Case studies

BlueScope Steel supplied 27,692 tonnes of steel for conversion into API 5L X70 strength pipe for use in the Eastern Gas project. The key attribute of the steel supplied was its excellent product consistency, benefiting both the pipe maker and the onsite construction team.

Location

The Eastern Gas Pipeline, which was designed and constructed by Duke Energy International to supply gas from Longford in Victoria to Sydney in New South Wales, was developed as an alternative to gas supplied to Sydney via Moomba in South Australia. This dual supply of gas into the Sydney region provides consumers with improved security and reliability of supply as well as the benefit of competing gas retailers. The pipeline is now owned and operated by Jemena

The pipeline itself extends 795 kilometres from Longford through East Gippsland via the Cann River in the north of Victoria, then north through Bombala and Cooma. From there it heads to the coast before passing through Nowra and Port Kembla on its way to Horsley Park in Western Sydney. The pipeline was completed at an estimated cost of $450 million.

Construction

The Eastern Gas Pipeline is 457mm (18") in diameter, manufactured to API 5L X70 specifications, with an operating pressure of 14.89MPa and a design gas delivery rate of 65 petajoules per annum. The 90,000 tonnes of pipeline steel required for this project was sourced from both domestic and international suppliers.

OneSteel Oil and Gas at Kembla Grange in New South Wales converted 27,692 tonnes of high grade steel supplied by BlueScope Steel to finished API 5L X70 pipe for this project.

BlueScope Steel commenced production of the pipeline steel in May 1999. The steel's low carbon, manganese, molybdenum, niobium, titanium chemistry was custom designed to meet the project's stringent mechanical and welding requirements, while maintaining the ductility required for the production of such high strength pipelines.

The excellent through-coil and coil-to-coil consistency of the BlueScope Steel's product used in this project was obtained by:

• closely controlling the chemical composition of the steel during the steelmaking process
• stringently controlling the finishing and coiling temperatures during final rolling in the hot strip mill.

This enabled the manufacture of pipes with consistent mechanical properties and aided weld quality and repeatability in the field.