Process and quality controls for production of linepipe slabs for sour service applications at ArcelorMittal Lazaro Cardenas, Mexico

There has been an increased interest in the requirements of API grade linepipe steels for the transportation of crude oil or sour gas. In addition, several recent pipeline projects have more stringent acceptance criteria than API. Successful production of sour service pipes depends to a large extent on the internal quality of the primary slabs in order to guarantee excellent cleanliness from non-metallic inclusions and least possible centerline segregation and porosity. Additionally, the steel slab also needs to contain the minimum possible dissolved hydrogen gas content for effective resistance to hydrogen flaking in the skelp and hydrogen induced cracking (HIC) in the final product. ArcelorMittal Lázaro Cárdenas (AMLC) in Mexico has implemented key steelmaking and casting technologies to cater for the challenges of sour service slab making. Key process controls and effective design of steelmaking and casting technologies have been introduced for the production of ultra clean, sound slabs with the least dissolved hydrogen content. Significant tonnages of sour service slabs have been made at AMLC and supplied to customers worldwide for making HIC resistant skelp and pipes. Excellent HIC resistance has been reported in all forms of final products thus qualifying AMLC’s capability to produce quality slabs for sour service applications. The current paper discusses some of the salient features of steelmaking and casting processes at AMLC along with some HIC test results from the final products. (AU) © CBMM