Presentation on theme: "METALS.. METALS: Popularly, the name is applied to certain hard, fusible metals, as gold, silver, copper, iron, tin, lead, zinc, nickel, etc and also."— Presentation transcript:
METALS: Popularly, the name is applied to certain hard, fusible metals, as gold, silver, copper, iron, tin, lead, zinc, nickel, etc and also to the mixed metals or metallic alloys as brass, bronze, steel, bell metal. TYPES OF METALS MOSTLY USED IN CONSTRUCTION: STEEL (Stainless Steel): Steel containing chromium that makes it resistant to corrosion. ALUMINUM: The metallic base of Alumina. This metal is white, but with a bluish tinge, and is remarkable for its resistance to oxidation, and for its lightness.
COPPER: A common metal of a reddish color, both ductile and malleable, and very tenacious. It is one of the best conductors of heat and electricity. Copper is the only metal which occurs native abundantly in large masses. BRONZE: An alloy ( usually yellow) of copper and zinc. TITANIUM: A light strong gray lustrous corrosion-resistant metallic element used in strong light-weight alloys; the main sources are Rutile (a mineral consisting of titanium dioxide in crystalline form) and Ilmenite (a weakly magnetic black mineral found in metamorphic and plutonic rock (igneous rock that has solidified beneath the earth’s surface.)
STAINLESS STEEL: Steel Containing iron and a minimum of 11 percent chromium, making it corrosion resistant. Is relatively expensive compared to aluminum but it has a low maintenance and replacement costs. It is also more durable than most sheet metals. The stainless steel is capable of being polished. Stainless steel cannot be stained but occasionally dulls or will show oily finger prints. STAINLESS STEEL PROBLEMS: Despite its corrosion resistance, this chemical process, still is one of its problems. -Corrosion: This metal is Sensitive to hydrochloric acids ( a colorless, corrosive gas found in commercial and general chemical work.) -Corrosion under intense heat (900 to 1500 degrees Fahrenheit): The chromium content of stainless steel is removed by intense heat. The damaged area is recognizable by the presence of a blue and orange stain around the affected area. -Galvanic Corrosion: Stainless steel can become corrosive when comes in contact with lead, nickel, copper, copper alloys and graphite. -Pitting (indentation): Can occur when the metal is prevented from producing the chromium oxide film that protects it. This can result from dirt build-up on the surface that keeps oxygen from reaching the surface and developing this protective film. -Dents and Scratches: Common in high-traffic areas. -Warping (distortion): Can be caused by thermal expansion and exposure to intense heat.
STAINLESS STEEL APPLICATIONS FOR ARCHITECTURE: -Column covers -Escalators & moving walks cladding -Ornamental & decorative cladding -Curtain walls -Door & window frames -Canopies -Wall and corner guards -Grilles and screens -Ornamental handrails & railings -Wall panels -Ceiling systems and panels -Storefront displays -Architectural signage systems -Dimensional & channel letters -Architectural trims and accents -Mirrors -Building trims and accents -Specialty furniture
ALUMINUM: Aluminum is a lightweight silvery metal. Unlike many other metals it requires advanced technology to extract in pure form. As a building material aluminum offers several advantages. The metal does not corrode, and therefore requires almost no maintenance. It is extremely light, and its reflective and insulating properties work together to conserve energy. ALUMINUM APPLICATIONS FOR ARCHITECTURE: Aluminum is used in buildings for a wide variety of applications: -Roofing. -Windows. -Pre formed sheet cladding features. -Doors. -Canopies. -Front stores. -Architectural hardware and fittings. -rainwater goods. Aluminum structures and cladding are also used to refurbish many of the concrete structures built in the 's which are now showing signs of deterioration and spoiling. In building applications the aluminum can be protected by painting or anodizing. Anodized films may be clear, to preserve the `aluminum' finish or in a limited range of colors. Painting offers a wider range of colors and an appearance similar to other painted metals. These finishing operations may also, of course, be used for purely decorative effects.
ALUMINUM PROBLEMS AND DETERIORATION: -Natural Corrosion: Created by heavy deposits of soiling when the aluminum surface has been neglected and not cleaned regularly -Chemical Corrosion: Aluminum has good corrosion resistance to: Atmospheric gases, moisture and soil. Aluminum has poor corrosion resistance to: Alkalis, hydrochloric acid, lead-based paints, some wood preservatives, and chlorides. Aluminum may also corrode when in contact with wet lime mortar, Portland cement, plaster, or concrete before they are fully cured, damp, porous brickwork and stonework. Acids from unseasoned wood, damp oak, cedar, and redwood may also attack aluminum. Corrosion will result from direct contact between wet wood and aluminum, water draining off a roof of un weathered wood shingles will also corrode aluminum. -Galvanic Corrosion: Galvanic action will occur, causing the aluminum to corrode, if the aluminum comes in contact with other metals such as tin, iron and steel (if they are not painted), and especially copper. -Erosion: Aluminum features are extremely vulnerable to erosion because this metal is so soft. When exposed to abrasive agents. -Fatigue: Fatigue is one of the most common failures resulting from the stresses associated with expansion and contraction.
COPPER: Copper is initially bright reddish-brown in color, but when exposed to the atmosphere, it acquires a protective patina that turns from brown to black to green over an eight to ten year period. This patina is a copper carbonate or copper sulfate formed on the surface of the metal when hydrogen sulfide combines with oxygen or sulfur dioxide. This naturally occurring corrosion resists further corrosion. Though copper does corrode, this protective patina makes copper a corrosion-resistant material. COPPER APPLICATIONS FOR ARCHITECTURE : -Decorative detailing -Flashing, gutters and downspouts. - Piping systems: Copper's strength and resistance to corrosion by most types of soils and water make it appropriate for use in plumbing. - Electrical wiring, telephone wiring, and heating and air conditioning systems: Copper's high capacity for thermal and electrical conductivity makes it suitable for these applications.
COPPER PROBLEMS AND DETERIORATION: -Chemical corrosion: Copper is attacked by alkalis, ammonia, and various sulfate compounds that can combine with water to form sulfuric acid. Some bituminous roofing cements will attack copper, as will sulfate-reducing bacteria, which act as a catalyst for corrosion. Copper is also attacked by rainwater that has become acidic through contact with moss, lichen, algae, and occasionally wood shingles. - Galvanic Corrosion: Galvanic corrosion occurs when two dissimilar metals come in contact with one another and an electrolyte, such as rainwater, condensation, dew, fog, etc. is present. Such a reaction will cause one or the other of the metals to corrode. Direct contact of copper with other metals will cause those metals to corrode. Iron, steel, zinc and galvanized steel, tin and aluminum are especially susceptible to corrosion if put into contact with copper. -Erosion: Caused by continuous exposure to rain and snow which scours the surfaces as it drains. - Fatigue: Anything which restricts movement due to normal expansion and contraction will cause fatigue.
BRONZE: an alloy of copper which can vary widely in its composition. It is often used where a material harder than copper is required, where strength and corrosion resistance is required and for ornamental purposes. There are three major classes or types of "bronzes" used in sculpture and construction: 1.Statuary Bronze - approximately 97% copper (Cu), 2% tin (Sn) and 1% zinc (Zn) 2. Architectural Bronze - actually more of a "leaded brass", is commonly composed of approximately 57% copper (Cu), 40% zinc (Zn) and 3% lead (Pb). 3. Commercial Bronze - composed of approximately 90% copper (Cu) and 10% zinc (Zn). BRONZE TYPICAL USES: Statuary bronze: typically used in outdoor sculpture. Its forms are almost limitless since it may be cast in any shape for which a mold can be devised. Architectural bronze is typically used for: 1. door and window frames 2. door and window hardware 3. mail boxes and chutes 4. trim or rails 5. furniture hardware.
BRONZE PROBLEMS AND DETERIORATION: -Bronze has good resistance to: Industrial, rural and marine atmospheres and weak acids. -Bronze has poor resistance to: Ammonia and ferric and ammonia compounds -Corrosion: Corrosion of one form or another is the head cause of the deterioration of metals, including statuary and architectural bronze. Most bronze corrosion can be characterized as "general" or "uniform" and "pitting", with occasional signs of selective attack. Galvanic corrosion appears mostly in connection with pins, bolts, and replacement parts in different metal. Erosion is apparent only in bronzes in fountains. Stress corrosion is less apparent in bronze than in brass, but could be a factor in some cases in bronze sculptures. -Abrasion: Causes removal of the protective metal surface. Some metals such as zinc are relatively soft and therefore vulnerable to abrasion damage, especially in areas similar to roof valleys where the metal can be worn paper-thin. -Fatigue: Failure of metal that has been repeatedly stressed beyond its elastic limit, due to failure to provide necessary allowances for thermal expansion and contraction caused by temperature differences. -Heat: Usually in the form of fire, will cause many metals to become plastic, distort, and fail. - Warping (distortion): Permanent deformation or failure may occur when a metal is overloaded beyond its yield point because of increased live or dead loads, thermal stresses, or structural modifications altering a stress regime.
TITANIUM: A shiny, dark-grey transition metal. The characteristics of titanium are "Light Strong and Anti-corrosion". Comparing to steel, titanium is only two thirds in unit weight, same strength and strong corrosion resistant. Titanium has been used in the Jet Engine Airplane and artificial satellites for long time. Recently, new characteristics such as "non-harmful to human body“ are discovered and is newly used in the medical industry and accessories. Titanium is watched in many in areas as a new material, specially in architecture. Titanium can often bridge the gap between aluminum and steel by providing many of the properties of each. Like aluminum, titanium has a low density and is non magnetic. At the same time, titanium has the high strength characteristics of steel coupled with corrosion resistance that is superior to stainless steel. Titanium's outstanding corrosion resistance is due to the formation of a tightly adherent oxide film on its surface. When damaged, this thin invisible layer immediately reforms, maintaining a surface which is completely resistant to corrosive attack in sea water and all natural environments. This oxide is so resistant to corrosion that titanium components often look brand new even after years of service. TITANIUM APPLICATIONS FOR ARCHITECTURE: Titanium reinforcement rods are being used in the restoration of antiquities such as the Parthenon. Commercially pure titanium is being used for roofing, window frames, eaves and gables, flashing, curtain walls, railings, ventilators, and interior and exterior finishes.
STANDARD EXPANDED METAL: FLATTENED EXPANDED METAL:
1/16" Diameter. 1/8" Staggered Centers. 75 Holes per Sq. inch. 23% Open Area ¼" Diameter. 1/2" Staggered Centers. 4 Holes per Sq. inch. 20% Open Area 5/64" Diameter. 1/8" Staggered Centers. 75 Holes per Sq. inch. 36% Open Area 5/32" Diameter. 7/32" Staggered Centers. 24 Holes per Sq. inch. 46% Open Area 5/16" Diameter. 7/16" Staggered Centers. 6.5 Holes per Sq. inch. 50% Open Area PERFORATED METALS: 3/32" Diameter. 5/32" Staggered Centers. 47 Holes per Sq. inch. 33% Open Area 3/16" Diameter. ¼" Staggered Centers Holes per Sq. inch. 50% Open Area 3/8" Diameter. 1/2" Staggered Centers. 5 Holes per Sq. inch. 52% Open Area 3/32" Diameter. 3/16" Staggered Centers. 33 Holes per Sq. inch. 25% Open Area 3/16" Diameter. 5/16" Staggered Centers. 12 Holes per Sq. inch. 32% Open Area
3/8" Diameter. 9/16" Staggered Centers. 4 Holes per Sq. inch. 40% Open Area 1/8" Diameter. 3/16" Staggered Centers. 33 Holes per Sq. inch. 40% Open Area ¼" Diameter. 5/16" Staggered Centers. 12 Holes per Sq. inch. 58% Open Area ½" Diameter. 11/16" Staggered Centers Holes per Sq. inch. 48% Open Area 1/8" Diameter. ¼" Staggered Centers Holes per Sq. inch. 23% Open Area ¼" Diameter. 3/8" Staggered Centers. 8.5 Holes per Sq. inch. 40% Open Area 5/8" Diameter. 13/16" Staggered Centers Holes per Sq. inch. 54% Open Area 5/32" Diameter. 3/16" Staggered Centers. 33 Holes per Sq. inch. 63% Open Area ¼" Diameter. ½" Staggered Centers. 5 Holes per Sq. inch. 23% Open Area ¾" Diameter. 1" Staggered Centers. 1.1 Holes per Sq. inch. 51% Open Area
WIRE MESH : Plain weave Lock crimp Inter crimp Flat top weave
IN SUMMARY: All metals are malleable and ductile. These qualities are generally summed up by saying that metals are workable. They can be hammered into thin sheets without breaking. Instead, they change their shapes or bend. They can also be drawn into a fine wire. All metals are good thermal conductors. Metals have the ability to easily transmit heat. That is why the highest quality pots and pans are made out of metals. All metals are good electrical conductors. Metals will readily allow electricity to pass through them with very little loss. Other substances may allow electricity to pass through them, but much of the electricity is lost through a quality known as resistance. All metals have luster. Metals are shiny as a result of the fact that they reflect a high percentage of incident light.