PENGARUH JENIS BAHAN DAN PROSES PENGERASAN TERHADAP KEKERASAN DAN KETAHANAN AUS PISAU TEMPA MANUAL

Komponen pemotong banyak dijumpai pada mesin-mesin pertanian dan pengolahan makanan. Kemampuan komponen pemotong ditentukan oleh kualitas bahan dan metode pembuatan yang digunakan. Komunitas knife making mengenal dua metode pembuatan pisau yang berkulitas yaitu metode damaskus dan pattern welding. Kedua metode tersebut sama dengan metode yang digunakan pende besi tradisional namun berbeda dari segi bahan yang digunakan. Pande besi tradisional memproduksi piasu dengan pengetahuan metalurgi yang terbatas, sehingga pisau-pisau yang dihasilkan berkualitas rendah. Secara teori, kualitas pisau produksi pande besi tradisional dapat ditingkatkan dengan cara pemilihan bahan, proses pembuatan, perlakuan panas serta finishing yang tepat. Penelitian dilakukan untuk mengamati pengaruh jenis bahan dan proses pengerasan terhadap kekerasan dan ketahan aus pisau tempa manual. Jenis bahan yang ditempa adalah baja AISI 1050, AISI 4340, baja AISI L-6, dan baja JIS SUP 9. Pembuatan pisau dilakukan dengan cara pemanasan bahan mencapai temperatur berkisar antara 900-950oC kemudian ditempa berulang-ulang secara manual sampai penurunan temperatur berkisar antara 650-675oC. Pemanasan dan penampaan dilakukan beberapa siklus untuk membentuk sebuah pisau. Pengerasan dilakukan dengan cara memanaskan pisau mencapai temperatur austenisasi, kemudian dilakukan pendingin cepat (quenching) dengan menggunakan media pendingin air. Pengujian kekerasan dan pengamatan struktur mikro dilakukan pada permukaan dan penampang pisau sedangkan pengujian keausan dilakukan pada sisi tajam. Hasil penelitian menunjukkan bahwa kekerasan dan ketahanan aus dipengaruhi oleh jenis bahan dan proses perlakuan. Proses pengerasan dapat meningkatkan nilai kekerasan dan menurunkan laju keausan. Kekerasan tertinggi diperoleh pada pisau baja JIS SUP 9 dangan pengerasan menggunakan tungku elektrik adalah sebesar 62 HRC di permukaan dan 60,2 HRC di penampang dan laju keausan terendah sebesar 2,27x10-5 mm3/Nm diperoleh pada pisau baja AISI L-6 dengan pengerasan menggunakan tungku elektrik. Pengamatan struktur mikro pada jenis bahan pisau setelah dikeraskan menunjukkan bahwa pada permukaan dan penampang didominasi oleh struktur martensit dan sedikit austenit sisa. ================================== There are many kinds of cutting devices in machinery and food processing equipment. The quality of the cutting component depends on the material characteristics and its production method. Traditionally, a blacksmith uses manual forging to make a knife. Com monly knives produced by traditional blacksmiths have poor quality, i.e. soft and blunt. There are two common methods to make the traditional blade, i.e. pattern welding and Damascus method. The pattern welding process consists of forge two dissimilar stee ls to have a combined properties of the knife. While the Damascus method forges a single bar of steel with engineered composition. Theoretically knife’s quality which produced by blacksmith can be improved with right material choice, good manufacturing process, and perfect finishing process. In this work, we study the traditional forging method done by the local blacksmith to make a knife from a various composition of the steel. Our goal was to know the process parameter to control the hardness and wear resistance of the blades. Materials used in this work were steels with different chemical compositions, i.e. JIS SUP 9, AISI L6, AISI 1050 and AISI 4340. The forging process was in high - temperature ranges of hot work process using the hammer. The forging temperature was between 650 to 950oC. Hardening process on the sharp side was done with heat up the knife to 800oC then quenching to room temperature. Hardness measurement and metallographic examination were done on the surface side and cross-section of the knife, whereas the wear test conducted on the sharp side. The results showed that the hardness and wear resistance is influenced by the type of material and treatment process. Hardening process can increase the hardness and lower wear rate. The highest hardness obtained on steel blades JIS SUP 9 with hardening using an electric furnace is about to 62 HRC and 60,2 HRC on the surface in cross-section and low wear rate is about 2,27x10-5mm3/Nm obtained on AISI steel blade L-6 with hardening using electric furnaces. Observation of microstructure on knife material is after hardening process showed that on the surface and cross section is dominated by a martensite structure and a bit of retained austenite

Modifikasi Alternator dan Sistem Kelistrikan Untuk Peningkatan Daya Listrik Sepeda Motor 125 cc

The alternator on the motor is one component of the vehicle that can be used to improve its utilization.  Modifications to the alternator on the vehicle are made to increase electric power. The working principle of an electric generator is in accordance with the law of faraday if a conductor is rotated in a magnetic field until it crosses the magnetic force line (GGM), it will cause an electric force line (GGL) in volts at the end of the conductor. In the alternator to be used, the lighting coil resistance is 0.24 - 0.36 Ω and the charging is 12.3 - 13.3 V at 1500 rpm. The research conducted was an experiment by comparing the alternator output voltage before it was modified with the alternator output that had been modified. Modification of the alternator is done by the method of load variation and replacement of the diameter of the coil along with the number of turns on the alternator. Measurement of alternator before and after modification shows results that are directly proportional to the output of the alternator at 1,000 rpm - 8,000 rpm. The results of three tests can be concluded that the modification of the alternator has increased from 6.42 A for the standard alternator to 13.7 A for the modification alternator

Investigation of the effect of flow rate on fluid heat transfer in counter-flow helical heat exchanger using CFD method

Heat exchangers are generally used in the process of heat transfer between two different fluids separated from each other by a solid wall in order to save time and reduce expenses. Fluids behavior change by adding a wire-insert in its path. To investigate heat transfer parameters, we need to simulate the whole system. In this study, heat transfer of counter-flow helical double pipe heat exchanger was modelled by using Computational Fluid Dynamics (CFD) in "Ansys CFX". The cold and hot fluids temperature were in the ranges of 10-20C° and 30-50C° respectively. The Reynolds number of flows were in the range of 4×103 to 42×103 and the process was singlephase. The model was eventually evaluated by experimental data after simulation. The results indicated that the model was able to interpret the experimental results with correlation coefficients of 0.98 and 0.97 for hot and cold streams respectively. Furthermore, the wire-insert installed to the cold flow path caused more fluid turbulence and increased the temperature difference of the cold fluid inlet and outlet proportional to the hot fluid

Simulasi proses pemesinan cetakan propeller blade dengan permodelan profil airfoil

XI+32hlm.;29c

Investigation of knife quality by using forging and flame hardening methods

The research was conducted to investigate the quality of knives the material and the forging process against wear resistance. The forged material is AISI 1050 steel, AISI 4340 steel, AISI L-6 steel, and JIS SUP 9 steel. The manufacturing of the knives ware done by heating the material to a temperature ranging from 900-950°C then forged repeatedly manually until the temperature drop in between 650-675°C. Heating and forging are carried out several cycles to form a knife. Hardening was done by heating the knives to reach austenite temperature by flame hardening method, then quenching using water cooling media. research of wear resistance was done on the sharp side by using an actuator tribometer pin-on-plate. The results showed that wear and tear were influenced by the material and the treatment. The flame hardening process can be reduced the wear rate, the wear rate found on AISI 1050 steel knives is 5.439 x 10−4 mm3/Nm after being forged, while the lowest wear rate was found on AISI L-6 steel knife which ware 2.44 x10−5 mm3/Nm after flame hardening. The flame hardening process can reduce the wear rate, highest wear rate found on AISI 1050 steel knives ware 5.439 x 10−4 mm3/Nm after being forged, while the lowest wear rate was found on AISI L-6 steel knife which is 2.44 x 10−5 mm3/Nm after flame hardening. Therefore, it can be conclude that traditional knife quality especially the wear resistance can be improved by optimizing the heat treatment schedule