1 IT 111 MANUFACTURING MATERIALS Lecture 3 Thomas E. Scott

2 Standards Organizations American Society for Testing and Materials (ASTM) American Iron and Steel Institute (AISI) Society of Automotive Engineers (SAE) American Institute of Astronautics and Aeronautics (AIAA) NASA Department of Defense (DOD)

3 ASTM Standards provide: Letter designation for standards that include: specifications, test methods, definitions, classification, suggested practices –A. Ferrous Metals –B. Nonferrous Metals –C. Cement, ceramics –D. Miscellaneous materials –E. Miscellaneous Subjects F. Specific applications of materials G. Corrosion, deterioration H. Emergency Standards

4 Ferrous Metals (Iron) In industry, iron is mainly used in the form of steel Steel – an iron carbon alloy with less than 2% carbon Cast Iron – more that 2% but less than 4% carbon

5 Production of Iron Very little pure iron produced –Usually ingot or iron powders Mostly steels – with alloys carbon, silicon, nickel, chromium, manganese –Plain carbon steel – less that 1% alloying element of carbon, silicon, and/or manganese –Low-alloy steel – have small quantities of the above plus nickel, chromium, molydenum or others that alter the properties of steel –High-alloy steel – have more than 5% of alloying elements

6 Source of Iron (Fe) Ores of iron –Magnetite – contains 65% iron Ferric oxide (Fe 2 O 3 ) and Ferrous oxide (FeO) Highly magnetic (Lodestone) –Hermatite – contains 50% iron Ferric oxide (Fe 2 O 3 ) Commonly know as rust Blood red –Taconite – contains 30% iron Green colored Contains a lot of silica

7 Refining Iron Ore Heat ore in a furnace where air (oxygen) has been removed –Produces coke Blast furnace – force air at 1100 F to permit carbon oxygen combustion –Iron melts –Slag provides a protective barrier for purified iron –Pure iron captured as ingots (Pigs) –Contains roughly 4% carbon (cast iron) Yield is about 50% tons of ore to produce 3000 tons of pig iron

8 Production of Steel (Conversion) Burn off carbon –Blow hot air across the pigs and scrap iron –Let the carbon burn –Add exact amounts of carbon and alloys –Draw off liquid into ingots Open Hearth – 200 tons in 12 hours Bessemer – 25 tons in 15 minutes Electric arc – Expensive because of energy used (for finishing)

9 Commercial Shapes of Steel Ingots –Blooms Beams Channels Tubes –Slabs Plates Pipe Sheets Coils –Billets Bars Rods Wire

10 Commercial Shapes of Steel

11 Carbon in Steel NAME% CarbonExample Low Sheet, Structural Medium Machinery, Re-bar, auto, aerospace High Machine tools, knives, hammers Cast Iron>2.00 Castings

12 Effect of carbon addition (Small increase – approx 0.1%) More expensive Less ductile – more brittle Harder Loses machinability Higher tensile strength Lower melting point Easier to harden Harder to weld

13 Characteristics of Carbon Steels Cold working –Plastic deformation at room temp Decrease thickness 4% Increase tensile strength 50% Work hardening results May require heat treating –Examples Cold rolled steel Cold drawn tubing

14 Other elements in steel Aluminum –Oxygen remains in steel – undesirable –Adding aluminum (killed steel) causes oxygen to react with aluminum and negates rust formation (good for forging and piercing) –Aluminum also promotes small grain size and therefore, toughness

15 Other elements in steel Manganese –Sulfur accumulates at grain boundaries – undesirable –Causes the steel to lose strength at high temp –Manganese ties up the sulfur –Increases strength, hardenability, and hardness

16 Other elements in steel Boron – increases hardenability Copper – increases corrosion resistance Chromium – corrosion resistance and hardenability Niobium – increases strength Titanium – high strength at high temp Tungsten carbide – high hardness Vanadium – toughness and impact resistance

17 Steel Free Cutting – (High sulfur) –e.g., AISI 1111 up to 1151 –Easy machining –Higher carbon XX44 for example, greater hardness and flame case hardening

18 Nomenclature for steels Steel – AISI and SAE Four digit designator describes alloy content NumberType of SteelNumberType of Steel 10-- Plain Carbon 43-- Ni Cr Moly 11-- Sulfurized 46-- Ni Moly 12L-- Leaded 5--- Chromium 13-- Manganese 6--- Chrom Van 2--- Nickel 7--- Unused 3--- Nickel-Chromium 8--- Low-Ni Cr Moly 40-- Molybdenum 9--- Ni Cr small -Moly 41-- Chrome Molybdenum

19 Nomenclature for steels Examples 1010 – Plain carbon (C = 0.1%) 4030 – Steel with 0.30% Molybdenum Standards table required to determine actual content, suggested use and properties Web access to clarify material properties - Often have to pay for it

20 Nomenclature for steels Table 3-B of Kazanas Table 3-C of Kazanas Table 3-D of Kazanas Table 3-E of Kazanas Table 3-F of Kazanas Table 3-G of Kazanas Table 3-H of Kazanas

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29 Tool Steels High carbon – high alloy High wear and heat resistance High strength – hard Letter classification TypePurpose A O WAir or Oil or Water hardening HHot working M-THigh-speed containing Moly or Tungsten PMold (plastic) Steels SShock resistant, med carbon, low alloy DHigh Chromium L-FSpecial Purpose

30 Tool Steels Examples W-1 – Water hardening 1% carbon used for cold working of metals D3 – High chromium with 2.25% carbon for cold working applications S2 – Shock resistant hammer or chisel steel

31 Tool Steels Table 3-I of Kazanas Table 3-J of Kazanas Table 3-K of Kazanas

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34 Tool Steels Must sustain high loads Often loads concentrated on surface May have elevated temperatures Often substantial shock loading Must be immune to cracking Often particular steel alloy types Seven basic types of tool steel

35 Tool Steels Properties for tool steels –Wear resistance –Impact resistance –High temperature capability –Toughness

36 Alloys in tool steels Carbon – hardenability (>0.6%) Manganese – reduce brittleness (<0.6%) Silicon – for hot forming, strength and toughness (<2%) Tungsten – hot hardness Vanadium – hardness and wear resistance Molybdenum – deep hardening, toughness Cobalt – hot hardness Chromium – hardenability (up to 12%) Nickel – toughness and wear resistance

37 Cast Iron More than 2% carbon Lower strength since carbon flakes produce minute cracks Very susceptible to breaking (brittle) Grey cast iron – almost no ductility White cast iron – 1% silicon making it hard

38 Nodular Cast Iron Nodular cast iron – small amounts of calcium, cerium, lithium, magnesium, sodium Slow cooling produces spheres instead of plates Improves ductility – 60:40:20 –Tensile 60K, Yield 40K, 20% elongation Engine blocks, pistons, crankshafts

39 Stainless Steel Normal Steels corrode rapidly if left uncoated Higher temperature, more rapid corrosion Chromium and nickel slow corrosion Stainless steels have Cr > 12%

40 Stainless Steel Ferritic – can be strengthened by work hardening –Jewelry, utensils, automotive trim Austenitic – non-magnetic –18/8 – 18% Cr, 8% Ni –Low carbon – low strength –Food utensils Martensitic – High strength –Knives, Maraging – superalloys, contain Moly and Titan

41 Stainless Steel Numbering system –200’s and 300’s – Austenitic –400’s – Ferritic and Martensitic

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43 Corrosion (Rust) Galvanic corrosion (electrolytic process) Corrosion sped up by – Temperature –Metal fatigue –Cold working Retarded by –Alloys –Coatings