Tata Steel Limited

Prashant Pathak

Saurabh Kundu

Appa Rao Chintha

Subrata Mukherjee

Hrishikesh Shastri

Badirujjaman Syed

Amar Nath Bhagat

Basudev Bhattacharya

Gyanaranjan Mishra

Tapas Chanda

Monideepa Mukherjee

G Senthil Kumar

Vinay V Mahashabde

Sushil Kumar Giri

Appa Rao Chintha Chintha

Subhankar Das Bakshi

Soumendu Monia

The present disclosure relates to designing of steel composition for line pipe steel to be used for sour environment. The developed steel of the present disclosure exhibits enhanced tensile properties in accordance with API 5L PSL-2 specification for X-65 grade steel, along with superior hydrogen induced cracking resistance with crack length ratio (CLR) of less than 10%, crack thickness ratio (CTR) of less than 5%, crack sensitivity ratio (CSR) of less than 2%. The developed steel is designed such that it is readily hot/cold formed and welded to form linepipe tubes to be used for the transportation of natural gas or crude oil, especially of sour grade. The present disclosure also provide a method of manufacturing the said steel having the composition of the present disclosure.

Steel composition in accordance with API 5L PSL-2 specification for X-65 grade having enhanced hydrogen induced cracking (HIC) resistance, and method of manufacturing the steel thereof

A process for making a hot rolled high strength steel (HRHSS) product including the steps of casting a steel slab having, in weight percent, C: 0.18-0.22, Mn: 1.0-2.0, Si: 0.8-1.2, Cr: 0.8-1.2, S: 0.008 max, P: 0.025 max, Al: 0.01-0.15, N: 0.005 max, Nb: 0.02-0.035, Mo: 0.08-0.12, the remainder iron (Fe) and incidental impurities, hot rolling the steel slab into strip at a finish rolling temperature (FRT) of 850-900&#xb0; C., cooling the hot rolled strip at 40&#xb0; C./s or more over a run out table (ROT) until the strip reaches 380-400&#xb0; C., coiling the hot rolled strip, and then air cooling to room temperature.

Hot rolled high strength steel (HRHSS) product with tensile strength of 1000-1200 MPa and total elongation of 16%-17%

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Jamshedpur, India

Prashant Pathak