STUDY OF AUSTENITIZATION HOLDING TIME EFFECT ON RAPID HEATING INDUCTION HARDENING ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AISI 4340 STEEL
It is estimated that in 2025, the steel demand will increase to 19.2 million tons. However, the domestic industry was only able to supply 5.4 million tons. One of the steel alloys that is often needed is medium carbon steel with a carbon content of 0.3 - 0.6% which can be heat treated so that it has...
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| Format: | Final Project |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/51390 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | It is estimated that in 2025, the steel demand will increase to 19.2 million tons. However, the domestic industry was only able to supply 5.4 million tons. One of the steel alloys that is often needed is medium carbon steel with a carbon content of 0.3 - 0.6% which can be heat treated so that it has better mechanical properties. Low alloy medium carbon steel which is also special steel so it is used in the aircraft industry and in manufacturing, one of which is AISI 4340 steel. Induction heating is an instrument that can be used in heat treatment to heat steel with a high heating rate. Induction heating technology is currently an alternative heating technology in many industrial applications due to its advantages regarding efficiency, fast heating, and precise control. In this study, the effect of austenitizing holding time on rapid heating induction hardening was studied on the microstructure and mechanical properties of AISI 4340 steel.
References related to research topics are collected and analyzed regarding the heat treatment parameters used. The heat treatment parameters used include the austenitizing temperature, the highest heating rate, and the initial microstructure. From the analyzed parameters it can be predicted that the austenitizing zone is achieved to carry out austenitizing retention. The austenization zone in this heat treatment is divided into three, namely the intercritical zone, the nonhomogeneous austenitizing zone, and the homogeneous austenitizing zone. Furthermore, it will be obtained the effect of the length of time of austenitization on changes in the microstructure and mechanical properties of AISI 4340 steel.
From the references that have been analyzed, the results show that in the homogeneous austenitizing zone, the shorter the holding time, the finer the grain size so that the hardness and tensile strength values are higher than the nonhomogeneous and intercritical austenitizing zones. In the nonhomogeneous austenitizing zone, the longer the holding time of the austenitization, the more evenly the carbon concentration is distributed so that the ghost pearlite fraction is decreasing. However, the effect of grain growth is more dominant so that the tensile strength value decreases and the total elongation increases. In the intercritical zone, the longer the austenitizing holding time, the more austenite fraction is formed so that the martensite fraction also increases after quenching and results in increased tensile strength and decreased total elongation. |
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