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ATI Allegheny Ludlum Supplies Proprietary Alloy for Oilfield Project

10/23/2006 -  

Oct. 23, 2006 — A proprietary ATI Allegheny Ludlum alloy was used in a subsea flow line system for the Kikeh Field Development Project, offshore Sabah, East Malaysia.

AL 2003 lean duplex alloy is an economic alternative to higher nickel-bearing 300 Series stainless steels and the conventional 2205 duplex alloy. It provides cost savings and can also provide enhanced performance over conventional 300 series, 2205 duplex, or super martensitic grades.

Allegheny Ludlum supplied over 1.2 million pounds (550,000 kg) of its new proprietary AL 2003™ lean duplex alloy to Wellstream International, Ltd. for the project. Wellstream International, located in Newcastle, U.K., manufactured flexible pipe for this project.

The Kikeh Field Development Project consists of approximately 13.7 miles (22 km) of various flow-line systems (production, water injection, and gas export) operating in water depths of over three quarters of a mile (1200 meters). About 9.6 miles (15.5 km) of flow line systems were made with the AL 2003 lean duplex alloy.

AL 2003 lean duplex alloy was chosen over Type 316L stainless steel due to cost savings resulting from the lower alloy content and greater strength of AL 2003 lean duplex alloy. Major alloying elements of AL 2003 alloy include chromium (21%), nickel (3%), and molybdenum (1.5%), which compares to 16% chromium, 10% nickel, and 2.5% molybdenum for 316L. An advantage for using AL 2003 alloy in applications under high pressure in deep water is the yield strength of AL 2003 alloy, which is more than double that of 316L. A 316L design would have used a thicker strip with more weight per length of pipe and less throughput of oil well recoverables. In addition, AL 2003 alloy is designed to maintain superior corrosion resistance to chloride pitting and stress corrosion cracking compared to 316L.

AL 2003 lean duplex stainless alloy in strip and plate product forms is NORSOK-qualified under Standard M-650. The NORSOK standards are developed by the Norwegian petroleum industry and are intended to identify metals used in oil and gas applications that are safe and cost effective.

ATI Allegheny Ludlum, an Allegheny Technologies company, is a world leader in the production and marketing of sheet, plate, and strip specialty materials including stainless steel, nickel-based alloys, titanium, and titanium-based alloys. The company also produces grain-oriented silicon electrical steel products, and tool steel plate.