Jurnal Desiminasi Teknologi, \ b l u m & 3 , No. 1, Januari 2 0 1 5

P E N G A R U H K O N S T R U K S I B A J A Y A N G T E R B A K A R D I B E R I P E R L A K U A N P E N D I N G I N A N A I R

Zulkarnain Fatoni*)

Abstrak: P e n e l i t i a n i n i b e r t u j u a n u n t u k m e n g e t a h u i p e r b e d a a n n i l a i k e k e r a s a n p a d a p r o s e s p e r l a k u a n p a n a s ( H e a t T r e a t m e n t ) y a n g d i b e r i m e d i a p e n d i n g i n b e r u p a a i r , o l i , p a s i r d a n u d a r a seca ra m e n d a d a k ( Q u e n c h i n g ) y a n g k e m u d i a n d i l i h a t s t r u k t u r m i k r o n y a p a d a ba ja k a r b o n m e n e n g a h . H a s i l p e n g u j i a n k e k e r a s a n ba ja y a n g t e l a h m e n g a l a m i p e m a n a s a n d a n d i d i n g i n k a n d i d a l a m a i r l a u t d a n a i r t a w a r ( t a b e l 1 sebesar 5 7 , 4 2 H R c d a n t a b e l 2 sebesar 4 5 , 2 4 H R c ) , k e d u a t a b e l m e n u n j u k k a n d a t a k e c e n d r u n g a n s e m a k i n t i n g g i t e m p e r a t u r p e m a n a s a n s e m a k i n k e r a s b a j a t e r s e b u t . H a l i n i d i k a r e n a k a n s e m a k i n t i n g g i t e m p e r a t u r p e m a n a s a n , a u s t e n i t y a n g t e r b e n t u k s e m a k i n b a n y a k , d a n d e n g a n w a k t u p e n a h a n a n y a n g c u k u p p a d a t e m p e r a t u r t e r s e b u t , a u s t e n i t s e m a k i n h o m o g e n . A u s t e n i t i n i l a h y a n g m e m u n g k i n k a n d a p a t b e r t r a n s f o r m a s i m e n j a d i m a r t e n s i t e p a d a saa t d i l a k u k a n p e n d i n g i n a n cepa t . A k i b a t d a r i p e n d i n g i n y a n g s a n g a t cepat m a k a s t r u k t u r y a n g t e r b e n t u k a d a l a h m a r t e n s i t ( G a m b a r 11 s.d 2 1 ) , i n i p u l a l a h y a n g m e m b u a t b a j a s e m a k i n k e r a s k a r e n a s t r u k t u r m a r t e n s i t a d a l a h s t r u k t u r y a n g p a l i n g k e r a s d i d a l a m ba j a , s a y a n g n y a s t r u k t u r i n i d i i k u t i o l e h s i f a t y a n g t i d a k b a i k y a i t u s i f a t y a n g ge t a s d a n s a n g a t r e n t a n t e r h a d a p b e b a n s e l n j u t n y a . J i k a k i t a b a n d i n g k a n h a s i l p e n g u j i a n k e k e r a s a n a k i b a t d i d i n g i n k a n d i d a l a m a i r l a u t d a n a i r t a w a r ( G a m b a r 1 1 ) , p e n d i n g i n d e n g a n m e d i a a i r l a u t m e n g h a s i l k a n s i f a t k e k e r a s a n l e b i h t i n g g i . H a l i n i d i s e b a b k a n t e m p e r a t u r a i r l a u t l e b i h r e n d a h d i b a n d i n g t e m p e r a t u r a i r t a w a r o l e h p e n g a r u h k a d a r g a r a m . S e h i n g g a l a j u p e n d i n g i n a n a i r l a u t l e b i h cepa t , k a r b o n y a n g t e r j e b a k d a r i s t r u k t u r a u s t e n i t ( F C C ) m e n j a d i m a r t e n s i t ( B C T ) l e b i h b a n y a k d a n a u s t e n i t e s i sa p a d a t e m p e r a t u r k a m a r y a n g t i d a k s e m p a t b e r t r a n s f o r m a s i m e n j a d i m a r t e n s i t l e b i h s e d i k i t , h a l i n i l a h y a n g m e n y e b a b k a n k e k e r a s a n d e n g a n p e n d i n g i n a i r l a u t l e b i h t i n g g i d a r i p e n d i n g i n a n j i k a m e n g g u n a k a n a i r t a w a r . K e d u a m e t o d e p e n d i n g i n i n i b i l a k i t a b a n d i n g k a n d e n g a n b e n d a u j i t a n p a p e r l a k u a n , k e d u a -d u a n y a m e m p u n y a i n i l a i k e k e r a s a n j a u h l e b i h t i n g g i , a r t i n y a b a j a y a n g t e l a h t e r b a k a r a k a n m e n a i k k a n n i l a i k e k e r a s a n , m e n a i k k a n k e k u a t a n t e t a p i m a t e r i a l m e n j a d i s anga t ge tas . P e n e l i t i a n i n i d a p a t d i s i m p u l k a n b a h w a n i l a i k e k e r a s a n d e n g a n m e m b e r i p e r l a k u a n p a n a s d a n d i b e r i p e n d i n g i n a n a i r l a u t d a n a i r t a w a r , a i r laut l e b i h k e r a s d a n l e b i h t i n g g i d i b a n d i n g k a n p e n g a r u h p e r u b a h a n m i k r o d a r i p a d a a i r tawar. Kata kunci: Heat Treatment, Quenching, Austenit, Martensit, FCC, BCT.

Abstract: This studyaims to determine the differences i n hardness values in theprocess of heat treatment (heat treatment) were given a cooling medium such as water, oil, s a n d and a i r sudde^nly (Quenching) a r e then seen micro structure on medium carbon steel. Results of hardness testing of steel that has experienced warming and cooling i n the sea water and fresh mter (Table 1 HRc at 5 7 . 4 2 andat 45.24 HRc Table 2 ) , the secondtable shows the trend ofthe data the higher the heating temperature the harder the steel. This is because the higher the heating temperature, the austenite formed more and more, and mth surUcient holding t i r m at that temperature, the more homogeneous austenite, Austenite is u h a t a l l o v A to transform to martensite d u r i n g r a p i d cooling. As a result of r a p i d cooling the martensitic structure is formed (Fig. 11 to 21), this is preciscly what makes steel the harder because of the structure of martensite is the hardest

*) Dosen P r o g r a m Studi TeknikMesin, Fakultas Teknik, Universitas TridinantiPalembang

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Pengaruh Konstruksi Baja l&ng Terbakar D i b e r i Perlakuan Pendinginan Air

structure in the steel, unfortunately this structure is followed by a good trait that is the na ture o f the brittle and highly susceptible t o subsequen t loa d. Ifwe compare the test results as a result of violence in the refiigerated sea water and ftesh water (Figure 11), cooling with sea water medium resulted in higher hardness properties. This is due to the sea water temperature is lower than the temperature offresh water by the influence of salinity. So that the rate of cooling sea water more quickly, which trapped carbon from austenite (FCC) to martensite (BCT) and more residual austenite at room temperature which couldnot transform to martensite less. thisis viiatcauses the violence with cooling sea wa ter is higher than ifusing fresh m ter cooling. Both of these cooling methods when we compare U with that ofthe untreated specimen, both have much higher hardness values , meaning that the steel has been burned will increase the value of hardness, increase strength but the m a t e r i a l becomes very br i t t l e . It can be concluded tha t the hardness value byproviding heat trea tment and given cooling sea water and lresh water, sea water harder and higher compared influence ofthe micro changes in fresh water. Kcywords: Heat Treatment, Quenching, Austenite, Martensite t FCC t B C T .

P E N D A H U L U A N

B a j a k a r b o n m e n e n g a h a d a l a h m a t e r i a l y a n g d a l a m p e n g g u n a a n n y a k e b a n y a k a n s e b a g a i b a h a n d a r i k o n t r u k s i u m u m . K a r e n a b a j a k a r b o n m e n e n g a h m e m p u n y a i k e u l e t a n y a n g t i n g g i d a n m u d a h d i m e s i n , t e t a p i k e k e r a s a n n y a r e n d a h d a n t i d a k t a h a n a u s .

S i f a t m e k a n i k l o g a m d i p e n g a r u h i o l e h s t r u k t u r m i k r o l o g a m . S t r u k t u r m i k r o l o g a m d i p e n g a r u h i b u k a n h a n y a k o m p o s i s i k i m i a , t e t a p i j u g a o l e h p e r l a k u a n p a n a s y a n g d i a l a m i l o g a m t e r s e b u t . M e s k i p u n k o m p o s i s i k i m i a s a m a , j i k a p e r l a k u a n p a n a s y a n g d i a l a m i l o g a m t e r s e b u t b e r b e d a m a k a s t r u k t u r m i k r o n y a b i s a b e r b e d a . K i t a b i s a d e n g a n s e n g a j a m c r u b a h s i f a t m e k a n i k l o g a m d e n g a n c a r a m e r u b a h s t r u k t u r m i k r o l o g a m m e l a l u i p e r l a k u a n p a n a s y a n g t e p a t .

P e r l a k u a n p a n a s a d a l a h s u a t u p r o s e s k o m b i n a s i b a i k o p e r a s i p e m a n a s a n m a u p u n p e n d i n g i n a n y a n g d i l a k u k a n s e c a r a t e r k o n t r o l u n t u k m e n d a p a t k a n s i f a t m e k a n i k y a n g d i i n g i n k a n ( G e o r g e E , 1 9 9 7 ) .

P e r l a k u a n p a n a s y a n g s a l a h a k a n m e n y e b a b k a n k e r u g i a n y a n g t i d a k s e d i k i t n i l a i n y a , s e p e r t i s e r i n g n y a t e r j a d i k e b a k a r a n a p a k a h i t u d i d a r a t : g e d u n g , p e r k a n t o r a n , m a l l , p a s a r , d a n l a i n - l a i n , d i s u n g a i a t a u d i l a u t ; d e r m a g a , k a p a l , d a n l a i n - l a i n , d i m a n a b a i k

p e m a n a s a n m a u p u n p e n d i n g i n a n t i d a k d i l a k u k a n s e c a r a t e r k o n t r o l .

A t a s d a s a r u r a i a n s i n g k a t i n i l a h p e n u l i s m e l a k u k a n p e n e l i t i a n t e n t a n g p e n g a r u h y a n g d i t i m b u l k a n o l e h k e b a k a r a n , s e r i i n g g a n a n t i n y a d a p a t m e m b e r i k a n r e k o m e n d a s i k e p a d a p a r a p i h a k y a n g m e l a k u k a n p e m a d a m a n a t a u p a r a p e n g g u n a k o n t r u k s i b a j a b a i k y a n g d i d a r a t m a u p u n d i l a u t .

B e r d a s a r k a n u r a i a n d i a t a s m a k a p e r l u d i a d a k a n p e n e l i t i a n d a l a m b e n t u k s i m u l a s i t e r j a d i n y a s u a t u k e b a k a r a n u n t u k m e n g e t a h u i g a m b a r a n y a n g j e l a s t e n t a n g : Pengaruh Konstruksi Baja Karbon Menengah }&ng Terbakar Diberi Perlakuan Pendinginan Air Laut Dan Air Tawar".

M E T O D E P E N E L I T I A N

M e t o d e p e n e l i t i a n y a n g d i g u n a k a n a d a l a h M e t o d e A n a l i s a L a b o r a t o r i u m , y a n g d i l a k u k a n d i L a b o r a t o r i u m T e k n o l o g i M e k a n i k d a n L a b o r a t o r i u m M e t a l u r g i J u r u s a n T e k n i k M e s i n U n i v e r s i t a s T r i d i n a n t i P a l e m b a n g . P e m e r i k s a a n k o m p o s i s i m a t e r i a l u j i d i l a k u k a n p a d a L a b o r a t o r i u m M e t a l u r g i P T . P u p u k S r i w i j a y a P a l e m b a n g . U n t u k d a p a t m e l a k u k a n p e n e l i t i a n d e n g a n b a i k d a n m e m u d a h k a n m e l a k u k a n a n a l i s a d a t a , p e r l u d i s u s u n s u a t u k e r a n g k a

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m e t o d e p e n e l i t i a n y a n g m e n g u r a i k a n l a n g k a h k e g i a t a n y a n g d i l a k u k a n .

Material _

Perlakuan Panas pada Temperatur Austenit Ti T 2 T 3 T a T 5

750 °C 775 °C 800*0 825 "C 850°C Didinginkan di dalam airtawardan air laut

1

Pengujian Kekerasan 4

Metalographi

Data

Kesimpulan

G a m b a r 1 . A l i r a n P r o s e s P e n e l i t i a n

1 . M a t e r i a l M a t e r i a l y a n g d i g u n a k a n d a l a m p e n e l i t i a n i n i a d a l a h b a j a k a r b o n m e n e n g a h d e n g a n k a d a r k a r b o n a n t a r a 0 , 3 A 0 , 5 5 % s e b a n y a k 1 1 b u a h .

0 E mm

t mm

G a m b a r 2 . D i m e n s i S p e s i m e n B a j a K a r b o n M e n e n g a h

2 . A l a t P e n e l i t i a n P e r a l a t a n y a n g d i g u n a k a n d a l a m p e n e l i t i a n i n i a d a l a h s e b a g a i b e r i k u t : > a . A l a t u j i k o m p o s i s i b . A l a t u j i k e k e r a s a n c . M e s i n A m p l a s d . A l a t M i k r o s k o p O p t i k e . K a m e r a P h o t o

3 . M e t o d e P e n g u j i a n P a d a p e n e l i t i a n i n i y a n g d i g u n a k a n a d a l a h m e t o d e e k s p e r i m e n t a l y a n g d i l a k u k a n d i L a b o r a t o r i u m T e k n i k M e s i n U n i v e r s i t a s T r i d i n a n t i P a l e m b a n g . P e n e l i t i a n m e m e r l u k a n l a n g k a h - l a n g k a h a t a u t i n d a k a n y a n g t e r s u s u n s e h i n g g a m e n j a w a b p e r m a s a l a h a n y a n g d i t e l i t i . L a n g k a h p e n e l i t i a n i n i a d a l a h s e b a g a i b e r i k u t . a. P e m b u a t a n s p e s i m e n a t a u m a t e r i a l b . U j i k o m p o s i s i

4 . P r o s e s P e m a n a s a n S e b e l u m p r o s e s p e m a n a s a n , m a t r i a l y a n g a k a n d i u j i t e r l e b i h d a h u l u d i b e r s i h k a n d e n g a n a m p l a s a g a r p e m a n a s a n n y a l e b i h b a i k t e r h a d a p m a t e r i a l y a n g a k a n d i u j i . P r o s e s p e m a n a s a n t e r d i r i d a r i : a . P e m a n a s a n p a d a t e m p e r a t u r e 7 5 0 °C,

7 7 5 °C, 8 0 0 °C, 8 2 5 ^ 8 5 0 °C. b . S e t i a p p e m a n a s a n d i l a k u k a n t e r h a d a p

d u a s a m p e l y a n g s a m a b a i k u k u r a n m a u p u n j e n i s m a t e r i a l n y a .

c. P a d a t e m p e r a t u r e a u s t e n i t e d i t a h a n b e b e r a p a s a a t u n t u k m e n d a p a t k a n s t r u k t u r a u s t e n i t e y a n g h o m o g e n .

d . P e n d i n g i n a n d i l a k u k a n d e n g a n d u a m a c a m m e d i a y a n g b e r b e d a , y a i t u a i r t a w a r d a n a i r d i n g i n .

5 . P e n g u j i a n k e k e r a s a n P e n g u j i a n k e k e r a s a n i n i d i l a k u k a n d e n g a n a l a t u j i k e k e r a s a n , l a n g k a h p e n g u j i a n i n i a d a l a h ( H a r m e r E . D a v i s , 1 9 8 2 ) : a . M e m a s a n g s p e s i m e n p a d a d u d u k a n n y a . b . M e n e n t u k a n b e s a r p e m b e b a n a n .

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Pengaruh Konstruksi Ba j a ^ng Terbakar D i b e r i Perlakuan Pendinginan A i r

c . M e n d o r o n g t o m b o l b e l a k a n g u n t u k m e n g u n c i t i t i k b e b a n i n d e n t o r ,

d . M e m u t a r h i n g g a s p e s i m e n m e n y e n t u h i n d e n t o r b o l a b a j a m a u p u n k e r u c u t i n t a n .

e . M e n a r i k t o m b o l d e p a n u n t u k m e l e p a s k a n k u n c i y a n g t e l a h d i b e b a n i .

G a m b a r 3 . A l a t u j i k e k e r a s a n

6 . M e t a l o g r a p h i S e b e l u m m e l a k u k a n p e n g a m b i l a n p h o t o , b e n d a u j i t e r l e b i h d u l u d i a m p l a s , d i p o l e s , d a n d i e t s a ( G e o r g e F . V a n d e r V o o r t , 1 9 8 4 ) . P e n g a m p l a s a n d i l a k u k a n d e n g a n m e s i n a m p l a s u n t u k m e n g a m p l a s b a g i a n p e r m u k a a n m a t e r i a l , m e n g g u n a k a n k e r t a s a m p l a s y a n g m e m p u n y a i k e k a s a r a n d a r i ; 1 2 0 , 3 2 0 , 4 0 0 , 6 0 0 , 1 0 0 0 , 1 5 0 0 , k e m u d i a n d i p o l e s m e n g g u n a k a n p a s t a i n t a n s a m p a i m e n g k i l a p . D i l a n j u t k a n d e n g a n e t s a N i t a l 3 % ( 3 % H N 0 3 d a n 9 7 % A l k o h o l ) k u r a n g l e b i h 5 d e t i k k e m u d i a n d i c u c i d e n g a n d e t e r g e n d a n d i k e r i n g k a n m e n g g u n a k a n a l a t p e n g e r i n g p a n a s y a n g s e b e l u m n y a b e n d a u j i d i s i r a m d e n g a n a l k o h o l 7 0 %. H a s i l n y a b a r u d i l i h a t d e n g a n m e n g u n a k a n m i k r o s k o p e o p t i k d a n u n t u k m e r e k a m g a m b a r k i t a p e r g u n a k a n k a m e r a d i g i t a l .

G a m b a r 4 . M i k r o s k o p O p t i k

H A S I L P E N E L I T I A N D A N P E M B A H A S A N

H a s i l P e n e l i t i a n H a s i l p e n e l i t i a n b e r u p a n i l a i k e k e r a s a n m a s i n g -m a s i n g b e n d a u j i b a i k y a n g d i l a k u k a n d e n g a n m e d i a p e n d i n g i n a i r l a u t d a n a i r t a w a r s e c a r a q u e n c h i n g , j u g a p h o t o s t r u k t u r m i k r o . 1 . U j i K o m p o s i s i

H a s i l u j i k o m p o s i s i y a n g d i l a k k a n d i P T . P u s r i P a l e m b a n g s e p e r t i d a t a d i b a w a h i n i : C o m p o s i t i o n

[ Elemen t ^ W c i g h t % " /j

C ~ 0 . 3 2

M n 0 . 1 4 . .

P 0 . 1 7 ( m a x ) • •

S . 0 . 0 5 ( m a x )

P a d a u j i k o m p o s i s i y a n g t e l a h d i l a k u k a n d a p a t d i k e t a h u i b a h w a k a d a r k a r b o n p a d a b e n d a u j i s e b e s a r 0 , 3 2 % C d a n k a d a r k a r b o n i n i s u d a h t e r m a s u k d a l a m b a j a k a r b o n m e n e n g a h .

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2 . P e m a n a s a n P e r l a k u a n p a n a s d i l a k u k a n p a d a s u h u 7 5 0 °C s / d 8 5 0 °C d e n g a n i n t e r v a l 2 5 °C d a n d i d i n g i n k a n d e n g a n c e p a t k e d a l a m a i r l a u t d a n a i r t a w a r .

3 . U j i K e k e r a s a n • P e n g u j i a n k e k e r a s a n d i l a k u k a n d e n g a n m e t o d e R o c k w e l l - C ( R c ) p e n g u j i a n k e k e r a s a n d i l a k u k a n s e b a n y a k 5 t i t i k h a s i l n y a d i r a t a - r a t a k a n , h a s i l n y a d a p a t d i l i h a t p a d a t a b e l d i b a w a h i n i :

T a b e l 1 . P e n g u j i a n k e k e r a s a n d e n g a n p e n d i n g i n a i r l a u t

Na Temperatur Pemanasan

Nilai Kekerasan

Nilai Rata-rata

I 2 3 4 5 HRC 1 750°C 58 54,5 53,5 56 54,5. 55,3 2 775°C 57 58,5 59 54,5 56 57 3 800 °C 58 57,5 59,5 56,5 57,5 57,8 4 825 °C 58,5 60 57,5 56^ 58

5 850^ 59,5 49,5 48,5 59 59,5 60

Nilai Rata-rata 57,42

G a m b a r 5 . A n g k a K e k e r a s a n D e n g a n M e d i a P e n d i n g i n A i r L a u t

T a b e l 2 . N i l a i K e k e r a s a n D e n g a n P e n d i n g i n A i r T a w a r

No. Temperatur Pemanasan

Nilai Kekerasan

Nilai Rata-rata

HRC

No. Temperatur Pemanasan

1 2 3 4 5

Nilai Rata-rata

HRC

1 750°C 38,5 42 41,5 38,5 45,5 4 U 2 775°C 40,5 43 42,5 39,5 42,5 41,4

3 800°C 49,5 47,5 45,5 42 44 45,7

4 825°C 50,5 49 47 47,5 48 48,4

5 850°C s y 49,5 48,5 48,5 46,5 44,4

Nilai Rata-rata 45,24

G a m b a r 6 . N i l a i K e k e r a s a n D e n g a n P e n d i n g i n A i r T a w a r

T a b e l 3 . P e n g u j i a n K e k e r a s a n b e n d a u j i a w a l

No. Benda Uji

Nilai Kekerasan

Nilai Rata-rata

Awal 1 2 3 4 5 HRC

1. Tanpa Pemanasan 25,5 26,0 27,0 '25,0 24,0 25,5

2 0

Pengaruh Konstruksi Ba j a 'teng Terbakar D i b e r i Perlakuan Pendinginan A i r

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G a m b a r 7 . P e r b a n d i n g a n N i l a i K e k e r a s a n

4 . M e t a l o g r a p h i S t r u k t u r m i k r o b e n d a u j i d i l i h a t d e n g a n m e n g g u n a k a n m i k r o s k o p o p t i k , h a s i l n y a d i r e k a m d e n g a n m e n g g u n a k a n k a m e r a d i g i t a l , d a p a t d i l i h a t p a d a l a m p i r a n .

P e m b a h a s a n H a s i l p e n g u j i a n k e k e r a s a n b e n d a u j i t a n p a p e r l a k u a n m a s i h d a p a t d i u k u r m e n g g u n a k a n u j i k e k e r a s a n m e t o d e r o c k w e l l - c h a l i n i d i k a r e n a k a n s t r u k t u r y a n g t e r b e n t u k a d a l a h p e a r l i t e .

J i k a k i t a p e r h a t i k a n h a s i l p e n g u j i a n k e k e r a s a n b a j a y a n g t e l a h m e n g a l a m i p e m a n a s a n d a n d i d i n g i n k a n d i d a l a m a i r l a u t d a n a i r t a w a r ( t a b e l 1 d a n t a b e l 2 ) , k e d u a t a b e l m e n u n j u k k a n d a t a k e c e n d r u n g a n s e m a k i n t i n g g i t e m p e r a t u r p e m a n a s a n s e m a k i n k e r a s b a j a t e r s e b u t .

A k i b a t d a r i p e n d i n g i n y a n g s a n g a t c e p a t m a k a s t r u k t u r y a n g t e r b e n t u k a d a l a h m a r t e n s i t , i n i p u l a l a h y a n g m e m b u a t b a j a s e m a k i n k e r a s k a r e n a s t r u k t u r m a r t e n s i t a d a l a h s t r u k t u r y a n g p a l i n g k e r a s d i d a l a m b a j a , s a y a n g n y a s t r u k t u r i n i d i i k u t i o l e h s i l a t y a n g t i d a k b a i k y a i t u s i f a t y a n g g e t a s d a n s a n g a t r e n t a n t e r h a d a p b e b a n s e l n j u t n y a .

J i k a k i t a b a n d i n g k a n h a s i l p e n g u j i a n k e k e r a s a n a k i b a t d i d i n g i n k a n d i d a l a m a i r l a u t d a n a i r t a w a r , p e n d i n g i n d e n g a n m e d i a a i r l a u t m e n g h a s i l k a n s i f a t k e k e r a s a n l e b i h t i n g g i . H a l

i n i d i s e b a b k a n t e m p e r a t u r a i r l a u t l e b i h r e n d a h d i b a n d i n g t e m p e r a t u r a i r t a w a r o l e h p e n g a r u h k a d a r g a r a m . S e h i n g g a l a j u p e n d i n g i n a n a i r l a u t l e b i h c e p a t , k a r b o n y a n g t e r j e b a k d a r i s t r u k t u r a u s t e n i t ( F C C ) m e n j a d i m a r t e n s i t ( B C T ) l e b i h b a n y a k d a n a u s t e n i t e s i s a p a d a t e m p e r a t u r k a m a r y a n g t i d a k s e m p a t b e r t r a n s f o r m a s i m e n j a d i m a r t e n s i t l e b i h s e d i k i t , h a l i n i l a h y a n g m e n y e b a b k a n k e k e r a s a n d e n g a n p e n d i n g i n a i r l a u t l e b i h t i n g g i d a r i p e n d i n g i n a n j i k a m e n g g u n a k a n a i r t a w a r .

K e d u a m e t o d e p e n d i n g i n i n i b i l a k i t a b a n d i n g k a n d e n g a n b e n d a u j i t a n p a p e r l a k u a n , k e d u a - d u a n y a m e m p u n y a i n i l a i k e k e r a s a n j a u h l e b i h t i n g g i , a r t i n y a b a j a y a n g t e l a h t e r b a k a r a k a n m e n a i k k a n n i l a i k e k e r a s a n , m e n a i k k a n k e k u a t a n t e t a p i m a t e r i a l m e n j a d i s a n g a t g e t a s .

K E S I M P U L A N B e r d a s a r k a n d a r i h a s i l p e n e l i t i a n d a n

p e m b a h a s a n t e n t a n g p e n g a r u h p e m a n a s a n d e n g a n m e d i a p e n d i n g i n a i r l a u t d a n a i r t a w a r y a n g d i d i n g i n k a n s e c a r a c e p a t ( q u e n c h i n g ) , d a p a t d i a m b i l k e s i m p u l a n s e b a g a i b e r i k u t : 1 . B a j a k a r b o n m e n e n g a h y a n g b i a s a n y a

d i p e r g u n a k a n u n t u k b a j a k o n s t r u k s i j i k a m e n g a l a m i p e m a n a s a n a t a u t e r b a k a r d a n d i d i n g i n k a n d e n g a n c e p a t a t a u p i h a k p e m a d a m k e b a k a r a n m e n d i n g i n k a n d e n g a n m e n y e m p r o t k a n a i r a p a k a h i t u a i r t a w a r m a u p u n a i r l a u t m a k a s t r u k t u r y a n g t e r b e n t u k a d a l a h m a r t e n s i t y a n g k e r a s t e t a p i d i i k u t i o l e h s i f a t y a n g g e t a s .

2 . M a t e r i a l y a n g t e l a h m e n i n g k a t k e k e r a s a n n y a y a n g d i i k u t i d e n g a n m e n u r u n n y a k e u l e t a n ( g e t a s ) , a k a n r e n t a n t e r h a d a p b e b a n s e l a n j u t n y a .

3 . P e n d i n g i n a n m e n g g u n a k a n a i r l a u t l e b i h b e r b a h a y a j i k a d i b a n d i n g k a n d e n g a n p e n d i n g i n m e n g g u a n a k a n a i r t a w a r , k a r e n a k e r e r a s a n y a n g t e r j a d i a k a n l e b i h b e s a r d a n s e m a k i n g e t a s , n a m u n k e d u a - d u a n y a t e t a p b e r b a h a y a p a s c a t e r j a d i n y a k e b a k a r a n .

2 1

Zulkarnaia Fatoni r

S A R A N P a r a p e n g g u n a b a j a h a r u s b e r h a t i - h a t i

( p e n g g u n a , p e r a n c a n g , p e m b o r o n g , p e k e r j a ) j i k a k o n t r u k s i b a j a ( b a j a k a r b o n m e n e n g a h ) t e l a h m e n g a l a m i p e m a n a s a n a t a u t e r j a d i k e b a k a r a n d a n m e n d a p a t p e r l a k u a n p e n d i n g i n y a n g s a n g a t c e p a t , a p a k a h d i d i n g i n k a n d e n g a n a i r t a w a r a t a u a i r l a u t m a k a b a j a a k a n g e t a s d a n r e n t a n t e r h a d a p b e b a n s e l a n j u t n y a .

D A F T A R P U S T A K A

B i b i t S u g i t o , 2 0 0 5 . Pengaruh Annealing Terhadap Sifat Fisis dan Mekanis Pahat HSS Dengan Unsur Paduan Utama Chrom. J u r n a l M e d i a M e s i n 6 ( 1 ) : 1 7 - 2 2

D a l i l . M , P r a y i t n o A d h y & I n o n u I s m e t , 1 9 9 9 . Pengaruh Perbedaan V&ktu Penahanan Suhu Stabil (HoldingTime) Terhadap Kekerasan Logam.

J u r n a l N a t u r I n d o n e s i a . 1 1 ( 1 ) : 1 2 - 1 7 .

G e o r g e E . T o t t e n , 1 9 9 7 . Steel Heat Treatment Handbook. N e w Y o r k : M a r c e e l D e k k e r I n c .

G e o r g e F . V a n d e r V o o r t , 1 9 8 4 . Metallography Principles and Practice. N e w Y o r k : M c . G r a w - H i l l B o o k C o m p a n y .

G e o r g e E . D i e t e r , 1 9 8 6 . Mechanical Metallurgy. N e w Y o r k : M c . G r a w - H i l l B o o k C o m p a n y .

H a r m e r E . D a v i s , 1 9 8 2 . The testing of engineering materials, N e w Y o r k ; M C G r a w - H i l l B o o k C o m p a n y .

H o n e y c o m b e , 1 9 8 1 . Steelsmicrostructureand properties. C a m b r i d g e : E d w a r d A r n o l d .

P a u l M . U n t e r w e i s e r , 1 9 8 2 . Heat treaters guide Standard practices and procedures for steel. O H I O : A m e r i c a n S o c i e t y f o r M e t a l s M e t a l s P a r k .

S i d n e y H . A v n e r , 1 9 8 7 . Introduction to Physical Metalurgy. 2 r d . N e w Y o r k : M c . G r a w - H i l l B o o k C o m p a n y U n i t e d S t a t e s S t e e l C o r p o r a t i o n , 1 9 5 3 . T h e A t l a s o f I s o t h e r m a l T r a n s f o r m a t i o n d i a g r a m s . P i t t s b u r g h : U S S .

W i l l i a m D . C a l l i s t e r . J r , 2 0 0 3 . Material Science and Engineering. U S A : J h o n W i l l e y & S o n s . I n c .

2 2