Welding Nonferrous Metals 212

1XXX

An aluminum alloy that is close to pure aluminum and contains minimal alloying elements. 1XXX is a non-heat-treatable alloy.

2XXX

An aluminum alloy in which the primary alloying element is copper. 2XXX is a heat-treatable alloy.

3XXX

An aluminum alloy in which the primary alloying element is manganese. 3XXX is a non-heat-treatable alloy.

4XXX

An aluminum alloy in which the primary alloying element is silicon. 4XXX is a non-heat-treatable alloy.

5XXX

An aluminum alloy in which the primary alloying element is magnesium. 5XXX is a non-heat-treatable alloy.

6XXX

An aluminum alloy in which the primary alloying elements are both magnesium and silicon. 6XXX is a heat-treatable alloy.

7XXX

An aluminum alloy in which the primary alloying element is zinc. 7XXX is a heat-treatable alloy.

AC

Alternating Current. Current that reverses direction at regularly recurring intervals of time. In the United States, AC reverses 120 times per second, or 60 hertz.

aged

Heated to a certain temperature to cause a change in grain structure. Metals are usually aged to increase their hardness.

age-hardenable nickel alloys

A nickel alloy that can be hardened through heat treatment such as precipitation hardening. Age-hardenable nickel alloys usually contain aluminum or

alloying elements

A material that is intentionally added to a metal in order to change its properties. Alloying elements can improve the strength, ductility, hardness, and toughness of a finished weld.

alloys

A material consisting of a mixture of two or more elements, at least one of which must be a metal. Alloys combine the beneficial properties of the mixed elements.

alternating current

AC. Current that reverses direction at regularly recurring intervals of time. In the United States, alternating current reverses 120 times per second, or 60 hertz.

aluminum

A lightweight, highly conductive, silvery metal. Aluminum has good weldability, but certain factors, such as its melting point, can make the process difficult.

aluminum oxide

A thin film that forms on the surface of aluminum when it reacts with oxygen in the air. Aluminum oxide must be removed before welding.

amperage

A measurement that indicates the amount of current flowing in a circuit. Amperage is measured in amperes.

annealing

The process of steadily heating a metal above the recrystallization phase and then gradually cooling it. Annealing can reduce hardness, improve machinability, and facilitate cold working.

arc length

The distance that electricity must travel from the tip of the electrode to the weld pool. Arc length is determined by voltage.

argon

A colorless, odorless inert gas commonly used as shielding for arc welding. Argon is much heavier than air, so it effectively shields the weld area.

atmospheric contamination

The negative impact of an environmental element on the quality and strength of a finished weld. Atmospheric contamination is often caused by ambient gases such as oxygen and nitrogen.

atoms

A tiny particle that makes up all materials. Atoms are the smallest distinguishable units of an element that retain the element's characteristics.

brass

An alloy of copper and zinc. Brass has high tensile strength and corrosion resistance.

brazing

A process in which a filler metal is melted at a temperature above 840°F (449°C), but below the melting point of the base metals to form a joint between two base metals. Brazing can be used to join dissimilar metals like silver, aluminum, copper, nickel, and gold.

brittle

Unwilling to be drawn, stretched, or formed. Brittle materials tend to fracture when subjected to these forces.

bronze

An alloy of copper and tin. Bronze is strong and highly corrosion resistant.

burnthrough

A discontinuity that occurs when weld metal from one side of a joint melts through to the other side. Burnthrough can leave an open hole in the joint, which must then be ground down and re-welded.

burr tools

A small cutting tool with hard edges or ridges. Burr tools can help clean surfaces before welding.

carbon monoxide

A colorless, odorless, poisonous gas made of carbon and oxygen. Carbon monoxide is produced when carbon dioxide is heated to high temperatures and dissociates.

carbon steel

The most basic form of steel, containing less than 3.0% alloying elements. Carbon steels are divided into low-, mild, medium-, and high-carbon steels.

cast

A metal that has been poured as a liquid into a mold and cooled into a solid shape. Cast nickel alloys are often difficult to weld because of their high silicon content.

chromium

A shiny, gray nonferrous metal that provides high corrosion resistance. Chromium is a common alloying element used in metals such as stainless steel.

cobalt

A common alloying element. Cobalt increases a material's thermal resistance, and can increase hardness or toughness depending on the material.

coefficient of thermal expansion

A value that indicates the degree to which a material increases in size as temperature increases. Higher coefficients of thermal expansion can lead to distortion in metals at high levels.

cold working

The shaping of metal at temperatures below the recrystallization temperature. Cold working is used most often with malleable, ductile metals.

composition

The contents of a metal or alloy, described as percentages of total weight. Composition effects mechanical and physical properties as well as weldability.

copper

A reddish metal that is very ductile, thermally and electrically conductive, and corrosion resistant. Copper is often used to make electrical components.

copper oxides

A chemical compound formed by copper and oxygen. Copper oxides can precipitate at grain boundaries during welding and weaken metal.

copper-lead alloys

An alloy of copper and lead that has good machinability. Copper-lead alloys have the poorest weldability of all copper alloys because the toxic lead often contaminates the weld and the atmosphere.

copper-nickel alloys

An alloy of copper and nickel that is strong and hard. Copper-nickel alloys, also known as cupronickels, form good welds when welded with the proper procedures.

corrosion resistance

The ability of a material to resist deterioration and chemical breakdown due to surface exposure to certain conditions. Corrosion resistance is an important physical property of finished welds.

cracking

Fracturing that develops in a weld after solidification. Cracking can be caused by excessive hardness in a weld or atmospheric contamination.

crystals

A group of atoms with regular, repeating patterns. Crystals help determine the properties of a metal.

cupronickels

An alloy of copper and nickel that is strong and hard. Cupronickels, also known as copper-nickel alloys, form good welds when welded with the proper procedures.

DCEN

Direct current electrode negative. Current that always flows in one continuous direction from the negative electrode to the positive workpiece. DCEN polarity is used for GTAW on steel and copper.

defects

An irregularity in the specified and expected composition of a weld that exceeds the part design's tolerances. A defect is an unacceptable discontinuity.

deoxidized copper

Copper containing a small percentage of an element that removes oxygen from the metal. Deoxidized copper is more weldable than pure copper.

deoxidizers

A material that removes oxygen from the molten weld pool and arc. Deoxidizers prevent oxygen from ruining a weld bead.

direct current electrode negative

DCEN. Current that always flows in one continuous direction from the negative electrode to the positive workpiece. Direct current electrode negative polarity is used for GTAW on steel and copper.

discontinuities

An irregularity in the expected composition of a weld that does not exceed specifications. A discontinuity is not always a defect.

distortion

The non-uniform expansion of weld metal during the heating and cooling process of welding. Distortion can be caused by using incorrect welding variables.

ductility

A material's ability to be drawn, stretched, or formed without breaking. Ductility is more common in softer metals.

electrical conductivity

The ability of a material to act as a medium for conveying electricity. Electrical conductivity is high for most metals.

electrode

A component in an electrical circuit that conducts electricity. A welding electrode can also act as filler metal.

fatigue

The weakening of metal caused by repeatedly applied force. Fatigue can weaken even very strong and hard metals over time.

ferrous metals

A metal that contains iron. Ferrous metals are the most common type of welded materials.

filler metal

Metal deposited into the weld to add strength and mass to the welded joint. Consumable electrodes provide filler metal in some welding processes.

flux

A material that is intended to protect the weld pool and solid metal from atmospheric contamination. Flux is often a part of an electrode.

flux-cored arc welding

FCAW. An arc welding process that uses a continuously fed consumable electrode with an inner core of flux. Flux-cored arc welding includes both self-shielded flux-cored arc welding (FCAW-S) and gas-shielded flux-cored arc welding (FCAW-G).

fumes

A potentially hazardous combination of gas and particulate matter generated at the electric arc during welding processes. Fumes include particulates from the electrode, shielding gas, base metal, and any coatings.

furnaces

A self-contained metal structure that can be heated to exceptionally high temperatures. Specialized furnaces can be used to preheat base metals before welding.

fusion zone

The area where welding joins the base metals and any filler metal. The fusion zone, also called the weld metal zone, is subjected to the highest temperatures during welding.

galvanized

Coated with zinc. Galvanized steel has better corrosion resistance than regular steel.

gas metal arc welding

GMAW. An arc welding process in which a bare wire electrode and shielding gas are fed to the weld through a welding gun. Gas metal arc welding releases more gases but less fumes than other arc welding processes.

gas tungsten arc welding

GTAW. A precise arc welding process that uses a non-consumable tungsten electrode and inert shielding gas. Gas tungsten arc welding is also known as tungsten inert gas welding (TIG welding).

GMAW

Gas metal arc welding. An arc welding process in which a bare wire electrode and shielding gas are fed to the weld through a welding gun. GMAW releases more gases but less fumes than other arc welding processes.

grain boundaries

The place where two grains meet. Grain boundaries help determine the microstructure of a metal.

grain structure

The size, arrangement, and orientation of the small, hard particles in a metal or alloy. Grain structure, also known as microstructure, helps determine the properties of a metal.

grains

A group of crystals. Grains have irregular shapes and sizes.

grinding

The use of an abrasive to wear away at the surface of a workpiece. Grinding removes surface impurities or undesirable materials from a metal before welding.

GTAW

Gas tungsten arc welding. A precise arc welding process that uses a non-consumable tungsten electrode and inert shielding gas. GTAW is also known as tungsten inert gas welding (TIG welding).

hardness

A material's ability to resist penetration, indentation, or scratching. Hardness in a metal may change due to the heat generated during welding.

HAZ

Heat-affected zone. The portion of the base metal immediately surrounding the weld metal zone. The HAZ does not melt during welding, but its mechanical and physical properties are altered.

heat dissipation

The loss or transfer of heat. Heat dissipation can help control thermal expansion.

heat sinks

A device that cools an electrical system by dissipating heat. Heat sinks are commonly used to cool central processing units in computers.

heat treatment

The controlled heating and cooling processes used to change the structure of a material and alter its physical and mechanical properties. Heat treatments include preheating and post-heating processes.

heat-affected zone

HAZ. The portion of the base metal immediately surrounding the weld metal zone. The heat-affected zone does not melt during welding, but its mechanical and physical properties are altered.

heating torch

A device that uses the controlled combustion of fuel gases to produce a flame. Heating torches are used to preheat base metals for welding.

heat-treatable alloys

An alloy that can be heated during or after welding to preserve or restore its strength. Heat-treatable aluminum alloys include series 2XXX, 6XXX, and 7XXX.

helium

A lightweight inert gas sometimes used as a shielding gas for arc welding. Helium is much lighter than air.

high-frequency arc starting

An arc starting method that uses a high voltage to generate a spark between the electrode and the workpiece to establish an arc. For the high-frequency start method, the welder holds the electrode near the workpiece and uses a control device to start a high frequency current that provides the spark.

hot cracking

Fracturing in the weld that is often caused by stress in thin materials during solidification. Hot cracking often occurs when welding copper alloys.

hydrogen

A colorless, odorless gas that is the most abundant element on the planet. Hydrogen can cause weld metal to crack.

inert

A chemically inactive substance that does not react with other materials. Inert gases are used to protect molten metal from atmospheric contamination in gas tungsten arc welding and some gas metal arc welding processes.

interpass temperature

The temperature of the weld metal between passes of a multi-pass weld. The interpass temperature is often maintained until the weld is complete.

iron

A common silvery-white metal found in nature as ore. Iron is alloyed with carbon to make steel.

joint

The meeting point of two materials that are fused together. Welding creates a permanent joint.

laser welding

A welding process that uses a laser to heat base materials. Laser welding can sometimes be performed by modified laser cutters.

lead

A toxic, bluish-white metal that is very soft and ductile and is a poor conductor of electricity. Lead creates toxic fumes when welded.

magnesium

A grayish white, extremely light metal that is brittle and has poor wear resistance. Magnesium can be combined with aluminum to create an alloy with excellent weldability.

malleability

A material's ability to be stretched or shaped by force. Malleability is an important characteristic of nonferrous metals such as copper.

manganese

A hard, brittle, gray-white nonferrous metal often added to electrodes. Manganese acts as a deoxidizer and increases strength and hardness in alloy steels.

mechanical properties

A characteristic that describes how a material responds to forces that attempt to compress, stretch, bend, scratch, dent, or break it. Mechanical properties include tensile strength and ductility.

microstructure

The size, arrangement, and orientation of the small, hard particles in a metal or alloy. Microstructure, also known as grain structure, helps determine the properties of a metal.

molybdenum

A hard, silvery-white metal that is strong and corrosion resistant. Molybdenum can add toughness, creep strength, and wear resistance to alloys.

natural aging

The process of allowing a metal to rest at room temperature to change its grain structure and properties. Natural aging increases strength and hardness.

nickel

A hard, malleable, silvery-white metal. Nickel is used in various alloys to add strength, toughness, and impact resistance.

niobium

A ductile, gray metal most often used as an alloy due to its superconducting properties. Niobium was formerly known as columbium.

nitric-hydrofluoric acid

Clear, acidic liquid that is used to etch and clean surfaces. Nitric-hydrofluoric acid is used to clean titanium before welding.

nitrogen

A colorless, odorless, tasteless gas that naturally makes up 78% of breathable air. Nitrogen can ruin a weld bead, so electrodes often contain elements to de-nitrify the molten metal.

nonferrous metals

A metal that does not contain a significant amount of iron. Common nonferrous metals include aluminum, titanium, copper, and nickel.

non-heat-treatable alloys

An alloy that relies primarily on cold working to increase its strength and hardness. Non-heat-treatable aluminum alloys include series 1XXX, 3XXX, 4XXX, and 5XXX.

nuclear magnetic resonance instruments

NMRIs. A medical diagnostic tool that uses magnetic fields and radio waves to create an image of the body. Nuclear magnetic resonance instruments often contain niobium.

OFW

Oxyfuel welding. A fusion welding process that uses a flame produced by a mixture of oxygen and acetylene gas. OFW is also known as oxyacetylene welding.

oxyfuel welding

A fusion welding process that uses a flame produced by a mixture of oxygen and acetylene gas. Oxyfuel welding is also known as oxyacetylene welding.

oxygen

A colorless, odorless, tasteless gas that naturally exists in the atmosphere. Oxygen can cause cracking, porosity, and rusting in welded metals.

physical properties

A characteristic of a material that describes how it responds to environmental, electrical, magnetic, and thermal forces. Physical properties include corrosion resistance and conductivity.

porosity

A weld discontinuity characterized by the appearance of tiny voids resulting from trapped gases. Excessive porosity can weaken a weld.

post-heating

o The application of heat to a weld immediately after welding, before the weld has cooled. Post-heating helps reduce stress in the weld metal.

post-weld heat treatment

PWHT. The process of heating a weld after welding is complete. Post-weld heat treatment reduces stress in the welded metal.

precipitate

To separate out of a solution. Precipitating elements in precipitation hardening increase the metal's hardness.

precipitation hardening

A type of heat treatment used to strengthen and harden more malleable materials, such as aluminum. Precipitation hardening heats an element to a temperature at which it precipitates and then cools it at a rate that prevents it from returning to the original structure.

preheating

o The application of heat to a base metal immediately before welding. Preheating provides several benefits, such as reducing hardness, improving ductility, and decreasing the likelihood of hydrogen cracking.

pressure vessels

A container designed to hold liquids or gases at high pressures. Pressure vessels are often made from non-heat-treatable aluminum alloys.

quenched

Rapidly cooled through the use of oil, water, or air. Quenched metals retain the grain structure they developed before quenching.

radiation shields

A device that contains the harmful energy transmitted by radioactive material. Radiation shields are commonly used in components found in nuclear power plants.

reactive

A chemically active substance that reacts with elements such as oxygen, hydrogen, and nitrogen. Reactive metals include titanium, nickel, and magnesium.

refractory metals

A metal with superior heat, wear, and corrosion resistance. Refractory metals are typically metals that have a higher melting point than iron.

shielded metal arc welding

SMAW. An arc welding process that uses a flux-coated, stick-like consumable electrode. Shielded metal arc welding is also referred to as stick welding or manual welding.

shielding gases

A gas that protects the weld pool and arc from atmospheric contamination. Shielding gases are used in gas metal arc welding, gas tungsten arc welding, and gas-shielded flux-cored arc welding.

silicon

A nonmetallic material that is often present in arc welding electrodes and flux. Silicon acts as a deoxidizer and is used as an alloying element in some alloy steels.

slag

A nonmetallic byproduct of flux that floats to the top of the molten weld pool and forms a hardened layer on top of the solidified weld metal. Slag protects the cooling metal and is chipped off after the weld has cooled.

solution

A mixture of components or elements. Solutions can be created in alloys through controlled heating and cooling processes.

solution heat treatment

The first step of precipitation hardening in which an alloy is heated to a temperature high enough to allow the alloying element to form a solution with the base metal. Solution heat treatment requires cooling and ageing to increase the metal's hardness.

stainless steel

A type of steel that contains 11-30% chromium and exhibits excellent hardness and corrosion resistance. Stainless steel can be welded with many different welding processes.

steel

An alloy of iron and carbon containing less than 2.0% carbon. Steels often contain other elements to enhance various aspects of the metal.

strength

The ability of a material to resist forces that attempt to break or deform it. A material exhibits tensile, compression, or shear strength, depending on the deforming force.

strength-to-weight ratios

The relationship between a material's strength and its weight. Strength-to-weight ratios are considered high when a metal is light and strong.

stress

The load or force applied to a material that attempts to deform or break it. Types of stress include compression, shear, and tensile stress.

superconductor

A metal that can channel extraordinary amounts of heat and electricity with great efficiency. Superconductors are used in transportation and medical diagnosis systems.

tantalum

A hard, blue-gray metal that is non-reactive to most chemicals. Tantalum has superior corrosion resistance.

tensile strength

A material's ability to resist forces that attempt to pull it apart or stretch it. Materials with high tensile strength tend to deform, bend, or stretch before breaking.

thermal conductivity

The ability of a material to act as a medium to convey heat. Materials with superior thermal conductivity include aluminum and copper.

thermal expansion

An increase in a metal's dimensions in response to heat. Thermal expansion varies for different metals.

tin

A soft, silver-white metal used in many alloys. Tin is often combined with copper to make bronze.

titanium

A silver-gray, strong, lightweight metal known for its corrosion resistance and strength-to-weight ratio. Titanium is often used in the aerospace and medical industries.

trailer shields

A device that attaches to a welding torch to extend shielding gas coverage. Trailer shields are used when welding metals that are particularly sensitive to atmospheric contamination.

travel speeds

The rate at which the welder moves the electrode along the joint to make the weld. Travel speed determines the size of the weld bead and is measured in inches per minute (in./min or ipm) or millimeters per minute (mm/min).

tungsten

A dense, brittle, gray metal that has excellent conductivity and the highest melting point of all pure metals. Tungsten is used to make non-consumable electrodes for GTAW.

ultra-high purity

UHP. A substance with impurities below 0.1 parts per million (ppm). Ultra-high purity argongas is used for shielding titanium welding.

vacuum-assisted welding chambers

An enclosed that provides an inert gas atmosphere for welding. Vacuum-assisted welding chambers are used for reactive metals like titanium and refractory metals.

vanadium

A hard, ductile metal typically used in small quantities in high-speed steel alloys. Vanadium increases the strength of certain steels.

voltage

A measure of electrical force or pressure that causes current to flow in a circuit. Voltage is measured in volts (V).

weld metal zone

The area where welding joins the base metals and any filler metal. The weld metal zone, also called the fusion zone, is subjected to the highest temperatures during welding.

weld pool

The small area of molten metal that forms during welding and that, when cooled, forms the permanent joint. Weld pools are sometimes called weld puddles.

weld toes

The point at which a weld's face meets the base metal. Weld toes can experience cracking and undercut.

weldability

The ability of a material to be welded under imposed conditions into a specific, suitable structure and to perform satisfactorily for its intended use. Weldability varies based on the type of metal being welded, its thickness, and environmental conditions.

welding procedure specification

WPS. A written document that contains all the specific information necessary for completing a weld. A welding procedure specification must be approved and tested before it can be used.

wire brush

A tool with wire filaments used to clean the surface of a workpiece. Wire brushes can remove impurities that could contaminate the weld and cause defects.

wrought

A metal that has been bent, hammered, or physically formed into a desired shape. Wrought nickel alloys are often welded under the same conditions as certain types of steel.

X-ray

An electromagnetic wave with a high frequency and low wavelength used in radiographic testing. X-rays are used to view the interior of solid objects during radiographic testing.

zinc

A bluish-white metal that is corrosion resistant and has a relatively low melting point. Zinc is often used as a coating on steel.

zinc oxide

A chemical compound of zinc and oxygen. Zinc oxide fumes are very hazardous during welding.