimize all your MIG and flux cored welds
you may want to consider my book "Gas Metal Arc and Flux Cored Weld. For
the book and the the most effective, CD, power point, FCAW process control training
program ever developed, click.
FLUX CORED WIRE CHOICE: If most of your welds are made in the flat or horizontal
weld positions on plate with "mill scale / rust issues"
the first choice for flat / horizontal welds is the E70T-1 flux cored wires using
When welding on plate
the optimum E70T-1 wire size to attain good weld puddle control with maximum
weld deposition rate potential is the 1/16 (1.6 mm) wire. Avoid
the larger diameter E70T-1, 3/32 (2.4 mm) and larger wires as the high current requirements
for optimum weld deposition rates, typically will not be attained. Note
many weld shops use the fast freeze slag E71T-1, all position flux cored wires
for the flat
or horizontal weld positions, be warned these wires
on these applications can result in severe porosity, slag inclusions, worm tracks,
poor fusion and a pock marked weld surface.
Ed What do you think about Metal Cored and self shielded weld wires?
Reply. In my opinion, Metal Cored wires are for the majority of carbon steel applications
a complete waste of time and money. As the weld benefits in contrast to solid wires are miniscule the reality is, If there were no metal cored wires available
for carbon steel welds, it would have zero impact on the welding industry.
Self Shield Flux Cored above: As
you can see from this picture any an insane peson or a company like Chrysler would allow self
shielded wires to make welds in their weld shop.
Mail Weld Question
June 19, 2003.
on Pipe Welds:
Ed. We are trying to utilize
GMAW-P on an HY-80 steel pipe welds. I was pushing for gas shielded flux cored
wires, but the engineers will not allow flux cored wires for our pipe procedures.
The engineers complain of poor mechanical properties from the flux cored wires
on the HY metal. We can't use MIG spray as many of the welds are out of position.
are having a difficult time passing UT with our Miller
Invision pulsed power source. The MIG pulsed parameters required provide
a wide arc zone and long arc length, we end up with extensive, inconsistent weld
fusion. We are thinking about switching to Lincoln Pulsed equipment, as they tell
us with their equipment that we can get the controls we require from their unique pulsed wave forms.
The Miller Equipment does not allow wave form manipulation from
the interface, you have to run off the factory resets. Do you have any suggestions
on getting better results with our GMAW-P equipment?
that pulsed MIG equipment and especially that Lincoln pulsedwave form nonsense. Your
question brings to light some of the <2003 pulsed process issues I have been
talking about for more than a decade. Pulsed variable parameters and pulsed arc
length sensitivity combined with a lower energy pulsed MIG arc plasma and good deposition rates combine and often result in weld quality issues. Of course to attain more weld energy with pulse one can always increase
the pulse parameters and lower the trim volts, however there are optimum pulsed parameter limits and when
those wire feed settings and pulsed parameters
are slightly outside the optimum pulsed parameter range, you will not likely be
pleased with the radiograph results.
I think you will find that wave
form control which sounds great coming from the mouth of a sales rep, is going
to have have little weld quality / productivity impact on your weld applications.
You may want to read one of my many experiences with the Lincoln Power Wave and
the ineffective wave forms when this equipment created serious weld quality (weld fusion) issues
for a tier one axle manufacturer. Check out the MIG equipment section for extensive pulsed MIG issues. The
real issue here is not the weld issues, its the stupidity of your engineers for
not allowing the superior flux cored process to be utilized.
Update from Ed: If using pulsed equipment > 2005, it's now possible to attain
improved pipe weld quality, however with pulsed "manual welds" you can still expect lack of weld
fusion, and from a weld quality / productivity point of view, the 2013 pulsed MIG
process still cannot compete with gas shielded flux cored wires for most all position
carbon steels and stainless welds.
you want defect free pipe welds, their is only one cost effective manual
process and its called the TIP TIG, (www.tiptigusa.com).
industries. Two Processes and Ed's Process Controls.
the 1990s, Ed set the robot MIG welds on the above Genie product used to lift
loads in the air, and in 2006 - 2007 brought "Best Flux Cored Weld Practices
and Process Controls" to the Aker Philadelphia Naval Ship Yard, in the back ground..
SHIELDED FLUX CORED WIRES.
International Welding Specifications:
Steel Wires|| |
Steel Wires|| |
Steel Wires|| |
Steel Wires|| |
Alloy Steel Wires|| |
Alloy Steel Wires|| |
Alloy Steel Wires|| |
- 3223 - 3241
Alloy Steel Wires|| |
Alloy Steel Wires|| |
FOR OPTIMUM STEEL- STAINLESS FLUX CORED WIRES MY PREFERENCE,
ESAB (ALLOY RODS) SANVIK AND KOBELCO WIRES:
Multipass 20 ft/lb 0F
Germany SGR1 /
Japan YFW 24
BEST WIRE SIZE
1/16 (1.6 mm)
For rusty dirty plate. Does not
weld as good as E70T-1
Japan YFW 22
|Use only for
single layer welds
20 ft/lb -
Japan YFW 24/
Argon 20-25CO2 or CO2. DCEP.
Japan YFW 24
WIRE SIZES 0.045 -
0.052 (1.2 - 1.4mm).
CAN USE CO2 OR ARGON
(MORE WELD ENERGY
Gas shielded Flux Cored Wires:
SHIELDED FLUX CORED. WORM TRACKS & POROSITY:
Weld porosity: As indicated in the picture, a cavities or discontinuities
have formed in the molten weld. The porosity can be trapped inside the weld or
evident at the weld surface.
Weld porosity is typically round in shape,
but can also be elongated.
Porosity is caused by the absorption of oxygen, nitrogen and hydrogen into the
molten weld pool. The gases are then released during weld solidification. As the
gases try to rise to the weld surface some gas pores will become trapped in the
weld metal, some pores pass into the weld slag, while other pores will combine
on the weld surface, usually in the weld center (last area to solidify) producing worm tracks.
Flux cored weld porosity from and Excess Gas Flow.
Ed's CD Flux Cored Training Program
PORE WELD POROSITY.
If weld surface is clean and does not look oxidized, large pore MIG / FCAW porosity
is often a result of "excessive gas flow".
gas flow causes weld surface turbulence. This porosity can result with gas flow
greater than 45 cuft/hr. Optimum MIG and flux cored gas flow for carbon steels
is 25 to 35 cuft / hr. The shielding gas flow should be measured as it exits the
If the weld surface is dirty (oxidized) the cause of larger
pore porosity is often a result of insufficient gas flow, less than 20 cuft /hr.
WELD POROSITY. A localized group of small gas pores with
random distribution. Causes.
[a] Arc blow,
[b] if surface oxidized,
[c] material or weld wire contamination,
[d] (low) weld
[e] welds too small or too wide and too thin.
WORM HOLES OR SOME CALL IT WAGON TRACKS. As
seen in bottom picture the "wagon tracks" are typically found in the
center of the gas shielded weld, parallel to weld axis, this is the last area
for weld solidification so the porosity congregates as one.
The worm holes or wagon tracks are elongated gas pores producing a herring bone
appearance on a radiograph. Worm hole porosity is common in gas shielded flux
cored welds when the electrodes have too much moisture
in the wire flux or the weld solidifies too rapidly.
If you purchase the flux core wire from a third world country, you are
almost guaranteed severe weld porosity
issues. The cheaper the flux cored wire , the greater the potential for wagon
tracks. If the weld shop you work in is cold - damp or humid, that flux cored wire will be affected.
To reduce porosity - wagon tracks,
[a] extend the wire stick out as this preheats the weld wire but remember
it also lowers the weld current,
[b] storing the wires in a dry environment
reduces this potential,
[c] reduce weld speeds,
[d] make welds larger,
[e] avoid weaves which thin out the weld layers,
[f] increase current and decrease voltage.
The best thing you can do is order a quality weld wire as attained from Kobelco or ESAB
SCATTERED WELD POROSITY. Weld
porosity scattered randomly throughout the weld. If the MIG weld surface is gray
and looks oxidized, the porosity is typically a result of insufficient gas flow.
If the weld surface looks clean with scattered porosity the porosity is usually
caused by the base metal part or electrode contamination, or perhaps the weld
data used causes the weld to freeze too rapidly.
above recommendations are intended to increase the weld arc energy and decrease
the weld cooling rate. If the porosity issues repeat, change your flux cored wire
ON FILLETS AND MIG WELD ROOT POROSITY. Weld Weld root porosity
frequently occurs with MIG weld fillets when using "argon oxygen" (oxidizing)
> 20% CO2 mixes on parts >6 mm. With mixes containing oxygen, the oxidation potential is
increased and a resulting fillet root weld is typically narrow, finger shaped. The
narrow root finger area solidifies rapidly trapping the oxide reactions (porosity).
To reduce root weld porosity, change to a higher energy less oxidizing argon
10 - 15% CO2 gas mix. Increase the weld parameters, slow the weld speed, increase
the weld throat thickness and avoid weld weaves. And forget about that ridiculous
three part, argon - CO2 - Oxy gas mix recommended by your local gas company.
CRACKS - CRACKS - CRACKS
are many reasons for cracks to occur in a pipe or plate.
 Cracks can develop
from material defects.
 Cracks can occur during the plate to pipe rolling
 Cold cracks can occur from hydrogen in the welds.
cracks can occur from excess weld heat, stresses or welds and parts with low weld ductility.
Cracks can occur from crater defects,
 Cracks are common from poor weld profiles susch as root beads or
fill passes which are too thin, too concave or simply too weak.
in the pipe or welds can grow due to fatigue during the pipe operation. In-service
crack growth mechanisms include hydrogen induced cracking, stress corrosion cracking
and sour service cracking.
of the following crack data is from GE.
Induced Cracking (HIC).
service pipelines are vulnerable to HIC
in the presence of water. The cracks can occur in pipeline steels of any strength.
The HIC is typically associated with non-metallic inclusions such as elongated
manganese sulfides. With x-rays or ultra sonic evaluation, the HIC in the pipe
walls will appear as cracks, but near the pipe surface may appear as rough convex
bumps. Acid corrosion will take place on H2O wet areas inside the pipeline and
hydrogen will be produced by this corrosion reaction. In the presence of sulfides,
scales on the steel surface form rather than being liberated as a gas. The atomic
hydrogen diffuses into the steel, forming blisters in the microscopic voids around
nonmetallic inclusions. The gas pressure in these blisters generates very high
localized stress, which initiates cracking along lines of weakness in the steel.
HIC develops as flat cracks in the rolling plane of the pipe material. Crack colonies
develop, and failure often occurs as colonies link together in a stepwise fashion.
For this reason, HIC is sometimes called stepwise cracking.
Hydrogen Induced Cracking (SOHIC).
special form of HIC may occur when local stress concentration is high in a sour
service pipeline. High stress fields can allow the hydrogen to accumulate without
the need for inclusions or other interfaces. For example, some types of spiral-welded
pipe exhibit highly stressed regions close to the seam weld, caused during the
edge forming process. Stacked arrays of HIC can form in these regions, leading
to rapid stepwise cracking failures.
Corrosion Cracking (SCC).
stress corrosion cracking on high-pressure pipelines is recognized in two forms:
high pH and near-neutral pH. Its believed that SCC cracks can initiate and grow
in a range of conditions, including predominantly intergranular cracking in alkaline
conditions and transgranular cracking in neutral pH environments. SCC can occur
in a wider range of restricted aqueous environments at the pipe surface, and in
extreme cases SCC has been confirmed on above-ground pipelines.
corrosion creates crack-like features aligned at right angles to the principal
stress. In most cases, the product pressure in the pipeline creates the principal
stress, so the cracks are aligned parallel to the axis of the pipeline. External
stresses such as ground movement can give rise to cracks at almost any angle through
to fully circumferential.
threshold for SCC crack initiation is at or about the actual yield, so in the
absence of a high residual stress or an externally imposed stress, SCC is not
expected in operational pipelines. However, the threshold for crack initiation
is reduced by stress or pressure cycling, and in cases where pipelines experience
large diurnal fluctuations, the threshold stress for crack initiation may be below
the mean operating stress. Some steels show a greater susceptibility than others.
On occasion, this difference in material susceptibility has been the main factor
in determining where high pH SCC has become an operational problem.
is also a key factor controlling the rate of high pH SCC crack growth. If all
other conditions remain unchanged, crack growth rate increases with temperature.
risk can be minimized on new pipelines by careful coating selection and preservation
of coating condition through the construction process. To reduce SCC risk, priority
should be placed on the long-term adhesion performance of the coating and its
resistance to adhesion loss from water uptake, cathodic disbonding, soil induced
loading and impact or gouging.
crack-like surface defects originate during the rolling process used to produce
the plate or strip from which pipe is fabricated. Surface cracks in the hot slab
become oxidized, which prevents them from welding to the adjoining metal during
subsequent rolling. The cracks remain on the outer layer of the steel and are
rolled over to become surface-breaking defects at a very shallow angle. They can
occur in any position around the pipe.
defects in the longitudinal weld occur during manufacture of the pipe, when inclusions
at the plate edge are turned out of the plane of the steel during the welding
process. They may pass the manufacturers initial hydrotest, but fail later
due to metal fatigue. It is the turning out of the metal at the weld that gives
the characteristic hook or J shape to the crack.
girth weld cracks can occur in
any position around the weld, they are most often
found at the
6 oclock mark inside the pipe, which is the position of maximum stress
movement of the internal clamp, when only the root bead has been made. The cracks
are formed almost exclusively during construction because of inadequate fit-up
and excessive stress.
fatigue is caused by repeated or fluctuating stresses whose maximum value is less
than the tensile strength of the material. They start as minute cracks which grow
steadily in reaction to pressure cycling, physical deformation of the pipeline
and other mechanical stresses.
Axial External Corrosion (NAEC).
this is not strictly a crack, it is one of a number of defects associated with
the seam weld, which are difficult to detect with standard metal loss tools because
of their axial orientation. It is caused when the pipewrap tents over
the seam weld bead, allowing moisture to enter and encouraging corrosion. The
resulting loss of metal parallel to the seam can result in rupture.
occurs at temperatures blow 200F after the weld solidification is complete. These
cracks can occur several days after welds are made. Cold cracks can occur in ferritic
and martensitic steels such as carbon steel, low alloy steel and high alloy steels
unless precautions are employed.
cracks are caused by the combined effects of;
 low ductility of the weld,
 residual stresses,
 diffusible hydrogen
in the weld.
cracking can be prevented by focussing on these three factors.
 A weld's
ductility may decrease with a "high carbon" equivalent
and a "high cooling" rate after solidification.
Residual stress in a weld can be larger than expected
if the weld contains weld discontinuities such as incomplete fusion, incomplete
joint penetration, overlap, undercut, slag inclusions, and weld porosity.
The source of diffusible hydrogen in a weld is typically
moisture in the welding consumable, the base material, the weld gas or from the
reduce the potential for cold cracking:
Preheat the base metal to reduce the cooling speed
of the weld. The preheat ensures no moisture is in the pipe. The preheat slows
down the cooling rate and prevents the embrittlement of the weld and allows dissolved
weld hydrogen to rise through the weld and escape to the atmosphere.
Prevent weld or joint discontinuities to avoid stress
build up and concentration.
Use low-hydrogen type
welding consumables to minimize diffusible hydrogen in the weld.
combined use of preheating, interpass temp control and if required post heat treatment
will be effective to prevent cold cracks occuring in a weld. On preheating, it
is important to determine the temperature appropriate to the base metal and filler
metal to be used. The appropriate temperature is generally determined for individual
work by taking into account several factors such as chemical composition, restraint
level, pipe or plate thickness, the weld process used, heat input, and the amount
of diffusible hydrogen in the weld metal. If you dont know the preheat use 300F.
If you use pre-heat then use the same temp for interpass temperature control,
which ensures minimum hydrogen and minimizes grain growth. Its beneficial to wrap
the weld in an insulating blanket immediately after the weld, this slows down
the cooling rate and ensures no delayed cracking when the parts or vessel is cooled.
you want to put too much weld in a single
pass or you don't control
interpass weld temperature
mult-pass welds, watch out for those hot cracks
that will often occur in the weld center or in the weld's
WELD LOGIC: Limit single pass fillet welds to a max size
of 5/16 (< 8 mm) and keep all multi-pass, interpass temps at a max of 350F.
Avoid thin weld passes and limit weave widths to a max 5/8. Watch that weave to
depth weld ratio.
Remember, there are two things that most alloys like.  The highest possible weld quality.  The lowest possible weld heat. There is only one manual - auto weld process that provides this capability, its called,
those desperate enough to use a gun with
self shielded flux cored weld wires,
THE WORLD'S LARGEST EARTH MOVING EQUIPMENT HAS AN ACCIDENT IT'S BOUND TO BE A
BIG ONE AND IT'S LIKELY TO BE REPAIRED WITH FLUX CORED WIRES. NOW ALL I WANT TO
KNOW, IS WHAT IDIOT LEFT THE DAM BULL DOZER IN FRONT OF THE BUCKETS?
Can you find the bull dozer?
LOGICAL WELD CONSUMABLES FOR WELD REPAIRS ON THIS TYPE OF EQUIPMENT WILL BE GAS SHIELDED FLUX CORED
WIRES. ONE WELD WIRE TYPE EX1T-1, SIZE 0.045 AND THREE WELD SETTINGS COULD DO EVERY WELD ON THIS
PART, DO YOU KNOW WHAT THIS DATA IS? IF NOT IT'S FOUND IN MY MIG / FLUX CORED BOOK AND IN MY CD FLUX CORED TRAINING PROGRAM.
The dozer was swept up like a toy and trapped in the wheel.
Strength of Gas Shielded Flux Cored Electrodes.
the ANSI/AWS Specification
60 - 80||410
means an argon mix with 75 to 80% argon balance CO2
DCEP E71T-1 Second number 1 = all position.
E70T-1 Second number 0 = flat and horizontal
Ed. We weld
carbon steel pipes and structural steel plates typically >6mm.
We are considering 0.045 - 0.052 and 0.062, (1.2 - 1.4 and 1.6 mm) flux cored
wires for all position welds. Which do you think is the optimum flux cored wire
size and who makes the best wires?
When welding all positions, the E71T-1 "0.045" (1.2mm) is the wire of
choice. The reason the 0.045 size is the wire of choice for vertical up, overhead
and horizontal positions, is the all position weld parameter range of 120 to 350
amps and the high weld deposition rate potential of 6 to 17 lbs/hr. Reference
the best wires. ESAB (Alloy Rods) or Kobellco would be my choice. I find these
two wires provide great weldability with high deposition rate potential.
Considering flux cored for robots or mechanized carriage applications? With mechanized,
all position pipe welds, the welding machines can provide many benefits and advantages
over manual welders. Mechanized flux cored welds will provide superior weld weave
configurations, controlled weld weave frequency, controlled weave width, controlled,
faster weld speeds and very important controlled Wire Stick Outs. The results will be shorter weld times and far superior weld
quality than any manual welder can attain.
WHAT'S THE BEST WAY TO TEST AN ALL POSITION FLUX
CORED WIRE SELECTED FOR PIPE
A good weld test on the weldability of a flux core wire is the wires ability for
overhead welds on 6 - 7 mm steel plates or pipes.
A flux cored wire with stable spray (small droplet) type transfer at low parametersy is
desirable. In the over head position, if at the weld parameters selected,
the weld is erratic globular transfer producing excess spatter, the weld will be difficult
to control. That excess weld spatter may block the contact tip bore, restricting the
weld wire as it exits the contact tip.
When you want to set that flux
cored wire for optimum weldability for vertical up or over head welds, there is
a simple way to set the optimum weld parameters and to test the weldability of
any flux cored wire, it's found in my Flux
Cored Book and Process Control Program.
Need more info, contact Ed at firstname.lastname@example.org, or why not get pipe welding
information from two of his books, Check out this sites weld education resources. Pipe
and flux cored data available in the "Management Engineers Guide to MIG"
and the "MIG - Flux Cored" book.
Ed we need good weldability with high impact properties. We use a Lincoln 3/32
(2.4 mm) E70T-5 wire (CO2) welding on steels with mill scale. The intention is
to attain good impact properties with tensile properties in the 90 to 100 ksi
range. The welders do not like the welding characteristics or fumes generated
from the Lincoln E70T-5 wire. I think we may have grind or sand blast the parts. We need
good impact properties. What wire do you recommend?
Answer: You pay a weldability price for using the
E70T- 5, basic slag, calcium fluoride electrode. If the mechanical properties
are compatible, try an Alloy Rod / ESAB E70T-1 wire called Dual Shield T-90C1
and by the way forget the 3/32 size. Use the 1/16 (1.6 mm) wire for better weldability
and less weld heat input, both will improve your impact property potential. When
I want a quality flux cored wire I typically will not give consideration to Lincoln
products (there L50 - L56 MIG wires are good) . Also when I want quality welds those welds will be on a surface free of millscale
HOW GOOD ARE WELD
GENERATORS AND FLUX CORED WELD WIRES?
Ed. We field weld gas
and oil pipes. We weld a variety of pipe
wall thickness. We like the gas shielded E71T-1 flux cored wires. With CV MIG
equipment we know these wires run good. I have three questions.
What about the E71T-1, gas shielded flux cored wire weld performance,
when using these wires
with a CC Generator?
 Can I use flux cored for the roots or should I stay with EXX10
SMAW electrodes or consider pulsed MIG or short circuit for the root? With our
pipe joints the root gap dimensions vary.
 What can I expect from
the short circuit MIG welding performance for external root welds made with a
generator with a CV adapter?
 When welding with the
flux cored wires, CC generators supplied with a "CV adapter" provide
great weld results Remember these wires were developed with CV MIG equipment. I tested both Lincoln and Miller generators with CV adapters.
These units provided the same weld performance as traditional CV MIG equipement
and superior weldability than that attained from sophisticated electronic inverters or multi-process MIG equipment.
Never use flux cored for a root. For 5G pipes the external pipe root pass, is easy with MIG, STT - RMD for rotated pipes the regular low cost short circuit mode is just as good as STT - RMD. If you have
the TIP TIG you have one great process for the root and fill.
Note: The SMAW / GTAW / TiP TiG
processes will always be best choice for the root pass if the root or pipe dimensions vary.
TAKES THE STING OUT OF POOR TANK WORKMANSHIP:
1992, Ed was hired by Textron to go to Thailand and manage weld repairs required
on dozens of Stingray Tanks sold to the Thai army.
These tanks were built
in Florida and had serious weld fabrication issues causing extensive weld cracks
which were revealed when the Thai army field tested the Tanks.
The military vehicle
defect was a major political issue in the middle east and a great cause of embarrassment for Textron
who was and still is a major global arms supplier.
finding the weld resolutions to the extensive weld cracks in the armor plate, I had to put a MIG
and flux cored tank weld repair procedure in place for the unusual 270.000 psi,
tensile armor plate. Making this application more difficult was the field weld
repairs were required around the weld failures in locations high in martensite,
(extremely brittle). Also
to add to the weld challenge was the daily visit by Thai Generals and politicians
who were concerned with the 200 plus million dollars their goverment had invested
in the project.
Thai soldiers who were allocated to do the field weld repairs had never MIG or flux
cored welded. With this in mind I developed a simple weld process control program
for both the MIG and flux cored process. In one week I taught the Thai soldiers
how to do the necessary MIG and flux cored welds on the complex armor plates.
To make the weld repairs on the armor plates, I had ordered Miller generators
with CV adapters. The adapter enabled MIG welds
and the use of gas shielded flux cored wires. For the all position welds I welded
the plate with Alloy Rods, E71T-1, gas shielded flux cored wires. Everything we
used at the site was shipped in from the USA.
Thai "soldier welders" were like those students you find in most third world countries,
great students, open minded and untarnished by weld process ignorance, weld myths or the salesmanship
you find in most industrial countries
understand the MIG and flux cored weld settings and
to ensure they did not "play
around" with their weld controls, I had the soldiers sit in a class room for two days provided the soldiers with my unique
Weld Clock training method
for process controls.
They soon picked up the necessary all position weld
skills and how to set optimum weld parameters, notice the low spatter content
in picture on left . An ironic weld fact, after my MIG and flux cored process
control classroom training session, the Thai solders knew more about MIG and flux
cored weld process controls than most global weld engineers and weld QC personnel.
Yes that's a cow passing through the Thai weld training classroom and I can assure
you there was no "BS" with that training program, pardon the pun I could
not help it.
welds the soldiers produced were made by Miller weld generators and weld consumables
I had selected in the USA.
 Miller Generators with CV output,
 Lincoln, L50 MIG wires,
 Argon - 15% CO2, this US gas mix ideal for both
MIG and flux cored. I developed this mix in the eighties for a AGA, a major US
gas supplier. As
for facilities, the tank welds were made in an open shed without electricity,
(used generators) in the jungles of Thailand.
tank sub assembly part (shown above) had to be MIG welded.The
solders who had never welded before with less than one weeks training used MIG
spray transfer with, 0.045 wire and 85 - 15 CO2 gas on the new
270K tensile armor plate. They then used MIG short circuit welds to repair
sub assembly stiffener was then welded to the tanks using all position gas shielded
flux cored wires again with the same argon 15 CO2.
Thai people and welding experience was wonderful, and at the end of the day the
lesson for North American manufacturers who are looking for optimum manual or
robot MIG / FCAW quality and productivity.
You do not need highly experienced weld personnel.
 You do not need
fancy training facilities.
 You do not require sophisticated, costly
with useless bells and whistles.
 You do not need the advice of a weld
 You will never need three part gas mixes or special Metal
cored weld consumables.
be aware that with this type of process control training, at the completion you
would have welders,
technicians, engineers, QC personnel
who finally understand MIG and flux cored weld process controls. These individuals
when using the MIG or flux cored process would not have to "play
around" with their MIG or flux cored weld controls. These individuals
would daily walk the same path and attain the highest possible manual weld quality
and productivity from low cost weld equipment and basic consumables.
FLUX CORED APPLICATIONS, WELD WIRES, AND WELD DATA.
Cored Wire type Diameter Size|| Weld
+ - 1 volt
+ - 10%
< 1/4 |
| E71T-1 |
up|| 25|| 150|| 360
| E71T-1 |
| 28|| 200|| 560
deposition for this application|
| E71T-1 |
hot for < 3/16|
> 6 mm
| E71T-1 |
- 26|| 200
- 250|| 300
/ 400 ipm|
choice. for pipe or bevel fill passes|
Pipes < 1/2 use
> 1/2 use 380 to 400 ipm with 24 to 27 volts
to 3/8 |
| E71T-1 |
30 || 280|
- 600 ipm|
7 - 13 lb/hr
vee preps or fillet welds|
up|| 25|| 190|| 190|
minimal weld deposition improvements for vert up, in contrast to 045|
| E71T-1 |
| 29||300|| 400
up|| 25|| 200|| 120|
| E71T-1 |
| 31|| 325|| 250
| E71T-1 |
| 31|| 325|| 250
To simplify your MIG - FCAW wire feed control settings, learn
Ed's unique, weld clock method in his books
and training programs.
how would you weld a 40 degree vee prep in 3/4 carbon steel plate. We use ceramic
backing. The root gap is a 1/4 (6 mm). We will use an 0.052 (1.4 mm) E71T-1 wire.
Root gap 1/4 (6 mm).
Flux Cored Wire 0.052 (1.4 mm E71T-1.
My wire choice. Kobelco as with straight CO2 superior weld fusion than argon mixes, without the spatter and weld fumes associated with CO2 wires.
Gas straight CO2.
would use Sabaco Ceramics as I beleive they are the best avalable in North America.
Vert Up #92A
Sabaco Horizontal 1B903H
Sabaco Flat same as Vert Up.
 6 passes
 Root weld on ceramic. WF 380 ipm - 29 V. 250 amps. Back
Hand to maintain arc on none conductive ceramic.
 Fill pass 430 ipm - 29 volts. 280 amps
 Three cap passes designed with lower settings to avoid undercut.
Use 350 ipm - 26 volts 240 amps.
 6 passes including root
 Root at 260 ipm volts 25 amps 190
2 passes at 320 ipm 28 vlts 240 amps
 3 capp passes same settings as fill.
 Root 240 ipm 23-24 volts - 190/200 amps.
 Hot pass 300
ipm 25 volts 220 amps.
 Cap same as as root.
Extensive grinding of trapped slage should be applied on each weld pass, especially
on the weld edges.
Ed. What's the best "size" flux cored wire for horizontal fillet welds
made on carbon steel plates >3/8 (> 9 mm? We use 3/32 (2.4 mm) wires.
As long as the parts are thicker
than >5/16 (>8mm), the best size flux cored
electrode for welding in the flat and horizontal positions is the 0.062 (1.6mm)
Many companies or weld personnel who simply don't know better
will purchase LARGE diameter weld wires like the 3/32 wire. The reason the 3/32
flux cored wires are less ideal for most applications is that they require over
400 amps to produce reasonable weld deposition rates. Welders don't like working
with >400 amps, and the high weld energy makes it difficult to control the
weld puddle. With the 3/32 flux cored wires most welders will set "low wire
feed rates". In weld reality with the large wires, welders end up producing
a lot of smoke and produce welds which are difficult to control. The weld deposition
rates they typically attain are usually lower than that attained with the more
controllable smaller 0.062. (1.6 mm) diameter wire.
Ed, why do we use straight CO2 and cannot use an argon mix with most E70T-1 flux
cored wires? Also why should we be concerned when using the E71T-1 flux cored
wires in the flat and horizontal weld positions on > 5 mm steel parts and steels
with mill scale?
Weld Answer: The E70T-1 wire is a basic electrode that contains substantial deoxidizers.
This wire provides a thick, slow cooling slag and this wire is designed to weld
carbon steels in the flat and horizontal
positions. The E70T-1 wire usually requires the high energy, high oxidizing CO2
In contrast to the E70T-1 wire, the E71T-1 flux cored wire is an electrode
that has a rutile slag with lower de-oxidizers than the E70T-1, (deoxidizers tend
to make welds more fluid). The E71T-1 wires also provides a thinner, "fast
freeze" weld slag. The lower de-oxidizers (less fluid weld) and fast freeze
slag help contain the molten metal when welding vertical up or over head.
The E71T-1 wire typically will use argon with 20 to 25% CO2, or straight
CO2. The argon mixes are preferable for many all position E71T-1 wires, however
in ship yards or for any companies that want minimal internal weld defects on
parts >3/8 (> 9 mm) I recommend the Kobelco DW 50 wires which use straight
As mentioned the E71T-1 wire and an argon mix produce lower weld
energy than CO2. Also the E71T-1 wire produces a fast freeze slag that will contain
minimum de-oxidizers. If you have to weld on mill scale and you are welding in
the flat and horizontal weld positions, the E71T-1 wires in contrast to an E70T-1
wire on mill scale applications can cause many weld issues. The E71T-1 wires
when used on these applications have greater potential to produce excessive weld
porosity, worm tracks, less weld fusion and inferior weld surface appearance.
FLUX CORED AND MILL SCALE?
mill scale or contaminated plates, when welding in the flat or horizontal weld
positions, the basic E70T-1 wire in contrast to the E71T-1 wire, provides more
de-oxidizers, provides improved weld fluidity. This wire can result in cleaner
(less porosity) welds with improved weld fusion profiles. The E70T-1 also produces
a thicker slow cooling slag that slows down the weld cooling rate and molds the
weld surface to a smoother, superior finish.
Ed, why do you think ESAB (Alloy Rods) has a better all position flux cored wire
versus a Lincoln wire?
Answer: For decades, it was my responsibility with
companies like AGA, Airgas, Linde and Liquid Carbonic to test weld consumables and in my opinion the flux cored products
invented by by both Alloy Rods and Kobelco are all I need.
about Lincoln flux cored wires: When Lincoln first brought it's all position gas
shielded flux cored wires to the market, I was working with AGA (one of Lincolns
biggest customers) located in Cleveland. Lincoln invited me to their facility
to test their new product. I found their lower cost product had a narrow, limited
weld parameter range, a lower weld deposition rate potential and the welds at the Lincoln plant ended
up full of porosity. Imn sure thaey have inproved their products, but after that demo I lost my confidence in them
During November, 2006 as I worked to establish best weld practices in the Aker
Shipyard (Phily Naval Shipyard). I recommended that the yard use the Kobelco DW
50 (0.045) wire with straight CO2. Easy to use, no spatter, great high depsition
rates and superior weld fusion to the argon CO2 flux cored wires.
Ed what is the most important thing
to do when
setting optimum all position, gas shielded flux cored
Start your welds in the optimum weld parameter ranges as indicated in my books
and CDs and be aware of how with the voltage
you can set the "required minimum
optimum arc length".
arc length is the gap between the wire tip and weld.
To set the correct arc gap with gas shielded flux cored "think
weld voltage". The ideal arc gap between the wire tip and weld will be approx.
0.020 to 0.030. If the arc gap is more than 0.060 the arc length may be too long
spreading the weld heat over a wider area of the weld surface making it difficult
to control the too fluid weld.
the recommended weld voltage (arc gap length) is critical in vertical up and overhead
E71-T1 steel applications. The weld wire should be as close as possible, allowing
the weld transfer to occur across the arc gap with minimal disruption of the weld transfer or weld.
If thearc gap is to small and the flux cored weld wire is too close to the weld, you will cause short circuits of the
weld transfer disrupting the weld and causing weld spatter. For the E71T-1 wire
stickout use 10 to 18 mm wire stick-out. This data and much, MUCH more in my MIG
/ Flux Cored Book.
up 3/16 to 1/4 (4.8 to 6 mm) fillet welds, start ou with 24 to 26 volts, either hold the gun steady or if required
use a very slight oscillation in the weld center outwards. For vert up fillet
welds larger than 6 mm the straight weave is preferred.
following photo is an ABB robot I set welding a 48 inch pipe, welding vertical up. The
weld wire was an Alloy Rod Dual Shield E71T-1 wire. The weld data used for
the vertical up weld produced 9 lb/hr with incredible weld quality results. It took
less than two hours to develop this robot weld procedure for this pipe weld.
1998, ED SET THIS ABB ROBOT TO FLUX CORED WELD A 48 INCH PIPE IN THE 5G POSITION.
THE WELDS WERE PERFECT
AND THE SLAG FELL AS THE WELDS WERE MADE.
contrast to what many skilled pipe welders may believe,
the world's best pipe
welder has always been a robot.
this pipe fill pass welds, Four robot program points and "one weld procedure"
was all that was needed to weld the fill passes in this 18 mm wall, 40 inch diameter
pipe. Welding from 6 to 12 o'clock. Its amusing today twenty years after robot
suitability for pipe line welds to see pipe companies using complex computerized
weld controls, limited flexibility mechanized carriage equipment and multi-complex
pulsed weld procedures for their automated pipe line welds.
out about Ed's million dollar savings
when the Alberta
pipe welders finally switched from SMAW to Flux
those of you who have never purchased a weld book
or process control CD, remember
weld process control
knowledge will always lead to the best weld jobs.
YOU WANT REAL WORLD, IN-DEPTH INFO, ON THE MIG OR FLUX CORED PROCESSES, CONSIDER
MY MIG - Flux Cored weld training resources
ASTM / API pipe steels / weld specification data is available in the steels program
All weld programs at www.weldreality.com.