Abstract:
A dillieull-to-eut material like hardened ~tccl i~ used predominantly in the
automotive and !>caring industries due t,) its exceptional ~-orrosi"n ami thcrmal re~istanee
and high shear strength. Ahnls;ve maLhining processes such as grinding have lypically
heen required to machine hardened steels, hut advances in machine tools and cutting
materials have allowed hard turning '.m modern lathes to become a realistic replacement
for many grinding applications. De:;pite so many advantages, implementation of hard
turning remains relatively low, primarily due tn concerns about the quality of hard turned
surfaces and a lack of understanding about the wear behavior of cutling took In general,
the most important point in machining proccsses is the productivity, achieved by cutting
the highest amount of material in the shortest possible time using t()l)ls with the longest
lifetime. Combining all the parameters involved in the machining process to maximize
productivity is, nevertheless, a very complex ta~k and becomes much more difficult when
working at high speed machining in hardened steels. To address thi~ concern, this research
investigated the ellcet:; of cbanging pmcess conditions on wear behavior when turning
harden~-dmedium carbon steel (56 HRC') with coaLedcarbide cutting tools.
The aim of this resean:h is to investigate the influence of fccd rate and cutting
speed on the wear behavior of both ShlMG and SNMM coated carbide inserts under high
pressure coolant condition. Invc>;tigation on the effC(;t of high pressure coolant on the
machined chip, culling tcmpcmturc, cutting force~ alld product quality is the prime
intention of this rcsC'<lfCh.
XlII
To become a realistic replac,'ment for grincing operation, surface roughness
produced by hard turning must be eomr<lL:~bleto grinding process if hard turned surfaces
are to be accepted, Steady and prugressive sUlfaee oollghnesses with dimensional deviation
have been investigaled in this research wInk. The rcsulls indiCllte that proper 'electi,," of
machining condilion and high PI\'SSUI\' cooling system yields acceptahle dimensional
accu,dCY and surface quality. It also allows adequate tool life by keeping the cutting zone
temperature and cutting forces at lower ievels.
