ASTM B690 / ASME SB690 NICKEL ALLOY PIPE( UNS N08366 AND UNS N08367/AL6XN) SEAMLESS PIPE

ASME SB690 covers iron-nickel-chromium-molybdenum alloys (UNS N08366 and UNS N08367)
cold-finished annealed or hot-finished annealed seamless pipe and tube intended for use in special corrosive service and for heat-resisting applications.

Overview

AL6XN is a superaustenitic stainless steel with outstanding resistance to chloride pitting, crevice corrosion and stress corrosion cracking. AL6XN is a 6 moly alloy that was developed for and is used in highly aggressive environments. It has high nickel (24%), molybdenum (6.3%), nitrogen and chromium contents that give it excellent resistance to chloride stress corrosion cracking, chloride pitting, and exceptional general corrosion resistance. AL6XN is primarily used for its improved pitting and crevice corrosion resistance in chlorides. It is a formable and weldable stainless steel.Because of its nitrogen content, AL6XN has greater tensile strength than common austentitic stainlesses, while retaining high ductility and impact strength.

Alloy AL6XN is a low carbon, high purity, nitrogen-bearing"super-austenitic"nickel-molybdenum alloy with excellent resistance to chloride pitting and crevice corrosion. Alloy AL6XN's high strength and corrosion resistance makes it a better choice than the conventional duplex stainless steels and a cost effective alternative to more expensive nickel-base alloys where excellent formability, weldability, strength and corrosion resistance are essential.

The high nickel and molybdenum contents provide improved resistance to chloride stress-corrosion cracking. Copper (Cu) has been intentionally kept to a residual level for improved performance in seawater40. The high alloy composition of the AL-6XN alloy resists crevice corrosion and pitting in oxidizing chloride solutions to a degree previously achieved only by nickel-base alloys and titanium.

Specification

ASTM B690-18 Standard Specification for Iron-Nickel-Chromium-Molybdenum Alloy (UNS N08367) Seamless Pipe and Tube.