INCONEL® alloy 686 (UNS N06686/W.Nr. 2.4606) is a single-phase, austenitic Ni-Cr-Mo-W alloy offering outstanding corrosion-resistance in a range of severe environments. Its high nickel (Ni) and molybdenum (Mo) provide good resistance in reducing conditions, and high chromium (Cr) offers resistance to oxidizing media. Molybdenum (Mo) and tungsten (W) aid resistance to localized corrosion such as pitting. Iron (Fe) is closely controlled to enhance properties. Low carbon (C) helps minimize grain boundary precipitation to maintain corrosion-resistance in the heat-affected zones of welded joints. Resistance to general, pitting and crevice corrosion increases with the alloying (Cr+Mo+W) content, and INCONEL alloy 686 scores higher than competitive materials. INCONEL alloy 686 is protected by U.S. patent 5,019,184. Table 1 - Limiting Chemical Composition, % Chromium....................................................................19.0-23.0 Molybdenum ...............................................................15.0-17.0 Tungsten..........................................................................3.0-4.4 Titanium.......................................................................0.02-0.25 Iron................................................................................2.0 max. Carbon........................................................................0.01 max. Manganese .................................................................0.75 max. Sulfur ..........................................................................0.02 max. Silicon .........................................................................0.08 max. Phosphorus ................................................................0.04 max. Nickel............................................................................Balance* Its matched composition welding products, designated as INCO-WELD® filler metals and welding electrode 686 CPT® also offer exceptional as-welded resistance to sulfuric or hydrochloric acids, to mixtures of the two, and to crevice or pitting corrosion in hot concentrated acid chloride solutions. These welding products are also used for dissimilar and overmatched welding applications (see pages 10 and 11). INCONEL alloy 686 is used for resistance to aggressive media in chemical processing, pollution control, pulp and paper manufacture, and waste management applications. Alloy Fe Ni Cr Mo W Cr+Mo+W UNS N06625 3 62 22 8.8 - 30.8 UNS N10276 6 57 15.5 16 3.9 35.4 UNS N06022 2 59.4 20.5 14.2 3.2 37.9 INCONEL alloy 686 1 57 20.5 16.3 3.9 40.7 Table 2 - Physical Properties Density, lb/in3 .....................................................................0.315 g/cm3 ......................................................................8.73 Melting Range, °F .....................................................2440-2516 °C .....................................................1338-1380 Electrical Resistivity, ohm•circ mil/ft .................................744.4 µΩ•m...............................................1.237 Permeability at 200 oersted (15.9 kA/m).........................1.0001 Table 3 - Thermal and Electrical Properties Temperature Electrical Resistivity Coefficient of Expansion Spec a ific Heat °F 10 ohm•circ mil/ft -6 Btu/lb•°F in/in•°F °C J/kg•°C µm/m•°C µΩ•cm a Mean coefficient of linear expansion between room temperature and temperature shown. Publication Number SMC-024 Copyright © Special Metals Corporation, 2005 (Feb 05) INCONEL, INCOLOY, INCO-WELD, INCOFLUX and 686CPT are trademarks of the Special Metals Corporation group of companies. -15 364 - - 20 373 - 123.7 100 389 11.97 124.6 200 410 12.22 125.7 300 431 12.56 126.3 400 456 12.87 127.2 500 477 13.01 128.9 600 498 13.18 129.5 700 519 - 127.9 *Reference to the ‘balance’ of an alloy’s composition does not guarantee this is exclusively of the element mentioned, but that it predominates and others are present only in minimal quantities.