METALS

ALUMINUM

• Soft, non-magnetic silvery white metal used in forming many hard, light alloys

• High thermal and electrical conductivity• Light in weight (1/3 of iron, brass or copper)

• Ductile, malleable

• Low Melting point – 1200⁰ F• Tensile strength 22,000 psi• Deficient in strength and soft – must be

alloyed• High degree of corrosion resistance due to

transparent film of oxide on its surface• Advantages: appearance & protection

• Can be riveted, bolted, welded, brazed, and soldered.

• Insulate from contact with other metals to prevent galvanic action (occurs between 2 dissimilar metals when enough moisture is present for electric current to flow. Will corrode one metal while plating the other)

• Isolate from alkaline materials – wet concrete, mortar and plaster.

• Used in extruded and sheet forms for secondary building elements – windows, doors, roofing, flashing, trim and hardware.

• Structural framing – high strength aluminum alloys

• Readily attacked by alkalis and hydrochloric acid and slowly attacked by dilute acids.

• Easily worked and can be hot or cold rolled, extruded, forged, pressed, drawn, molded, stamped, bent and shaped.

• Extrusion – process of shaping material by forcing it to flow through a shaped opening in a die.

ANODIZED ALUMINUM

• Following pretreatment, controlled oxidixing process that produces a thicker, denser, harder oxide coating that adds durability

• Exterior architectural application

“ALCLAD”

• Term applied to certain aluminum products and refers to the protective covering (cladding) applied, primarily for corrosion resistance, to thin sheets of alloy whose corrosion resistance has been decreased by the constituents added to give strength and other desirable characteristics.

TYPES OF ALUMINUM

• ALUMINUM SHEET AND STRIP, used for roofing, flashing, gutter, etc.

• ALUMINUM FOIL which is rolled to a thickness of 0.005” and is used mainly for thermal insulation and vapor barriers.

• CORRUGATED ALUMINUM –rigidized sheet fabricated of special aluminum alloys specifically developed for roofing and siding purposes

• STRUCTURAL ALUMINUM– Economical• No painting• Thickness can be reduced• Lightweight – increased efficiency w/ large bay spacing

• ALUMINUM DOORS AND WINDOWS• ALUMINUM PANELS – Are pre-fabricated units which are generally

manufactured on modular and non-modular window-width dimensions for the exterior of buildings and generally in 2’, 3’, and 4’ widths for interior partitions and dividers.

– Consists of vapor barriers, condensation drains and lead-offs, insulation and an interior finish

• SANDWICH PANEL – comprises a construction called skin construction. A cellular core of aluminum or other material has a skin of aluminum applied and bonded to both sides, thereby forming a unified whole in which all the components work as one.

ALUMINUM FINISHES

• MECHANICAL FINISHES – grinding, polishing, scratching, sandblasting, embossing,

• CHEMICAL FINISHES – chemical reactions with aluminum surface to achieve:– Etching, cleaning, or polishing of the surface to

remove any oxide film or surface irregularity and provide a design, a clean surface texture, or a polished effect.

• ORNAMENTAL ALUMINUM – railings, grilles, screens.

• ALUMINUM MESH AND WIRE CLOTH – fencing, particularly chain link fencing and insect screening.

– Oxidizing of the surface with aluminum or other metallic oxides that protect the surface or serve as a base for subsequent treatment or both.

ELECTROLYTIC FINISHES – anodized finishes, based on ability of aluminum to develop a protective coating of oxide on its surface. Oxide films are electrolytically applied.

ELECTROPLATING – aluminum can be covered with a protective or decorative film or another metal by electrodeposition.

• PORCELAIN OR VITREOUS ENAMEL – this finish forms a hard, resistant surface where colors are glassy instead of metallic.

• PAINT – paint, lacquer, and enamel (except lead base paint) can be applied as finishes to aluminum surfaces that have been prepared by a suitable chemical treatment finish.

IRON

• Tough, malleable silvery-white metal that is soft and ductile as copper.

• Easily magnetized

• CAST IRON– Iron-carbon alloy that contains more than 1.7%

carbon and is poured while molten into forms.– Easily cast into any shape, but too hard and brittle

to be shaped by hammering, rolling or pressing.– Pipings and fittings, ornamental ironwork,

hardware, circular stairs, vent, manhole covers, grating

• Absorbs energy and stop vibration

WROUGHT IRON

• Almost pure iron < 0.1% carbon• Soft• Malleable• Tough• Fatigue –resistant• Resistant to progressive corrosion• Has good machinability, can be

forged,bent,rolled, drawn and spun

• Plumbing• Heating• Air-con• Furniture• Railing• Fences• grilles

COPPER

• Ductile, malleable metallic element widely used for electrical wiring, water piping.

• Color and resistance to corrosion – excellent roofing and flashing.

• Will corrode aluminum, steel, stainless steel, zinc.

• Tensile strength – 36,000 to 70,000 psi

• Rods, bars, tubes, sheets.• Roofing, doors,

BRASS

• Any of various alloys consisting essentially of copper and zinc, used for windows, railings, trim and finish hardware

LEAD

• Heavy, soft, malleable, bluish gray metallic element used for flashing, sound isolation and radiation shielding. Although lead is the heaviest metal, its pliability makes it desirable for application over uneven surfaces. Lead dust and vapors are toxic

STEEL

• Iron-based alloy having a carbon content less than that of cast iron and more than that of wrought iron and having qualities of strength, hardness and elasticity.

• Used for light and heavy structural framing, windows, doors, hardware and fastenings

CARBON STEEL

• Unalloyed steel in which the residual elements such as carbon, manganese, phosphorous, sulfur and silicon are controlled. Any increase in carbon content increases the strength and hardness of the steel but reduces its ductility and weldability

KINDS OF CARBON STEEL

• MILD OR SOFT STEEL – low-carbon steel containing from 0.15% to 0.25% carbon.

• MEDIUM STEEL – contains 0.25% to 0.45% carbon. Most structural steel is medium-carbon steel. ASTM A36 is the most common strength grade with a yield point of 36,000 psi.

• HARD STEEL – high-carbon steel 0.45% -0.85% carbon

• SPRING STEEL – high-carbon steel 0.85%-1.8% carbon

ALLOY STEEL

• Carbon steel to which various elements such as chromium, cobalt, copper, manganese, molybdenum, nickel, tungsten, or vanadium have been added in a sufficient amount to obtain particular physical or chemical properties.

KINDS OF ALLOY STEEL

• STAINLESS STEEL – contains a minimum of 12% chromium, sometimes with nickel, manganese, or molybdenum so as to be highly resistant to corrosion

• HIGH-STRENGTH LOW-ALLOY STEEL – low-carbon steel containing less than 2% alloys in a chemical composition specifically developed for increase strength, ductility and resistance to corrosion. ASTM A572 is the most common strength with a yield point of 50,000 psi.

• WEATHERING STEEL – high-strength, low-alloy steel that forms an oxide coating when exposed to rain or moisture in the atmosphere. This coating adheres firmly to the base metal and protects it from further corrosion. This should be detailed to prevent the small amount of oxide carried off by rainwater from staining adjoining materials.

• TUNGSTEN STEEL - alloy steel containing 10% to 20% tungsten for increased hardness and heat retention at high temperatures.

FERROUS METALS• CAST IRON – hard, brittle, non malleable iron-

based alloy containing 2% to 4.5% carbon and 0.5% to 3% silicon cast in a sand mold and machined to make many building products such as piping, grating and ornamental work.

• MALLEABLE CAST IRON – annealed by transforming the carbon content into graphite or removing it completely.

• WROUGHT IRON – tough, malleable, relatively soft iron that is readily forged and welded,0.2% carbon and a small amount of slag

• GALVANIZED IRON – coated with zinc to prevent rust

NONFERROUS METALS

• ALUMINUM• COPPER• LEAD• BRASS

GALVANIC ACTION

• Occurs between two dissimilar metals when enough moisture is present for electric current to flow. This electric current will tend to corrode one metal while plating the other

REINFORCING BARS

• Steel sections hot-rolled with ribs or other deformations for better mechanical bonding to concrete.

WELDED WIRE FABRIC

• Consists of a grid of steel wires or bars welded together at all points of intersection. Typically used to provide temperature reinforcement for slabs but the heavier gauges can also be used to reinforce concrete walls. Size of grid in inches followed by wire gauge