hit counter script Brazing

 Brazing

What is Brazing

Involves melting a metallic filler material to form a permanent joint between two pieces of metal that are to be joined. The metals being joined are not melted in the process

Preparation of materials

Clean the pieces to be joined and locate them positively against one another. In school we use a brazing hearth and the materials are placed on firebricks to help us heat the metals uniformly) Apply flux to the surfaces to prevent oxidation when the metals are heated. The flux lets the filler run smoothly between the two surfaces without forming a clump and hence a weak joint.)

Process

Use the brazing torch to heat the metals to the right temperature (usually between 800 and 2000 C) depending on the metals being joined and apply the brazing rod between the metals where it melts and flows. As the brazing material cools it forms a strong permanent joint between the materials. . (At its liquid temperature, the molten filler metal interacts with a thin layer of the base metal, cooling to form an exceptionally strong, sealed joint due to grain structure interaction. The brazed joint becomes a sandwich of different layers, each metallurgically linked to each other. (http://en.wikipedia.org/wiki/Brazing))

 

Advantage over other processes

brazed joint are smooth and complete, creating an airtight and watertight bond.It also conducts electricity like the base alloys. Brazing can be used to join dissimilar metals such as bronze, steel, aluminum, wrought iron, and copper, with different melting points.

 

Health & Safety

http://www.tech.purdue.edu

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brazing rods

a) Clear area of all flammables such as rags, paper, wood, paint cans, solvent, and trash containers. Do not work in areas where flammables are present.

b) Wear Leather apron and Gloves The work area must have a fireproof  floor, concrete floors are recommended

c) Use Fire bricks to support the work.

d) Maintain an adequate suction ventilation system to prevent the concentration of oxygen/fuel gas, flammable gases, and/or toxic fumes.

e) Well lit area.

f) Use heat-resistant shields to protect nearby walls or unprotected flooring from sparks and hot metal.

g) Oil and grease in the presence can ignite and burn violently.