Studi Pengaruh Buttering Layer ERNiCr-3 Dan Post Weld Heat Treatment Pada Struktur Mikro Dan Sifat Mekanik Pengelasan Dissimilar Metal Tube Boiler T91 Dan 347H

Iwanata, Indra Surya (2022) Studi Pengaruh Buttering Layer ERNiCr-3 Dan Post Weld Heat Treatment Pada Struktur Mikro Dan Sifat Mekanik Pengelasan Dissimilar Metal Tube Boiler T91 Dan 347H. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pembangkit listrik superkritis dikembangkan sebagai upaya peningkatkan efisiensi pembangkit energi dan mengurangi emisi CO2 dengan temperatur operasi mencapai 538-565°C. Komponen tube boiler kombinasi reheater dan superheater membutuhkan dua jenis material yang berbeda berdasarkan kebutuhan temperature yang digunakan. Aplikasi yang umum digunakan pada temperatur tinggi adalah baja seri 304 tahan karat dengan T91 feritik yang disambung dengan teknik pengelasan, tetapi pada aplikasinya sering terjadi crack di Coarse Grain Heat Affected Zone (CGHAZ) dan garis fusi baja T91 feritik akibat perbedaan sifat mekanik setelah proses pengelasan. Penelitian ini mempelajari pengelasan tak sejenis T91 dan 347H. Metode yang digunakan adalah Gas Tungsten Arc Welding (GTAW) dengan logam pengisi (ERNiCr-3). Proses non-buttering dan buttering dilakukan dengan menggunakan tiga layer ERNiCr-3 pada interface T91 sebelum pengelasan dan dilakukan variasi temperatur PWHT 700°C dan 790ºC. Hasil pengamatan mikro menunjukan terbentuknya lapisan martensit pada interface T91 spesimen non-buttering. Perpindahan unsur kimia kandungan Ni28% dan Cr13% dari Coarse Grain Heat Affected Zone (CGHAZ) ke daerah las dibuktikan dengan hasil EDS disertai adanya pembentukan lapisan martensit pada interface T91 spesimen non buttering-PWHT 790oC. Kekerasan lapisan martensit mencapai 344HV pada spesimen non buttering-PWHT 700oC. Lapisan martensit tidak terbentuk pada pengelasan buttering. Pembentukan martensit diduga sebagai penyebab crack pada garis fusi. Penggunaan metode buttering ERNiCr-3 memberi dampak yaitu menghambat pembentukan lapisan martensit pada sisi interface T91. Variasi temperatur tempering yang digunakan memberi dampak refinement grainsearah dengan meningkatnya temperatur yang digunakan.
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Supercritical power plants were developed to increase energy generation efficiency and reduce CO2 emissions with operating temperatures reaching 538-565°C. The reheater and superheater combination tube boiler components require two different types of materials based on the temperature requirements used. Commonly used applications at high temperatures are stainless steel 304 series with ferritic T91 joined by welding techniques, but in its application cracks often occur in the Coarse Grain Heat Affected Zone (CGHAZ) and ferritic T91 steel fusion lines due to differences in mechanical properties after the welding process. This research studies dissimilar welding of T91 and 347H. The method used is Gas Tungsten Arc Welding (GTAW) with filler metal (ERNiCr-3). The non-buttering and buttering processes were carried out using three layers of ERNiCr-3 at the T91 interface before welding and varying the PWHT temperature of 700°C and 790ºC. The results of micro observations showed the formation of a martensite layer on the T91 interface of non-buttering specimens. The transfer of chemical elements containing Ni28% and Cr13% from the Coarse Grain Heat Affected Zone (CGHAZ) to the weld area was proven by the EDS results accompanied by the formation of a martensite layer at the T91 interface of the non-buttering PWHT specimen at 790oC. The hardness of the martensite layer reached 344HV on the 700oC non-buttering PWHT specimen. A martensitic layer does not form on welding buttering. The formation of martensite is thought to be the cause of the crack in the fusion line. The use of the ERNiCr-3 Buttering method has the effect of inhibiting the formation of a martensite layer on the T91 interface. The variation of the tempering temperature used gives the effect of grain refinement in the direction of increasing the temperature used.

Item Type:	Thesis (Other)
Additional Information:	RTM 671.52 Iwa s-1 2022
Uncontrolled Keywords:	PLTGU, Dissimilar welding, T91, 347H, PWHT, Buttering
Subjects:	T Technology > TN Mining engineering. Metallurgy > TN879.6 Welding
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Mr. Marsudiyana -
Date Deposited:	13 Feb 2025 01:50
Last Modified:	13 Feb 2025 01:50
URI:	http://repository.its.ac.id/id/eprint/118704

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