AB S T RAK
S IFAT KE KE RAS AN DAN KO M POS IS I KIMIA PE RMU KAA N B AJA S T 41 HAS IL
PROS E S PA C K C AR BUR IZING ME NGGU N AKAN ARAN G C AN GKAN G B UAH
KE T A PAN G S E B AGA I ME DIA KA RB ON PADAT
OL E H
S INGGIH T RE N GGO NO
Baj a k arbon rend ah (S T4 1) adalah jenis baja kons truksi yan g mempun yai kandungan karbon
dibawah 0,3 % memiliki ferrite yan g lebih b an ya k dibandin gkan pearl ite den gan tensile
strength (kekuat an tarik ) sebesa r 40 k g/ mm
2
. Akan tetapi , b aja karbon re ndah mempun yai
kelemahan ku alitas keke rasan ya n g rend ah. S alah satu ca ra menin gkatk an kualitas keker asan
baja karbon rend ah den gan dilakukan n ya p roses pack carburizing . Tujua n dari pen elitian ini
adalah untuk m en getahui pen garuh vari asi waktu penahan an den gan tempe ratur konstan pad a
proses pack carburizing ditinjau dari nilai ke kerasan dan komposisi kimia baja S T41 . P roses
pack carburizing ini menggunak an vari asi wakt u penahanan 30 menit, 45 menit, dan 60
menit dengan temp eratur konstan 850 ! . P enel itian ini menggunakan aran g can gkan g bua h
ketapan g s eba gai k arbon aktif dan can g k an g telur seba gai k atalisator. P en dinginan dilakuk an
dengan proses quen chin g menggun akan media air. P engujian yan g dilakukan adalah uji
kekeras an micro vickers dan uji komposisi kimia. Hasil penelitian menunjukkan bahw a
proses pack carburizing dapat meningk atkan nilai kekerasan baj a S T41. Nilai kekerasan pad a
baja sebelum proses pack carburizing adalah 137,4 HV, setelah dilakukan proses pack
carburizing dengan peni ngkat an nilai kekeras an tertinggi pada sa at wa ktu penahanan 60
menitsebesar 216,4 HV. nilai kekerasan menin gkat seiring den gan sema kin laman ya w aktu
penahan an. Da ri hasil uj i komposisi kimia dapat diketahui bahw a kandu ngan karbon pada
baja menin gkat setelah dilakukan proses pac k carburizing . Kandungan ka rbon pad a baja
sebelum proses pack c arburiz ing sebesar 0,115 (wt.%), setelah dilaku kan proses pack
carburizing dengan peni ngkat an kandun gan karb on tertinggi pada saat waktu penahanan 60
menit sebesar 0,353 (wt .%). S emakin lama wak tu penahan an sa at karbu rasi maka jumla h
kandungan ka r bon pad a baja semakin menin gk at, seirin g S emakin me ningkat n ya jumlah
kandungan ka rbon maka baja akan m empun ya i sif at ya n g lebih ker as.
Kata k u n ci : b aja k arb on ren d ah (S T 41), pack carbu rizin g , w ak tu p en ah an an , u ji
k ek erasan , u ji k omp osisi k imia.

A B S TR AC T
THE HA R DNE SS C HAR A C TE R IS TIC A N D CHE MIC A L C OMPOS ITION S UR F A C E
OF S TE E L S T41 RE S ULT PA C K C AR B UR IZING PR OC E S S US E D CHA R C OA L
K E TA PA NG S HE LL AS A C TIVA TE D C A R B ON
B y
S INGGIH T RE N GGO NO
L ow carbon steel (ST 41 ) is kind construction steel w hich has a carbon content below 0,3 %
has more ferrite than pearlite w ith tensile strengthof 40 kg/mm
2
.How ever, low carbon steel
has debility like low qu ality of hardness. One w ay to increase th e hard ness quality of low
carbon steel by used pa c k carburizing process. T he purpose of this resea rch is to determine
the effect of holding time on variation w ith the temp erature constant o f pack carburizing
process review ed from v alue of the hardness and chemical co mposition of the steel ST 41. T he
pack carburizing proc es s used 30 minutes, 45 mi nutes and 60 minutes va riation s of holding
time w hile the temp erature constant w as at 850 ! . this research used ch arcoal ketapang
shell as activated carbon and egg shell as catalys t. C ooling w as done by quenc hin g proces s
used w ater media. T his experiment w as micro vickers hardness exa mination and chemical
composition examination. T he result of the research is show ed that the pack carburizing
process can increase the hardness value of steel ST 41. H ardn ess value before being
processing pack carburiz ing steel w a s 137,4 HV, after done a pack carbu rizing process w ith
increase d the highest har dness during holding t ime of 60 minutes w hich equal to 216,4 HV .
Hardness value increas es w ith the length holding time. C hemical composition of the test
result s also show ed that the content of the carbon steel increased after pack carburizing
process. C arbon contentbefore processing pack carburizing steel w as 0,115 (w t.% ), after
done a pack carburizing process w ith increased the highest carbon conte nt during holding
time of 60 minutes w hich equal to 0,353 (w t.% ). T he longer the holding time during
carburizingthen T he amount of carbon content in steel increases , along w ith the increasing
amount of carbon conten tthen the higher of steel hardness w ill be.
K eyw ords : low carbon steel (S T41), pack carbu r izin g, h oldin g tim e, h ardn ess test, test of
ch em ical com position .