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Chapter 12 Manufacturing Materials Engineering Drawing and Design Engineering Drawing and Design Seventh Edition.

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Presentation on theme: "Chapter 12 Manufacturing Materials Engineering Drawing and Design Engineering Drawing and Design Seventh Edition."— Presentation transcript:

1 Chapter 12 Manufacturing Materials Engineering Drawing and Design Engineering Drawing and Design Seventh Edition

2 Cast Irons & Ferrous Metals Ferrous Metals: Iron and the large family of iron alloys called STEEL are the most frequently specified metals. Cast Iron: Low cost but its properties can vary greatly depending on how it is manufactured (rate of cooling, thickness of casting, how long it remains in mold) – Ductile (nodular) iron is used when higher ductility or strength is required than is available in gray iron. (crank shafts, heavy-duty gears, automobile door hinges) – Grey iron is a supersaturated solution of carbon in an iron matrix and is widely available. (automotive blocks, flywheels, brake disks & drums, machine bases, gears) – White iron is produced by chilling which prevents the graphite carbon from precipitating out. Wear resistant(mill liners, shot-blasting nozzles)

3 Cast iron continued High-Alloy irons: ductile, gray or white iron that contain over 3%alloy content Malleable iron (ferric and pearlitic) is produced by a 2-stage heating process and is strong and ductile, has good impact and fatigue properties, and excellent machining characteristics

4 Carbon Steel is an iron-carbon alloy with small amount of other elements Cast or wrought into different mill forms Wrought steel is either poured into ingots or sand-cast Carbon and low-alloy cast steels lend themselves to the formation of streamlined, intricate parts with high strength & rigidity High-alloy cast steel (minimum 8% nickel and/or chromium)

5 Carbon steels account for over 90% of total steel production The conditions under which the steel solidifies have a significant effect on its properties Steel specification: chemical or mechanical properties, by its ability to meet a standard specification, or by its ability to be fabricated into an identified part.

6 Chemical Composition of steel Carbon: the principal hardening element in steel (.85% gives greater hardness, less ductility) Manganese: increasing manganese increases the rate of carbon penetrations during carburizing but decreases weldability Phosphorus Silicon Sulfur Copper Lead

7 MANUFACTURING MATERIAL SCHEMATIC DIAGRAM OF A BLAST FURNACE

8 MANUFACTURING MATERIAL FLOWCHART FOR STEELMAKING

9 MANUFACTURING MATERIAL FLOWCHART FOR STEELMAKING

10 Classification Bodies SAE: Society of Automotive Engineers AISI: American Iron and Steel Institute ASTM: American Society for Testing & Materials ASME: American Society of Mechanical Engineers

11 SAE and AISI System of steel identification Four numbered code First number: major class of steel Second number: subdivision of major class Third & Fourth numbers: Carbon content (hundredths of one percent) Example: SAE 2335 is a nickel steel containing 3.5 % nickel and.35 of 1% carbon

12 MANUFACTURING MATERIAL CARBON STEEL DESIGNATIONS TYPE OF CARBON STEELNUMBER SYMBOL PRINCIPAL PROPERTIES COMMON USES Plain carbon10XX Low-carbon steel (0.06 to 0.20% carbon) 1006 to 1020Toughness and less strength Chains, rivets, shafts, and pressed steel products Medium-carbon steel (0.20 to 0.50% carbon) 1020 to 1050Toughness and strength Gears, axles, machine parts forgings, bolts and nuts High-carbon steel1050 and overLess toughness and greater hardness Saws, drills, knives, razors, finishing tools and music wire Sulfurized (free-cutting) 11XXImproves machinability Threads, splines, and machined parts Phosphorized12XXIncreases strength and hardness but reduces ductility Manganese steels13XXImproves surface finish

13 MANUFACTURING MATERIAL AISI DESIGNATION SYSTEM FOR ALLOY STEEL

14 Steel forms Carbon-steel sheets: flat rolled sheets made from heated slabs that are progressively reduced in size as they move through a series of rollers Hot-Rolled Sheets Cold-Rolled Sheets Carbon-Steel plates Hot-rolled bars Cold-finished bars Steel Wire Pipe : specified by OD and wall thickness Tubing: specified by OD, ID or wall thickness

15 Structural-Steel shapes Beams & channels: specified by depth and weight per length (lb/ft) Angles: specified by length of legs & thickness (or lb/ft) Tees Zees Wide-flange sections: specified by depth, width across flange, lb/ft

16 More types of Steel High-Strength Low- Alloy (HSLA) Low and Medium- Alloy steels Stainless steels: corrosion resistance Free-Machining

17 MANUFACTURING MATERIAL COMMON METHODS OF FORMING METALS

18 Nonferrous Metals Aluminum: 1/3 density of steel, but some alloys are stronger than steel & corrosion resistant Copper: good conductor, corrosion resistant Nickel Magnesium Zinc Titanium Beryllium Refractory metals Precious metals

19 MANUFACTURING MATERIAL WROUGHT ALUMINUM ALLOY DESIGNATIONS MAJOR ALLOYING ELEMENTDESIGNATION Aluminum (99% or more)1xxx Copper2xxx Manganese3xxx Silicon4xxx Magnesium5xxx Magnesium and silicon6xxx Zinc7xxx Other elements8xxx Unused series9xxx

20 Plastics : nonmetallic materials capable of being formed or molded with heat, pressure, chemical reactions, or combination Disadvantages of metals: corrode or rust, need lubrication, working surfaces wear readily, cant be used as electrical or thermal insulators, opaque & noisy, when they flex they fatigue rapidly Plastics (many) are chemical resistant, corrosion resistant, need no lubrication, quiet running, light weight, range of colors, adaptable to mass production methods, low cost Thermoplastics soften or liquefy and flow when heat is applied Thermosetting Plastics undergo an irreversible chemical change when heat is applied or a catalyst or reactant added Can be machined

21 MANUFACTURING MATERIAL COMMON TERMS FAMILY OF PLASTICS THERMOSETTINGTHERMOPLASTICS AlkydsABS AllylicsAcetal Resin Amino (Melamine and Urea)Acrylics CaseinCellulosics EpoxyFluorocarbons PhenolicsNylon Polyesters (fiberglass)Polycarbonate SiliconesPolyethylene Polystyrene Polypropylenes Urethanes Vinyls

22 Rubber Elastomers are derived from either natural or synthetic sources Has Elastic properties. Withstands large deformations and quickly recovers shape Mechanical rubber (tires, belts, bumpers) Cellular rubber (pads, weather stripping, foam rubber)


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