PROTEMPEOPLE
The first pipeline built in the world was built by independent oilmen in the USA in 1879
T
hese independent oilmen wanted to compete with Rockfeller´s position in transportation. They did not achieve to outerperform what Rockfeller did but they achieved some success. At that time, the safety of the operators, the quality of the welding preparation were not essential criteria. Nowadays, pipelines remain the safest way to transport oil and gas and they are nearly omnipresent in our lives. However a number of accidents
due to poor welding or poor welding preparation have marked history. Since 2010, there have been 4,215 pipeline incidents resulting in 100 reported fatalities, 470 injuries, and property damage exceeding billions $... Beveling and chamfering (along with other profiles) are applied to thicker pieces of metal prior to welding. Different types of joints can be performed
according to the welding process applied or to qualified welding procedure applying to meet the application´s requirements. The bevel provides a smooth clean edge to pipe and allows to achieve a correct shape preparation.
What are the risks of unproper welding procedures? Among others: ● Line pipe weld misalignment ● Incorrect pre-heat or interpass temperature ● Improper cleaning of the pipes prior to the welding operation ● Improper bevel and wall thickness sections ● Out of roundness due to cut induction bends ● No consideration of the influence of extreme temperatures or generally speaking extreme working conditions ● Other improper welding practices ● Improper welding preparation and welding inspections
Controversial welding and welding preparation techniques do represent the main reasons of the accidents occured in the pipeline industry since 1879. Even nowadays, certain preparatory operations for welding are done with a grinding wheel or other equally unsuitable tools. Poor preparation will affect the
end quality of the weld and lead to rejects, breakage or even leaks in use if defects are not detected in time. Good preparation for welding is even more important when mechanically welded structures are subject to heavy loads when in use (pressure, heat, mechanical stress, etc.). For example, this is the case in Nuclear Power or Oil and Gas industries, two domains where welding needs to be perfect.
Pipe Facing Machine PROTEM PFM HSB-620 operated on-site (photo courtesy of PROTEM)
Orbital Pipe Cutting & Beveling Machine PROTEM TTNG1200 operated in workshop (photo courtesy of PROTEM)
Edges for welding are to be performed when parts and assemblies require definitely strength. To achieve a perfect welding penetration, the edges of the
metal must be properly prepared. The welding material will then replace the removed material and does represent a kind of bridge between the parts which are to be joined. Many different welding processes are available. For the Pipeline Industry, 4 types of welding are generally applied: MIG, TIG, Stick and Flux-Cored arc welding. Besides the welding preparation itself, the pipes have also to be cleaned prior to any welding operation. This enables to avoid the risk of hydrogen inclusions.
If the welding preparation was made while using lubricants, it is also essential to clean the pipes. If this welding preparation was made with a flame cutting process and not with a cold cutting process, slags or oxide may have stayed on the edge.
26 IMT October 2019
www.internationalmetaltube.com
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