Metallurgy

OSG has extensive metallurgical experience using carbon steel, high strength low alloy steels, austenitic, martensitic (13Cr), duplex and super duplex stainless steels, titanium alloys, metallurgically clad and mechanically lined CRA pipe and other corrosion resistant alloys. In particular, OSG has experience regarding alloying elements, heat treatment and microstructures of these alloys. OSG can provide guidance and advice on some of the more important subject matters listed below for the more common alloys used in the offshore oil and gas industry


  • Carbon and HSLA Steel
  • Austenitic Stainless Steels
  • Martensitic Stainless Steels
  • Low, medium and high carbon steels
  • Q & T, TMCP and accelerated cooled low alloy steels including niobium, vanadium-niobium, niobium-molybdenum, vanadium-nitrogen, titanium, titanium-niobium, acicular ferrite (low carbon bainite) microalloyed steels
  • Weldability (effects of heat input on toughness)
  • Manufacturing processes, heat treatment
  • Effects of alloying elements on mechanical properties including weldability and fracture toughness
  • Heat treatment (e.g. normalizing, accelerated cooled, thermo mechanically controlled rolling)
304, 316, 316L 904 and 904L
  • Metallurgical advice on the base, weld  and heat affect zone material
  • Mechanical properties of the various grades
  • Corrosion properties in production and seawater environments
  • Sensitization issues (Cr carbide formation along the grain boundaries in the HAZ)
  • Hot shortness problems if ferrite content is less than 5%
  • Heat input control on welding to avoid cracking due to delta ferrite formation during cooling
  • Inspection requirements (attenuation problems causing defect sizing problems with UT)
  • Liquid metal embrittlement
13 Cr
  • Metallurgical advice of the base, weld and heat affect zone material
  • Mechanical properties of the various  grades
  • Corrosion properties in production and seawater environments
  • Cracking performance and its susceptibility to intergranular stress cracking and  hydrogen embrittlement
  • Welding techniques including properties of alternative welding consumables and the role of PWHT
  • Weld qualification testing issues
  • Theory and practice of cathodic protection at moderate potentials

 

.....continued....

  Next-->