Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
Please, read carefully the questions and give your answer clearly written and appropriately
illustrated with figures. Add additional sheets if necessary. Please, keep your handwriting and
figures as readable as possible!
Question 1 (max. 1 points)
Draw the equilibrium Fe-Fe3C diagram and fill in the phases (with red) and the structural
constituents (with blue)! Keep as much as possible correct scales for the temperatures and
concentrations!
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Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 2 (max. 2 points)
Plain carbon steels contain as main elements Fe and C but also additional elements which appear
during the metallurgical process. Please, comment:
1. What are the other elements that can be found in plane carbon steels (excluding Fe and
C) and which is their origin? (max.0.5point)
2. Which of the above elements have positive and which negative effect on the
technological and mechanical properties of steels? (max.0.5point)
3. How the elements with negative influence on the properties can be removed from steel?
Show example for the chemical reactions and place in the technological route where the
unwanted elements are removed. (max.1 point)
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 3 (max 2 points)
A complex shaped machine parts are often produced by casting. It is known that the cast irons are
very good material for casting. The best properties in the casting can be obtained in a cast iron
which has both -low solidification temperature and solidification is in very narrow temperature
range. In the table below 3 different cast irons compositions (in mass %) are shown indicated as A,
B and C:
element
grade
A
B
C
C
%
2.9
4.3
2.8
Si
%
3.35
3.3
2.1
P
%
0.95
0.8
0.5
Mn
%
0.3
0.6
0.5
1. Choose the material with the lowest solidification temperature and the narrowest
temperature interval for solidification and explain how you made your choice! (0.5 point)
2. Describe the expected microstructure in materials A, B and C after solidification in sand
mould if the wall thickness of the cast is 20 mm. (1 point).
3. Select the material among the grades A, B and C in which the best wear resistance
(abrasion resistance) can be obtained and explain how it can be produced. (0.5 point).
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 4 (max 1 points)
1. In heat treatment is often used a specific terminology. Please explain briefly:
 The meaning and the difference between “tempering” and “ageing”;(0.5 point)
 The meaning and the difference between “improving” and “normalization”.(0.5 point)
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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a.
b.
c.
d.
e.
0.45%C, 1%Cr, 1, 1%Ni, 0.6%Mo
0.01%C, 18%Cr, 10%Ni, 0.5%Ti
0.18%C, 1%Cr, 1%Mn, 0.5%Ti
0.2%C, 0.4%Mn, 0.2%Si
1.2%C, 0.4%Mn, 0.2%Si
Ø 900
Question 5 (max. 3 points)
Recommend a material and heat treatment (thermo-chemical treatment) for production
of gear wheels with dimensions shown in the figure below [in mm]. You have choice from
the following steel grades (all elements are in mass %):
200
Give as much as possible details and motivation for your answer. There is more than one
possibility. Use of graphs and illustrative charts in the answer is highly appreciated!
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 6 (max. 4 points)
Plate with a final thickness of 100 mm and width of 2500 mm should be rolled from a slab
with a thickness of 300mm, width of 2500 mm and length of 2000 mm. To execute the
rolling you have a reversed four high rolling mill with working rolls diameter of 600 mm,
which can apply a maximum force of 1500 t and the rolls operate at 100rpm. The friction
coefficient for hot rolling is assumed to be µ=0.35 (for all passes). The slab leaves the
reheating furnace with a temperature of 1150°C. Please, mention that you can use
effectively max 85% of the maximum rolling force of the rolling mill.
The mean flow stress of the steel (σ0) as a function of temperature is given in table 1.
Table 1
T, °C
1100
1075
1050
1025
1000
MFS, MPa 29.84 30.93 32.91 32.66
39.2
975
950
925
900
875
40.33 44.82 49.45 55.87 63.4
Calculate:
1. What will be the final length of the plate after rolling (assuming ideal plane strain
conditions) (0.5 point)
2. The minimum number of rolling passes that you should apply to obtain the final thickness
of the plate. (1.5 points)
3. The rolling force per each pass. (Neglect the contribution to the rolling force caused by
the rolls flattening). (2 points)
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 7 (max.2 points).
To evaluate the deep drawability of two steel sheets denominated as steel A and steel B, tensile
samples with long axis oriented 0°, 45° and 90° with respect to the sheet rolling direction were
tested. The samples were with initial gauge length L0 of 80mm and initial width W0 of 20mm. The
values obtained for the elongation (L) and contraction (W) are shown in the table 1 below, where
the number in the brackets shows the sample orientation with respect to the sheet rolling
direction (in degrees):
Table 1.
Sample/orientation
L0, mm
A (0)
80
A 45
A (90)
L, mm
W0, mm
W, mm
99
20
17
80
99
20
17.3
80
101
20
16.8
B(0)
80
95
20
18
B45
80
96
20
17.8
B(90)
80
96
20
17.7
Discuss the applicability of the materials for deep drawing application based on this test-deep
drawability (1 point) and earing formation (1 point).
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
Question 8 (max.2 points).
Write the names of the parts of the cast and the mold in the empty boxes.
Which part of the mold form mould gating system?
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Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 9. (max.1 point).
A steel slab with dimensions 250/1000/2000-mm is cast in mould with constant Cm=0.2min/mm2.
Calculate the total solidification time of the slab if the coefficient n in the formula for calculation
of the total solidification time is =2.
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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Question 10 (max.2 points)
Show which design is correct and which is wrong and explain why. What kinds of casting defects are
avoided by the correct design?
Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
Some formulas that you may need during the exam in case you do not
remember them:
Sc 
C%
4.23  0.31Si %  0.33P%  0.07 Mn %
V 
TST  C m  
 A
n
w0
w .
Normal anisotropy: R 
wL
ln
w0 L0
ln
P
hmax
2
3
L p
1 Q

e  1 b Rh  , Q 
, L p  Rh ;
h
Q

0


16(1   2 )
  R; C 
;
E
2
CP 

R  R 1 

 hb 
'
The lever a can be assumed to be 0.5 of Lp.
W  4aPN

1
1
MFS 
d
 1   0 0
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Name:.........................................................................................................................................
Exam: Technological aspects of metal processing (E066270), January 5th 2015, 8:30-12:30AM
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