Karakterisasi Ball Mill Import Pada Industri Semen Di Indonesia

The purpose of this research is to investigate the characteristics of import Ball Mill which is used at cement mills in Indonesia. There were two kind of import Ball Mill from PT. Semen Gresik, Tbk that used in this research which are A type (Ø 30 mm) and B type (Ø 40 mm). Visual investigation, chemistry composition, distribution of hardness, and microstructure photograph was conducted characterize these ball mill. Visually, the import Ball Mill has rough surface, white coloring when cut off, and small cracks at all specimens. Type A ball mill contains of 2,934% C, 11,231% Cr, and 0,177% Mo, where type B Ball Mill contains of 2,693% C, 12,31% Cr, and 1,103% Mo. Both are martensitic white cast iron ASTM A532 Class II type A. The surface are harder then the its core. The highest hardness on the surface are 720,82 kg/mm2 (type A) and 746,5 kg/mm2 (type B), where as lowest hardness on the core are 631,1 kg/mm2 (type A) and 544,0 kg/mm2 (type B). Microstructure investigation shows Perlit, Cementit, and Martensit

Modifikasi Sifat Mekanik Dan Ketahanan Korosi Paduan Fe-1,52Al-1,44C Dengan Proses Tempiring

Aluminum is third of biggest element in the world and cheaper relatively. The Fe-Cr-C alloy is promised alloy to replace the Fe-Cr-C alloy. The purpose of the research is to investigate influence of temperature to microstructure, tensile strength, hardness, and corrosion resistance of Fe-Al-C in the 3.5% NaCl solution. Raw material for casting is low Mn steel, FeMn HC, pure aluminum, slag remover. The melting used low frequency induction furnace which has 50 kg capacity. Hardening at 900oC, and then quenching in the water, the last temper along 1 hour with various temperature; 250oC, 300oC, 350oC, 400oC, 450oC and cooling in the air. Chemical composition, microstructure, tensile strength, hardness, and corrosion resistance of Fe-Al-C in the 3.5% NaCl solution were investigated. The result of the chemical composition investigation showed that Fe-Al-C alloy contained 1.52% Al, and 1.44% C. The microstructure of Fe-1.52 Al-1,44C alloy is ferrite and pearlite. The tensile strength of Fe-1.52 Al-1,44C alloy is 33.77 kg/mm2. The tensile strength raised after hardening process became 74.44 kg/mm2 and turn off again after tempering process. The Vickers hardness investigation showed that the Fe-1.52 Al-1,44C alloy has 232.4 VHN and raised after hardening became 298.7 VHN. Highest corrosion rate is 0,927 mm/year after hardening and lowest is 0.196 mm/year after tempering at 300oC (good category corrosion resistance)

REKAYASA PADUAN Fe-Al-Mn-C SEBAGAI PENGGANTI BAJA TAHAN KARAT KONVENSIONAL SS 304

Conventional stainless steel is austenitic stainless steel (Fe-Cr-Ni alloy) which is the most widely used in industry. Weakness of stainless steel is the high cost of production and limited reserves, so that it is necessary to find new alloys which can replace the conventional stainless steel. The Fe-Al-Mn alloy system is very interesting as a potential candidate to replace the conventional stainless steel, where Al and Mn replace Cr and Ni, respectively. This study aims to find composition of the Fe-Al-Mn-C alloy which completely replaces SS 304 austenitic stainless steel. The alloy was prepared from mild steel scrap, medium carbon ferromanganese, high purity aluminum and ferrocarbon. The alloy was fabricated in a high frequency induction furnace. Melting experiments was carried out to find the right process that can achieve the target composition. Characterization was carried out to determine the effect of Al content in the Fe-Al-C alloy and Mn content in the Fe-Al-Mn-C alloy. In the last stage, the Fe-Al-C and Fe-Al-Mn-C alloy were compared with the SS 430 and as cast of SS 304 conventional stainless steel. Sensitization and transition temperature properties of the Fe-Al-Mn-C alloy were investigated in detail. The results show that the Fe-Al-C and Fe-Al-Mn-C alloys can be alloyed in a high frequency induction furnace under argon atmosphere. The level of Al in the Fe- Al-Mn-C alloy is 7.5% because it has high corrosion resistance. Microstructures of as cast Fe-Al-C alloy are ferrite and pearlite. Enhancement of Al causes fraction of ferritic in these alloys. Enhancement of Al also decreases density and toughness, but increases hardness, tensile strength and corrosion resistance significantly. Microstructure of as cast Fe-Al-Mn-C alloy up to 20% Mn is ferrite and austenite. Fully austenitic microstructure is achieved at 25% Mn. Addition of Mn to Fe-Al-C alloy increases density, hardness, tensile strength and corrosion resistance significantly. The Fe-Al-C and Fe-Al-Mn-C alloy have no sensitization at a temperature of 600oC, and no brittle-ductile transition in the range of-90oC to 90oC. Both alloys are not hardenable. The Fe-7.5Al-25Mn-0.6C alloy is recommended to completely replace SS 304 conventional stainless steel

Development of Fe-5Al-1C Alloys for Grinding Ball

Our object of research is to combine the properties of Mn and the advantages of Fe-Al-C to improve the performance of grinding ball materials. Three Fe-5Al-1C alloys with compositions of 15 wt% Mn (FAM15), 20 wt% Mn (FAM20), and 25 wt% Mn (FAM25) were investigated. Argon gas was used to assist the removal of dissolved oxygen and to control the formation of metal oxides during Fe-Al-Mn-C (FAMC) fabrication. Microstructure analysis was conducted using scanning electron microscopy, and the Vickers microhardness tester was used to evaluate hardness. To guarantee the Fe-5Al-1C-Mn alloy phase, X-ray diffraction (XRD) test was performed. The EDS test was carried out to show the composition at different points and to observe the presence of several phases in the FAMC alloy system. A pin-on-disc method was employed for a dry sliding wear test, and corrosion testing was performed using the three-electrode cell polarization method. With the addition of Mn, the Vickers hardness of the FAMC alloy raised from 194.4 VHN at 15 wt% to 265 VHN at 25 wt%. The tensile strength and fracture elongation values were 424.69 MPa, 27.16 % EI; 434.72 MPa, 33.6 % EI; and 485.71 MPa, 38.48 % EI for FAM15, FAM20, and FAM25, respectively. A crucial factor for increasing the performance of grinding ball is the wear mechanism. The wear rate results for FAM25 show a decline of more than 57 % compared to FAM15 due to an increase in the hard intermetallic area. The addition of Mn elements increased the corrosion resistance of the FAMC alloys; the lowest corrosion rate occurred at 25 wt% Mn content at up to 0.036 mm/yr. According to the experimental results, the FAM25 alloys have the highest mechanical and corrosion resistance of the three types of alloys. The FAMC alloy is a promising candidate for application as a material for grinding balls by optimizing the Mn conten

An Analysis of SmBa0.5Sr0.5Co2O5+δ Double Perovskite Oxide for Intermediate–temperature Solid Oxide Fuel Cells

The main obstacle to solid oxide fuel cells (SOFCs) implementation is the high operating temperature in the range of 800–1,000 °C so that it has an impact on high costs. SOFCs work at high temperatures causing rapid breakdown between layers (anode, electrolyte, and cathode) because they have different thermal expansion. The study focused on reducing the operating temperature in the medium temperature range. SmBa0.5Sr0.5Co2O5+δ (SBSC) oxide was studied as a cathode material for IT-SOFCs based on Ce0.8Sm0.2O1.9 (SDC) electrolyte. The SBSC powder was prepared using the solid-state reaction method with repeated ball-milling and calcining. Alumina grinding balls are used because they have a high hardness to crush and smooth the powder of SOFC material. The specimens were then tested as cathode material for SOFC at intermediate temperature (600–800 °C) using X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), electrochemical, and scanning electron microscopy (SEM) tests. The X-ray powder diffraction (XRD) pattern of SBSC powder can be indexed to a tetragonal space group (P4/mmm). The overall change in mass of the SBSC powder is 8 % at a temperature range of 125–800 °C. A sample of SBSC powder showed a high oxygen content (5+δ) that reached 5.92 and 5.41 at temperatures of 200 °C and 800 °C, respectively. High diffusion levels and increased surface activity of oxygen reduction reactions (ORRs) can be affected by high oxygen content (5+δ). The polarization resistance (Rp) of samples sintered at 1000 °C is 4.02 Ωcm2 at 600 °C, 1.04 Ωcm2 at 700 °C, and 0.42 Ωcm2 at 800 °C. The power density of the SBSC cathode is 336.1, 387.3, and 357.4 mW/cm2 at temperatures of 625 °C, 650 °C, and 675 °C, respectively. The SBSC demonstrates as a prospective cathode material for IT-SOF