scholarly journals Analysis of Mechanical Properties and Micro Structure of Body Valve Bolts, Alloy Steel Grade B7 Material as a Result of Offshore Application

2020 ◽  
Author(s):  
Qamaruddin Qamaruddin ◽  
Mochamad Nur Irawan ◽  
Dwi Wulandari ◽  
Iskandar Purnomo
Keyword(s):  
Mechanical Properties ◽  
Alloy Steel ◽  
Steel Grade ◽  
Micro Structure

The Influence of Austenisation Temperature and Holding Time on Mechanical Properties, Scale Thickness, and Microstructure in Alloy Steel

2015 ◽  
Vol 776 ◽  
pp. 239-245
Author(s):  
Abdul Aziz ◽  
Maulud Hidayat ◽  
Indah Hardiyanti
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Alloy Steel ◽  
Impact Energy ◽  
Holding Time ◽  
Micro Structure ◽  
Scale Thickness ◽  
Alloy Steels ◽  
Steel Weight

The application of steel products have been widely used and various research have been developed to find a good and appropriate quality of steel and can be produced in the country without have to be imported, for example alloy steels. One of the alloy steels that have been constantly developed is Ni-Cr-Mo alloy steel with additional nickel, chromium and molybdenum which can increase hardness, tensile strength, ductility and toughness. The effect during the production process is at the heating process that causes the formation of iron oxide layer (scale) and the loss of steel weight. Therefore, the selection of heat treatment methods and techniques are required to increase the mechanical properties of steel, such as hardness, tensile strength, and toughness, with the scale is about <5% of steel weight. In this research, the heat treatment was carried out at austenisation temperature of 800°, 850°, 900°C and at holding time of 20, 40, 60 minutes, then followed by a rapid cooling (quenching) to improve the mechanical properties of hardness. This research also tested the mechanical properties of steel that consist of hardness test and impact test, and metallographic observation that consist of micro structure observation and scale thickness observation. The micro structure from heat treatment process is martensite, it is due to a rapid cooling (quenching) that rapidly change the austenite phase into martensite. The data showed the highest hardness is 588.35 HVN at 850°C of temperature and 60 minutes of holding time, 8.5 Joules of impact energy, and 91.5 μm of scale thickness. While the lowest hardness is 539.34 HVN at 800°C of temperature, 5 Joules of impact energy, and 47.81 μm of scale thickness.

Teknologi Inokulasi Besi Cor Kelabu FC-250 Untuk Mencegah Pengerasan Pada Dove Tale Produk Ragum Tipe 125

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Amin Suhadi ◽  
Seodihono
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Treatment Process ◽  
Gray Cast Iron ◽  
Spare Parts ◽  
Gray Cast ◽  
Micro Structure ◽  
Control Factors ◽  
Seed Inoculation ◽  
Casting Industry

Production technology of metal casting industry in Indonesia needs to be improved, especially in the manufacturing of spare parts and box engine made of gray cast iron which has various wall thick such as dove tale construction. Microstructure of gray cast iron is influenced by cooling rate during casting, chemical composition and melting treatment process (inoculation). The part which has the thinnest thickness has the fastest cooling therefore, the grain boundary is smaller compared to other section. As a result this part has highest hardness and difficult to be machined. This research is conducted to solve this problem by modifying melting and solidification treatment process. The research starting from micro structure analysis, composition and mechanical properties tests on the product, and then conducting modification treatment through Taguchi method approach. Experimental results obtained show that the best level settings to control factors which affect to the uniformity of the microstructure and mechanical properties in gray cast iron is the addition of seed inoculation super ® 75, as much as 0.25% with the method of inoculation material entering into the Transfer Ladle.Teknologi produksi pada industri pengecoran di Indonesia masih membutuhkan perbaikan terutama dalam pembuatan komponen mesin perkakas dan peralatan pabrik yang terbuat dari besi tuang kelabu yang mempunyai variasi ketebalan yang besar seperti konstruksi ekor burung (dove tale). Pada pengecoran, struktur mikro dari besi tuang kelabu sangat dipengaruhi oleh kecepatan pendinginan, komposisi kimia dan proses perlakuan pada logam cair (inokulasi). Bagian yang mempunyai ukuran paling tipis mempunyai kecepatan pendinigan paling tinggi karena itu ukuran butirnya jauh lebih kecil dari bagian lain, akibatnya bagian ini mempunyai kekerasan lebih tinggi dan sulit dilakukan pengerjaan mesin. Penelitian ini bertujuan untuk memperbaiki hal ini yang terjadi pada dove taledengan cara memodifikasi proses perlakuan pada cairan besi dan proses pendinginan. Penelitian dimulai dari analisa struktur mikro, pengujian komposisi kimia, pengujian sifat mekanis pada produk kemudian dilakukan modifikasi menggunakan pendekatan metode statistik Taguchi. Hasil penelitian menunjukkan bahwa pengaturan terbaik yang dapat diperoleh untuk mendapatkan keseragaman struktur mikro dan sifat mekanis pada pengecoran besi tuang kelabu adalah penambahan seed inoculation super ® 75, sebesar 0.25% dengan metode pemasukan inokulasi kedalam Ladle pengangkut logam cair.Keywords: carbon, micro structure, hardness, inoculation

scholarly journals The Effect of Different Annealing Strategies on the Microstructure Development and Mechanical Response of Austempered Steels

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1041
Author(s):  
Eliseo Hernandez-Duran ◽  
Luca Corallo ◽  
Tanya Ros-Yanez ◽  
Felipe Castro-Cerda ◽  
Roumen H. Petrov
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Mechanical Response ◽  
Steel Grade ◽  
The Other ◽  
Microstructure Development ◽  
Microstructural Refinement ◽  
Heterogeneous Distribution ◽  
Parent Austenite ◽  
Conventional Annealing

This study focuses on the effect of non-conventional annealing strategies on the microstructure and related mechanical properties of austempered steels. Multistep thermo-cycling (TC) and ultrafast heating (UFH) annealing were carried out and compared with the outcome obtained from a conventionally annealed (CA) 0.3C-2Mn-1.5Si steel. After the annealing path, steel samples were fast cooled and isothermally treated at 400 °C employing the same parameters. It was found that TC and UFH strategies produce an equivalent level of microstructural refinement. Nevertheless, the obtained microstructure via TC has not led to an improvement in the mechanical properties in comparison with the CA steel. On the other hand, the steel grade produced via a combination of ultrafast heating annealing and austempering exhibits enhanced ductility without decreasing the strength level with respect to TC and CA, giving the best strength–ductility balance among the studied steels. The outstanding mechanical response exhibited by the UFH steel is related to the formation of heterogeneous distribution of ferrite, bainite and retained austenite in proportions 0.09–0.78–0.14. The microstructural formation after UFH is discussed in terms of chemical heterogeneities in the parent austenite.

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