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Wahyono Suprapto
Jurusan Teknik Mesin Fakultas Teknik Universitas Brawijaya

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Analisis Fatigue Failure Suhu Rendah Struktur Batang Duralumin dengan Mesin Siklus Bending Tawaf, Nanang; Suprapto, Wahyono; Purnowidodo, Anindito
Jurnal Rekayasa Mesin Vol 5, No 3 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Generally non-iron metals use in industries, including aluminum alloy, because of their high strength to weight ratio and favorable (no sparking and high corrosion resistance). Aluminum alloy are often found and used in airplane. Recently, aluminum alloy begins so popular in cryogenic system where it is highly applied at oil industry, low temperature operated, and automotive industry. It is estimated that 50%-90% mechanical failures are due to fatigue failure. This research attempts to predict duralumin fatigue resistance at low temperature and to understand the effect of micro structure on duralumin at low temperature. Several states, which include 15, 30, and 45 in MPa, are given to bending cycle machine. The tested material is duralumin (alloy Al-Cu) which has passed the tests over porosity, fatigue level at low temperature (-19o C) and room temperature (27o C), microstructure, fractography, and macrostructure. Result of research indicates that fatigue resistance increases with lowering work tense at specimen. Average fracture of duralumin fatigue at low temperature is more than 17,8 x 10 cycles, while at room temperature is 13 x 10 5 cycles. During low temperature fatigue test, microstructure shows long and small grains. The deformation during low temperature fatigue test cause smaller grain produce greater slip resistance for specimen.Keywords: Fatigue Failure, Low Temperature, Duralumin, Bending Cycle
The Fluidity Characteristics of Liquid Duralumin by Piece Test Methode on Permanent Mold in Low Pressure Suprapto, Wahyono
Rekayasa Mesin Vol 3, No 1 (2012)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

The shrinkage and porosity is the casting failures which is often found in the casting products especially aluminum alloys. That failure is happen because the liquid metals cooling processes is not uniform or there is pit-fall gasses. The shrinkage and porosity significationcould reduce material mechanics characteristic significantly. The controlling parameters of the vibration the metals solidifications is implicated to the improvement of aluminum alloys casting products qualities.The objective of this experiment research is to compare the properties on castability, formability, and sub-surface defect on a piece duralumin cast of permanent mold casting. Low pressure mold cavity is an independent variable and fluidity, ductility, porosity are dependent variables, and pouring temperature is a control parameter which is plant in this research design. The research conclusion is while the pressure decrease on cavity would increase castability, ductility, and could reduced the sub-surface defect on duralumin casting.Keywords: fluidity, liquid duralumin, low pressure, solidification, sub-surface defect
The Fluidity Characteristics of Liquid Duralumin by Piece Test Methode on Permanent Mold in Low Pressure Suprapto, Wahyono
Jurnal Rekayasa Mesin Vol 3, No 1 (2012)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (94.082 KB)

Abstract

The shrinkage and porosity is the casting failures which is often found in the casting products especially aluminum alloys. That failure is happen because the liquid metals cooling processes is not uniform or there is pit-fall gasses. The shrinkage and porosity significationcould reduce material mechanics characteristic significantly. The controlling parameters of the vibration the metals solidifications is implicated to the improvement of aluminum alloys casting products qualities.The objective of this experiment research is to compare the properties on castability, formability, and sub-surface defect on a piece duralumin cast of permanent mold casting. Low pressure mold cavity is an independent variable and fluidity, ductility, porosity are dependent variables, and pouring temperature is a control parameter which is plant in this research design. The research conclusion is while the pressure decrease on cavity would increase castability, ductility, and could reduced the sub-surface defect on duralumin casting.Keywords: fluidity, liquid duralumin, low pressure, solidification, sub-surface defect
Pengaruh Kecepatan Pengadukan Proses Rheocasting terhadap Struktur Mikro dan Fluiditas Paduan Al-Cu Putra, Muhammad Rezki Fitri; Suprapto, Wahyono; Sonief, Achmad As’ad
Jurnal Rekayasa Mesin Vol 10, No 3 (2019)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2019.010.03.6

Abstract

Rheocasting with the aim of developing and offering solutions to problems related to the casting process. Rheocasting is a casting process that utilizes solidification agitation to change the dendritic structure to non-dendrite (globular) by giving a variation of the stirring speed. Al-Cu is a metal material that has high strength-to-weight ratio characteristics from steel, good fatigue resistance, and heat-treatable. But fluidity is low, this triggers casting defects such as shrinkage and miss-run. The defect occurs because the cooling process of liquid metal is not uniform or there is gas trapped in molten metal. Defects in casting can significantly reduce material mechanical properties. The results show morphological changes in the dendrites to rosette to globular with increased stirring speed and grain diameter decreasing with increasing stirring speed. Increasing the stirring speed also produces a positive trend of the fluidity value of Al-Cu alloys in each mold thickness.
Pengaruh Waktu dan Tekanan Gesek terhadap Kekuatan Tarik Sambungan Paduan Aluminium dan Baja Karbon pada Pengelasan Gesek Continuous Drive Pah, Jack Carol Adolf; Irawan, Yudy Surya; Suprapto, Wahyono
Jurnal Rekayasa Mesin Vol 9, No 1 (2018)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (745.566 KB) | DOI: 10.21776/ub.jrm.2018.009.01.8

Abstract

The objective of this research was to investigate the effect of friction time and friction pressure on the tensile strength of the joining of two dissimilar materials, aluminum alloy AA6061 and carbon steel, with continuous drive friction welding process. Variations of friction times of 5 seconds, 7 seconds, 9 seconds, and 11 seconds, at each variation of friction pressures of 24 MPa, 32 MPa, and 40 MPa. Controlled variables in this friction welding process were rotational speed of 1600 rpm, upset pressure of 79 MPa which was applied for 60 seconds and diameter of friction surface of specimens which were 15 mm. The resulting strength of the bonding were than evaluated on the basis of tensile strength. Observations of temperature change during the welding process, the distribution of Vickers hardness values around the bonds area, and micro photographs, were used as support to the analysis. The results showed that the longer friction time was applied, the higher tensile strength of the bonds would be, until it began to decrease after a certain maximum value of the tensile strength had been reached. Increased of the tensile strength of the bonding did not occur linearly due to the variation of friction pressure at 9 seconds and 11 seconds of friction time. At 5 seconds and 7 seconds of friction time, increase of friction pressure caused a linear increase of tensile strength. Higher temperatures in the welding process increased the thickness of brittle layer at the bonds boundary. The increase of the brittle layer thickness causes decrease of the tensile strength of the bonds.
Kekuatan Puntir dan Porositas Hasil Sambungan Las Gesek AlMg-Si dengan Variasi Chamfer dan Gaya Tekan Akhir Tyagita, Dicky Adi; Irawan, Yudy Surya; Suprapto, Wahyono
Jurnal Rekayasa Mesin Vol 5, No 1 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Friction welding is the most suitable method for joining aluminum alloys. Aluminum alloys have limitations heat to concentrate only in weld area when used arc or gas welding. That causes it is has good thermal conductivity. The parameters that influence on friction welding are friction time, compressive force, upset force, rotational speed, and chamfer angle. The purpose of the research was to know influence of chamfer angle and upset force on the Al-Mg-Si. The chamfer angles variated 0, 15°, 30°, 45° and upset force variated 157 kgf, 185 kgf and 202 kgf. Specimens were friction welded with rotation speed of 1600 rpm, compressive force 123 kgf for 120 seconds, and upset force variation by 157, 185, 202 kgf for 120 seconds. In addition torsion and porosity testing were also performed on friction welding product. Results showed that specimens with a chamfer angle 15 ° in various upset force has maximum shear strength, so were on specimens with a chamfer angle 15 ° has minimum percentage of porosity in various upset force.Keywords : shear strength, friction welding, chamfer angle, upset force, porosity and Al-Mg-Si
Pengaruh Fraksi Volume Serat Buah Lontar terhadap Kekuatan Tarik dan Kekuatan Impak Komposit Bermatrik Polyester Wahyudi, Slamet; Bella, Yustian; Suprapto, Wahyono
Rekayasa Mesin Vol 5, No 2 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

In the industrial world nowadays, natural fiber has been widely developed as an important part in the preparation of composite material. Lontar Fruit is a natural commodity enriched with fiber but still less maximally utilized. Lontar Fruit fiber is then composed with polyester matrix to be an alternative material to the preparation of polymer-based helmet and gas tube. Research attempts to examine the tensile and impact strengths of this application. In this research, therefore, polyester resin is composed with Lontar Fruit fiber and this composite is treated with alkali 5 % NaOH for 30 minutes. Preliminary test has indicated that the tensile strength of genuine single fiber (without treatment) is 33.3 N/mm2 and the maximal tensile strength of single fiber is 36.96 N/mm2 after treatment with alkali 5 % NaOH for 30 minutes. After this preliminary test, the composite is then tested by treating Lontar Fruit fiber with alkali 5 % NaOH for 30 minutes upset time against various volume fractions of Lontar Fruit fiber, respectively at 0 %, 5 %, 15 %, 25 % and 35%. It is then by the results, the favorable mechanic attributes, precisely the tensile strength and impact strength of the polyester matriculated composite with Lontar Fruit fiber as the reinforce, can be explained as follows. The best tensile strength of the composite is 47.7 MPa found at volume fraction variation of 15 %. The best impact strength of the composite is 30.1519179 J observed at volume fraction of 35 %.Keywords: Lontar Fruit Fiber,Tensile Strenght, Impact Strenght, Composite
Pengaruh Temperatur pada Proses Hot Isostatic Pressing terhadap Porositas, Keausan dan Mikrostruktur Sludge Powder Duralumin Multazam, Ahmad; Suprapto, Wahyono; Pratikto, Pratikto
Rekayasa Mesin Vol 5, No 3 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Sludge is the starting raw material in the process of forming wheels with forging method. Performance wheels strongly influenced by the quality of sludge. Sludge should have physical properties that light , soft and easy strengthened. One material that can be used as materials for sludge are: duralumin material. Duralumin is another name for aluminum & copper alloy (Al / Cu) with a Cu content of about 4 %. Making sludge powder duralumin with powder metallurgical methods can improve the quality of sludge.Making the specimen begins to weigh 100 g of powder duralumin and enter into a mold that has been in the preheating (100 ° C). Wait about 10-15 minutes until the mold temperature reached (450 ° C), (475 ° C) , (500 ° C) , and (525 ° C). Perform (hot iso- static pressing) HIPing by using a hydraulic press machine at 50 MPa and kept constant for 30 minutes. After the specimens were removed from the mold. The results showed the higher temperature tends to result in a percentage sitering porosity and wear rate decreases. This is evidenced by the percentage of porosity at a temperature of 450 ° C , 475 ° C , 500 ° C , and 525 ° C is 1.193 ° C , 1:03 ° C , 0757 ° C and 0733 ° C. While the wear rate at the sintering temperature of 450 ° C , 475 ° C , 500 ° C , and 525 ° C is 0.00095 g / s , 0.00080 g / s , 0.00059 g / s , 0.00050 g / s. Then from the microstructural observations with 500x magnification SEM image shown that with increasing temperature HIPing likely to result looks smooth surface of the test specimen.Keywords: Powder Metallurgy, Temperature HIPing, Duralumin, Sludge, Porosity, Wear, Microstructure.
Modus Pelunakan dan Pengerasan HAZ pada Manual GMAW Welded Joint Yurianto, Yurianto; Pratikto, Pratikto; Soenoko, Rudy; Suprapto, Wahyono
ROTASI Vol 21, No 2 (2019): VOLUME 21, NOMOR 2, APRIL 2019
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1261.768 KB) | DOI: 10.14710/rotasi.21.2.127-133

Abstract

Las manual gas metal arc welding banyak digunakan dalam industri manufaktur konvensional. Akhir proses pengelasan menghasilkan produk las yang diinginkan. Pada baja dengan tebal dan jenis yang sama, dan metode pengelasan yang sama tetapi operator berbeda menghasilkan kekuatan las yang berbeda. Keseragaman produk las antara satu dan operator lain dapat diperoleh dengan welding procedure specification. Namun prosedur ini tidak menjamin kekuatan sambungan sama meskipun operator berbeda. Kekuatan daerah terpengaruh panas tergantung pada parameter las yang digunakan seperti diameter elektroda; arus listrik; tegangan listrik, kecepatan pengelasan; logam tebal dan panas masuk. Selain itu, perlu dipertimbangkan unsur kimia baja yang dilas. Parameter pengelasan akan mempengaruhi dimensi daerah terpengaruh panas. Semakin lebar daerah terpengaruh panas akan menurunkan kekuatan sambungan las. Pernyataan masalah dalam penelitian ini adalah "bagaimana menurunkan dimensi daerah terpengaruh panas yang dipengaruhi oleh proses pembekuan logam las." State of the art dari penelitian ini adalah analisis pelunakan daerah terpengaruh panas dengan melibatkan pembekuan logam las. Tujuan dari penelitian ini adalah untuk mencari penyebab terjadinya pelunakan dalam daerah terpengaruh panas sambungan las gas metal arc welding manual. Hasil penelitian adalah kekerasan standard dan heat treated welded joint. Parameter perlakuan panas untuk mendapatkan kekerasan HAZ tertinggi.
Pengaruh Temperatur Karbonisasi terhadap Mikrostruktur dan Pembentukan Kristal pada Biokarbon Eceng Gondok sebagai Bahan Dasar Absorber Gelombang Elektromagnetik Radar Imammuddin, Azam Muzakhim; Soeparman, Sudjito; Suprapto, Wahyono; Sonief, Achmad As'ad
Rekayasa Mesin Vol 9, No 2 (2018)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (479.939 KB) | DOI: 10.21776/ub.jrm.2018.009.02.10

Abstract

Radar Absorbing Materials (RAM) or radar absorbing materials of radar electromagnetic waves are materials used to reduce or eliminate radiation of radar electromagnetic waves in order to avoid reflection of waves. At this time the development of RAM research leads to materials derived from nature. Some materials derived from nature that has been used as RAM such as rice husk, bamboo, coconut shell, coconut husk, wood fiber, and wood flour. In this study, eichornia crassipe is made into biocarbon or activated carbon for use as a base material for RAM. Carbonization is one way to transform water hyacinth into biocarbon or activated carbon. The method used in this research is Experimental Research. The independent variables of this research are carbonization temperature starting from temperature 500oC, 600oC, 700oC, 800oC, 900oC and 1000oC. The results showed that the higher the carbonization temperature, the more open pores will be with 2 μm diameter at 1000oC, and the higher the carbonization temperature than the percentage of carbon crystal formed higher with the value of 14% at temperatures 900oC and 1000oC. The biocarbon structure of eichornia crassipe is crystalline and amorphous making it suitable for use as RAM material.