Iron-chromium base brazing filler metals

A method for joining two or more metal parts to form a brazed joint in a brazed assembly, comprising the steps of:

• (a) juxtaposing said parts to define one or more joints therebetween;
• (b) supplying to the one or more joints an iron/chromium brazing filler metal;
• (c) heating said juxtaposed parts and said brazing filler metal to melt said brazing filler metal;
• (d) cooling said juxtaposed parts and said melted brazing filler metal to produce a brazed joint having brazed parts;
• and
• (e) conditioning the brazed parts by exposing said brazed joint to an elevated temperature, in an oxygen-containing atmosphere, for a sufficient time to substantially reduce the amount of nickel leaching into water or other fluids contacting the brazed joint in said brazed assembly.

A heat exchanger comprising at least two parts forming one of a plurality of brazed joints in a brazed assembly, said heat exchanger being produced by a process comprising the steps of:

• (a) juxtaposing said at least two parts to define one or more joints therebetween;
• (b) supplying to said one or more joints an iron/chromium brazing filler metal;
• (c) heating said juxtaposed parts and said brazing filler metal to melt the brazing filler metal;
• (d) cooling said juxtaposed parts and said melted brazing filler metal to produce a brazed joint having brazed parts;
• and
• (e) conditioning the brazed parts by exposing said brazed joint to an elevated temperature, in an oxygen-containing atmosphere, for a sufficient time to substantially reduce the amount of nickel leaching into water or other fluids contacting the brazed joints of the brazed assembly.

A method for the manufacture of heat exchangers and apparatuses having brazed parts, comprising the steps of:

• (a) juxtaposing at least two parts to define one or more joints therebetween;
• (b) supplying to said one or more joints an iron/chromium brazing filler metal consisting essentially of a composition having the formula FeaCrbCocNidMoeWfBgSih wherein the subscripts “a”, “b”, “c”, “d”, “e”, “f”, “g”, and “h” are in atom percent and wherein, “b” ranges from about 5 to 10, “c” ranges from 0 to about 10, “d” ranges from 0 to about 10, “e” ranges from 0 to about 3, “f” ranges from 0 to about 3, “g” ranges from about 8 to 15, “h” ranges from about 8 to 15, and the sum “a”+“b”+“c”+“d”+“e”+“f”+“g”+“h”=100, the balance being incidental impurities present in an amount up to about 1 percent by weight of the total composition;
• (c) heating said juxtaposed parts and said brazing filler metal under appropriate conditions in order to melt said brazing filler metal;
• and
• (d) cooling said juxtaposed parts and said brazing filler metal to produce a solid brazed joint of a brazed assembly.