Curling

Curling: Curling is the operation of forming the edges of a component into a roll or curl by bending the sheet metal in order to strengthen the edges and to provide smoothness to the surface.

Sheet metal Terminology

Lecture 3

• History of Foundry Engineering/ Casting

• World wide importance of foundry Engineering

• Applications

• Advantages and Limitations of metal casting processes

History of Foundry Engineering/ Casting

Ancient Greece; bronzestatue casting circa 450BC

Iron works in early Europe,e.g. cast iron cannons fromEngland circa 1543

Casting is 6000 years old process and is mentioned in religious books also, specially in Holy Quaran.

In ancient time the major applications of casting was in creating, idols for worship, agricultural and war implements

History of Foundry Engineering/ Casting

• Earliest castings include the 11 cm high bronze dancing girl found at Mohen-jo-daro (dated about 3000 BC).

• The remains of the Harappan civilization contain kilns for smelting copper ingots, casting tools, stone moulds, cast ornaments, figurines (is a statuette that represents a human, or animal) and other items of copper, gold, silver and lead.

• Iron has been mentioned in:– Holy Quaran in 57th Surah “AL-Hadid” and 25th verse which states:

– We sent down Iron, in which is (material for) mighty power, as well as many benefits for mankind..."

History of Foundry Engineering/ Casting– Vedas as ayas

• Iron pillars, arrows, hooks, nails, bowls dated 2000 BC or earlier have been found in Delhi, Roopar, Nashik and other places.

• Large scale state-owned mints and jewelry units, and processes of metal extraction and alloying have been mentioned in Kautilya’s Arthashastra (about 500 BC). The Arthashastra is an ancient Indian treatise on statecraft, economic policy and military strategy , whereas Kautilva’s is the author’s name.

• The Iron Pillar of Delhi, standing 23 feet, weighing 6 tonnes and containing 99.72% iron without any signs of rust, is a remarkable example of metallurgical science in 5th century AD.

History of Foundry Engineering/ Casting• One of the first cast iron objects, a 270 kg tripod, was cast by

Chinese in 600 BC • A colossal (very large in size) statue of the Great Buddha in tin lead

bronze was completed in 1252 AD at Kamakura in Japan• The casting technology was transferred from India and Middle East

to Europe through Portugese explorers in 14th century, where it blossomed (developed) as a fine art. (Portugal is the westernmost country Located in southwestern Europe)

• Vannocio Biringuccio, head of Papal Foundry in Rome (around 1500 AD) is considered as the father of foundry industry in the West. He has been quoted as saying: – “The art of casting… is closely related to sculpture, … it is highly

esteemed… it is a profitable and skillful art and in large part delightful.”

• Indeed, the bronze sculptures represent the craftsman’s artistry as well as the capability of the casting process

Ancient Sculpture

Latest Sculptures

Metal Casting History• Therefore casting as an ancient art and

dates back 6000 years

• More intricate shapes have been made by casting then by hammering– First metals cast were probably gold and

copper.• Cu melts at 1084° C• Au melts at 1064° C

– Egyptians were expert at investing or “lost wax” casting• Allowed small intricate shapes to be cast.

Metal Casting History

• First cannons were made Belgium 1313 CE

Metal Casting History• Bronze casting

– Made when people realized that copper tin alloys cast much easier than copper alone.

• Bronze casting of bells became important• Over time, they found the purity of the sound

came from the purity of the casting» Size, shape, thickness, thinness» Chemical composition.

Importance of Foundry Engineering• Approximately 14 million pounds of castings are

produced every year• Cast metal products are found in 90 percent of

manufactured goods and equipment.• From critical components for aircraft and automobiles to

home appliances and surgical equipment, cast metal products are integral to our economy and our way of life.

• Metal casting companies/ foundries are often at the heart of the economy in the communities where they reside. For Example– The U.S. metal casting industry is the world’s largest supplier of

castings, hipping cast products valued at over $18 billion annually and directly employing 225,000 people.

– Of the 2,950 metal casting establishments located throughout the United States, over 80 percent are small businesses.

Importance of Foundry Engineering

• The following are the outstanding features of metal casting industry at global level.– At globally it is competitive and environmentally responsible industry– It is well-capitalized and profitable industry– It has a source of challenging and well-paying careers– It is the preferred supplier of engineered, net-shape metal components– It has the world’s benchmark for technology and innovation

• The most common materials cast are gray iron, ductile iron, aluminum alloys, and copper alloys

• 35% of the market is in automotive and light truck manufacturing• Castings are used in applications ranging from agriculture to railroad

equipment and heating and refrigeration

Picture shows the largest piece of steel ever cast in one piece. Its weight is 140,000 punds and cost was $400,000 estimated in 1893. It needed two machines 1,000 horse power

The History of the Ferris Wheel Pittsburgh Commercial Gazette,

17 June 1893

Lecture-4Applications

• Metal and Alloys

• Shapes

Applications (Ferrous casting alloys)

• Cast irons represent the largest amount of all metals cast and can cast into complex shapes.– Cast Iron is an alloy of iron and carbon in which the carbon is in excess

of the amount that can be retained in solid solution in austenite at the eutectic temperature. Carbon is usually present in the range of 1.8% to 4.5%, in addition, silicon, manganese, sulphur and phosphorus are contained in varying amounts

• Types of iron:– Wrought iron and alloys (Commercial iron consisting slag (iron

silicate fiberes) in ferrite matrix.– Cast iron and alloys

• Gray cast iron• Ductile iron (nodular iron)• White cast iron • Malleable iron

– Cast steels– Cast stainless steels

Cast iron• White Cast Iron

– Characterized by the prevalence (i.e. quality and quantity) of carbides, impacting – high compressive strength – hardness – good resistance to wear

• Gray Cast Iron– Characterized with graphite in the microstructure, giving good machinability – good resistance to wear and galling

• Ductile Cast Iron– Gray iron with small amounts of magnesium and cesium which nodulates the

graphite,  resulting – high strength – high ductility

• Malleable Cast Iron– White cast iron heat-treated to improve – higher ductility

• Cast alloys–solidified in near-net shape–segregation often leans to microstructural inhomogeneities–does not require expensive shaping, forming and machining

processes

• Wrought alloys–shaped from large ingots–hot/warm/cold working evens out inhomogeneities–cold working strengthens an alloy

Cast Iron vs. Wrought AlloysCast Iron vs. Wrought Alloys

Applications (Nonferrous casting alloys)

• Aluminium-based alloys

• Magnesium-based alloys

• Copper-based alloys

• Zinc-based alloys

• High-temperature alloys

Galling

• According to ASTM standard G40 (2006), is: “a form of surface damage arising between sliding solids, distinguished by microscopic, usually localized, roughening and creation of protrusions (i.e., lumps) above the original surface”. ...

Applications (Comparative Study)

G-good, E-Excellent, F-fair, D- difficult

Applications (Parts/Shapes)

• Big parts: engine blocks and heads for automotive vehicles, wood burning stoves, machine frames, railway wheels, pipes, church bells, big statues, and pump housings

• Small parts: dental crowns, jewelry, small statues, and frying pans

• All varieties of metals can be cast, ferrous and nonferrous

Some Impressive Castings

Casting Examples

Figure 11.2 Typical gray-iron castings used in automobiles, including transmission valve body (left) and hub rotor with disk-brake cylinder (front). Source: Courtesy of Central Foundry Division of General Motors Corporation.

Figure 11.3 A cast transmission housing.

Cast Parts

Figure 12-17 A variety of sand cast aluminum parts. (Courtesy of Bodine Aluminum Inc., St. Louis, MO)

Engine Block

Cylinder block

Six wheel motor truck frame

DieselLocomotive

1.5 m Stainless Steel Propeller

MaritimeUse

Maritime may refer to things related to the sea or ocean,

107 m3 Shovel Shoes

38 shoes per assembly

4 assemblies pershovel

Total cast weight333 tons

Crane used for lifting heavy material

Examples of cast parts :Examples of cast parts :

Metal: Aluminum Process: Die Cast Weight: 14.6 lbs Size: Large(over 12X12) Market: Automotive Description: Transmission Gear Case

Examples of cast parts :Examples of cast parts :

Metal: Magnesium Process: Die Cast Weight: 90 grams Size: Medium(3X3 to 12X12) Market: Computer/Electronics Description: Military Hand Held Radio Housing

Examples of cast parts :Examples of cast parts :

Metal: Zinc Process: Die Cast Weight: 0.39 lbs Size: Medium(3X3 to 12X12) Market: Automotive Description: Police/Commercial Spot Light.

Examples of cast parts :Examples of cast parts :

Metal: Aluminum Process: Die Cast Weight: 19 lbs Size: Large(over 12X12) Market: Automotive Description: Lower crankcase

Examples of cast parts:Examples of cast parts:

Metal: Zinc Process: Die Cast Weight: 0.244 oz Size: Very Small(1X1) Market: Computer/Electronics Description: A shielded cable header for housing electrical connector pins

Examples of cast parts:Examples of cast parts:Metal: Aluminum Process: Die Cast Weight: xx Size: Medium(3X3 to 12X12) Market: Sports/Recreation Description: wankel snowmobile engine rotor housing

The Wankel engine is a type of internal combustion engine which uses a rotary design to convert pressure into a rotating motion instead of using reciprocating pistons. Since its introduction the engine has been commonly referred to as the rotary engine. The most extensive automotive use of the Wankel engine has been by the Japanese company Mazda .

Most Impressive!

BUDDHAat the Po Lin Monastery

on Lantau Island

His head isone

piece

Advantages of Casting

• Can create complex part geometries• Can create both external and internal

shapes• Some casting processes are net shape;

others are near net shape• Can produce very large parts • Some casting methods are suited to mass

production• It is economical to use in some cases

Disadvantages of Casting

• Limitations on mechanical properties

• Poor dimensional accuracy and surface finish for some processes; e.g., sand casting

• Safety hazards to workers due to hot molten metals

• Environmental problems