Analisis Pengaruh Post Weld Heat Treatment Terhadap Sifat Mekanik dan Struktur Mikro Pada Pengelasan Ulang Baja Karbon A36 Pada Pondasi Mesin Kapal

Putra, Pradesta Wienpy Kurnia Handika (2017) Analisis Pengaruh Post Weld Heat Treatment Terhadap Sifat Mekanik dan Struktur Mikro Pada Pengelasan Ulang Baja Karbon A36 Pada Pondasi Mesin Kapal. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Proses pengelasan ulang dapat terjadi pada material yang mengalami pekerjaan replating akibat kesalahan dalam pekerjaan di lapangan. Dalam praktek lapangan, proses replating merupakan proses kadanglah dilakukan dalam perawatan kapal. Post Weld Heat Treatment (PWHT) merupakan metode perlakuan panas yang dilakukan dalam pengelasan. Tujuan utama dari perlakuan panas adalah untuk merubah atau mengembalikan sifat mekanis dari sebuah logam. Tujuan dari Tugas Akhir ini untuk mengetahui pengaruh Post Weld Heat Treatment pada pengelasan ulang.
Dalam Tugas Akhir ini dilakukan pengelasan ulang sebanyak 3 kali dengan perlakuan Post Weld Heat Treatment (PWHT). Suhu PWHT sebesar 595OC. Proses pengelasan yang digunakan untuk pengelasan baja karbon ASTM A36 adalah shielded metal arc welding (SMAW) dengan ketebalan 16 mm. Kemudian dilakukan pengujian yang mencakup: uji tarik, uji kekerasan, dan uji struktur mikro.
Dari hasil pengujian dapat diketahui nilai kuat tarik tertinggi sebesar 466.08 N/mm2 pada 1 kali pengelasan (no repair) dan nilai kuat tarik terendah sebesar 458.35 N/mm2 pada 4 kali pengelasan (3 x repair). Nilai kekerasan tertinggi terdapat pada daerah weld metal dengan spesimen 1 kali pengelasan (no repair) sebesar 197.7 HV dan nilai kekerasan terendah terdapat pada daerah base metal dengan spesimen 4 kali pengelasan (3 x repair) sebesar 170.4 HV. Hasil pengujian impact diketahui bahwa nilai energy absorb semakin besar. Dari hasil uji struktur mikro dapat diamati bahwa butiran pearlite dan ferrite terbentuk semakin kecil dan rapat karena ada pengaruh panas yang diberikan saat pengelasan ulang dan proses PWHT (Post Weld Heat Treatment), ¬¬¬dimana semakin kecil butir akan semakin besar angka dari kekerasan sebuah material.
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Re-welding process occur against material which was on replating due to failure work process on field, replating processes are usually done in ship maintenance. Post Weld Heat Treatment (PWHT) is heat treatment method in welding process. Main objective from this heat treatment are to change or restore mechanical properties. The purpose of these final project is to understand Post Weld Heat Treatment effect on re-welding.
On this project, three times welding process were conducted with Post Weld Heat Treatment (PWHT) of 595OC of PWHT. Shielded Metal Arc Welding (SMAW) was used for welding process against carbon steel ASTM A36 of 16 mm thickness. Then, material testing such as: tensile strength, hardness, impact and micro structure have been done.
A given result was a nominal value of maximum tensile strength is 466.08 N/mm2 in one welding process (no repair) and the minimum tensile strength is 458.35 N/mm2 in four time welding process (three times repair). The highest hardness value was found on weld metal specimen with one welding process (no repair) of 197.7 HV and the lowest value of hardness was found on base metal area with 4 times welding process (3 times repair) is 170.4 HV. Test result from material impact give a conclusion that absorb energy is getting higher. From microstrctur test, it can be observed that a pearlite and ferrite particle formed a smaller and tight because of hot effect due to either re-welding process or Post Weld Heat Treatment (PWHT), where as if a particle getting smaller then a value of material hardness will get higher.

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	ASTM A36, jumlah repair, PWHT, kuat tarik, kekerasan, impact, struktur mikro, number of repair, tensile strength, hardness, microstructure
Subjects:	V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User:	Pradesta Wienpy Kurnia Handika Putra
Date Deposited:	18 Oct 2017 05:21
Last Modified:	09 Jan 2018 06:15
URI:	http://repository.its.ac.id/id/eprint/46579

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