The offshore deep and ultra deep water explorations summed to the distant points of the Brazilian coast bring to national industry important technological challenges. Considering production and transportation need of large volumes of natural gas and oil in a safe condition from offshore installations, the use of large diameter steel pipes produced by UOE-SAWL process is an important alternative and already applied in some important projects. However, due to the hostile environment in which the new fields are placed, it is necessary to develop new products in order to meet the rigorous mechanical properties and Sulfide Stress Cracking (SSC) and Hydrogen Induced Cracking (HIC) resistance requirements. This work presents the evaluation of mechanical properties and SSC resistance of OD 20 inches, WT 25,4 mm APL 5L X70MS line pipe, for both pipe material and girth weld joints.
For this work, plates were produced with very restrict metallurgical control, including chemical control and state of art rolling as Thermo-Mechanical Controlled Process with Accelerated Cooling — TMCP-ACC. Very good CHARPY and CTOD values were achieved at −20°C and −40°C respectively, in both conditions, and the pipes presented good (SSC and HIC) resistance even for the girth weld joint performed with a low and high heat inputs simulating the range of conditions that an operator would find in offshore welding operations.