Residual Stress Measurements on the TIG Weld Joint of 57Fe15Cr25Ni Austenitic Steel for Structural Material Applications by Means X-Ray Diffraction Techniques

Parikin, Parikin; Ismoyo, Agus Hadi; Iskandar, Riza; Dimyati, Arbi

doi:10.7454/mst.v21i2.3080

Cited by 8 publications

(12 citation statements)

References 11 publications

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“…This was identified to be the same phase as large precipitates. The mechanisms of hardening and corrosion (as well as oxidation resistance) in high alloyed steel are well known, and they have been reported in many publications (Sumijanto et al, 2015;Parikin et al, 2017;Besnard et al, 2017;Geers et al, 2017). In this work, it was assumed that the hardening mechanism of the alloy was associated with the presence of precipitation.…”

Section: Crystal Structurementioning

confidence: 98%

A New Precipitation Hardened Austenitic Stainless Steel Investigated by Electron Microscopy

Dani¹,

Dimiyati²,

Iskandar³

et al. 2018

IJTech

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The 56Fe16.6Cr25Ni0.9Si0.5Mn austenitic superalloy has been produced in an induction furnace; it was made from granular ferro-scrap, ferrochrome, ferrosilicon, and ferromanganese materials. Originally, this alloy had been proposed for use in high mechanical loads and high temperature conditions (such as in nuclear and fossil fuel power plant facilities). Tensile strength tests showed that the alloy has an average yield strength of about 430.56 MPa, which is higher than Incoloy A-286 (a commercially available alloy). A combination of microscopy techniques by means of an optical microscope, X-ray diffraction [XRD], scanning electron microscopy [SEM], and transmission electron microscopy [TEM] techniques were applied in order to get detailed information about the fine structure of the alloy. XRD confirmed that the alloy matrix exhibits an FCC crystal structure with a lattice parameter of about 3.60 Å and grain sizes ranging from 50 to 100 µm. The results of the TEM analysis revealed the new type of precipitations that formed at the grain boundaries. These needle-like precipitations, probably Fe/Cr-rich precipitations of the (Fe,Cr)xCy type, acted as the source of intergranular corrosion (IGC). Small coherent plate-like and much smaller granular precipitations were found distributed homogenously along grain boundaries and inside the grains. Combining the tensile strength test and microstructure analysis suggested that these precipitations play significant roles in the hardness of the investigated sample.

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Section: Crystal Structurementioning

confidence: 98%

A New Precipitation Hardened Austenitic Stainless Steel Investigated by Electron Microscopy

Dani¹,

Dimiyati²,

Iskandar³

et al. 2018

IJTech

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“…In Figure 3A, according to the EDX measurements from previous studies [8], the light area contains abundant nickel, otherwise the dark area is poor. Carbon diffuses along the grain boundaries (see blue rectangle in Figure 3A) and looks like a black streak.…”

Section: Figure 3 Microstructures Of Specimen Around the Tig Weld Jomentioning

confidence: 77%

“…Other studies [8], [13], [18] reported that chromium carbide (Cr23C6) precipitation could also affect the increase in material hardness.…”

Section: Figure 5 Crystal Structures Of the Specimen Subjected To Timentioning

confidence: 99%

“…The interesting phenomenon is visible in the center of the weld. Two phases [8] overlap in the form of cast structure (columnar dendrites) mixed with austenitic structure. The center of the weld metal is dominated by the cast structure.…”

Section: Figure 3 Microstructures Of Specimen Around the Tig Weld Jomentioning

confidence: 99%

“…The four areas formed during welding are weld center (weld metal), heat affected zone (HAZ), thermomechanically affected zone (TMAZ), and base metal (BM). In 2015, a study investigated the effects of welding on austenitic steel plate containing 57%Fe15%Cr25%Ni [8]. This work hypothesized that the most critical steel structure occurred in metal connections (weld joints) where the concentrations of stress and residual stress are very high.…”

Section: Introductionmentioning

confidence: 99%

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Microstructures and Hardness of the Experimental 57Fe15Cr25Ni Steel Around TIG Weld-Joints for Reactor Structure Materials

Parikin

Dani

Rivai

et al. 2018

MST

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The microstructures and hardness of tungsten inert gas (TIG) welded experimental 57Fe15Cr25Ni steel were investigated through optical-scanning electron microscopy analyses and with a hardness tester, respectively. The welding process restructured the constituent atoms into regular and irregular crystal lattices. Rapid cooling of the weld metal allowed the formation of a dendritic (columnar) structure, with porous grains. By contrast, slow cooling influenced HAZ and led to the formation of grain structures. The crystal lattice became more organized and larger than other zones. Meanwhile, the base metal formed circular nets that covered large area inside thick and thin grain boundaries. The diffraction patterns revealed texturing in the weld metal. The crystallite orientation changed from (111) to (200) and (220) planes. The weld metal profile broadened (amorphous) and had full width at half maximum (fwhm) value larger than those in HAZ and the base metal. The weld metal possessed hardness of 121 HV, which is slightly lower than the hardness of the base metal (130 HV). HAZ exhibited the highest hardness value (152 HV). Hardening was influenced by carbon and outer oxygen migration to the grain boundaries, which formed colonies, i.e., chromium carbide, aluminum carbide, aluminum oxide, silicone oxide, and silicon carbide (precipitation hardening). Welding (heat) may change the microstructure and hardness of HAZ and the weld metal region, which would be brittle and very critical in responding to applied loads. AbstrakStruktur Mikro dan Kekerasan pada Las TIG Baja Experimental 57Fe15Cr25Ni. Pengamatan pengaruh panas las pada pembentukan struktur mikro dan kekerasan plat baja 57Fe15Cr25Ni menggunakan mikroskop optik (OM)electron (SEM), dan Microhardness Vickers Testing Machine yang beridenter diamond telah dilakukan. Hasil memperlihatkan bahwa mekanisme panas las mampu mempengaruhi proses penataan ulang atom-atom penyusun kisi kristal menjadi teratur dan tidak teratur. Karena mengalami pendinginan yang cepat, struktur mikro pusat las (weld metal) berbentuk dendrit columnar berpori dalam lingkupan struktur matriks, sedang efek pendinginan melambat di daerah HAZ mengakibatkan penyusunan kisi kristal menjadi lebih teratur dan berukuran lebih besar daripada ukuran butir matrik. Di daerah logam matrik (base metal) struktur mikro berbentuk jejaring melingkar besar dan kecil yang dilingkupi batas butir (grain boundary) tebal dan tipis. Texturing terdeteksi di daerah pusat las. Kristal mengubah orientasi dari bidang refleksi (111) ke bidang refleksi (200) dan (220). Profil pusat las melebar (amorf), menyebabkan angka lebar setengah puncak maksimum (fwhm) lebih besar dari pada daerah HAZ dan basemetal, dan sangat sesuai dengan pengamatan struktur mikro permukaan bahan. Nilai rerata kekerasan pada daerah weld metal sekitar 121 HV, lebih rendah daripada daerah base metal sekitar 130 HV, sedang daerah HAZ memiliki nilai rerata kekerasan yang paling tinggi sekitar 152 HV. Pengerasan ini juga dipengaruhi oleh migrasi carbon dan oxyge...

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Ketahanan Oksidasi Baja Super Austenitik 15%cr-25%ni Pada Temperatur 850 °c

Parikin¹,

Sugeng

Dani

et al. 2017

jsmi

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KETAHANAN OKSIDASI BAJA SUPER AUSTENITIK 15%Cr-25%Ni PADA SUHU 850 C. Ketahanan korosi suhu tinggi atau ketahanan oksidasi merupakan prasyarat penting bahan logam yang akan diterapkan dilingkungan operasi bersuhu tinggi. Pengujian ketahanan oksidasi baja super austenitik 15%Cr-25%Ni pada suhu 850 C selama 5 jam lebih telah dilaksanakan. Satu sampel as-cast sebagai acuan awal yang tidak diperlakukan panas dan dua (2) kelompok sampel (masing-masing 3 buah) disiapkan dalam eksperimen. Satu kelompok sampel as-cast setelah dipanaskan (pada 850 C/5 jam lebih) dan didinginkan perlahan kemudian ditimbang. Satu kelompok sampel quench yang dilakukan penurunan cepat suhu (dari 850 C/5 jam lebih) ke dalam air, kemudian ditimbang. Percobaan dilakukan selama 15 jam lebih pada masing-masing kelompok. Hasil memperlihatkan bahwa walaupun terjadi kenaikan berat sangat kecil pada sampel as-cast dan quench, tetapi foto morfologi mikroskop elektron (SEM) pada kedua sampel tersebut tidak memperlihatkan perubahan yang signifikan. Demikian pula hasil analisis fasa menggunakan difraksi sinar-X, tidak memperlihatkan pertumbuhan fasa produk oksidasi. Hasil pengamatan strukturmikro permukaan bahan menggunakan mikroskop optik (MO), juga tidak memperlihatkan kerusakan dan perubahan ukuran butir oleh proses oksidasi. Kebolehjadian pada fenomena ini adalah selain pembentukan spinel unsur Ni diperkuat juga oleh kemampuan unsur Cr untuk membentuk lapisan pasif (Cr 2 O 3) dipermukaan bahan yang sangat besar dengan mengikat unsur O, sehingga bahan mampu menanggulangi produk oksidasi yang sangat kecil. Disimpulkan bahwa baja super austenitik memiliki ketahanan oksidasi yang baik pada suhu 850 C.

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Residual Stress Measurements on the TIG Weld Joint of 57Fe15Cr25Ni Austenitic Steel for Structural Material Applications by Means X-Ray Diffraction Techniques

Cited by 8 publications

References 11 publications

A New Precipitation Hardened Austenitic Stainless Steel Investigated by Electron Microscopy

A New Precipitation Hardened Austenitic Stainless Steel Investigated by Electron Microscopy

Microstructures and Hardness of the Experimental 57Fe15Cr25Ni Steel Around TIG Weld-Joints for Reactor Structure Materials

Ketahanan Oksidasi Baja Super Austenitik 15%cr-25%ni Pada Temperatur 850 °c

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