Low-frequency electric resistance weld, LF-ERW is Electric resistance welded (ERW) pipe manufactured by cold-forming a sheet of steel into a cylindrical shape. Current is then passed between the two edges of the steel to heat the steel to a point at which the edges are forced together to form a bond without the use of welding filler material. Initially this manufacturing process used low frequency A.C. current to heat the edges. This low frequency process was used from the 1920s until 1970. In 1970, the low frequency process was superseded by a high frequency ERW process which produced a higher quality weld. Over time, the welds of low frequency ERW pipe was found to be susceptible to selective seam corrosion, hook cracks, and inadequate bonding of the seams, so low frequency ERW is no longer used to manufacture pipe. The high frequency process is still being used to manufacture pipe for use in new pipeline construction. The Poplar Pipeline was built in the 1950s using pipe made with low-frequency electric resistance welds as was the Pegasus Pipeline.

Poplar Pipeline

On January 19, 2015 oil from a broken

pipeline Pipeline may refer to: Electronics, computers and computing * Pipeline (computing), a chain of data-processing stages or a CPU optimization found on ** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...

seeped into the

Yellowstone River The Yellowstone River is a tributary of the Missouri River, approximately long, in the Western United States. Considered the principal tributary of upper Missouri, via its own tributaries it drains an area with headwaters across the mountains an ...

, and contaminated the water supply 10 miles south of Glendive, Montana. The release was from Bridger Pipeline LLC's 12-inch Poplar line, which can carry 42,000 barrels a day of crude from the

Bakken Formation The Bakken Formation () is a rock unit from the Late Devonian to Early Mississippian age occupying about of the subsurface of the Williston Basin, underlying parts of Montana, North Dakota, Saskatchewan and Manitoba. The formation was initi ...

and runs from Canada south to Baker, Montana. Bridger Pipeline is a subsidiary of True Cos., a privately held Wyoming-based company. The company said in a statement that the pipeline was shut down within an hour of the leak.

Pegasus Pipeline

The

2013 Mayflower oil spill The 2013 Mayflower oil spill occurred on March 29, 2013, when the Pegasus Pipeline, owned by ExxonMobil and carrying Canadian Wabasca heavy crude from the Athabasca oil sands, ruptured in Mayflower, Arkansas, about northwest of Little Rock r ...

occurred when ExxonMobil's 20-inch Pegasus crude oil pipeline spilled near

Mayflower, Arkansas Mayflower is a city in Faulkner County, Arkansas, United States. The population was 2,234 at the 2010 census, up from 1,631 at the 2000 census. History Mayflower is a small town located along Interstate 40 southeast of Conway (Faulkner County) ...

on March 29, causing crude to flow through yards and gutters, and towards Lake Conway. Wildlife was coated in some places. Twenty-two homes were evacuated, due to the fumes and fire hazard. Some estimates say the total amount spilled could reach upwards of 300,000 gallons

diluted bitumen Dilbit (diluted bitumen) is a bitumen diluted with one or more lighter petroleum products, typically natural-gas condensates such as naphtha. Diluting bitumen makes it much easier to transport, for example in pipelines. Per the Alberta Oil Sands B ...

were spilled. Hook cracks and extremely low impact toughness in the LF-

ERW Welsh units of measurement are those in use in Wales between the Sub-Roman Britain, Sub-Roman period (prior to which the Britons (Celtic people), Britons used Roman units) and the 13th-century conquest of Wales by Edward I, Edwardian conquest (aft ...

seam were identified as causes of the failure.

Notes and references

{{reflist Pipe manufacture