الخلاصة:
ABSTRACT
Inconel 718, a representative nickel base superalloy, is widely used
plants, petrochemical industries and Chemical due to its high temperature
endurance properties and excellent corrosion resistance. However, the
turning of Inconel 718 produces more generations heat in the cutting zone
than that of greatest other materials and alloys which makes this material
pruned to surface defects. The aim of this study is to evaluate the effect of
different turning parameters i.e. cutting speed (v),feed rate (f) and depth of
cut(d) on the responses i.e. surface integrity including surface
roughness(Ra), microhardness(HV) ,residual stresses and corrosion
behavior for nickel base superalloy (Inconel 718) during dry turning using
coated carbide tools. Experiments was designed using design of experiment
(DOE) Taguchi method and experimental runs are conducted for various
combinations of turning parameters to find the optimum machining
parameters that achieves better surface quality with minimum corrosion
rate. Analysis of variance (ANOVA), correlation and regression techniques
are employed to determine the significance turning parameters. In addition,
a numerical model using 3D finite element method (FEM) is performed by
ABAQUS software to examine the machined surface temperature
II
distribution and residual stresses induced by turning and the results of the
models are validated by comparison them with experimental results. The
comparison showed a good agreement more than (90%) between the 3D
FEM modeling of the oblique machining and experimental results.
Moreover, the results showed that the feed rate has the most
significant(66%) effect on the surface roughness and the best surface
quality is achieved using the highest cutting speed and lowest feed rate and
depth of cut. The cutting speed has the most significant(56%),(63%)and
(50%) respectively effect on the residual stresses(Rs), microhardness(Hv)
and machined surface temperature . Also, it was found that the
temperature generation during high-speed turning of is found to play a
major role in residual stress magnitude. The surface roughness and
compressive residual stresses are very important factors which play major
effect on the corrosion behavior of Inconel 718. In this way, the feed rate is
showed the most significant(72%) factors for minimizing the corrosion rate
in Inconel 718 alloy .The results obtained by this research will be fruitful
for various industries and researchers who are working in this field.
