657M

The filler metal belonging to this classification is specifically designed for cladding ferrous materials intended for high-temperature applications and for homogeneous welding of nickel-chromium-iron alloys with steel, using GTAW and GMAW processes. The resulting welds offer excellent resistance to high-temperature oxidation, as well as carburization and sulfidation. This product is particularly suitable for use in heat exchangers, piping, vessels, and evaporators in sectors such as offshore, marine, chemical, petrochemical, and power engineering. The DAIKO 657M wire is applied in a wide range of components for oil furnaces and boilers, such as tube sheets, pipe supports, and spacers used in ships, power plants, refineries, and petrochemical plants.

The nominal composition (wt. %) of filler metal of this classification is 60 Ni, 37.5 Cr, 0.95 Al, and 0.6 Nb plus Ta.

Austenitic.

For cladding of ferrous materials used in high temperature applications, and the welding of nickel-chromium-iron alloy to itself, and to steels.

• ASTM: B163, B166, B167, B168
• UNS: N06690, N08810
• PROPRIETARY: Incoloy® 671 (Special Metals), Incoloy® 800H (Special Metals)

Before proceeding with the welding or heating of any nickel-based alloy, it is essential to thoroughly clean the base metal. Components such as oil, grease, paint, lubricants, marking pencil graphite, temperature indicators, and threading compounds often contain sulfur or lead, which, if present during welding or heating processes, can cause cracking or embrittlement of the base or filler metal. Nickel alloys do not require preheating, except to bring the metal in the welding zone to room temperature or typical shop temperature to prevent moisture condensation. It is essential to maintain low heat input, maximum 1.5 kJ/mm, along with an interpass temperature not exceeding 150 °C. In most cases, solid solution nickel alloys do not require post-weld heat treatment for corrosion-resistant service. However, precipitation-hardened alloys do require heat treatment after welding to develop their maximum strength.