PROPERTIES of MATERIALSMachine elements are often made of the following metal or metal alloys:

a) steel d) zincb) aluminum e) titaniumc) cast iron f) bronze

Ductility- is the degree to which a material will deform before the ultimate fracture and the opposite

of brittleness.- measure in percent elongation

% Elongation = Lf -Li x 100% Ductile > 5% Li Brittle ≤ 5%

Creep- progressive elongation of a material over time especially if operating at elevated temperatures.

Strain rate, єr = Δє Δt

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UNIFIED NUMBERING SYSTEM

Number Series Types of Metals and AlloysResponsible Organization

Non-ferrous metals and AlloysA00001-A99999C00001-C99999E00001-E99999L00001-L99999M00001-M99999N00001-N99999P00001-P99999R00001-R99999Z00001-Z99999

Aluminum and Aluminum alloysCopper and Copper alloysRare earth metals and alloysLow-melting metals and alloysMiscellaneous non-ferrous metals and alloysNickel and Nickel alloysPrecious metals and alloysReactive and refractory metals and alloysZinc and zinc alloys

AACDAASTMASTMASTMSAEASTMSAEASTM

Ferrous metals and alloysD00001-D99999F00001-F99999G00001-G99999H00001-H99999J00001-J99999K00001-K99999S00001-S99999T00001-T99999

Steels; mechanical properties specifiedCast irons and cast steelsCarbon and alloy steels(including SAE)H-steels; specified hardenabilityCast steels (except tool steels) Miscellaneous steels and ferrous alloysHeat and corrosion resistant(stainless)steelsTool steels

SAEASTMAISIAISIASTMASTMASTMAISI

Carbon and Alloy Steels Carbon – has the strong effect on the strength, hardness and ductility of any steel alloy.Other elements – affect hardenability, toughness, corrosion resistance, machinability and strength retention at high temperatures.

Designation System

AISI X X XX └ carbon content Specific alloy in the group Alloy group: indicates major alloying element

Importance of Carbon As carbon content increases, strength and hardness also increases under the same conditions of processing and heat treatment.

Low carbon steel: 0-0.30% C content Medium carbon steel: 0.30%-0.50% C content High carbon steel: 0.50%-0.95% C content

Bearing steel nominally contains 1.0% C. Common grades: 50100, 51100 and 52100

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AISI Alloy Groups Numbering System

10xx11xx12xx12Lxx13xx15xx23xx25xx31xx33xx40xx41xx43xx44xx46xx48xx5xxx51xx511005210061xx86xx87xx92xx93xx

Plain carbon steel; carbon and less than 1.0% Mn; non-resulfurizedFree-cutting steel; resulfurized. S ≈ 0.10%Free-cutting steel; resulfurized and rephosphorizedFree-cutting steel; Lead addedManganese steel ≈ 1.75% Mn; non-resulfurizedCarbon steel: nonresulfurized; Mn > 1.0%Nickel steel: nominally 3.5% NiNickel steel: nominally 5.0% NiNickel-chromium steel: nominally 1.25%Ni; 0.65% CrNickel-chromium steel: nominally 3.4%Ni; 1.5% CrMolybdenum steel: 0.25% MoChromium-Molybdenum steel: 0.95% Cr; 0.2% MoNi-Cr-Mo steel: 1.8%Ni; 0.5%-0.8% Cr; 0.25% MoMolybdenum steel: 0.5% MoNi-Mo steel: 1.8% Ni; 0.25% MoNi-Mo steel: 3.5% Ni; 0.25% MoChromium steel: 0.40% CrChromium steel: 0.80% CrChromium steel: 1.0% Cr; bearing steel, 1.0% CChromium steel: 1.45% Cr; bearing steel, 1.0% CChromium-Vanadium steel: 0.50%-1.10% Cr; 0.15% VNi-Cr-M- steel: 0.55% Ni; 0.50% Cr; 0.20% MoNi-Cr-Mo steel: 0.55% Ni; 0.50% Cr; 0.25% MoSilicon steel: 2.0% SiliconNi-Cr-Mo steel: 3.25% Ni; 1.2% Cr; 0.12% Mo

Stainless Steel- characterized with high level of corrosion resistance, chromium ≥ 10%- AISI designation from 200, 300 to 400 series

Strainless steel grouping: Austenitic – falls in AISI 200-300 series; general purpose grades, non-heat-treatable

and non-magnetic Ferritic – belong to the AISI 400 series [ 405, 409, 430, 446, etc]; non-heat-treatable

but magnetic Martensitic – AISI 400 series: 403,410,414,416,420,431 and 440 types; can be teat-

treated, magnetic and higher strength than the 200-300 series

Tool Steels- used for cutting tools, punches, dies, shearing blades, chisels and similar uses.

Types:a) High Speed

o M – molybdenum: AISI M2 (UNS: T11302), M10(T11310), M42(T11342)o T – tungsten: T1(T12001), T15(T12015)

b) Hot-workedo H – Chromium: H10(T20810); Tungsten-H21(T20821); Mo-H42(T20842)

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c) Cold-worked

TYPICAL SECTIONS OF VARIOUS STRUCTURAL STEEL APPLICATIONS

Figure 1- round pipes Figure 2- rectangular tubing Structural Steel

- ASTM designated number system

Name of Shape Symbol Example Designation (English system)

Angle LL4 x 3 x ½ [ L-shape; 4- length of longer leg; 3- length of shorter leg; ½ - thickness of the legs]

Channel CC15 x 50 [ C-standard C shape; 15- nominal depth of web vertical; 50-weight per unit length]

Wide flange beam W W14 x 43 [ W-shape; 14- nominal depth; 43-weight per unit length]American standard beam

S S10 x 35 [S-shape; 10-nomial depth; 35-weight per unit length]All in inches

Structural tubing-square 4 x 4 x ¼ [4-depth; 4-width; ¼-wall thickness]Tubing-rectangular

6 x 4 x ¼ [6-depth of the longer side; 4-width of the shorter side; ¼-wall thickness, all in inches]

Pipe 4” standard weight, 4” schedule 40

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