A Copper Alliance Member
Glossary of Technical Terms
Adhesion. (1) A sticking (to something) or being stuck together. (2) The force that holds together the molecules of unlike substances.
Alloy. A homogeneous mixture or solid solution of two or more metals, the atoms of one replacing or occupying interstitial positions between the atoms of the other: Brass is an alloy of zinc and copper.Back to Top
Bag alloy. High silver content brazing filler metal containing copper and other elements
Balling up. The formation of globules of molten brazing filler metal or flux due to lack of wetting of the base metal.
Base material. The material that is welded, brazed, soldered, or cut.
Base metal. The metal or alloy that is welded, brazed, soldered, or cut.
Braze. A weld produced by heating an assembly to the brazing temperature using a filler metal having a liquidus above 840°F (450°C) and below the solidus of the base metals. The filler metal is distributed between the faying surfaces of the joint by capillary action.
BCuP alloy. Copper-Phosphorous brazing filler metal.
Braze interface. The interface between filler metal and base material in a brazed joint.
Braze welding. A welding process variation in which a filler metal, having a liquidus above 840°F (450°C) and below the solidus of the base metals, is used. Unlike brazing, in braze welding the filler metal is not distributed in the joint by capillary action.
Brazeability. The capacity of a material to be brazed under the fabrication conditions imposed into a specific, suitably designed structure, and to perform satisfactorily in the intended service.
Brazement. An assembly having at least one brazed joint.
Brazer. One who performs manual brazing.
Brazing. A group of welding processes that produces coalescence of materials by heating them to the brazing temperature in the presence of a filler metal having a liquidus above (840°F) 450°C and below the solidus of the base metal. The filler metal is distributed between the closely fitted faying surfaces of the joint by capillary action.
Brazing alloy. A nonstandard term for brazing filler metal.
Brazing filler metal. The metal that fills the capillary joint clearance (capillary space) and has a liquidus above 840°F (450°C) and below the solidus of the base materials.
Brazing procedure. The detailed methods and practices involved in the production of a brazement.
Brazing procedure qualification record (BPQR). A record of brazing variables used to produce an acceptable test brazement and the results of tests conducted on the brazement to qualify a brazing procedure specification.
Brazing rod. A nonstandard term for brazing filler metal rod.
Brazing technique. The details of a brazing operation that, within the limitations of the prescribed brazing procedure, are controlled by the brazer.
Brazing temperature. The temperature to which the base material is heated to enable the filler metal to wet the base material and form a brazed joint.
Brazing temperature range. The temperature range within which brazing can be performed.
Butt joint. A joint between two members aligned approximately in the same plane.Back to Top
Capillary action. The force by which liquid, in contact with a solid, is distributed between closely fitted faying surfaces of the joint to be brazed or soldered.
Code. A systematic collection of regulations and rules of procedure or conduct: a building code.
Cohesion. The molecular attraction or joining of the surfaces of two pieces of the same substance.
Cold braze joint. A joint with incomplete coalescence caused by insufficient application of heat to the base material during brazing.
Complete joint penetration. Brazing filler metal penetration for the full extent of the intended joint.
Complete penetration. A nonstandard term for complete joint penetration.
Corrosion. The degradation of a material resulting from an electrochemical reaction between that material and its environment..
Crack. A fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement.Back to Top
Defect. A discontinuity or discontinuities that by nature or accumulated effect (for example, total crack length) render a part or product unable to meet minimum applicable acceptance standards or specifications. This term designates rejectability. See also discontinuity and flaw.
Differential thermal expansion. The difference between the dimensional changes of two (or more) materials having different expansion coefficients, which is caused by temperature changes at constant pressure.Back to Top
Electrolysis. Results from an imposed (external) stray DC current.
Erosion. (1) A condition caused by dissolution of the base metal by overheating or mechanical induced, resulting in a reduction of base metal thickness, (2) To eat into; wear away; disintegrate, (3) to form by wearing away gradually.
Erosion corrosion. Erosion/corrosion is a mechanically induced failure which may be caused by any or all of the following conditions: lack of reaming of the tube ends, water at high velocity, numerous, abrupt changes in direction in the piping system, protrusions into the flow stream, excessive water temperature.Back to Top
Face feed. The application of filler metal to the joint, usually by hand, during brazing or soldering.
Faying surface. That mating surface of a member that is in contact with or in close proximity to another member to which it is to be bonded.
Filler metal. The metal or alloy to be added in making a welded, brazed, or soldered joint.
Fillet. A radius region of brazing filler metal (located at the face of a joint) where work pieces are joined.
Fit. A nonstandard term for joint clearance.
Flowability. The ability of molten brazing or soldering filler metal to flow or spread over a surface.
Flux. A material used to hinder or prevent the formation of oxides and other undesirable substances in molten metal and on solid metal surfaces, and to dissolve or otherwise facilitate the removal of such substances.
Flux coated rod. Brazing filler metal in rod form that is coated with flux.
Fuel gas. A gas usually used with oxygen for heating; examples include acetylene, natural gas, hydrogen, propane (LP), methyl acetylene propadiene stabilized (Mapp), and other synthetic fuels and hydrocarbons.
Flux induced corrosion. Pitting corrosion in copper tube induced by improper or excessive application of non-water flushable fluxes.Back to Top
Galvanic corrosion. Self-induced current created by electrical potential of two dissimilar metals in contact with an electrolyte.
Gap. A nonstandard term for joint clearance.
Gas brazing. A nonstandard term for torch brazing.Back to Top
Hard solder. A nonstandard term for silver base brazing filler metals.
Hazardous material. A substance that can harm humans.
Heat-affected zone. The portion of the base metal whose mechanical properties or microstructure have been altered by the heat of welding, brazing, soldering, or thermal cutting.
Hot crack. A crack that develops during solidification.Back to Top
Incomplete fusion. A condition in which some of the brazing filler metal in a joint did not melt.
Incomplete joint penetration. Joint penetration that is unintentionally less than the thickness of the weld joint.
Indistinct fillet. A condition in which the brazing filler metal did not result in a fully formed fillet.
Inert gas. A gas that normally does not react chemically with materials.
Interstices. Spaces, especially small or narrow ones, between things or parts. (e.g. intergranular spaces in copper surface)Back to Top
Joint. The junction of members or the edges of members, which are to be bonded or have been bonded.
Joint brazing procedure. The materials, detailed methods, and practices employed in brazing a particular joint.
Joint clearance. The distance between the faying surfaces of a joint. In brazing, due to thermal expansion of the work pieces, joint clearance may vary as the work pieces are heated and cooled.
Joint design. The joint geometry together with the required dimensions.Back to Top
Lack of fill. A non-standard term for incomplete penetration.
Lap joint. A joint between two overlapping members in parallel plates.
Liquation. The separation of a low melting constituent of an alloy from the remaining constituents, usually apparent in alloys having a wide melting range.
Liquidus. The lowest temperature at which a material is completely liquid.
Longitudinal crack. A crack with its major axis approximately parallel to the joint axis.Back to Top
Manual brazing. A brazing operation performed and controlled completely by hand.Back to Top
Non-corrosive flux. Brazing flux which in neither its original form nor its residual form chemically attacks the base metal.Back to Top
Oxide. A chemical compound containing oxygen and one other chemical element.Back to Top
Patina. A thin greenish layer, usually basic copper sulfate, which forms on copper or copper alloys, such as bronze, as a result of corrosion.
Peel test. A destructive method of inspection, which mechanically separates a lap joint by peeling.
Penetration. A non-standard term for joint penetration.
Porosity. Cavity type discontinuities formed by gas entrapment during solidification.
Post-heating. The application of heat to an assembly after welding, brazing, soldering, thermal spraying, or thermal cutting.
Preform. Brazing filler metal fabricated in a shape or form for a specific application.
Preheat. The heat applied to the base metal or substrate to attain
and maintain preheat temperature.
Preheating. The application of heat to the base material immediately before brazing or soldering.
Preheat temperature. The temperature of the base metal or substrate in the welding, brazing, soldering, thermal spraying, or thermal cutting area immediately before these operations are performed. In a multi-pass operation, it is also the temperature in the area immediately before the second and subsequent passes are started.
Procedure. The detailed elements of a process used to produce a specified result.
Procedure qualification. The demonstration that a brazed joint or a soldered joint made by a specific procedure can meet prescribed standards.Back to Top
Quench. Accelerated cooling, frequently in liquid (oil, water).Back to Top
Ream. To enlarge tube end opening; de-burr.
Remelt temperature. The temperature necessary to melt a brazing filler metal in a completed joint.
Repair brazing. The process of re-brazing a joint that exhibited repairable defects.
Resistance brazing. A brazing process that uses heat from the resistance to electric current flow in a circuit of which the work pieces are a part.Back to Top
Shrinkage void. A cavity type discontinuity normally formed by shrinkage during solidification.
Silver alloy brazing. A non-standard term for brazing with silver containing filler metal.
Silver soldering. A non-standard term for brazing with a silver-base filler metal.
Slag inclusion. Nonmetallic solid material entrapped in filler metal or between filler metal and base material.
Soldering. A group of welding processes that produces coalescence of materials by heating them to the soldering temperature and by using a filler metal having a liquidus not exceeding (840°F) 450°C and below the solidus of the base metals. The filler metal is distributed between closely fitted faying surfaces of the joint by capillary action.
Solidus. The highest temperature at which a material is completely solid.
Standard. A specification that is either widely used and accepted or is sanctioned by a standards organization.
Stress relief cracking. Inter-granular cracking in the heat-affected zone or filler metal as a result of the combined action of residual stresses and post-braze exposure to an elevated temperature.Back to Top
Thermal expansion. The dimensional change exhibited by solids, liquids, and gases, which is caused by temperature changes at constant pressure.
Thermal expansion coefficient. The fractional change in length or volume of a material for a unit change in temperature at constant pressure.
Thermal stress. Stress resulting from non-uniform temperature distribution or differential thermal expansion.
Torch brazing. A brazing process using heat from a fuel gas flame.Back to Top
Undercut. A groove melted into the base metal adjacent to the braze and left unfilled by filler metal.Back to Top
Velocity. Rate of change of position in relation to time (speed).Back to Top
Wetting. The spreading and adherence of a liquid filler metal or flux in a thin continuous layer on a surface.
Work-piece. A part being brazed, soldering or welding.Back to Top
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October '11: The Fall issue focuses on the benefits of copper at healthcare institutions. Read about a new copper HVAC system that makes AC systems more energy efficient; a medical campus that relies on copper for their state-of-the-art information network; copper trends in building and construction projects; how copper provides shielding for MRI systems to improve accuracy, and the importance of copper to ensure cleanliness, reliability and efficiency in medical gas systems.
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CDA Tube, Pipe and Fittings Council members:
Industry News: Selection of recent copper tube, pipe and fittings industry developments, technology advances, etc to keep you up to date.
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