Company Name: Cranfield University

Sector: Industrial plant construction/assembly plant

Material:
Steel

Process:
GMAW/TimeTwin
GMIW/TimeTwin

Component welded:
Pipelines


Initial contact and short description:
Cranfield University was assigned by BP Exploration and TransCanada PipeLines to complete a feasability study on cost reduction options combined with the application of automated welding processes for pipeline construction. The Cranfield Automated Pipewelding System (CAPS) was proposed and BP Exploration and TransCanada Pipelines agreed to fund development and testing of the system.

The new process is aimed at large diameter, long distance gas transmission pipelines like the proposed Alaskan Gas Pipeline, a 3200 km pipeline between Alaska and Chicago. Much of the Alaskan construction will be conducted in the winter under extreme weather conditions with temperatures as low as -50C.

Requirements:
a) The Alaskan pipeline sections can only be installed and welded during winter since in summer the soil is too soft for construction work in Alaska.
b) 24m-long pipe lengths are strung out for welding along the pipeline right-of-way. The welding is performed in a welding shelter where temperatures may be as low as -20C. Welding power supplies are powered by a diesel generator and stored outside on the back of a welding tractor. The tractor carries the welding shelter and welding equipment to each girth weld.
c) CAPS is a dual-tandem welding process with 4 welding arcs operating simultaneously on each side of the pipe which has a significant potential cost saving compared to current mechanised GMAW techniques.
d) The proposed pipeline is also likely to use a new X100 linepipe material.

Cranfield University has purchased four Fronius Time Twin Digital systems and these have been tested at Cranfield and in Canada at temperatures as low as -42C.

Solution:
Project characteristics:
a) Use of Tandem GAMW for all position welding.
b) First application of Dual-Tandem welding in the pipeline sector (in this case four welding arcs are used simultaneously on each side of the pipe)

Fronius has made the following adaptions in order to cope with the extreme temperatures:
a) Time Twin torch with new geometry and lightwight construction method
b) Adapted hose package for extreme temperatues.
c) Time Twin Digital power sources equipped with operation safeguard (until max. –10C°) due to safety reason
d) New coolant fluid of up to –50°C
e) Implementation of Cranfield’s welding database which was developed specifically for the process and filler material

Parameters:
a) Base material: X100 and X80
b) Pipeline diameter: 36", 40" and 52"
c) Thickness: Upto 23mm
d) Filler material: G3Ni1Mo, 1,0mmf

Products in application:
4 Time Twin Digital 5000
WeldOffice
Ethernet
RCU 5000i
VR 1500
Special torch
Can Open
Used products:
4pcs