International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014 ISSN 2319 - 4847
1
AMIT VISHAL,
2
RAHUL DAVIS
1,2
Mechanical Engineering Department Shepherd School of
Engineering & Technology,India
Cryogenic treatment has been widely used in the field of material science for improving hardness, toughness, wear resistance of tool materials. A comparative study of thermally treated H-13 grade high speed steel specimens has been presented in this paper.
Specimens initially subjected to conventional heat treatment at quenching temperature of 1050
0 c and quenched in to cold water, subsequently subjected to deep cryogenic treatment at -196
0 c for 24hrs followed by double tempering at 550
0 c. Variation in mechanical properties such as toughness ,wear resistance, hardness, tool life was studied. Hardness of the specimen which was only heat treated followed by quenching and tempering had maximum value than the specimen which was heat treated and then cryogenically treated. But toughness and wear resistance have higher value in heat treated and cryogenically treated specimen as compare to the specimen which was only heat treated.
Key words: Cryogenic Treatment, Heat Treatment, Tool Life, Toughness, Impact Value.
Steel is widely used and most recycled metal on earth. Production of steel is extremely great energy intensive. However once produced steel can be used again and again. With a global recovery rate of more than 70% steel is the most recycled material on planet. Up to 97% of by-products from steel manufacturing can also be reused. For example, slag from steel plants is often used to make concrete [1]. According to World Steel Association there are over 3500 different grade of steel.
Steel is composed of iron and carbon and additional alloying elements that determines the properties of each steel grade.
Tool steel contains tungsten, molybdenum, cobalt and vanadium in varying quantities to increase heat resistance and durability, making them ideal for cutting and drilling equipment[2] . To improve mechanical properties like toughness, hardness, wear resistance, hot hardness, etc conventional heat treatment and cryogenic treatment are performed on tool steel[3]. Cryogenic treatments on tool materials are frequently used by researchers recently. Cryogenic treatment consists of two stages. First, shallow cryogenic treatment in which cooling of tool material takes place from room temperature to temperature as low as-84
0 c. Second stage is slow cooling up to low temperature -196
0 c and soaking time 24hrs[4]. During operation tools are subjected to various type of cutting forces. So there is a need to improve the mechanical properties of tool steel. For improving mechanical properties various types of heat treatment like quenching, tempering, surface hardening etc are done on tool steel[5]. These heat treatments improve hardness, wear resistance considerably [6]. Cryogenic treatment followed by heat treatment improves toughness, tool life considerably. Cryogenic process can produce harder more wear resistance material with many other beneficial properties. Cryogenic treatment is a process to supplement the heat treatment to improve the mechanical properties of materials. No doubt it is costly process, but one time permanent treatment affects the entire section of the component. The notable effects of cryogenic treatment include, changes in the mechanical properties and the microstructure of material. In case of cutting tool materials high –speed-steel is the most ideal and unique in performance due to its ability to absorb shocks and vibrations during machining operations. Though addition of alloying elements make it suitable for specific metal cutting application. Cryogenic treatment is another option that helps to improve wear resistance and life of tool steel[7].
2.1. Materials and Procedures
For proposed research work H-13 tool steel is selected. There are 24 specimens, divided in four groups. Each group has 6 specimens. From Group I, all specimens were kept in electric furnace and heated up to temperature
1050
0 c, and quenched in cold water. Then tempering was done on specimens. Specimens were heated up to temperature 550
0 c and cooled slowly in the air. Hardness test, Impact test, Tool Life test were performed on these specimens. Now specimens Group II, were subjected to same process of quenching and tempering respectively.
Then these specimens were subjected to deep cryogenic treatment at -196
0 c for 24hrs. Then these very specimens

International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014 ISSN 2319 - 4847 were subjected to tempering process again at same temperature. Now specimens Group III, were subjected to same process of quenching and tempering respectively. Then these specimens were subjected to deep cryogenic treatment at -196
0 c for 24hrs. No further any heat treatment was done on Groupie specimens. Now specimens
Group IV were subjected to quenching process first at temperature 1050
0 c. Then these specimens were subjected to deep cryogenic treatment at -196
0 c for 24hrs. Then these very specimens were subjected to tempering process again at temperature 550
0 c, and cooled slowly in air. In this experiment quenching temperature, tempering temperature, cryogenic temperature and medium of cooling were same for all groups.
Table1: Chemical Composition of H-13 Tool Steel
5% Chromium
Vanadium 1%
Molybdenum 1.5%
Carbon 0.35%
Image 1(Heat Treated) Image 2(Cryogenically Treated)
2.2 Mechanical Testing
Brinell Hardness test was performed on single specimen from each group. Spherical indenter steel ball of diameter 4.5mm was used to forced into surface of the metal to be tested. For calculation the tool life hard steel and mild steel were used as work piece. Spindle speed, feed rate were fixed at 140rpm,0.1mm/rev respectively and depth of cut was 0.1mm in case of hard steel and0.2mm for mild steel for Impact value
Charpy Test was performed on single specimen from each group. Dimension of specimen was
6.5mm×1.8mm×1.8mm.Notch angle and depth were 45
0 and 0.3mm respectively.
.
:
Group I:- Total number of specimen: six;
Sequence of heat treatment/cryogenic treatment
Raw Material → Quenching(1050
0 c) → tempering(550
0 c)
MATERIAL HARDNESS NO. IMPACT VALUE
Raw Material
Specimen G1
68.093kg/mm
2
104.07kg/mm
2
3.7J
4.1J
Tool Life
Specimen (Groupie I)
Work Piece
Hard Steel
Mild Steel
Depth of Cut
0.2mm
0.1mm
Tool Life
14sec
38sec

International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
Group II:- Total number of specimen: six;
Sequence of heat treatment/cryogenic treatment
Raw Material → Quenching(1050
0 c) → tempering(550
0 c)
↓ cryogenic treatment(-196
0 c)
↓
tempering(550
0 c)
MATERIAL HARDNESS NO. IMPACT VALUE
ISSN 2319 - 4847
Raw Material
Specimen G2
68.093kg/mm2
72.663kg/mm2
Tool Life
Specimen (Groupie II)
Work Piece Depth of Cut
Hard Steel
Mild Steel
0.2mm
0.1mm
Group III:Total number of specimen: six;
Sequence of heat treatment/cryogenic treatment
Raw Material → quenching (1050
0 c) → tempering (550
0 c)
↓
cryogenic treatment(-196
0 c)
MATERIAL HARDNESS NO.
3.7J
5.8J
Tool Life
22sec
68sec
IMPACT VALUE
Raw Material 68.093kg/mm2 3.7J
Specimen G3 84.118kg/mm2
Tool Life
4J
Specimen (Group III)
Work Piece
Hard Steel
Mild Steel
Depth of Cut
0.2mm
0.1mm
Tool Life
18sec
1.16sec
Group IV:- Total number of specimen: six;
Sequence of heat treatment/cryogenic treatment
Raw Material → Quenching(1050
0 c) → cryogenic treatment
↓ tempering(550
0 c)
MATERIAL HARDNESS NO. IMPACT VALUE
Raw Material 68.093kg/mm2
Specimen G4 72.663kg/mm2
3.7J
6J

International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
Tool Life
Specimen(Group IV)
Work Piece Depth of Cut Tool Life
ISSN 2319 - 4847
Hard Steel
Mild Steel
0.2mm
0.1mm
7sec
51sec
.
:
Specimen of Groupie I, were subjected to heat treatment only. Hardness Number of this group is greatest in all remaining group. Specimen of Groupie III, were subjected to cryogenic treatment after heat treatment. They have attained second position in Hardness Number .Tool Life has higher value of GIII specimen as compare to GI specimen. Cryogenic treatment has improved hardness and tool life consideribely.GII and GIV, were subjected to tempering after cryogenic treatment. Both groups have equal Hardness Number and less than that of GI and GIII.
But impact value of GII and GIV has much greater than remaining two. Tool Life is maximum is case of GIII while mild steel was selected as work piece.
It is seen that some of the mechanical properties like hardness, wear resistance were increased due to heat treatment. But toughness and tool life did not increase considerably. When heat treated tool steel were subjected to cryogenic treatment, it was observed that toughness, impact value and tool life were increased considerably.
Appreciation is expressed to those who have reviewed and made contributions to this research work. I am especially indebted to Er. Rahul Davis Assistant Professor Department of Mechanical Engineering
S.S.E.T.,Allahabad, under his guideline my research work has been done. I am also indebted to Noel, Kemi who helped me in laboratory for performing practical work. I am also highly grateful to Sashi who helped me in mathematical calculation .
[1] The White Book of Steel
[2] World Steel Association
[3] P.N.Raw; “Manufacturing Technology Volume2”,The McGraw-Hill.
[4] A.Bensely,D.Sentikumar,D.Mohanlal,G.Nagarajan; “Effect of cryogenic Treatment on tensile behavior of case carburized steel-815 M17”; Materials characterization, 58, 2007, pp.485-491
[5] Materials science & engineering an introduction; “William D. Callister, Jr
[6] D.Mohanlal,S.Ranganarayanan and A.Kalanidhi, “Cryogenic treatment to augment wear resistance of EN13 steel”; Materials and manufacturing process 23(4), 2008,pp.369-376.
[7] Poolo, Buldissera,Cristiana Delprete, “Effect of deep cryogenic treatment on static Mechanical properties of
18 Nichrome Carburized Steel”, Materials and Design 30,2009,435-1440.