Powdered High-Melting Materials Assist Brazing Filler Metals in Filling Large Joint Clearances in Protective Atmosphere Furnace Brazing
When brazing must be done on parts having clearances that exceed recommendations, Nicrogap™ alloys can be very helpful. Using the alloys, strong, ductile, nonporous joints can be brazed in parts having clearance gaps ranging from 0.25 – 2.5 mm (.010 – .100 “). They are effectively used with a wide variety of base metals and Brazing Filler Metals. Correctly employed, Nicrogap™ alloys will eliminate the problems of underfill, voids in the joint, excessive filler metal flow, and excessive erosion.
Several compositions are currently available, formulated for use with almost any copper, silver, gold, or nickel-based Brazing Filler Metal. The base metal can be any type of carbon steel, alloy steel, stainless steel or heat-resistant alloy. Nicrogap™ 108 alloy is available in powder form, -140 mesh (-106 µm) and Nicrogap™ 100 as -325 mesh (-45 µm), in the following nominal compositions by % weight:
|100||–||–||–||–||99.0 min||USA & UK|
In most brazing operations, joint clearances are accurately controlled. But, if the joint gaps are too large, the Brazing Filler Metal may flow profusely and leave voids. If joint clearances are too small, incomplete flow of the Brazing Filler Metal may occur. Nicrogap™ alloys are valuable when brazing structures and components in which wide or variable joint gaps cannot be economically avoided. Joints up to 2.5mm (.100”) clearance can be brazed with a suitable Brazing Filler Metal using Nicrogap™ 108 alloy on any stainless steel or heat resistant alloy.
Nicrogap™ 100 is a fine mesh -325 (-45 µm), pure nickel powder that can be added directly to the brazing filler metal up to about 15% by weight to make a filler metal more sluggish during brazing, to aid in the filling of variable joint clearances. Use on mild and low-alloy steel, any stainless or heat-resistant alloy, especially 300 and 400 series.
Nicrogap™ alloys can also be used to aid in filling large flaws in castings. Choose a grade matching the base metal composition and size of flaw to be repaired.