INVESTIGATION ON PRECIPITATIONS AND DEFECTS OFTHE Fe-24Cr-2Si-0.8Mn FERRITIC SUPER ALLOY STEEL

Dani, Mohammad; Parikin, Parikin; Iskandar, Riza; Dimyati, Arbi

doi:10.17146/jsmi.2017.18.4.4123

Cited by 4 publications

(5 citation statements)

References 13 publications

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“…These defects may have been induced by machining processes. These defects were also observed in previous reports for a similar sample [20] and for austenitic sample [21]. Figure 5 shows the TEM image of about 3.5 µm crosssection depth (transverse direction) from the surface of the ferritic super alloy steel sample.…”

Section: Resultssupporting

confidence: 83%

Comprehensive Inspection on the Experimental Ferritic Stainless Steel by Means of Transmission Electron Microscopy and Neutron Diffraction Techniques

Parikin¹,

Dani²,

Iskandar³

et al. 2020

MST

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The field of physical metallurgy is one of the primary beacons that guide alloy developments for multipurpose materials such as the in-core structure materials for pressure vessel components and heat exchangers. The surface microstructure of new ferritic steel with significant local constituent materials was characterized by high resolution powder neutron diffractometer (HRPD) and transmission electron microscope (TEM), combined with the energy dispersive X-ray spectroscopy (EDX). The alloy contains73% Fe, 24% Cr, 2% Si, 0.8% Mn, and 0.1% Ni, in %wt. The charge materials were melted by the casting techniques. The neutron diffractograms obtained shows five dominant diffraction peaks at (110), (200), (211), and (220) reflection planes, which is a typical structure for a body centered tetragonal system. The pattern also included some unidentified peaks which were verified to be Al 2 O 3 .54SiO 2 , Cr 23 C 6 , and SiC crystals. A piece of alloy which taken from the middle of the ferritic ingots was also characterized by the HRPD; no unidentified peaks were observed. Results from the scanning transmission electron microscopy (STEM) combined with EDX analyses confirmed the neutron identified phase distributions. Also, oxides and carbides were observed to form mainly close to the surface of the steel. Cracks and pores which probably formed during the preparations were also identified close to the surface. Although the ferritic steel was successfully synthesized and characterized, some unidentified phases and defects could still be found in the produced ingots.

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Section: Resultssupporting

confidence: 83%

Comprehensive Inspection on the Experimental Ferritic Stainless Steel by Means of Transmission Electron Microscopy and Neutron Diffraction Techniques

Parikin¹,

Dani²,

Iskandar³

et al. 2020

MST

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“…Meanwhile, the eutectic structure of Fe-Cr-C in grain boundaries consists of discontinuous carbide islands surrounded by -austenite zones, also known as particlefree zones. These carbide islands in A2 ASS as-cast as a part of the eutectic structure develop preferentially at the grain boundary [13]- [14].…”

Section: Resultsmentioning

confidence: 99%

Effect of Arc Plasma Sintering on the Structural and Microstructural Properties of Fe-Cr-Ni Austenitic Stainless Steels

Parikin

Dani

Dimyati

et al. 2021

MST

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X-ray diffraction techniques were performed to determine the actual crystal structure of A2 austenitic stainless steel (ASS) as-cast and A2 ASS after arc plasma sintering (APS) for 2 s. Computations were conducted on the basis of the Bragg arithmetic formula by comparing the S 2 arithmetic with the interplanar spacing. The Bragg arithmetic formula is a simple series for the determination of the crystalline phase of materials based on the Miller indices of cubic shapes or other shapes. A2 ASS as-cast was identified to have a crystal structure of face-centered cubic with lattice parameter a = 3.58 Å. A similar crystal structure can still be detected in A2 ASS after APS for 2 s with lattice parameter a = 3.60 Å. This finding was confirmed by neutron diffraction measurements and optical-electron microscopy observations. Under the same conditions, both A2 ASS as-cast and A2 ASS after APS for 2 s have similar cast structures. The grain boundary formed in A2 ASS as-cast is thinner than that in A2 ASS after APS for 2 s, which is visible in its boundaries. Moreover, the grain structure of A2 ASS after APS for 2 s, which was originally elongated particles, became globular particles. Similarly, granular precipitates became concentrated and encompassed the steel matrix along the grain boundaries. Furthermore, scanning electron microscopy with energy-dispersive X-ray analysis showed that particles and islands in steel are distributed in the grains and at the grain boundaries, respectively. Precipitates are composed of C, Cr, Fe, and Ni. The elemental contents of Cr and C are dominant; thus, Cr23C6 precipitate is formed at the grain boundaries. AbstrakPengaruh Sintering Arc-Plasma pada Sifat Mikro dan Struktur Baja Tahan Karat Austenitik Fe-Cr-Ni. Dalam penelitian ini, teknik difraksi sinar-X dilakukan untuk mengetahui bentuk struktur kristal dan parameter kisi sebenarnya baja nirkarat austenitik (ASS) A2 as-cast dan A2-ASS yang disinter plasma selama 2 detik. Perhitungan dilakukan dengan menggunakan dasar rumus Bragg, dengan membandingkan nilai S-aritmatika dan jarak antarplanar. Aritmatika Bragg adalah rangkaian sederhana dari penentuan kristal suatu bahan berdasarkan bentuk kubik Indeks Miller atau lainnya. ASS teridentifikasi memiliki struktur kristal face centered cubic (FCC) dengan parameter kisi a = 3,58 Å. Struktur kristal yang serupa masih ditemukan di ASS setelah arc plasma sintering (APS) selama 2 detik dengan parameter kisi a = 3,60 Å. Hasilnya dikonfirmasi dengan pengukuran difraksi neutron dan pengamatan struktur mikro menggunakan Mikroskop Optik (MO) dan Elektron (SEM). Dengan asumsi kondisi yang sama saat proses pengecoran, kedua ASS A2 memiliki struktur cor yang sama, batas butir yang dibentuk dalam ASS A2 as-cast lebih tipis daripada batas butir dalam ASS A2 setelah APS selama 2 detik yang cenderung sangat terlihat sangat jelas batas-batasnya. Sementara, pola butiran dalam A2 ASS setelah APS selama 2 detik, partikel yang awalnya memanjang berubah menjadi partikel globular pada struktur butir. Demikian juga, e...

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“…Meanwhile, microstructure observation was conducted with standard procedures [10,11]. Characterization was carried out using Optical Microscope and Electron Microscope (SEM-JEOL type JSM-6510LA).…”

Section: Experiments Methodsmentioning

confidence: 99%

“…EDX is taken at an average dead time value of between 20% and 40%. More detailed information has been discussed in previous publications [10]. After going through the surface etching process the test sample becomes a dop, using an optical microscope, the surface microstructure can be observed.…”

Section: Experiments Methodsmentioning

confidence: 99%

MICRO-CRYSTAL STRUCTURE OF 57Fe15Cr25Ni0.32Mn0.96Si AUSTENITE STEEL AFTER 850°C-5H TEMPERATURE-QUENCHING TREATMENTS FOR HIGH TEMPERATURE MATERIAL APPLICATIONS

Parikin¹,

Rudi

Sumaryo³

et al. 2018

jsmi

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MICRO-CRYSTAL STRUCTURE OF 57Fe15Cr25Ni0.32Mn0.96Si AUSTENITE STEEL AFTER 850°C-5H TEMPERATURE-QUENCHING TREATMENTS FOR HIGH TEMPERATURE MATERIAL APPLICATIONS. A serial austenite stainless steel, namely A2-type, has been synthesized by using casting technique at temperature more than 1250 °C in the induction furnace that used an electromagnetic inductive-thermal system. The steel is dedicated for structural component material in multi-purpose applications such as in high-temperature operating environments. So, the material must be resistant to mechanical loads, high temperature, corrosion and irradiation. In order to increase the strength of materials, temperature-quenching treatments are required in some cooling media. Mineral element was extracted from crude ores of Indonesian mines and commercial scrap materials, i.e: ferro scrap, ferro chrome, nickel, manganese, and ferro silicon; all of them in granular shape were prepared to alloy the steel. Titanium was not added to this austenite low carbon steel. The OES-chemical composition in %wt of the materials is 57%Fe, 15%Cr, 25%Ni, 0.34%C and less than 0.1% of impurities that comprised of: titanium, phosphor, copper, niobium and sulphur elements in the steel. X-ray diffraction pattern shows that ascast material had an fcc crystal structure with lattice parameter of 3.632 Å. Meanwhile, two of samples, i.e: annealing and oil quench, have strictly similar lattice parameter to that of air (normalizing) quench (3.580 Å). On the other hand, the lattice parameter of water quenched samples has a slightly lower lattice parameter than the ascast lattice , i.e. 3.587 Å. The peak shift of (111) and (200) -plane in the diffraction profile, is very significant, approximately 0.63 degrees between ascast sample and the last two samples. Ascast microstructure reveals that the austenite phase grains look large and describe an undeformed structure, with an average grain size of about 6 mm, while the annealed sample was larger. Air- and oil- quenched sample microstructures showed a fine grain which was very different to water quenched sample microstructure that showed a coarse grain. The viscousity (h) of the quenching medium had an important role in the formation of grain boundary, because the rate of decreasing temperature was heavily influenced by the diffusion of heat from the high to low temperature spaces.

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INVESTIGATION ON PRECIPITATIONS AND DEFECTS OFTHE Fe-24Cr-2Si-0.8Mn FERRITIC SUPER ALLOY STEEL

Cited by 4 publications

References 13 publications

Comprehensive Inspection on the Experimental Ferritic Stainless Steel by Means of Transmission Electron Microscopy and Neutron Diffraction Techniques

Comprehensive Inspection on the Experimental Ferritic Stainless Steel by Means of Transmission Electron Microscopy and Neutron Diffraction Techniques

Effect of Arc Plasma Sintering on the Structural and Microstructural Properties of Fe-Cr-Ni Austenitic Stainless Steels

MICRO-CRYSTAL STRUCTURE OF 57Fe15Cr25Ni0.32Mn0.96Si AUSTENITE STEEL AFTER 850°C-5H TEMPERATURE-QUENCHING TREATMENTS FOR HIGH TEMPERATURE MATERIAL APPLICATIONS

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