686

Tailored with precision, these consumables are designed to replicate the composition and characteristics of alloy 686. The heightened levels of Nickel (Ni) and Molybdenum (Mo) offer robust resistance in reducing conditions, complemented by the substantial Chromium (Cr) content providing resilience against oxidizing media. Notably, the inclusion of Molybdenum (Mo) and Tungsten (W) enhances resistance to localized corrosion, specifically addressing issues such as pitting. The low Carbon (C) content plays a pivotal role in minimizing grain boundary precipitation, ensuring the preservation of corrosion resistance within the heat-affected zones of welded joints. Remarkably versatile, this alloy also furnishes a durable Nb-free weld metal, suitable for dissimilar welds involving superaustenitic and superduplex stainless steel, or combinations thereof with Nickel-based alloys. Furthermore, it exhibits exceptional as-welded resistance to sulfuric or hydrochloric acids, their mixtures, and displays resilience against crevice or pitting corrosion in hot concentrated acid chloride solutions. Predominantly applied in chemical and petrochemical processing, pollution control, oil and gas extraction, oil refining, and marine environments, these consumables are invaluable. Their utility extends to dissimilar metal welding applications, providing protection against preferential weld-metal attack, particularly when joining Molybdenum-containing alloys or alloy-clad steels.

The nominal composition (wt. %) of the filler metal of this classification is 57 Ni, 21 Cr, 16 Mo, and 4 W.

Single-phase austenitic Ni-Cr-Mo-W alloy.

Used for welding nickel-chromium-molybdenum alloy to itself, to steel, to other nickel-base alloys, and for cladding steel using the GTAW, GMAW, and SAW processes. It is also suitable to weld overmatching 625, C276, C4, C22, 59 alloys and superduplex and superaustenitic steels.
EN W.Nr.: 2.4606 (NiCr21Mo16W).
UNS: N06686, N06022, N06059, N06200, N08367, NO8926, NO8031.
PROPRIETARY: Inconel® Alloy 686 (Special Metals), Incoloy® Alloy 25-6MO, 27-7MO (Special Metals).

Prior to welding or subjecting any nickel-base alloy to heat, it is imperative that the base metal undergo thorough cleaning. Common substances such as oil, grease, paint, lubricants, marking pencils, temperature-indicating materials, and threading compounds frequently contain sulfur or lead, posing a potential risk of inducing cracking (embrittlement) in both the base metal and the weld metal if present during welding or heating. When conducting welding activities involving fully austenitic and nickel base steels, meticulous attention must be paid to minimize factors such as heat input, interpass temperature, and dilution with the parent metal. Striving for a low heat input is essential, with a strict maximum of 1.5 kJ/mm, coupled with a stringent interpass temperature limit of 100°C. It is noteworthy that, in this context, no post-weld heat treatment is deemed necessary to restore corrosion resistance. These precision-oriented measures are critical in ensuring the integrity and performance of welds in fully austenitic and nickel base steels, particularly with regard to corrosion resistance.