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EXPERIMENTAL STUDY OF THE INFLUENCE OF

QUENCHING AND PARTITIONING TEMPERATURE

VARIATION ON RETAINED AUSTENITE FRACTION IN

AISI 4140 STEEL

Student Name : Surya Aditya Chamora

NRP : 2108 100 097

Department : Teknik Mesin FTI-ITS

Advisor : Prof. Dr. Ir. Wajan Berata, DEA

Abstract

Heat treatment is one of the easiest ways in improving

mechanical properties of material. The principle of heat

treatment is austenite decomposition into other phases.

Quenching partitioning process is process which increase

austenite volume fraction in room temperature. This research was

conducted in AISI 4140 steel used in many equipment such as

shaft, and sprocket.

Quenching and partitioning process was conducted in AISI

4140 steel by heating the steel in furnace until its austenizing

temperature, 885ºC, and was hold for 1 hour. Process was

continued with immersing the specimen in salt bath which

quenching temperature was varied 220ºC, 230ºC, 240ºC, and

250ºC, and hold for 120 seconds. The quenched specimen then

was immersed in salt bath, which the partitioning temperature

was varied 350ºC, 400ºC, and 450ºC, hold for 10 seconds.

Quench media after partitioning was water. The microstructure of

the tested specimen was looked using optical microscope and x-

ray diffraction (XRD).

Result of the research is that increasing quenching

temperature will increase the austenite fraction, whereas

increasing partitioning temperature doesn’t have significant

influence in austenite fraction. Partitioning temperature have

influence on the shape of martensite. In constant partitioning

temperature, as example 400ºC, the austenite fraction was

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increased from 8.86% to 17.56% as the quenched temperature

increased from 220ºC to 250ºC. In constant quenching

temperature, as example 220ºC, the austenite fraction was not

change significantly. The austenite fraction was 4.15% for

partitioned in 350ºC, and 8.84% for partitioned in 450ºC

Keyword : AISI 4140, quenching dan partitioning, austenite

fraction.