Investigation of surface roughness in machining of aisi 1040 steel

1. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING
17 – 19, July 2014, Mysore, Karnataka, India
AND TECHNOLOGY (IJMET)
ISSN 0976 – 6340 (Print)
ISSN 0976 – 6359 (Online)
Volume 5, Issue 9, September (2014), pp. 36-43
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36
IJMET
© I A E M E
INVESTIGATION OF SURFACE ROUGHNESS IN MACHINING OF
AISI 1040 STEEL
Akshaya T Poojary1, Rajesh Nayak2
1(B. Tech Student, Mechanical Engg, Manipal University, India)
2(Assistant Professor, Mechanical Engg, Manipal University, India)
ABSTRACT
This paper presents the optimized method of machining process for improved surface finish of AISI 1040 steel
which was turned under dry, wet (SAE 90 soluble oil) and cryogenic (dip in LN2) condition. The surface roughness was
measured using Surtronic 3+.The values of surface roughness for each of the machining process were plotted with variant
feed rate. Cryogenic machining showed remarkable reduction in surface roughness compared to both dry and wet
machining especially at high feed rates. The percentage reduction in surface roughness observed in cryogenic machining
compared to wet machining was 7.54%-19.52%.
Keywords: AISI 1040 Steel, Cryogenic (dip in LN2), Dry, Surface Roughness, Wet.
1. INTRODUCTION
Steel has wide applications in industries and also the demand of steel is increasing day by day. The only way to
meet the increasing demand of consumers is to increase the rate of production and processing. This urge to meet high rate
of production causes generation of high temperature zone at the tip of the tool (tool wear) and also detoriates the quality
(surface finish, dimensional accuracy) of product manufactured. But no compromise can be allowed with surface finish
and dimensional accuracy of the product and at the same time the life of the cutting tool has to be taken care too. In order
to overcome these problems during machining either coated cutting tools or appropriate cutting fluids are used.
[1]There are varieties of soluble oil, mineral or vegetable oil base and mineral oil used to reduce the tool tip
temperature and increase the quality of the product. These oils perform two significant tasks of cooling and lubricating.
Some of these oils are used as emulsions and some as neat oils. In general oil-and-water emulsions have large heat
absorbing capacity than neat oils hence they are more often used where cooling is required. They are used in machine
tools with varying percentage of water and oil. Neat oils are used where lubrication plays a vital role such as gear cutting,
thread cutting etc. [2]But these conventional coolants fail to provide desirable control over cutting temperature in the
cutting zone and it also creates some techno-environmental problems.
[3]The use of conventional coolants not only restricts itself with these problems but also effects workpiece and
the parts of the machine tool by causing corrosion which ends up in the failure of the part. In recent years of
investigations performed on machining, use of cryogenic liquid as coolant was found. Cryogenic cooling involved a
liquid coolant whose boiling point is at subzero temperature. This coolant acting as sink would absorb the heat from the
tool tip temperature which forms the source of heat generation. This is based completely on the principle of flow of heat
from higher temperature to lower temperature. There are experiments conducted on steel using carbon dioxide as the
cryogenic coolant. Even though CO2 is cheaper and available in abundant it has two major disadvantages such as
affecting the respiratory system of the operator whose is in contact with it for prolonged period of time during machining

2. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
and it also has adverse impact on the greenhouse effect as CO2 is a greenhouse gas. Due to this major disadvantage
Liquid Nitrogen(LN2) is much preferred compared to carbon dioxide(CO2) when it comes to cryogenic cooling.[4,5,6]
Cryogenic cooling provided less cutting forces, reduced cutting temperature, better surface finish and improved tool life
compared to dry machining. The physical properties of LN2 are:-
Boiling Point : -195.8°c
Liquid Density : 808.607 kg/m3 (1.013 bar at boiling point)
37
Among the variety of steel grades available AISI 1040 steel is widely used in industries for manufacturing of
crankshaft, fasteners, coupling and cold headed parts.Thus the current work experimentally shows the comparison and
analysis of surface roughness for turning of AISI 1040 steel at various feed,speed and depth of cut using High speed steel single
point cutting tool for dry machining,machining using conventional cutting fluid(SAE 90 Soluble oil) and cryogenic cooling(dip
in LN2).
2. LITERATURE REVIEW
There has been a lot of research work conducted on machining (turning, grinding) of mild steel. [7]In dry
machining of a metal in lathe, oxygen jets were directed at tool-chip interface to perform the work of a coolant. It was
found that oxygen was particularly effective in reducing cutting forces and improving surface finish.[8]In an
experimental study conducted on metal cutting under high hydrostatic pressure, a hydrostatic pressure of 0MPa-150MPa
was applied using a pressure vessel. The orthogonal cutting process was carried out using hydraulic oil ISO VG 32 as
hydraulic fluid. It was concluded that hydrostatic pressure was successful in penetrating hydraulic oil into chip-tool
interface and at tool workpiece interface and thereby improving the surface finish with the increase in hydrostatic
pressure for both aluminium and steel workpieces.
[9]In an comparative study experiment conducted on 1045 cold rolledsteel for dry machining, flood cooling
using water based cutting fluid and micropool lubrication using cutting oil and solid lubricant, it was observed that
micropool lubrication supplies minimum amount of lubricant to the chip-tool interface resulting in improving the metal
to metal contact conditions by reducing the coefficient of friction.[10]In an investigational study of applicability of solid
lubricant in turning of AISI 1040 steel a new setup was designed for the application of fine solid lubricant powder(2μm
average size particle) at tool and work interface. The solid lubricant powder used for machining was molybdenum
disulphide. It was found that this method of solid lubricant machining was successful in reducing the surface roughness
and chip thickness ratio. It also improved the surface finish by 5% to 30%. [11]In turning of C45 steel under compressed
air, oil water emulsion, water vapour as coolant and lubricant and dry cutting, it was found that the use of water vapour
as coolant and lubricant reduced the values of various significant parameters such as cutting force, friction coefficient,
chip deformation coefficient and further it reduced the values of surface roughness thus improving the surface finish.
[12]In a turning operation performed on ANSI 1045 steel material using cemented carbide tool P10 under
variety of coolants such as oil water emulsions,CO2,O2,water vapour, WVC (mixture of water vapour and carbon
dioxide gas),WVO (mixture of water vapour and oxygen gas) and machining under dry conditions it was observed that
water vapour, gases andmixture of water vapour and gas as a coolant and lubricant emerged out to give better results than
the remaining machining conditions.[13]In comparison of applications of gases, wet and dry turning of AISI 1040 steel
oxygen, nitrogen and carbon dioxide gases were used at constant cuttingspeed with three different levels of feeds and
depth of cut. The cutting tools used for turning operation were P20 grade TPUN160312 type uncoated inserts and the tool
holder used was CTGPR2020. Results revealedthat finer surface finish was obtained at high feed rates with the
application of gases. [14] A new method of lubrication was proposed, which uses supercritical carbon dioxide (scCO2)
along with straight soyabean oil. The soyabean oil-in-scCO2 is sprayed during tapping operation and it was observed that
CO2 due to its rapid expansion cools the cutting zone and the combination of both high pressure and low surface tension
are primarily responsible for supplying the straight soyabean oil at interstitial spaces between the tool-wokpiece interface
thus providing better desired results than only straight petroleum mineral oil and petroleum oil.
[15] During turning of AISI 1045 steel under cryogenic condition(cryogenic coolant CO2),wet machining and
under dry machining it was concluded that application of CO2 gas improved the surface finish by 5%-25% compared to
wet machining.[16]In plain turning of stainless steel work under dry and cryogenic conditions it was concluded that
cryogenic cooling is more beneficial for higher machining rate with better quality but the consumption of liquid nitrogen
was high which lead to increase in overall cost of machining.[17] An experiment was conducted on turning of AISI 4037
steel under dry, soluble oil and cryogenic condition by spraying the jet of liquid nitrogen at tool tip. The experiment was
conducted at industrial feed-speed combination using a coated carbide insert. It was also concluded that application
cryogenic cooling resulted in better surface finish and higher dimensional accuracy compared to dry and wet
machining.[2] An experimental investigation was performed on turning of AISI 1045 steel and aluminium 6061-T6 alloy
using multi coated carbide and uncoated carbide cutting tools respectively. The jet of liquid nitrogen was sprayed at the
rake face of the tool (Rake cooling).The application of LN2 jet reduced the chip thickness ratio by 25% compared to dry
machining and the shear angle in cryogenic machining was increased up to 30%.

3. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
Material
C
Mn
P
S
AISI 1040 Steel
0.37-0.44
0.60-0.90
0.040
0.050
Work specimen AISI 1040 steel (Ø24mm and 304.8mm long)
Cutting tool Single point high speed steel cutting tool
Process Parameters
Feed 0.1mm/rev,0.13mm/rev and 0.18mm/rev
Depth of Cut 0.25mm,0.5mm and 0.75mm
Cutting Speed 27.14m/min, 33.92m/min and 43.73m/min
Machining Environment Dry, Wet and Cryogenic conditions
38
[4] A cryogenic cooling experiment on plain turning of AISI 1060 steel was performed by spraying
liquidnitrogen jet. The experiment was conducted at industrial speed-feed combination by using two different carbide
inserts of different geometric configurations. Cryogenic cooling reduced tool wear, improved tool life and surface finish
compared to dry machining.[18]N. R. Dhar et al. machined(turning) AISI 4140 steel under cryogenic cooling and
compared the values of various parameters with dry cutting. The different cutting tool inserts used for this operation were
SNMG 120408-26 and SNMM 120408.Improved surface finish and dimensional accuracy were obtained by adopting the
method of cryogenic cooling. [19] A variety of methods used to machine difficult to cut materialsusing cooling and
lubrication such as minimum quantity lubrication (MQL), high pressure coolant (HPC), compressed air cooling, solid
lubricants/coolants and cryogenic cooling using carbide inserts were performed. Cryogenic cooling showed better results
at high feed rates thus it was concluded that this method had the potentialof increasing the productivity.
3. EXPERIMENTAL SETUP
The turning operation was performed on medium carbon steel AISI 1040 in PSG A141 lathe (2.2 KW) using
High Speed Steel (HSS) single point cutting tool under dry cutting, conventional cutting fluid and cryogenic cooling
conditions. The workpiece of 24mm diameter and 304.8mm length was used to conduct the experiment. The chemical
composition of AISI 1040 Steel is as shown in Table 1.
Table 1: Chemical Composition of the workpiece material AISI 1040 steel, by weight [20]
The values for 3 different cutting speed, feed and depth of cut are as shown in Table 2:
Table 2: Experimental Conditions
Figure.1: cryogenic machining
The workpiece used for each of the machining conditions (dry, wet and cryogenic) were separate but were taken
from the same parent material so as to avoid any deviation in the results obtained due to variation in chemical
composition. The workpiece was dipped in cryogenic liquid (LN2) for a specified period of time and then fixed on to the
chuck for turning. TheFig.1 showsturning of AISI 1040 steel which was dipped in cryogenic liquid (LN2).

4. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM
The surface roughness of the machined workpieces were measured using Taylor Hob
instrument Surtronic 3+ (112/1590).The length for which roughness test was carried out was 4mm.It had a selectable
range of 10μm, 100μm and 500μm.Resolution used to carry out the experiment was 0.5μm.The instrument had a
selectable cut off value of 0.25mm, 0.8mm and 2.50mm.Skid pick up stylus with diamond tip radius of 5μm was used to
measure the surface roughness. The software used for data acquisition and evaluation of surface roughness was Taly
Profile 3.1.TheFig..2 2 shows the photographic
view of surface roughness measurement conducted.
Figure. 2: photographic view of surtronic 3+
4. RESULTS
Surface roughness (Ra) plays a significant parameter in deciding the level of surface finish obtained with the
respective machining condition. The undesirable surface finish of the machined part will not allow it to be assembled
with another mating part which together forms a component. In order to avoid the occurrence of such problems the best
method to obtain surface finish must be selected and put to practice.
cutting forces and specific cutting energy w
workpiece.[22,10]Studies of Brinksmeieret al.
roughness compared to that of 4% emulsion and dry machining conditions
depends upon various parameters such as the machining conditions, material composition of work, tool and coating over
it and the combination of feed, speed and depth of cut considered for machining.
This experiment conducted on mild steel specim
cutting speed, feed and depth of cut was conducted to obtain the surface roughness in each of the machining process to
analysis them and to conclude the optimized me
finish. All the graphs below show the variation of surface roughness with respect to feed obtained during machining of
AISI 1040 steel under dry, wet (SAE 90 soluble oil) and cryo
amount of reduction noticed in surface roughness obtained due to wet machining compared to dry and surface roughness
further reduced compared to wet machining with the use of cryogenic liquid in c
Figure. 3: surface roughness vs. feed for
17 – 19, July 2014, Mysore, Karnataka, India
39
ich [21, 10]Earlier studies revealed that reduction in
would certainly lead to improvement of the surface quality of the
et concluded that graphite assisted machining results in reduction in surface
conditions. The quality of surface finish obtained
onducted specimen on three different machining conditions and at 3 different
method of machining condition for arriving to the highest possible surface
cryogenic cooling condition. For Fig.3 there was an appreciable
cryogenic machining.
cutting speed = 27.14m/min and depth of cut = 0.25mm/rev
-2014
Hobson manufactured
ould thod .3 ryogenic

5. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM
Figure. 4: surface roughness vs. feed for cutting spee
. speed = 27.14m/min and depth of cut = 0.5mm/rev
Figure. 5: surface roughness vs. feed for
cutting speed = 27.14m/min and depth of cut = 0.75mm/rev
In Fig.4 it was observed that high feed rate for wet machining resulted in better surface finish because the
soluble oil was successful in entering the interstitial space between tool
roughness.In Fig.5 the surface roughness for cryogenic cooling at high feed rate did not reduce to
but wet machining reduced the surface roughness almost
decrease in surface roughness was noticed at high feed rate for cryogenic cooling.
Figure. 6: surface roughness vs. feed for
17 – 19, July 2014, Mysore, Karnataka, India
40
ig.tool-work interfaces thus thereby reducing the surface
.5 much expected value
to a value nearer to cryogenic machining. In
cutting speed = 33.92m/min and depth of cut = 0.25mm/rev
-2014
InFig.6 a remarkable

6. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM
17 – 19, July 2014, Mysore, Karnataka, India
Figure. 7: surface roughness vs. feed for cutting speed = 33.92m/min and
In Fig.7 again a reduction in surface roughness was obtained in wet machining
rate. In Fig.8 better surface finish was seen for cryogenic cooling at low feed rate even though the depth of cut was high.
This was due to low feed rate which allowed the chip to flow easily over the cutting tool without damag
surface and simultaneously cryogenic cooling was provided to reduce the cutting zone temperature.
Figure. 8: surface roughness vs. feed for c
Figure. 9: surface roughness vs. feed for cutting speed = 43.73m/min and
In Fig.9 cryogenic cooling was successful in reducing the surface roughness of the workpiece at high speed low
feed rate and also at high speed high feed rate with low depth of cut for both conditions.
41
depth of cut = 0.5mm/rev
compared to dry at high feed
cutting speed = 33.92m/min and depth of cut =0.75mm/rev
depth of cut = 0.25mm/rev
.9 eed -2014
damaging the machined

7. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM
Figure. 10: surface roughness vs. feed for
Figure. 11: surface roughness vs. feed for
-2014
17 – 19, July 2014, Mysore, Karnataka, India
cutting speed = 43.73m/min and depth of cut = 0.5mm/rev
cutting speed = 43.73m/min and depth of cut = 0.75mm/rev
In Fig.10 it was observed that again for low feed rate with high cutting speed was successful in reducing the
surface roughness due to cryogenic cooling compare
surface roughness was observed at high speed and feed rate in cryogenic machining compared to that of wet and dry
machining.
5. CONCLUSION
The use of cryogenic LN2 as cutting fluid along with dip method for machining of AISI 1040 mild steel and
comparing the surface roughness values with that of dry and wet machining the following conclusions can be made:
• It was evident from the surface roughness vs. feed graph th
finish of the workpiece compared to other two environments of machining for any given combination of cutting
speed, depth of cut and feed.
• The SAE 90 soluble oil was found to reduce the surface roughness u
compared to dry machining due to its excellent feature of reducing the cutting temperature and reducing friction
at tool-work interface.
• For cryogenic cooling it was observed that as the cutting speed increased be
was obtained. Cryogenic cooling showed decrease of surface roughness to a significant extent for high feed rates
compared to dry and wet machining due to the property of LN2 to reduce the cutting zone temperature and
thereby causing easy flow of chips through the tip of the tool.
• The percentage reduction in surface roughness of wet machining compared to dry was 6.54%
percentage reduction in surface roughness of cryogenic machining compared to wet
19.52%.
42
ig.e compared to dry and wet machining. In Fig.11 a beneficial reduction in
that dry machining could never improve the surface
usually at high feed rates and low speeds
better surface finish of the workpiece
ereby machining was 7.54%
ig.made:-
at sually tter 6.54%-9.06% and the
7.54%-

8. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
43
• Thus it was evident from the above results that cryogenic cooling using dip method was successful in reducing
the surface roughness value and thus improving the surface finish of the workpiece compared to dry and wet
machining.
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