Brazing of the hottest carbon steel and low alloy

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Brazing of carbon steel and low alloy steel (lower)

(2) brazing flux or shielding gas is required when brazing carbon steel and low alloy steel with flux. The brazing flux is often determined by the selected filler metal and brazing method. When tin lead solder is used, zinc chloride and ammonium chloride can be selected. In fact, when we choose universal experimental machine products, the radionuclide limit of building materials GB 6566 ⑵ 001 is the most important thing, but its relevant configuration (i.e. the internal configuration of the experimental machine) is the mixed liquid as brazing flux or other special brazing. The residue of this flux is very corrosive, and the joint should be strictly cleaned after brazing

when brazing with copper zinc filler metal, fb301 or fb302 flux (see JB/t604592 flux for brazing, the same below) should be selected, that is, borax or the mixture of borax and boric acid: in flame brazing, the mixture of methyl borate and formic acid can also be used as flux, in which B2O3 steam plays the role of film removal

when silver copper zinc solder is used, fbl02, fbl03 and 1fbl04 flux can be selected, that is, the mixture of borax, boric acid and some fluorides. The residue of this flux is corrosive to a certain extent and should be removed after brazing

3 brazing technology

use mechanical or chemical methods to clean the surface to be welded to ensure that the oxide film and organic matter are completely removed. The cleaned surface should not be too rough and should not adhere to metal chips or other dirt

carbon steel and low alloy steel can be brazed by various common brazing methods. During flame brazing, neutral or slightly reducing flame should be used. During operation, direct heating of solder and flux by flame should be avoided as far as possible. Rapid heating methods such as induction brazing and dip brazing are very suitable for brazing quenched and tempered steel. At the same time, quenching or brazing at a temperature lower than tempering should be selected to prevent softening of the base metal. When brazing low-alloy high-strength steel in protective atmosphere, not only high purity of gas is required, but also gas flux must be used to ensure the wetting of solder on the surface of base metal. It also needs to be completely and effectively checked and wet but spread

the residue of flux can be removed by chemical or mechanical methods. The residue of organic brazing flux can be wiped or cleaned with gasoline, alcohol, acetone and other organic solvents: the residue of strong corrosive brazing flux such as zinc chloride and ammonium chloride should be neutralized in NaOH aqueous solution first, and then cleaned with hot and cold water; The residue of boric acid and borate flux is not easy to remove, and can only be solved by mechanical method or soaking in boiling water for a long time

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