MATERIAL SELECTION IN MECHANICAL ENGINEERING

01.

Performance index = 𝜎

ƥ

Figure 01: Material property table for question 1

Table 01: Material properties for selected materials for question 1

Medium carbon steel is used to design because it had high performance index and low cost

Material Strength (MPa)

Density (Kg/m3)

Performance index (m2/s2)x106

Cost SLR/Kg

Remarks

Wrought Precipitation Hardened Stainless Steel

1007.5 7.8 129.17 243.7 good corrosive resistence/expensive

Nodular (spheroidal, ductile) Cast Iron 502.5 7.15 70.28 40.6 low cost

Cast ferritic stainless steel, ASTM CC-50, low nickel

447.5 7.525 59.47 139.3 low ductility

Medium Carbon Steel 1030 7.85 131.21 40.6 high strength/low cost

Wrought Ferritic Stainless Steel 435 7.65 56.86 208.9 expensive

02.

Performance index = 𝜎32

𝐸

Figure 02: Material property table for question 2

Table 02: Material properties for selected materials for question 2

Material Strength Youngs modulus Performance index Relative cost Remarks

Polypropylene (PP) - 20% CaCO3 23 2000 0.055 75.4 Use as coatings

Polytetrafluoroethylene (PTFE) GF1 (PTFE+25% Glass Fibre) 20 1400 0.064 986.5 Use for non stick applications

Chloro TriFluoro Ethylene (CTFE) 23 1600 0.069 3597 High Chemical resistivity

Ethylene TetraFluoro Ethylene (ETFE) 26 1400 0.095 1972.5 Use as film

Polypropylene (PP) - 20% Talc 28.5 2300 0.066 86.6 Us for fiber reenforcement

Polytetrafluoroethylene (PTFE) GF1 (PTFE+25% Glass Fibre) is selected for the designing though it had somewhat high cost because for

safety proposes

Material Strength (MPa)

Young’s modulus (GPa)

Performance index (MPa0.5)x10-3

cost (SLR/Kg)

Remarks

Polypropylene (PP) - 20% CaCO3 23 2000 0.055 75.4 Use as coatings

Polytetrafluoroethylene (PTFE) GF1 (PTFE+25% Glass Fibre)

20 1400 0.064 986.5 Use for non-stick applications

Chloro TriFluoro Ethylene (CTFE) 23 1600 0.069 3597 High Chemical resistivity

Ethylene TetraFluoro Ethylene (ETFE) 26 1400 0.095 1972.5 Use as film

Polypropylene (PP) - 20% Talc 28.5 2300 0.066 86.6 Us for fiber reinforcement

03.

Performance indices

M1 = 𝐾𝐼𝐶 M2 = 𝐾𝐼𝐶

𝜎𝑓 M3 =

𝐾𝐼𝐶2

𝜎𝑓 M4 = 𝜎𝑓

Figure 03: Material property chart for question 3

Table 03: Material properties for selected materials for question 3

Wrought Ferritic Stainless Steel is selected for the design because it had good PI and good thermal properties

Material Fracture thougness(PI1)

Strength(PI4) Performance index 2 Performance index 3 Cost Remarks

Wrought Ferritic Stainless Steel 100.5 435 0.231 23.22 208.5 Good thermal properties

Low Carbon Steel 61.5 322.5 0.191 11.73 40.5 Low PI

Cast Austenitic Stainless Steel 141.5 330.5 0.428 60.58 324.9 Expensive

Wrought Precipitation Hardened Stainless Steel 102.5 1007.5 0.102 10.43 243.5 Expensive/Corrosive resistence

Cast Duplex Stainless Steel 100.5 510 0.197 19.80 231.5 Good corrosive resistence

Material Fracture toughness(PI1)

(MPa.m0.5)

Strength(PI4) (MPa)

Performance index 2 (m0.5)

Performance index 3

(MPa.m)

Cost (SLR/Kg)

Remarks

Wrought Ferritic Stainless Steel 100.5 435 0.231 23.22 208.5 Good thermal properties

Low Carbon Steel 61.5 322.5 0.191 11.73 40.5 Low PI

Cast Austenitic Stainless Steel 141.5 330.5 0.428 60.58 324.9 Expensive

Wrought Precipitation Hardened Stainless Steel

102.5 1007.5 0.102 10.43 243.5 Expensive/Corrosive resistance

Cast Duplex Stainless Steel 100.5 510 0.197 19.80 231.5 Good corrosive resistance

04.

Performance index = 𝛼12

𝜆

Figure 04: Material property chart for question 4

Table 04: Material properties for selected materials for question 4

Material Thermal diffusivity Thermal conductivity Performance index Relative cost Remarks

Medium Density Wood (Transverse) (0.45-0.85) 0.0000001245 0.1395 0.002529 493 Flammable/Expensive

Common Hard Brick 0.0000006231 0.9 0.000877 63 Low thermal conductivity

Cement 0.0000003228 0.85 0.000668 8 High thermal expansion

Normal Density Concrete 0.0000006678 1.65 0.000495 4.5 High thermal expansion

Granite 0.0000012773 2.85 0.000397 203 Expensive

Common hard brick is selected for the design because it’s low cost and ,thermal conduction and easiness of manufacture

Material Thermal diffusivity

(m2s)

Thermal conductivity

(W/m.k)

Performance index

(s0.5/W.k)

cost (SLR/KG)

Remarks

Medium Density Wood (Transverse) (0.45-0.85)

0.0000001245 0.1395 0.002529 493 Flammable/Expensive

Common Hard Brick 0.0000006231 0.9 0.000877 63 Low thermal conductivity

Cement 0.0000003228 0.85 0.000668 8 High thermal expansion

Normal Density Concrete 0.0000006678 1.65 0.000495 4.5 High thermal expansion

Granite 0.0000012773 2.85 0.000397 203 Expensive

05.

Performance index = σ2

E

Figure 05: Material property chart for question 5

Table 05: Material properties for selected materials for question5

Material Strength Youngs modulus Performance index Relative cost Remarks

Wrought Ferritic Stainless Steel 435 200 0.946 208.9 Chemical and corrosive resistence

Nodular Graphite Cast Iron 205 117.5 0.358 59 use as gas manifolds

Blackheart Malleable Cast Iron 224.5 170 0.296 43.1 not good corrosive resistence

Nodular (spheroidal, ductile) Cast Iron 502.5 172.5 1.464 40.6 Low cost/ high PI

Cast Ferritic Stainless Steel 430 200 0.925 139 Excellent corrosive resistence

Nodular (spheroidal, ductile) Cast Iron is selected for the design because it had good PI and low cost.

Material

Strength (MPa)

Young’s modulus (GPa)

Performance index (MPa)

Cost (SLR/Kg)

Remarks

Wrought Ferritic Stainless Steel 435 200 0.946 208.9 Chemical and corrosive resistance

Nodular Graphite Cast Iron 205 117.5 0.358 59 use as gas manifolds

Blackheart Malleable Cast Iron 224.5 170 0.296 43.1 not good corrosive resistance

Nodular (spheroidal, ductile) Cast Iron 502.5 172.5 1.464 40.6 Low cost/ high PI

Cast Ferritic Stainless Steel 430 200 0.925 139 Excellent corrosive resistance

6.1

Performance index = E12

Cv,R

Figure 06: Material property chart for question 6.1

Table 06: Material properties for selected materials for question6.1

Material Youngs Modulus Cost Performance index Remarks

Low Alloy White Cast Iron 185 34.8 0.3908 Good abration resistence

Wrought Aluminium Alloy 75 168 0.0515 Light weight

Low Carbon Steel 210 40.5 0.3578 Used in engineering applications

Wrought Ferritic Stainless Steel 200 208.5 0.0678 Expensive

Cast ferritic stainless steel, ASTM CC-50, low nickel 200 139 0.1017 Low nickle content

Low Carbon steel is selected for design because of its High young’s modulus and low cost.

Material Young’s Modulus (GPa)

Cost (SLR/Kg)

Performance index (GPa.Kg/SLR)

Remarks

Low Alloy White Cast Iron 185 34.8 0.3908 Good abrasion resistance

Wrought Aluminum Alloy 75 168 0.0515 Light weight

Low Carbon Steel 210 40.5 0.3578 Used in engineering applications

Wrought Ferritic Stainless Steel 200 208.5 0.0678 Expensive

Cast ferritic stainless steel, ASTM CC-50, low nickel 200 139 0.1017 Low nickel content

6.2

Performance index =

𝜎𝑓

23

𝐶𝑉,𝑅

Figure 07: Material property chart for question 6.2

Table 07: Material properties for selected materials for question6.2

Material Strength Cost Performance index Remarks

Low Alloy White Cast Iron 345 34.8 1.4135 Good abration resistence

Wrought Aluminium Alloy 270 168 0.2487 Light weight

Low Carbon Steel 322.5 40.5 1.1612 Used in engineering applications

Wrought Ferritic Stainless Steel 435 208.5 0.2754 Low PI

Cast ferritic stainless steel, ASTM CC-50, low nickel

447.5 139 0.4209 Low nickle content

Low Carbon steel is selected for the design because it had high PI and low cost

6.3

According to the results in 6.1 and 6.2 Low Carbon steel is suitable for low cost, stiff and strong beam

Abbreviation

Material Strength Cost Performance index Remarks

Low Alloy White Cast Iron 345 34.8 1.4135 Good abrasion resistance

Wrought Aluminum Alloy 270 168 0.2487 Light weight

Low Carbon Steel 322.5 40.5 1.1612 Used in engineering applications

Wrought Ferritic Stainless Steel 435 208.5 0.2754 Low PI

Cast ferritic stainless steel, ASTM CC-50, low nickel

447.5 139 0.4209 Low nickel content

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