Metallurgy continued

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Metallurgy (cont)

Duplex & Super Duplex

Stainless Steels (22 Cr, 25 Cr)

Development of various grades
Metallurgical background including the detection and significance of intermetallic phases
Development of optimum welding procedures
Mechanical properties of established and newly emerging duplex grades
Corrosion properties in producing environments and seawater
Overview of welding concerns
Hydrogen embrittlement and advice on cathodic protection requirements
Coating requirements

Clad and Lined CRA Line Pipe

Cladding/lining alloy and backing steel selection criteria
Welding experience including knowledge on local hard zones
Cost effective cladding methods (e.g. conventional vs. J pipe)
Inspection requirements for dissimilar metal welds
Production methods and manufacturers (e.g. metallurgical bonded vs. lined pipe and improving end dimensional tolerances)
Gripping strength requirements of lined pipe
Expansion coefficient variations between the liner and carbon steel
Compression test requirements to determine lined pipes resistance to buckling

6% Molybdenum (super austenitic stainless steels)

Inconel 625 and Incoloy 825

Strength and toughness properties in the temperature range cryogenic to 2000oF, due to solid solution effects
Fatigue strength
Chloride stress corrosion cracking resistance
Scaling and oxidation resistance levels at high temperatures
Heat treatment (e.g. high and low solution anneal and stress relief)
Weldability (PWHT requirements)

High Nickel Alloy Steels for Low Temperature Service

Nickel effects on reducing the impact transition temperature
5%, 9% and 36% nickel grades (ASTM A333 Gr 8, ASTM A553, ASTM A671 Cl 13, UNS, K93602, ASTM A333 Gr 11)
Mechanical property requirements
Weldability (preferred welding methods GTAW, GMAW)
Inspection
Corrosion resistance limitations
Suitable grades for LNG service
Manufacturers