Lucas-Milhaupt Premabraze 131 Gold Based Brazing Alloy

Applications:Premabraze 131 can be used on any of the common nickel- and iron base heat-resistant alloys, such as in jet engines, etc. Because of its low penetration of the base metal, it is well suited for brazing thin section, such as thin-wall tubing or electronic vacuum tubes. It has also been used extensively for nuclear power applications, except in high flux regions and in contact with such liquid metals as sodium and potassium. Characteristics:Premabraze 131 wets a wide range of high temperature iron and nickel based alloys such as the stainless steels, A286, Inconel and Inconel X very well. It does not alloy excessively with these materials nor produce the severe intergranular penetration normally associated with the nickel based brazing alloys contained boron. A minimum brazing temperature of 1800EF (980EC) is suggested for furnace brazing in hydrogen or dissociated ammonia having a -40EF dew point or drier on 300 and 400 series stainless steels which do not contain additions of Ti or Al. Stainless steels of the 17-7 PH variety require dew points of -70EF or drier for furnace brazing. Brazing is done in inert atmospheres or in vacuum. For torch brazing, protection with Handy Hi-Temp Flux is recommended. Where base metals containing elements which produce refractory oxides are encountered, Handy Hi-Temp Flux Boron Modified will promote better wetting. Joint clearances of 0.0015" - 0.003" are normally suggested.Gold and nickel are completely soluble in all proportions at temperatures above 1490EF (810EC) and this specific composition (82% Au- 18% Ni) represents the minimum in this system so that the solidus (melting point) and the liquidus (flow point) are identical. Normally, Premabraze 131 would not be used for joining copper based and silver based alloys. In addition to have a flow point very close to the melting point of silver, and above that of the silver-copper eutectic, it would alloy quite readily with copper based alloys.Specifications:Premabraze 131 conforms to: AWS A5.8 BVAu-4, Grade 1 Information provided by Lucas-Milhaupt, Inc.