BrazeLet® Ni7DW-9007

Nickel-based brazing alloy

The nickel-based brazing alloy BrazeLet BNi7 is a free-flowing material suitable for brazing stainless steels. It is suitable for brazing in vacuum or protective atmospheres (dry hydrogen or argon). It allows brazing at lower temperatures than most of the other nickel-based brazing alloys. It is particularly suitable for brazing deep narrow joints as it maintains the excellent flowability with limited P diffusion into most base materials. It is recommended that gaps do not exceed 30 µm as wider gaps risk the formation of a crack-sensitive brittle centre line. Typical applications for this brazing alloy include thin-walled components such as honeycomb seals, industrial heat exchangers and tubular heating elements for drinking water applications.

The water-based brazing paste BrazeLet Ni7DW-9007 can be used for dispensing applications, typically found on heat exchanger inlet and outlet tubes, housing to core joints and hole plates to tube joints. It dries quickly and sticks to all bevel and vertical positions without the need of pre-drying. It can be easily removed with water. The paste has a very low polymer content and the binder is specially designed to decompose cleanly at low temperatures, as to minimise need for furnace maintenance, while preventing pre-oxidation of brazing filler metal powder in marginal furnace atmospheres. It shows extremely good residue-free brazing results in both vacuum and continuous belt furnace brazing.

BrazeLet Ni7DW-9007 properties allow reliable application in a wide speed range as a result of the dispensing equipment / automatisation as well as the needle diameter. The paste can be delivered in cartridges for use in automated applications or different sized cans. It can be frozen and brought back to room temperature for use without any damage to its properties.

     
 

Nominal composition: Ni – 14Cr – 10.1P
Powder type: Gas atomised
Melting range: 890 °C
Minimum brazing temperature: 980 °C
Recommended gap clearance: 0 – 30 µm
Applicable specifications: ISO 17672 Ni710, AWS A5.8M/A5.8 BNi-7, ISO 3677 B-Ni76CrP-890

Solvent type: Water
Metal content: 90 wt%
Particle size: <106 µm
Recommended drying temperature: RT – 170 °C (RT – 340 °F)
Evaporation temperature of binder: 250 – 300 °C (480 – 570 °F)
Typical Brookfield viscosity (2.5 rpm @ 20 °C): 1000 Pas (T-spindle E)
Typical density: 4.5 g/cm3

 
     

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