ME 303: MANUFACTURING TECHNOLOGIES
HW:2
Instructor
Sinan Kesriklioğlu
Prepared by; Emirhan Ekerci
Submission Day
8.12.2025
ABDULLLAH GUL UNIVERSTY
KAYSERİ, 2025
Q1(A): Isometric View Of the Part:
Isometric View 1
Q1(C):
Cross Section(1)
Cross Section (2)
Cross Section (3)
Q1(B)
Functionality of the part: This designed part is commonly used in automobiles. Its function is
to connect the wheel to the suspension and drive system. It prevents wheel rotation problems
by supporting wheel bearings. It also carries the vehicle's radial weights and axial loads. On the
drive axles, it enables torque to be transmitted from the drivetrain to the wheels.
Why forging is a better manufacturing choice than casting for my part ?
The Impression Die Forging without Flash method was used in the production of this wheel
hub. There are two main reasons for this choice.
1: The goal is to ensure structural integrity and eliminate porosity. Casting methods can create
some internal defects. Gas voids and shrinkage cavities are among the most important. Forging
produces a dense, compact part free of these internal voids. By eliminating porosity, the part's
fatigue life is increased, increasing the part's likelihood of success under the cyclic loading
conditions experienced by a rotating wheel.
2: The wheel hub is a critical safety component because it is subjected to high dynamic loads
and shocks from the road. This superior safety requires increased mechanical strength. In the
casting process, the internal structure of the metal is formed randomly, while in the forging
process, the internal grain structure of the metal is oriented to conform to the shape of the part.
This directional alignment significantly increases the strength, toughness, and impact resistance
of the part compared to casting.
Q2(A)
Because forging is done at room temperature, it is considered a cold forging process. Cold
forging dies are subjected to much higher surface pressures and wear conditions compared to
hot forging dies. Therefore, AISI D2 Cold Work Tool Steel was selected to fo rge both
aluminum and copper alloys.
According to literature studies, AISI D2 steel shows an extraordinary wear resistance and high
compressive strength with the hard carbide structure it creates thanks to its high carbon and
high chromium content. According to the study conducted by Das et al. in 2009, it was
emphasized that AISI D2 steel is an industrial standard for cold forming dies and the wear
performance of this material under high loads was confirmed.
References:
Maldonado, G., & Camelio, J. (2024). Variation of the friction conditions in cold ring
compression tests of aluminum 1100-O and aluminum 6061-T6. Cogent Engineering, 11(1),
2399961.
Male, A. T., & Cockcroft, M. G. (1964). A Method for the Determination of the Coefficient of
Friction of Metals under Conditions of Bulk Plastic Deformation. Journal of the Institute of
Metals, 93, 38-46.
Das, D., Dutta, A. K., & Ray, K. K. (2009). Influence of varied cryotreatment on the wear
behavior of AISI D2 steel. Wear, 266(1-2), 297-309.
Q2(B)
To ensure accurate calculations of forging forces, coefficients of friction between the workpiece
and die were selected from scientific articles based on ring compression test data, which is
considered the most important factor in metal forming in the literature. This test method most
accurately simulates the high contact pressures and surface cleaning required in real forging
operations.
Maldonado and Camelio (2024), who investigated the friction behavior in cold forging of
aluminum 6061 alloy, experimentally determined that the friction coefficient varies between
0.12 and 0.16 under lubricated conditions. Taking this study as a reference, the value of 0.12
was selected in the analyses as representing the most suitable lubrication condition.
Based on the work of Male and Cockroft (1964), which is one of the main sources in the field
of tribiology, the coefficient of friction during the plastic deformation of copper materials was
determined to be approximately 0.15 in the cold forming process of copper.
Apendix
clc; clear; close all;
%% 1. input of the geometery parameters
D0 = 60; %initial diameter (mm)
h0 = 120; %initial height (mm)
r0 = D0 / 2 ; % initial radius (mm)
reduction = 60/100; % reduction is 60
%CVolume of the Cylinder (mm^3)
Volume = pi*(r0^2) * h0 ;
% Final height calculation
h_final = h0*(1-reduction);
% Material 1: Aluminum Alloy
K_Al = 205; %Strength coeef
n_Al = 0.20; %strain hardening
mu_Al = 0.12; % ref (maldonado & camelio)
% Material2: Copper Alloy
K_cu = 315; % strength coefficient (mpa)
n_cu = 0.54; % strain hardening expon
mu_cu = 0.15; % friction coef (male & cockfort)
% calculation
steps = 50;
h_vector = linspace(h0, h_final, steps);
radius_vector = zeros(1,steps);
Force_Al = zeros(1, steps);
Force_Cu = zeros(1,steps);
for i = 1:steps
h_current = h_vector(i);
r_current = sqrt(Volume / (pi * h_current));
radius_vector(i) = r_current;
epsilon = log(h0 / h_current);
if epsilon == 0
epsilon = 0.0001;
end
Yf_Al = K_Al * (epsilon ^ n_Al);
Yf_Cu = K_cu * (epsilon ^ n_cu);
Area = pi * (r_current^2);
Force_Al(i) = Yf_Al * Area * (1 + (2 * mu_Al * r_current) / (3 *
h_current));
Force_Cu(i) = Yf_Cu * Area * (1 + (2 * mu_cu * r_current) / (3 *
h_current));
end
% For Pilotting
Force_Al_kN = Force_Al / 1000;
Force_Cu_kN = Force_Cu / 1000;
figure;
plot(radius_vector, Force_Al_kN, '-b', 'LineWidth', 1.5); hold on;
plot(radius_vector, Force_Cu_kN, '--r', 'LineWidth', 1.5);
grid on;
xlabel('Workpiece Radius (mm)');
ylabel('Forging Force (kN)');
title('Forging Force vs. Radius (Al & Cu)');
legend('Aluminum Alloy (mu=0.12)', 'Copper Alloy (mu=0.15)', 'Location',
'northwest');
xlim([min(radius_vector) max(radius_vector)]);