ADVANCED PIPE WELDING WITH GMAW IIW International Conference on High Strength

Materials – Challenges and Applications

Dr. Petteri Jernström

Director, Product Management and Technology Services

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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

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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

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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.

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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.

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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.

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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

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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.

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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.

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• 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