ADVANCED PIPE WELDING WITH GMAW IIW International Conference on High Strength
Materials – Challenges and Applications
Dr. Petteri Jernström
Director, Product Management and Technology Services
2
1. This is Kemppi
2. Introduction
2.1. Root pass welding
2.2. Fill passes welding
2.3. The WiseRoot+ process
3. Experimental work
4. Conclusions
Content
Executive
Chairman of the
Board
Mrs. Teresa
Kemppi-Vasama
1. This is Kemppi
Private
family-owned
company
Established
1949
Headquarters
in Lahti,
Finland
Global revenue
114 MEUR
(2014)
16
subsidiaries
globally
650 people in
16 different
countries
CEO
Mr. Anssi
Rantasalo
Parent company:
Kemppi Group
Oy
Executive
Chairman of
the Board
Mr. Antti
Kemppi
4
2.1. Root pass welding
• Over the last twenty years, developments in GMAW
have enabled welding with consistent quality and
efficiency.
• External one-sided welding without copper backing
has become possible thanks to the introduction of
advanced power source technology.
• Many manufacturers have recently introduced
products designed specifically for this purpose.
2. Introduction
5
2. Introduction
2.2. Fill passes welding
• For welding the fill passes, mechanised or
automatized orbital welding with flux-cored wire
and CO2 or argon/CO2 shielding gas mixture is
often used.
• Welding is typically performed using the uphill
technique in the 6-to-12 o’clock position with
oscillation.
6
2. Introduction
The behaviour of the current and
voltage in the WiseRoot+ process
over one short-circuit cycle.
2.3. The WiseRoot+ process
• Once the power source has recognised a short
circuit, a controlled increase in current triggers the
transfer of a droplet. When the current reaches a
specific value, it is quickly reduced before the
droplet detaches and the short circuit ends.
• The short circuit ending at a point of low current
produces a smooth transfer of the droplet without
spatter. After the short circuit is broken, a pulse of
current is created to heat the weld pool.
7
2. Introduction
2.3. The WiseRoot+ process
• WiseRoot+ offers excellent welding performance in
all positions and over a wide range of materials.
• A suitable welding programme is selected on the
basis of the filler-metal wire and shielding gas used.
After this, the welder selects the desired wire feed
rate.
• In addition, the welder can use a fine-tuning option
to adjust the heat input and thus penetration.
8
2.3. The WiseRoot+ process
• With Kemppi FastMig X, parameter adjustments
can be done without interruptions as the
MatchChannel function allows the welder to
change the memory channel ‘on the fly’.
• For example, when welding fixed pipes, the welder
can save the parameters for the first sector in the
memory channel 1, and for the second sector in
the channel 2.
2. Introduction
9
2. Introduction
2.3. The WiseRoot+ process
• With thicknesses from 1 to 5 mm, an I joint can be
used. Gap accordingly from 0 to 3 mm.
• With thicker plates, a V groove joint preparation is
recommended.
• When the plate thickness exceeds 12 mm, it is
more cost-effective to use a compound bevel V
joint or a U joint, both of which help to decrease
the joint volume.
10
3. Experimental work
• The welding tests were performed manually with the WiseRoot+ process.
• The objective of the test was to evaluate the feasibility of the new process
for the welding of horizontal fixed X60 steel pipe with a diameter of 600 mm.
• The wall thickness of the pipe was 12 mm with a V joint configuration. The
gap width was between 2 to 3 mm, with the root face of 1.5 to 2 mm.
The parameters
used in the tests.
11
• The welding tests demonstrated the beneficial
effect of the new process on arc stability, weld pool
control, penetration formation, and welding speed.
• Smooth, consistent root passes with complete
penetration and sidewall fusion were obtained. The
maximum welding speed was three to four times
higher than with GTAW.
• In addition, the results clearly showed that it is
easier to compensate for variations in the gap width
than with a conventional short circuiting process.
4. Conclusions
Thank you