BrazeLet® F300P-9012

Iron-based brazing alloy

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 F300P-9012 is typically in use for printing thick paste layers of about 0.2 to 0.6 mm on flat parts or on top of structured parts by use of screens or stencils. A typical application is printing of paste on hole plates of tube bundled heat exchangers. The use of rubber squeegees is recommended. Reliable printing requires precise positioning fixture tool by use of vacuum table or clamping device. Typical printing speed is 100 mm/s. Thin printing lines should at least have a width twice the printing thickness and the small dots diameter should be three times the printing thickness or greater. Printing accuracy is very precise as the paste maintains its shape during drying. 

The solvent based BrazeLet F300P-9012 increases productivity wherever drying of the paste is an issue. It has no settlement, and no stirring is needed in the equipment. However, when opening a can from stock it is always recommended to stir the paste. The printed parts can be dried with standard drying process (hot air) at 120 – 170 °C. Here, the drying time needs to be established as it varies depending on thermal mass, parts design and the used furnace. After drying, the paste has excellent adhesion to the metal sheet.

     
 

Nominal composition: Fe – 20Ni – 20Cr – 7P – 6.5Cu – 4Si 
Powder type: Gas atomised
Melting range: 1025 – 1060 °C
Minimum brazing temperature: 1100 °C
Recommended gap clearance: 25 – 150 µm
Applicable specifications: ISO 3677 B-Fe42CrNiPCuSi-1025/1060

Solvent type: Oil
Metal content: 90 wt%
Particle size: <106 µm
Recommended drying temperature: 120 – 170 °C (250 – 340 °F)
Evaporation temperature of binder: 350 – 450 °C (660 – 840 °F)
Typical Brookfield viscosity: (2.5 rpm @ 20 °C): 300 Pas (T-spindle D)
Typical density: 4.0 g/cm3

 
     

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