Manufacturing
The production of casing pipes are from steel smelted in electric furnaces, treated with synthetic slag and cast by continuous casters. This steel-making process guarantees the attainment of chemically pure steel, given the phosphor and sulfur contents. This provides highly ductile, malleable and corrosion-resistant pipes, which can operate at low temperatures in a number of corrosive media. Steel grades and heat-treatment regime application allows production of high-strength pipe.
Specifications
Steel casing pipes should have minimum yield strength of 35,000 psi. Casing pipes need to have smooth walls and be exceptionally straight and round. Casing pipe and joint construction should be of uniformly thick steel to avoid any matter leaking from the casing. The outside diameter, size and wall thickness should conform to ASTM Designation A252. Use pull-on or wrap-around rubber varieties of “casing end seals” to seal the ends of the steel casing pipe. Apply corrosion-proofing water-based paint to the exterior pipe surface to safeguard against atmospheric corrosion during shipping and storage.
Quality Control
In accordance with the requirements of ANSI/AWS D1.1, all welding should be performed by qualified welding operators. Complete one reduced section tension test specimen for each lot of 1,000 feet of each size and wall thickness. Verify that the tensile strength is not less than 95 percent of the minimum strength specified for the grade of steel used, except when waived by the customer. No hydrostatic testing is required. Examine all connections to make sure they are free of injurious defects at the time of shipment. Otherwise, prior to shipping, reject and repair that section.
Production Standard, Grade, Steel No:
API 5L PSL1 L175/A25, L210/A, L245/B, L290/X42, L320/X46, L360/X52, L485/X70
PSL2 L245R/BR, L290N/X42N, L320N/X46N, L360N/X52N, L415/X60N
API 5CT PSL1, PSL2, PSL3, H40, J55, K55, N80
GB/T 9711.1 L175, L210, L245, L290, L320, L360
GB/T 9711.2 L245NB, L290NB, L360NB
GB/T 9711.3 L245NC, L290NC, L360NC
