By, Parmar Vishwarajsinh [4VP11ME075] EFFECTS OF NITRIDING ON THE WEAR AND CORROSION PROPERTIES OF TOOL STEEL At HMT Machine Tools Limited Bangalore Under the Guidance of, Mr. Veerasekharachari K Deputy Engineer (QI) HMT machine Tools Limited Mr. Rajendra M AGM (TC) HMT Training Institute, HMT Machine tools limited
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By,
Parmar Vishwarajsinh [4VP11ME075]
EFFECTS OF NITRIDING ON THE WEAR AND CORROSION PROPERTIES OF TOOL STEEL
At HMT Machine Tools Limited
Bangalore
Under the Guidance of,
Mr. Veerasekharachari KDeputy Engineer (QI)HMT machine Tools Limited
Mr. Rajendra MAGM (TC)HMT Training Institute,HMT Machine tools limited
CONTENTS• About Company
• Introduction
• Materials
• Heat Treatment
• Nitriding
• IS – T110W6Cr4 properties
• JIS – SK3 properties
• AISI – M35 properties
• Overall comparison
• Conclusion
• References
ABOUT HMT• HMT was incorporated in 1953 by the Govt. of India as the Machine tool Manufacturing
company
• In 1960, Launched a Bold plan of Diversification & Expansion which resulted in Duplication of Bangalore unit & setting of New units in PINJORE, KALAMASSERY, and HYDERABAD
• In 1967, Recession struck Indian Engineering Industry. Thus helped to bring two latest strength of HMT namely URGE TO SURVIVE and CONFIDENCE TO INNOVATE
• In 1980, launched units to manufacture CNC systems and Ball Screws
• In 1990, Formation of Machine Tool Business group & Formation of Central Re-conditioning division at Bangalore
• In 1998, bagged FIE award for best design, quality and Appearance of a Product at IMTEX
• In NEW MILLENIUM Production suffered due to slowdown in the economy coupled with stiff competition from imported machines.
HMT’S VISION AND MISSION• Vision:
• To be an engineering company of international repute, providing best of products and services with contemporary technology to suit the customer needs.
• Mission:
• To establish ourselves a one of the world’s premier company in the engineering field having strong international competiveness.
• To achieve market leadership in India through ensuring customer satisfaction by supplying internationally competitive products and services.
• To achieve sustained growth in the earnings of the group on behalf of shareholders.
INTRODUCTION
• Tool steels are used for applications such as gauge blocks, cutting tools and other where higher reliability is required.
• Reliability of a machine depends on its wear and corrosion resistance properties.
• Nitriding is a chemical case hardening process, which is used to improve the case hardness thus improving the wear and corrosion properties.
MATERIAL – IS – T110W6CR4• Tungsten alloyed high carbon tool steel.
• Used for gauge blocks, vernier callipers etc.
• Requires very good resistance to corrosion as well as wear.
Chemical Composition:
T110Mn4W6Cr4 as per IS - 1570 (Pt. 6) - 1996
ELEMENTS COMPOSITIONS (in % by wt.) SPECIFICATIONS
C 1.053 1.00 - 1.20
Si 0.28 0.10 - 0.35
Mn 0.91 0.90 - 1.30
P 0.012 0.035 max
S 0.009 0.035 max
Cr 0.94 0.90 - 1.30
W 1.26 1.25 - 1.75
MATERIAL – JIS – SK3• Manganese alloyed high carbon tool steel.
• Was commonly used for tools back in 1940s’.
• Now used for other common purposes such as watch casings.
• Requires very good resistance to corrosion as well as wear.
Chemical Composition:
C105W2
ELEMENTS COMPOSITIONS (in % by wt.) SPECIFICATIONS
C 1.008 1.00 - 1.10
Si 0.24 0.10 - 0.30
Mn 0.22 0.10 - 0.35
P 0.005 0.030 max
S 0.007 0.030 max
MATERIAL – AISI – M35• Chromium, Tungsten, Vanadium, Molybdenum, Cobalt alloyed high speed tool steel.
• Used for all high speed cutting applications such as in CNC lathes.
• Has very good wear and corrosion resistance properties.
• But good is not enough.
Chemical Properties:
XT90W6Co5Mo5Cr4V2 as per IS - 1570 (Pt. 6) - 1996
ELEMENTS COMPOSITIONS (in % by wt.) SPECIFICATIONS
C 0.919 0.88 - 0.96
Si 0.32 0.45 max
Mn 0.16 0.40 max
P 0.03 0.030 max
S 0.03 0.030 max
Cr 4.07 3.80 - 4.50
Mo 4.61 4.70 - 5.20
V 2.03 1.70 - 2.00
Co 4.97 4.50 - 5.00
W 6.59 6.00 - 6.70
HEAT TREATMENT
• It is a thermal hardening process.
• Changes the material structure from ferrite and pearlite to martensite structure.
• Martensite structure increases the hardness.
• Process time and temperature is different for different types of steels.
HEAT TREATMENT FOR IS – T110W6CR4• Pre heating – 15 minutes at 180°C.• Hardening – 20 minutes at 860°C.• Tempering – 1 hour at 180°C.
HEAT TREATMENT FOR JIS – SK3• Pre – heating : for 15 minutes at 180°C.
• Hardening : For 20 minutes at 840°C.
• Tempering : For 1 hour at 180°C.
HEAT TREATMENT FOR AISI – M35• Pre- heating : 15 minutes at 180°C.
• Hardening: 20 minutes at 1120°C.
• Tempering: Needs triple tempering at 540°C for 2 hours.
NITRIDING• Nitriding is a chemical case hardening process which will increase the case hardness of a
material keeping the core intact.
• Nitriding is done at 540°C for 72 hours for best effects of nitriding.
MATERIAL PROPERTIES
• Mechanical and metallurgical properties of samples are checked at each and every step.
• The materials showed different behaviours at different conditions.
• All the data we obtained are practical values.
MATERIAL PROPERTIES• Hardness is checked in Brinell, Rockwell and Vickers as per IS: 1500- 2000, IS 1586 -
1999 and IS: 1586 – 2000.
• For comparison basis we have used Vickers scale.
• The conversion from Brinell, Rockwell to Vickers is based on IS: 4258 – 1982.
• Rubbing velocity test (Pin on Disc) for wear is tested as per ASTM G99.
• Corrosion test is done for 72 hours and is as per ASTM B117 and ISO 9227.
• Microstructure is done by etching the polished samples with 3% Nital solution.
• Case depth is checked with Micro Vickers apparatus as per IS: 6416 – 1988.
IS – T110W6CR4 PROPERTIES - HARDNESS
raw material Heat treated NitridedHardness [HV] 215 700 762