Studi Pengaruh Buttering Layer ERNiCr-3 dan ERNICrMo-3 pada Dissimilar Metal Welding antara Baja Feritik-Martensitik T91 dan Baja Tahan Karat Austenitik 347h

Santoso, Andik (2021) Studi Pengaruh Buttering Layer ERNiCr-3 dan ERNICrMo-3 pada Dissimilar Metal Welding antara Baja Feritik-Martensitik T91 dan Baja Tahan Karat Austenitik 347h. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Peningkatan kebutuhan ketenagalistrikan dengan emisi CO2 yang lebih rendah dapat dipenuhi melalui peningkatan efisiensi pembangkit. Efisiensi dari pembangkit listrik tenaga uap (PLTU) berbahan bakar batubara merupakan fungsi dari tekanan dan temperatur kerja uap yang digunakan. Kenaikan parameter temperatur dan tekanan uap ini menyebabkan kebutuhan spesifikasi material yang digunakan menjadi lebih tinggi. Hal ini menyebabkan banyak material baru yang dikembangkan untuk menjawab tantangan ini. Adanya perbedaan material yang digunakan menyebabkan pengelasan logam beda (DMW) menjadi suatu hal yang tidak bisa dihindari. Proses pengelasan pada sambungan DMW menyebabkan tantangan tersendiri dalam pelaksanaan. Pengaruh buttering, filler material basis nikel – Inconel (ERNiCr-3 dan ERNiCrMo-3), dan perlakuan panas (PWHT) terhadap karakteristik DMW antara tube baja feritik/ martensitik T91 dan pipa baja tahan karat austenitik 347H dipelajari dalam penelitian ini. Digunakan pendekatan Schaeffler dan Rosenthal untuk prediksi sifat hasil pengelasan. Pengujian berupa pengamatan metallography, short term creep test dan pengamatan hasil patahan dilakukan untuk mendapatkan karakteristik material penelitian. Hasil penelitian menunjukkan pendekatan Schaeffler bisa digunakan untuk memprediksi sifat weld metal berupa fase austenitik, pendekatan Rosenthal mendekati struktur mikro dan fase material penelitian dengan perbedaan pada lebar masing-masing fase sesuai siklus thermal yang dialami material. Nilai faktor reduksi ketahanan material las perlakuan direct welding FM ERNiCr-3 dan ERNiCrMo-3 sebesar 0,32 berada di bawah ambang persyaratan sehingga tidak direkomendasikan untuk digunakan di temperatur 600 oC. Nilai faktor reduksi ketahanan material las perlakuan buttering FM ERNiCrMo-3 sebesar 0,6 berada di ambang bawah persyaratan dan kurang sesuai untuk penerapan di temperatur 600 oC. Perlakuan buttering FM ERNiCr-3, buttering dilanjutkan PWHT FM ERNiCr-3 dan ERNiCrMo-3 berada di atas ambang persyaratan sehingga sesuai digunakan di temperatur 600 oC.
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Increased demand of power generation with lower CO2 emmisions can be fulfilled with improvement on coal powerplant efficiency. Efficiency of coal powerplant is a function of steam temperature and pressure. New advanced material is developed to fulfill these steam parameter improvement. Different material used causing dissimilar metal welding (DMW) inevitable. Welding processes on DMW is a chalenge due to the differences of mechanical properties, creep rupture strength, high temperature corrosion and oxidation and microstructure stability must be considered. Influence of buttering, nickel based filler material (FM) – Inconel (ERNiCr-3 dan ERNiCrMo-3), and heat treatment (PWHT) on DMW between ferrictic/ martensitic steel T91 and austenitic stainless steel 347H characteristics are studied on this research. Schaeffler diagram and two dimensional Rosenthal equation approach are used to predict weld metal microstructure. Mechanical testing on room and elevated temperature such as tensile, hardness, metallography and creep conducted to gain knowledge of weld characteristics. Results indicated that microstructural analysis is as predicted by Schaeffler diagram and Rosenthal approach, however width of each phase depends on the thermal cycle of material. Weld conducted with ERNiCr-3 shows slightly better creep strength compared with ERNiCrMo-3. Buttering with PWHT on T91 shows highest creep strength, while direct welding has least strength.Weld Strength Reduction Factor using time inisiation of tertiary creep (WTRF) is used to material capability. WTRF of direct welding with ERNiCr-3 and ERNiCrMo-3 FM both are 0.32 and under requirement of 600 oC application. WTRF of FM ERNiCrMo-3 is 0.6 and on the minimum requirement. WTRF of Buttering using ERNiCr-, buttering continued with PWHT using ERNiCr-3 or ERNiCrMo-3 are 0.65, 0.89 and 0.78 respectively above minimum requirement therefore applicable for 600 oC requirement.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	DMW, T91, 347H, buttering, Inconel, PWHT
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA418.74 Corrosion and anti-corrosives T Technology > TJ Mechanical engineering and machinery > TJ263.5 Boilers (general) T Technology > TS Manufactures > TS227 Welding.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Andik Santoso
Date Deposited:	27 Aug 2021 22:45
Last Modified:	27 Aug 2021 22:45
URI:	http://repository.its.ac.id/id/eprint/91079

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