Elements of Machine Design ME5I 22564 EMD

1. 22565 EMD : 1.5 : Fundamental of Design
Standardization
Definition : A set of specifications or procedure for the
design analysis, testing, manufacturing of a system
component or product to achieve uniformity, quality,
interchangeability and safety and to put reasonable
limits on the variety.
Purpose : To establish mandatory norms for product
development
Types :
1) Company standard or Local standard
2) National standard (IS, ISI, BIS, ANSI)
3) International Standard (ISO, ASTM, IBWM)

2. 22565 EMD : 1.5 : Fundamental of Design
Advantages of Standards
1) Interchangeability
2) Quality, reliability
3) Mass production
4) Safety
5) Reduction in manufacturing time and efforts
6) Reduction in product price

3. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
1) Designation of steel as per Mechanical Properties
IS: 1570 (Part–I)- 1978 (Reaffirmed 1993)
Based on Minimum Tensile strength
Symbol Fe < minimum tensile strength >
for e.g. Fe 280 : Steel with minimum tensile
strength of 280 N / mm2
Based on Yield strength
Symbol FeE < yield strength >
for e.g. FeE 320 : Steel with yield strength of
320 N / mm2

4. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
2) Designation of Grey Cast Iron as per Mechanical
Properties IS : 210 – 1993
Based on Minimum Tensile strength
Symbol FG < minimum tensile strength >
for e.g. FG 150 : Steel with minimum tensile
strength of 150 N / mm2
3) Designation of Nodular Cast Iron as per Mechanical
Properties IS : 1865-1991
Based on Minimum Tensile strength
Symbol SG < minimum tensile strength >
for e.g. SG 300 : Steel with minimum tensile
strength of 300 N / mm2

5. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
4) Designation of Carbon Steel as per chemical composition
IS : 1570 (Part II/Sec I)-1979
(a)Figure indicating 100 times the average percentage of
carbon content,
(b) Letter ‘C’, and
(c) Figure indicating 10 times the average percentage of
manganese content.
For e.g. 40C8
(a)40 / 100 = 0.4 % Carbon
(b) Letter ‘C’
(c) 8 / 10 = 0.8 % Manganese

6. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
5) Designation of Free Cutting Steel as per chemical composition
IS : 1570 (Part III)-1979
(a)Figure indicating 100 times the average percentage of
carbon content,
(b) Letter ‘C’, and
(c) Figure indicating 10 times the average percentage of
manganese content.
(d) Symbol ‘S/Pb’ followed by the figure indicating the
100 times the average content of Sulphur / Lead.
For e.g. 14C14S14
(a) 14 / 100 = 0.14 % Carbon
(b) Letter ‘C’
(c) 14 / 10 = 1.4 % Manganese
(d) 14 / 100 = 0.14 % Sulphur

7. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
6) Designation of Low and Medium Alloy Steel as per chemical
composition IS : 1762 (Part I)-1974
(a) Figure indicating 100 times the average percentage carbon.
(b) Chemical symbol for alloying elements each followed by the
figure for its average
For e.g. 40 Cr 4 Mo 2
(a) 40 / 100 = 0.4 % Carbon
(b) 4 / 4 = 1 % Chromium
(d) 2 / 10 = 0.2 % Molybdenum
Element factor
Cr, Co, Ni, Mn, Si and W 4
Al, Be, V, Pb, Cu, Nb, Ti, Ta, Zr and Mo 10
P, S and N 100

8. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
7) Designation of High Alloy Steel as per chemical composition
IS : 1762 (Part I)-1974
(a) Letter ‘X’.
(b) Figure indicating 100 times the percentage of carbon content.
(c) Chemical symbol for alloying elements each followed by a
figure for its average percentage content rounded off to the
nearest integer.
(d) Chemical symbol to indicate specially added element to allow
the desired properties.
For e.g. X 10 Cr 18 Ni 9
(a) 10 /100 = 0.1 % Carbon
(b) 18 = 18 % Chromium
(c) 9 = 9% Nickel

9. 22565 EMD : 1.5 : Fundamental of Design
Designation of material as per IS Code
8) Designation of High Speed Tool Steel as per chemical
composition IS : 1762 (Part I)-1974
(a) Letter ‘XT’.
(b) Figure indicating 100 times the percentage of carbon content.
(c) Chemical symbol for alloying elements each followed by a
figure for its average percentage content rounded off to the
nearest integer.
(d) Chemical symbol to indicate specially added element to allow
the desired properties.
For e.g. XT 75 W 18 Cr 4 V 1
(a) 75 /100 = 0.75 % Carbon
(b) 18 = 18 % Tungsten
(c) 4 = 4% Chromium
(d) 1= 1% Vanadium

10. 22565 EMD : 1.5 : Fundamental of Design
Preferred Number Series (IS 1076 – 1985)
1) Developed to reduce unnecessary variations in size
2) Standardize product range
3) Set of numbers in Geometric Progression
Basic
sizes
Addition
factor
Preferred Numbers
R5 5
10 =
1.58
1.00, 1.60, 2.50, 4.00, 6.30, 10.00
R10 10
10 =
1.26
1.00, 1.25, 1.60, 2.00, 2.50, 3.15, 4.00, 5.00, 6.30, 8.00, 10.00
R20 20
10 =
1.12
1.00, 1.12, 1.25, 1.40, 1.60, 1.80, 2.00, 2.24, 2.50, 2.80, 3.15,
3.55, 4.00, 4.50, 5.00, 5.60, 6.30, 7.10, 8.00, 9.00, 10.00
R40 40
10 =
1.06
1.00, 1.06, 1.12, 1.18, 1.25, 1.32, 1.40, 1.50, 1.60, 1.70, 1.80,
1.90, 2.00, 2.12, 2.24, 2.36, 2.50, 2.65, 2.80, 3.00, 3.15, 3.35,
3.55, 3.75, 4.00, 4.25, 4.50, 4.75, 5.00, 5.30, 5.60, 6.00, 6.30,
6.70, 7.10, 7.50, 8.00, 8.50, 9.00, 9.50, 10.00