BrazeLet^® Ni613R-9003

The nickel-based brazing alloy BrazeLet Ni613, features a best in class wetting behaviour on stainless steel material in vacuum or protective atmosphere (dry hydrogen or argon). Its high level of alloyed chromium results in a superior hot gas and acid corrosion resistance. The brazing alloy is best suited for brazing heat exchangers such as exhaust gas recirculation (EGR) coolers in automotive or drinking water applications. Compared to most of the standard nickel-based brazing alloys, BrazeLet Ni613 is able to fill larger gaps without brittle phase lines or cracks. The resulting micro hardness in the brazed joint microstructure is less than half when compared to BrazeLet BNi5. This leads to a more reliable and safe brazing as well as more flexibility in part tolerances.

The brazing paste BrazeLet Ni613R-9003 can be used for roller coating fins or structured plates, typically found in flat heat exchanger designs. Depending on type of roller used the paste can be applied with thin layers either on top or on the side of the fin tips. Gap size between the paste roll and the scraper of 0.08 – 0.12 mm is recommended. The amount of paste is controlled by weight and is a function of the fins or structured plate design. BrazeLet Ni613R-9003 properties allow reliable application in a wide range of coating speeds, tested with good results from 3 m/min up to 20 m/min. The oil-based paste ensures reliable coating over time without drying on the roll. BrazeLet Ni613R-9003 has higher metal content and lower binder content compared to standard roller coating pastes, which decreases packaging and transportation needs for the same amount of brazing filler metal.

The coated fins can be dried with standard drying process (hot air) at 120 – 170 °C. The drying time depends on thermal mass, parts design and the used furnace and thus needs to be established. When dried, the paste has excellent adhesion to the metal sheet.