Presentation on theme: "Development, Specifications, and Application Experience with 80 ksi (552 MPa) Linepipe by J. Malcolm Gray Paper presented at the ABM Annual Congress Vitoria,"— Presentation transcript:
Development, Specifications, and Application Experience with 80 ksi (552 MPa) Linepipe by J. Malcolm Gray Paper presented at the ABM Annual Congress Vitoria, Brasil 23 July 2007
Overview Introduction Application Metallurgical Approaches Chemical Compositions Specifications Weldability Fracture Control
Figure 1. Development periods for high strength linepipe
Figure 2. Increase in North American natural gas pipeline operating pressures 1)
Macro Trends Higher Pressures Thicker Wall Higher Toughness Lower Carbon Higher Alloy Contents Need for updated specifications. Cost pressures due to steel prices. Globalization of manufacture.
TypeCMnNbVTiMoCrOther Nb – V 0.05/0.121.50/1.650.050.080.01-- Nb – Ti 0.061.50/1.700.06-0.02-- Nb - Mo 0.041.700.09-0.020.30-Cu + Ni Nb – Cr 0.03/0.061.650.09-0.01-0.30Cu + Ni Table III
Figure 4. Comparison of HAZ hardnesses for mechanized welds in Nb-Mo, Nb-Cr & Nb-V Steel.
Steel Type CMnSiNbVTiCrMoCuNiNPcm Nb-V0.1041.710.330.0410.0920.0070.04-0.050.040.0040.22 Nb-Cr0.041.580.130.098-0.0110.24-0.200.100.0040.15 Nb-Mo0.031.680.270.095-0.0190.030.30 0.120.010 Table IV Chemical Compositions of X-80 Pipe Use For Recent Projects
(a)No prior use of X-70/80 acicular ferrite steels. (b)Lack of knowledge or confidence. (c)Isolation. (d)Committee squabbling. (e)Copy and paste mentality at Engineering companies. (f)No platform for change. (g)Bureaucratic inertia. (h)Long term bad habits.
Table V Summary of EWI Microalloying Recommend Chemical Composition Limits