Environmentally Conscious Design & Manufacturing

1. Environmentally Conscious Design & Manufacturing Class16: Material Selection Prof. S. M. Pandit

2. Agenda • Generic automobile materials • Engineering materials • Properties of materials • Guidelines for materials selection • Steels, cast iron, alloys, and ceramics

3. Generic Automobile Materials

4. The Flow of Aluminum Unit: kg

5. Materials Use in Automobile Unit: kg

6. Design Process Need for a device or product Product Function? Synthesis (Creativity-Ideas) Redesign • Change • material? • process? Material selection Product part (prototype) Satisfactory Unsatisfactory Evaluate performance Put Part into Service

7. Engineering Materials • Ferrous metals: carbon, alloy, stainless, and tool and • die steels • Nonferrous metals and alloys: aluminum, magnesium, • copper, nickel, titanium, low-melting alloys • Plastics: thermoplastics, thermosets, and elastomers • Ceramics: glass ceramics, glasses, graphite, and • diamond • Composite materials: reforced plastics, metal-matrix • and ceramic-matrix composites, and honeycomb • structures.

8. Engineering Materials (cont.) High strength, Moderate modulus, High ductility Metals Poor corrosion Resistance High modulus Abrasion resistant Low modulus High strength Polymers creep at low temp Ceramics brittle Composites Corrosion resistant Corrosion resistant Elastomers creep at low temp Glasses Brittle

9. Properties of Materials • Mechanical properties:strength, toughness, ductility, • hardness, elasticity, fatigue, and creep • Physical properties: density, thermal expansion, • conductivity, specific heat, melting point, and electrical • and magnetic properties • Chemical properties:oxidation, corrosion, toxicity, • and flammability • Manufacturing properties: castability, formability, • machinability, weldability, and hardenability by heat • treatment.

10. Properties of Materials (cont.) Environmental Aspects Recycling Composition Production Resource depletion Energy Effluents

11. Guidelines for Materials Selection • Traditional guidelines for materials selection: • Desired mechanical, physical, and chemical • properties • Shapes of commercially available materials • Reliability of supply • Cost of materials and processing

12. Guidelines for Materials Selection (Cont.) • Guidelines for materials selection from the ECDM viewpoint: • Choose abundant, non-toxic, nonregulated • materials • Choose materials familiar to nature • Choose easily recycled materials • Minimize environmental impact without loss • of product quality

13. Low-Impact Materials • Non-hazardous materials • Non-exhaustable/renewable materials • Low-energy content materials • Recycled and recyclable materials

14. Energy Aspects • Energy to mine raw materials • Energy to extract and refine ore • Energy to from product • Energy to ship product • Energy to use product • Energy to disposal of product

15. Part is remanufacturable – Example: starter, transmission Steel, aluminum, lead, and copper have good recycling records. Organic material for energy recovery, that cannot be recycled. Example: Tires, rubber in hoses. Inorganic material with no known technology for recycling. Material Recyclability

16. Types of recycled material home scrap pre-consumer post-consumer Design considerations ease of disassembly material identification simplification and parts consolidation material selection and compatibility Material Life Extension

17. Improvements of Existing Products • Substitution (water based coatings instead of • volatile organic compounds) • Reformulation (e.g., unleaded gasoline is a • reformulation of the leaded variety) • Elimination

18. Reduced Material Intensiveness • Dematerialization • - Less materials means less consumption, • saves energy and money. • Shared use of product • Integration of functions • Functional optimization of product and • components

19. Weight reductions reduce energy needed to move the product. Avoid over-dimensioning the product via good design Reduction in volume (space required for transport and storage) Reduction of Material Usage

20. Example (Xerox) Source: Calkin, P., 1998

21. The Results of Efforts • Reduced solid waste generation by 73 percent • Increased the factory recycle rate by 141 percent • Reduced releases to the environment by 94 percent • Realized over $ 200 million in annual savings

22. Steels • Plain carbon steels • Low-carbon steel (0.02% - 0.3%C), used for manufacturing • bolts and nuts, bars and rods • Medium-carbon steel (0.3% - 0.6 %C), used to harden tools • such as hammers, screw drivers, and wrenches. • High-carbon steel (0.6 % - 1.5%C), for edge cutting tools • such as punches, dies, taps, and reamers. • Alloy steels • Addition of alloying elements (Cr, Mn, Mo, Ni, T, V) • improves mechanical properties of steels

23. Cast Iron • Alloy of iron and carbon (1.7%-4.5%C) • Gray cast iron, used in machine tool, automotive, • and other industries • White cast iron, used for the production of malleable • iron casting • Chilled cast iron, used for products with wear-resisting • surface • Alloy cast iron, used in automotive engine, brake, • and other systems, machine tool casting, etc. • Malleable iron castings, used in industrial applications • that require a highly machinable metal, great strength • ductility and resistance to shock.

24. Aluminum and its Alloy • Properties: • High strength-to-weight ratio • Resistance to corrosion • High thermal and electrical conductivity • nontoxicity, ease of recycling • reflectivity, ease of machinability • Uses: • Con and foil • Construction (building etc.) • Transportation (aircraft, automobile, etc.) • Electrical conductors, and appliances

25. Nonferrous Alloys • Copper-based alloys (ex. Brasses and bronzes) • - good strength, hardness, conductivity. • Aluminum-based alloys • - increased tensile strength, weldability, ductility • Nickel-based alloys • - high strength and corrosion resistance • Zinc-based alloys • - good corrosion resistance, strength, and ductility

26. Ceramics • Types • Oxide ceramics, carbides, nitrides, cermets, sialon • General properties • Brittle, high strength, high hardness, low toughness, • low density, low thermal expansion, and low thermal and • electrical conductivity • Applications • Automobile components, electronics, cutting tools, fiber • optics