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  2. Brazing Alloy
  3. Technological Data

Brazing AlloyTechnological Data

Brazing Alloy are used to weld items without melting the material of the items, using lead ash.

Caution required when designing molds

  • 01Consider the flow of lead.
  • 02Make the outlet for Flux and Gas.
  • 03Give moderate heat
  • 04Maintain the appropriated interval in Brazing.
  • 05Do make higher strength for coefficient than the lowest strength of basic material.
  • 06Avoid the shear strength concentration as possible.

Welding intervals

Brazing uses the phenomenon to fill the brazing interval by the capillary and absorbance of molten lead, and this interval is one of the important factors since it influences on the joint strength in future.

Work method

Processing of Brazing
Brazing is composed of Brazing and lead clearance, preprocessing, Heating, Clearance after Brazing, and Post processing.
Pre-treatment of Brazing
It is required to maintain the heater JIG and fixing tool by determining the basic material, morphology, dimension and brazing method for application before brazing. It must be used the proper JIG and fixing tool of refractories, ceramics, graphite, and heat resisting steel by brazing temperature or brazing method.
Preprocessing is important Because the clearance of joint surface influences on the quality of molten lead and joint strength.
Surface state of the metal required before Brazing
Joint must be the clear one of metal surface to sufficiently show the wetting with weak flux.
Flux is for separating or melting oxidation film and preventing oxidation from heating, and it must not to be contaminated with dust and fingerprint as follows
  • 01dust or mote
  • 02oil, grease, fingerprint
  • 03each kind of chemicals such as carbonic chemicals.
Removal method
  • 01Chemical removing by such acid washing
  • 02Mechanical removing (Wire Brush, Sand Paper, Blast).

Considerations for selection

Brazing should be selected by considering the working condition, the operational environment and usages of basic material, and economics, in particular, the followings must be remembered.
Economy
For Silver Filler Metal, it is more economics the amount of silver is lesser, but the decrease of silver may cause the problems related to m.p. and flexibility, as well as Corrosion Resistance, electrical conductivity, and mechanical features. Therefore it must be considered the operating condition of Brazing Joint and workability. Moreover, it must be reliable that the silver content control which is the most important factor of quality and prime cost.
Melting point
The lower to better. If m.p is high its operating Temperature becomes also high, which results in transformation and flaming of basic material.
Temperature range for melting
It's better that the temperature difference between liquid phase and solid is lesser, and it must be decreased as the interval between basic materials becomes to be shallow. If the temperature difference is large, it is difficult to work for the elution of partial melting.
Liquidity and spreadability
It is required to review the tensile strength, shear strength, electric conductivity, corrosion resistance and Arc resistance, and it must be determined that the selection of solder, the property of basic material, and Joint design. It's not a simple process.
Mechanical characteristics
It is required to review the tensile strength, shear strength, electric conductivity, corrosion resistance and Arc resistance, and it must be determined that the selection of solder, the property of basic material, and Joint design. It's not a simple process.
Others
For vacuum and environmental brazing, a vapor pressure is to be a critical factor. It should be used as the alloy the Sn and In instead of easily volatile elements Cd and Zn, and also considered the processing and color.

Certificates

The following certificates are required in approving Construction Company.
  • - Business Registration Certificate
  • - Factory Registration Certificate
  • - Each kind of Certificate of JIS and ISO for Phosphate-Copper Filler Metal
  • - Analysis Result by Certified Organization