The exploration and transportation of fluids from corrosive fields or reserves demand corrosion-resistant pipelines. The pipelines for sour-service application demand higher resistance to H2S corrosion because of higher sulphur content observed in the geographical locations. The pipelines laid in the corrosive and marshy lands demand high wall thickness to allow for wall thinning due to corrosion. The linepipes manufactured using TMCP plates are widely accepted for sour-service applications. The use of cut-to-length sheets from hot rolled coils for the manufacturing of LSAW pipes is economical but having limited acceptance by the pipeline operators.
Welspun took an initiative to develop the linepipes for an onshore sour-service application using API 5L X60MS grade cut-to-length sheets from TMCP hot rolled coils procured from an approved steel mill. The LSAW pipes of 24” OD × 14.27 mm WT were manufactured by the JCO-E press at Welspun Pipes Mill in Anjar-Gujarat-India. The experience of 24”OD × 14.30 mm WT, API 5L X60MO grade pipes manufacturing using TMCP plates procured from another approved steel mill, was used to decide factors such as alloy design, cleanliness, strength, DWTT, hardness, HIC, SSCC, CVN for the selection of cut-to-length sheets. This paper deals with sheet-to-pipe behavioural changes in properties before and after cold mechanical expansion. Wherever possible, the comparison was also made with plate-pipe behavioural changes in properties.