lecture4

lecture4 - ENGR 2220 Structure Properties of Materials...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
NGR 2220 NGR 2220 – ENGR 2220 Structure & Properties of Materials Lecture 4 Overview of material properties Chapter 6 Chapter 6 – Continued Continued nd and Chapter 2
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Engineering Properties F = F o A σ o A τ θ γ tan = 0 l l Δ = ε G = E = y x υ = = z z
Background image of page 2
Hardness Mineral Absolute Hardness Image HARDNESS 1 T alc (Mg 3 Si 4 O 10 (OH) 2 ) 1 Gypsum 2 (CaSO 4 ·2H 2 O) 2 3 Calcite (CaCO 3 )9 l it F 1 4 Fluorite (CaF 2 ) 21 5 Apatite (Ca 5 (PO 4 ) 3 (OH-,Cl- ,F-) 48 6 Orthoclase (KAlSi 3 O 8 ) 72 7 Quartz (SiO 2 ) 100 8 Topaz (Al 2 SiO 4 (OH- ,F-) 2 ) 200 9 Corundum (Al 2 O 3 ) 400 10 Diamond (C) 1500 Mohs’ scale: Friedrich Mohs 1822 Comparative not scaler.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
HARDNESS Resistance to permanently indenting the surface. Large hardness means: sistance to plastic deformation or cracking in --resistance to plastic deformation or cracking in compression. --better wear properties. e.g., 10mm sphere apply known force (1 to 1000g) measure size of indent after removing load d D Smaller indents mean larger hardness. most plastics brasses Al alloys easy to machine steels file hard cutting tools nitrided steels diamond increasing hardness Adapted from Fig. 6.18, Callister 6e. (Fig. 6.18 is adapted from G.F. Kinney, Engineering Properties and Applications of Plastics , p. 202, John Wiley and Sons, 1957.)
Background image of page 4
Hardness: Measurement Table 6.5
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Hardness: Measurement Rockwell No major sample damage Each scale runs to 130 but only useful in range 0 00 20-100. Minor load 10 kg Major load 60 (A), 100 (B) & 150 (C) kg A = diamond, B = 1/16 in. ball, C = diamond HB = Brinell Hardness TS (psia) = 500 x HB TS (MPa) = 3.45 x HB
Background image of page 6
Hardness: Conversion
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Variability of Material Properties • Variations in test data – Test method – Variations in specimen fabrication – Operator bias – Apparatus calibration – In homogeneities within material – Slight compositional changes from lot to lot • Statistics: typical & standard deviations
Background image of page 8
DESIGN OR SAFETY FACTORS Design uncertainties mean we do not push the limit.
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 35

lecture4 - ENGR 2220 Structure Properties of Materials...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online