BrazeLet^® F300R-9003

Höganäs’ unique and patented iron-chromium based stainless brazing alloy BrazeLet F300-20 offers excellent wetting properties and great corrosion resistance particularly developed for brazing of stainless steel materials in vacuum or protective atmospheres (dry hydrogen or argon). With excellent wetting properties, low brazing temperature and high corrosion and oxidation resistance it is a good choice for automotive and industrial heat exchangers. It is well suited for drinking water applications with strict requirements on metal ion leaching. Compared to nickel-based brazing alloys it offers a more attractive and stable cost. Compared to most of the standard nickel-based brazing alloys, BrazeLet F300-20 is able to fill larger gaps without brittle phase lines or cracks, which leads to a more reliable and safe brazing as well as more flexibility in part tolerances.

The brazing paste BrazeLet F300R-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 F300R-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 F300R-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.