scholarly journals THE EFFECTS OF PACK CARBURIZING USING CHARCOAL ON PROPERTIES OF MILD STEEL

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Supriyono Supriyono
Keyword(s):  
Mild Steel ◽  
Tensile Test ◽  
Carbon Content ◽  
Hardness Test ◽  
Holding Time ◽  
Raw Material ◽  
Core Zone ◽  
The Core ◽  
Carburizing Process ◽  
Hypoeutectoid Steel

The aim of this research is to study the effects of pack carburizing using charcoal on properties of mild steel. The properties are represented by the results of microstructure, hardness test and tensile test.  The carburizing process was conducted in the temperature of 930oC which is the austenite temperature of the mild steel. The source of carbon was charcoal. The specimens were held for 2, 3 and 4 hours at the carburizing temperature. The carbon content of the raw amterial was 0.17%. The raw material was hypoeutectoid steel with ferrite and pearlite phases in its microstructure.  After the carburizing process, the microstructure can be divided into two zones e.i. case zone and core zone. The case zone consists of hypereutectoid, eutectoid, and hypoeutectoid sub-zone. The core zone is the same as raw material. The longer the holding time will result in the deeper the case zone and the stronger the material.

Vickers Microhardness Dependence Load and Determining of Tensile Strength of HQ 705 Steel from Microhardness Curves

2016 ◽  
Vol 842 ◽  
pp. 43-52 ◽  
Author(s):  
Viktor Malau ◽  
Latif Arifudin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Alloy Steel ◽  
Vickers Hardness ◽  
Vickers Microhardness ◽  
Hardness Test ◽  
Indentation Load ◽  
Holding Time ◽  
Raw Material ◽  
Vickers Hardness Number

Vickers microindentation hardness test has been applied for a long time to determine the mechanical properties of a small volume of samples. The procedure of this hardness test consists of using a constant load on a rigid indenter and measuring the dimensions of the indenter residual impression (indentation imprint) on the surface of the sample tested after loading and unloading. The objective of this research is to characterize the mechanical properties and material constants of HQ (High Quality) 705 alloy steel mainly its VHN (Vickers Hardness Number) and tensile strength before and after quenching and tempering heat treatments. The characterization is based on Vickers microhardness dependence load curves.Quenching treatment was performed in a furnace by heating the samples at austenite temperature of 850 o C with holding time of two hours and then the samples were rapidly cooled in oil bath. Tempering processes were conducted by heating again the quenching samples to temperatures of 150, 200, 250, 300, 350, 400, 450, 500, 550 and 600 o C with holding time of two hours for each sample. Finally, all samples were slowly cooled in atmospheric temperature. The mechanical properties of samples were characterized by using Vickers microhardness dependence load curves.The results show that VHN (Vickers Hardness Number) depends on indentation load and VHN increases with increment of load for indentation load lower than 5 N. VHN is almost constant for indentation load greater than 5 N. The raw material (without heat treatment) has the VHN and tensile strength of 3413 MPa and 1050.61 MPa respectively and the quenched samples have the VHN and tensile strength of 5407 and 1861 MPa respectively. The Vickers hardness and tensile strength decrease with the increment of tempering temperatures. The higher tempering temperature produces lower hardness and tensile strength. The raw material tensile strength of 1058.8 MPa obtained by tensile test is comparable to its tensile strength of 1050.61 MPa obtained by Vickers indentation. This result indicates that Vickers microindentation is valid to use for evaluating the tensile strength of HQ 705 alloy steel.

Welding Performance of a Homemade Friction Stir Welding Tool

2013 ◽  
Vol 446-447 ◽  
pp. 660-664
Author(s):  
Irfan Hilmy ◽  
Erry Yulian T. Adesta
Keyword(s):  
Friction Stir Welding ◽  
Mild Steel ◽  
Tensile Test ◽  
Low Cost ◽  
Hardness Test ◽  
Milling Machine ◽  
Friction Stir ◽  
Mechanical Performances ◽  
Tensile Test Result ◽  
Test Result

Homemade Friction Stir Welding (FSW) Tool utilizing conventional milling machine has been developed. The FSW tool made from mild steel was designed and fabricated. Experimental investigation of FSW process of the Aluminum alloy specimens to observe its mechanical performances was performed. To evaluate its performance, hardness test, tensile test as well as visual inspections of the welding result were performed. Hardness number in the welding region was measured about 40-60% lower than the base metal, and heat affected zone region. The tensile test result varies with maximum 100 MPa. The imperfection of final form of metal due to the stirring mechanism was inspected. The presence of void/crack at cross-section of the welded specimen was observed. It was found that by applying suitable configuration, the use of mild steel as the FSW tool was reasonable for performing FSW process. It was concluded that, using a relatively low cost FSW tool, a quite satisfactory result of welding performance was achieved.

scholarly journals PENGARUH VARIASI HOLDING TIME DAN MEDIA PENDINGIN TERHADAP KEKERASAN DAN STRUKTUR MIKRO BAJA SUS 630 METODE HARDENING

JTAM ROTARY ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 149
Author(s):  
Dwi Herizen ◽  
Rudi Siswanto
Keyword(s):  
Salt Water ◽  
Hardness Test ◽  
Residual Austenite ◽  
Optical Microscope ◽  
Holding Time ◽  
Raw Material ◽  
Material Engineering ◽  
Hardening Process ◽  
Water Salt ◽  
Cooling Media

SUS 630 memiliki kekerasan 30,9 HRC dan kandungan Chromium 12% berdasarkan pemakaiannya di PT. Pupuk Kalimantan Timur merekomendasikan kekerasan sebesar 55 HRC, untuk meningkatkan kekerasan material dapat dilakukan dengan teknik material engineering yaitu Hardening. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh variasi waktu tahan dan media pendingin terhadap kekerasan dan mikrostruktur baja sus 630. Proses pengerasan dilakukan hingga mencapai suhu 1020 0C kemudian waktu tahan dengan variasi 10, 20, 30, 40, dan 50 menit kemudian dicelupkan ke dalam air, air garam, dan minyak sampai suhu kamar. Struktur mikro diuji menggunakan mikroskop optik dengan perbesaran 400x dan kekerasan menggunakan kekerasan Rockwell C dengan beban 150 kg. Pengamatan struktur mikro setelah pengerasan struktur yang terbentuk adalah bilah martenstie, sisa austenit, dan karbida logam. Hasil uji kekerasan tertinggi pada media pendingin air (34,2 HRC), air asin (34,2 HRC), dan minyak (34,1 HRC) dan bahan baku (30,9 HRC). Dari penelitian ini dapat disimpulkan bahwa proses pengerasan dapat meningkatkan nilai kekerasan. SUS 630 Steel hardness is 30.9 HRC and Chromium content is 12%, based on its use at PT. Pupuk Kalimantan Timur recommended a hardness of 55 HRC, to increase material hardness can be done by means of material engineering, namely Hardening. The aim of the study was to determine the effect of variations in holding time and cooling media on the hardness and microstructure of steel sus 630. The hardening process was carried out to reach 1020 0C then holding time with variations of 10, 20, 30, 40, and 50 minutes then dipped into water , salt water, and oil to room temperature. Microstructure was tested using an optical microscope with 400x magnification and hardness using Rockwell C hardness with a load of 150 kg. The observation of the microstructure after hardening of the structure formed is the martenstie lath, residual austenite, and metal carbide. The hardness test results were highest in water cooling media (34.2 HRC), salt water (34.2 HRC), and oil (34.1 HRC) and raw material (30.9 HRC). From this study it can be concluded that the hardening process can increase the value of violence.

scholarly journals Interlayer Effect on Connection of Mild Steel ST37 and Stainless Steel 201 on Rotary Friction Welding

2021 ◽  
Vol 65 (1) ◽  
pp. 23-30
Author(s):  
Yohanes Yohanes ◽  
◽  
Muhammad Heriansyah ◽  
Keyword(s):  
Stainless Steel ◽  
Mild Steel ◽  
Tensile Test ◽  
Friction Welding ◽  
Solid Phase ◽  
Welding Process ◽  
Hardness Test ◽  
Welding Parameters ◽  
Test Results ◽  
Rotary Friction Welding

Friction welding is a type of solid state welding where the welding process is carried out in a solid phase to combine various types of ferrous and non-ferrous metals that cannot be welded by the fusion welding method but for welding different metals the welding results are less than optimal due to cracks on the surface of the welding results and differences in mechanical properties that cause the welding result to be brittle, therefore an interlayer is used. In this study, observations were made on the process and results of the joint friction welding using dissimilar metal material between mild steel ST37 and stainless steel 201 with copper interlayer. The results of the test will be a tensile test to see the maximum tensile strength and a hardness test to see the hardness value of the interlayer variation of 0.3 mm, 0.5 mm, 1 mm and without an interlayer. The conclusions obtained are: (1) The effect of the addition of an interlayer on the rotary friction welding process includes the friction phase, the forging phase and the results of welding parameters in the form of motor power, motor angular speed, the change in specimen length is greater without using an interlayer compared to using an interlayer while the duration of welding time is greater using an interlayer than without using an interlayer. (2) The maximum tensile test results were obtained at the 1 mm interlayer at 482.43 MPa and the maximum hardness test results obtained at the 1 mm interlayer were 321.34 VHN.

scholarly journals ST37 Steel Carburization with Coconut Charcoal

2021 ◽  
Vol 3 (1) ◽  
pp. 29-35
Author(s):  
Melya Dyanasari Sebayang
Keyword(s):  
Mechanical Properties ◽  
Carbon Content ◽  
Carbon Steels ◽  
Coconut Shell ◽  
Low Carbon ◽  
The Core ◽  
Coconut Charcoal ◽  
Hardening Process ◽  
St37 Steel ◽  
Carburizing Process

The carburization process is a surface hardening process where carbon is added to the surface without changing the core properties of the material. This process is carried out at the austenite temperature so that the carbon can diffuse into the phase. This process can only be done on low carbon steels with content below 0.25%. This research was conducted on ST37 steel, which is steel with low carbon content with 0.18% carbon content. This type of steel is surface hardened with a carburizing temperature of 850 C with a long lasting time of 1 hour, then it is carried out under moderate cooling with outside air media. And change its mechanical properties from the comparison of the initial mechanical properties of the specimen. The highest hardness value occurs in the carburizing process of coconut shell charcoal, but this hardness value occurs not because of the carburization process but because of the enlarged grain size caused by heating at temperatures below 723⁰ C, thus reducing the elongation properties of the material. Carburizing with battery stone media is more efficient than coconut shell charcoal at temperatures below 723 C. Because the temperature is below the austenite temperature, the absorbed carbons cannot diffuse as happened in the carburization process, but the absorbed carbons can bind the grain boundaries and change their hardness by 4%. In the microstructure research that occurs in this process nothing can change its phase because the temperature does not reach the austenite temperature. However, there are differences in the microstructure between the carburization process with coconut shell charcoal media.

The Effect of Multiple Forging and Cold Rolling on Bending and Tensile Behavior of Al 7075 Alloy

2012 ◽  
Vol 729 ◽  
pp. 464-469 ◽  
Author(s):  
Tareg S. Ben Naser ◽  
György Krállics
Keyword(s):  
Tensile Strength ◽  
Cold Rolling ◽  
Tensile Test ◽  
Hardness Test ◽  
Mechanical Tests ◽  
Raw Material ◽  
Bending Test ◽  
Rolled Sheet ◽  
Al 7075 ◽  
7075 Alloy

This work studies the effect of multiple forging (MF), followed by cold rolling, on the tensile and bending behavior of Al 7075 alloy. The raw material was received as a rod shape. The specimens were subsequently cut and annealed at 450 °C for 30 minutes. The cylindrical specimens were subjected to MF at 250°C for three passes, then the bulk of multiple forging specimens were faced rolling at room temperature. Three different base materials were tested, raw material (as received then annealed), MF material, and rolled sheet. Hardness test, tensile test, and bending test were carried out in order to measure the mechanical properties, which are affected by the MF and cold rolling. It has been proved that the MF base specimens have higher tensile strength and better maximum elongation comparing with the raw material specimens. Rolled sheets specimens have got the highest tensile strength and lowest ductility. The result of bending test was similar to the tensile test results, beside these mechanical tests some metallographic samples were performed to help finding an explanation of this properties change.

Determination of core zone of marine sanctuary in Bahoi Village, North Minahasa Regency

2013 ◽  
pp. 10
Author(s):  
Sonny Tasidjawa ◽  
Stephanus V Mandagi ◽  
Ridwan Lasabuda
Keyword(s):  
Conventional Method ◽  
Local Community ◽  
Marine Protected Area ◽  
Final Decision ◽  
Marine Biota ◽  
Small Community ◽  
Community Based ◽  
Simple Method ◽  
Core Zone ◽  
The Core

Bahoi village is located in West Likupang District of North Minahasa Regency. It is one of the villages that is included in the conservation network of North Sulawesi Province. A marine sanctuary has been established in this village in 2003 and it has been managed by local community, known as community-based marine sanctuary management, since then, this sanctuary has been in operation. As a small community-based marine protected area with lots of users, it requires an appropriate method to determine the Core Zone that allows an effective preservation of the marine biota. This is the driving factor of this study.  The purpose of this study is to examine the processes and output of determining the core zone of a Marine Sanctuary using a conventional method and Marxan Method. The conventional method is a simple method in determining a core zone such as using manta tow technique. While Marxan, it only requires input of data such as spatial and figures to generate information for determining the core zone. After comparing the processes of these two methods in the study site, it was found that Marxan method was more effective and more accurate with lower costs than the conventional one. In addition, the final decision of the core zone depended on the outcome of the village meetings when the conventional method was applied. This long process could be avoided when Marxan method was used. Therefore, it is highly recommended to use Marxan in determining core zones© Desa Bahoi terletak di Kecamatan Likupang Barat Kabupaten Minahasa Utara. Desa ini merupakan salah satu desa yang masuk dalam jejaringan kawasan konservasi di Provinsi Sulawesi Utara. Sebuah Daerah Perlindungan Laut telah didirikan di desa ini pada tahun 2003 dan dikelolah oleh masyarakat setempat, yang dikenal sebagai pengelolaan Daerah Perlindungan Laut Berbasis Masyarakat, sejak saat itu Daerah Perlindungan Laut ini telah beroperasi. Sebagai Daerah Perlindungan Laut Berbasis Masyarakat yang kecil namun memiliki banyak pengguna, diperlukan metode tepat yang akan menentukan Zona Inti yang memungkinkan pelestarian biota laut menjadi sangat efektif. Ini adalah faktor pendorong dari penelitian. Selanjutnya, tujuan dari penelitian ini adalah untuk mengkaji proses dan hasil penentuan zona inti Daerah Perlindungan Laut dengan menggunakan metode konvensional seperti survei manta tow dan marxan. Metode konvensional adalah metode sederhana dalam menentukan zona inti seperti teknik manta tow. Sedangkan marxan, hanya perlu memasukan data seperti spasial dan angka untuk menghasilkan informasi penentuan zona inti. Setelah membandingkan proses dari dua metode di lokasi penelitian, ditemukan bahwa metode marxan jauh lebih baik dari pada metode konvensional, karena lebih efektif, lebih akurat dengan biaya yang lebih rendah. Selain itu, keputusan akhir dari zona inti tergantung pada hasil rapat desa ketika metode konvensional diterapkan, proses panjang ini dapat dihindari jika metode marxan digunakan©

Abundance of coral-polyp-eating gastropods Drupella cornus in Bunaken National Park, Indonesia: indicating anthropogenic impact?

2013 ◽  
Vol 1 (1) ◽  
pp. 17
Author(s):  
Farnis B Boneka ◽  
N Gustaf F Mamangkey
Keyword(s):  
National Park ◽  
Anthropogenic Impact ◽  
Coral Cover ◽  
Human Intervention ◽  
Core Zone ◽  
The Core ◽  
Human Interventions ◽  
Coral Polyp ◽  
Intervention Zone ◽  
Drupella Cornus

Corallivorous gastropods, Drupella cornus are living in the Indo Pacific coral reefs. To assess the distribution of the snails at Bunaken National Park in Indonesia, a study has been conducted on three zones established in three main islands of the park: core, tourism, and exploitation zones. The zones represent degrees of human interventions in which the least intervention is for core zone, moderate for tourism zone and high for the exploitation zone. The results showed that degrees of human interventions are related to the density of snails where the least human intervention zone (the core zone) had low numbers of snails while the high human intervention (exploitation) zone had high numbers of snails. Three corals in the zones that were preferred by the snails were: Montipora spp., Acropora spp., and Porites spp. The numbers of snails living on the corals followed the percent of coral cover© Gastropod pemakan polip karang, Drupella cornus hidup di areal terumbu karang Indo-Pasifik. Untuk mengetahui distribusi dari siput di Taman Nasional Bunaken, sebuah studi telah dilakukan pada tiga zona yang ditetapkan di tiga pulau utama di taman nasional ini: zona inti, zona pariwisata, dan zona pemanfaatan. Hasil penelitian ini menunjukkan bahwa tinggi-rendahnya intervensi manusia berhubungan dengan kepadatan siput di mana zona yang memiliki intervensi terendah (zona inti) memiliki jumlah siput sedikit sementara zona dengan intervensi tertinggi (zone pemanfaatan) memiliki jumlah siput terbanyak. Tiga spesies karang di ketiga zona ini yang disukai oleh siput adalah Montipora spp., Acropora spp., and Porites spp. Jumlah siput yang hidup di karang mengikuti jumlah persen tutupan karang©

scholarly journals Preparation and application of carbon and hollow TiO2 microspheres by microwave heating at a low temperature

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 200-209
Author(s):  
Caiyun Zhang ◽  
Chunhong Li ◽  
Bolin Ji ◽  
Zhaohui Jiang
Keyword(s):  
Low Temperature ◽  
Microwave Heating ◽  
Raw Material ◽  
Carbon Microspheres ◽  
Microwave Assisted ◽  
The Core ◽  
Good Crystallinity ◽  
Carbon Core ◽  
Microwave Assisted Method ◽  
Uniform Particle Size

Abstract A fast, simple, and energy-saving microwave-assisted approach was successfully developed to prepare carbon microspheres. The carbon microspheres with a uniform particle size and good dispersity were prepared using glucose as the raw material and HCl as the dehydrating agent at low temperature (90°C) in an open system with the assistance of microwave heating. The carbon microspheres were characterized by elemental analysis, XRD, SEM, FTIR, TG, and Raman. The results showed that the carbon microspheres prepared under the condition of 18.5% (v/v) HCl and heating for 30 min by microwave had a narrow size distribution. The core–shell structure of the carbon core and TiO2 shell was prepared with (NH4)2TiF6, H3BO3 using the microwave-assisted method. The hollow TiO2 microspheres with good crystallinity and high photocatalytic properties were successfully prepared by sacrificing the carbon microspheres.

Experimental Study on Carbonization of Low-Rank Pulverized Coal with High Temperature Heat Pipe

2014 ◽  
Vol 953-954 ◽  
pp. 1035-1039
Author(s):  
Li Qun Wang ◽  
Zhong Bo Yi ◽  
Zhong Xiang Wei
Keyword(s):  
High Temperature ◽  
Heat Pipe ◽  
Pulverized Coal ◽  
Holding Time ◽  
Raw Material ◽  
Low Rank ◽  
Experimental Result ◽  
Operating Characteristics ◽  
Temperature Heat ◽  
High Temperature Heat Pipe

Aimed at improving the utilization of pulverized coal, high-temperature heat pipe technology was introduced into lignite carbonization.Under the design of power of 10kw semi-industrial pulverized coal carbonization test equipment, Fugu lignite coal as raw material to investigate the operating characteristics of the device and carbonization characteristics. Experimental result shows that the high temperature heat pipes heat steadily and meet the temperature requirement of low-temperature carbonization. With the extension of the holding time, the semi-coke fixed carbon content increasing, but volatile matter vice versa, however, holding time above 60 minutes, the effect of carbonization is not obvious, and the best carbonization time is 30 ~ 60 minutes. The length of the holding time has little effect on gas composition, the content of H2 and CH4 are relatively higher than the rest gas, (H2 + CH4) gas accounted for 70% of the total, the heating value remains at 18.76 ~ 19.22MJ/m3, belongs to medium-high value gas, could provide for industrial and civilian use.

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