Sumpena Sumpena scite author profile

2018

The purpose of this research is to determine the effect of heat treatment hardening of AlMgSi-Fe12% casting aluminium alloys on wear. The tests were carried out on specimens of raw materials and heat-treated specimens with variations of temperature used were 550 oC, 575 oC, 600 oC, and 625 oC, and used 15 minutes of holding time in each heat treatment, then quenching in SAE 20 oil. The method used for wear-tested was high speed ogoshi universal testing machine wear. The result had shown on raw material a specific wear rate was 2.256102E-07 mm2/kg. Test results on the specimens that have received heat treatment hardening temperature 550 oC increased the wear value decreased to 1.7471E-07 mm2/kg. In materials with temperature heat treatment, 575 oC causes wear values were increased when compared with raw material, respectively, 2,83739E-07 mm2/kg. In materials with temperature heat treatment 600 oC also causes wear values were increased when compared with raw material, respectively, 2,65105E-07 mm2/kg. Test results on the test material that has received heat treatment temperature 625 oC increased the wear value decreased to 2.16777E-07 mm2/kg.

The effectivity of used-oil as quenching medium of 42-CrMo4 steel for automotive materials

Hariningsih¹,

Sukarjo

2020

ARSTech

The research aims to investigate the effect of the cooling medium on the hardness characteristic and microstructure of the 42CrMo4 steel due to hardening treatment at a temperature of 830°C and holding time of 30 minutes. Various oil such as SAE-10W40, SAE-20W50, SAE-40, and used oil was used in the cooling medium. The changes in product size, hardness, and microstructure have been carefully assessed. The results indicated that the viscosity of the coolant medium strongly influenced the cooling rate of the cooling medium, hardness, and microstructure. SAE-10W40 oil and SAE-20W50 oil only needed 2 hours to return within room temperatures before quenching, whereas SAE-40 oil and used oil took 3 hours. The sample size did not change after hardening-quenching. However, there was a residual carbon layer on the sample surfaces. Quenching caused the changes of microstructure from pearlite and ferrite to ultrafine double phase, consisting of martensite and austenite, which were unable to transform during rapid cooling. The highest hardness value was achieved by the treated product, which was quenched in SAE-10W40, which had 54.59 HRC. The high hardness was attributed to the content of 95% martensite. However, used-oil caused in similar hardness as SAE-20W50.

Pengaruh Variasi Temperatur Hardening dan Tempering Paduan AlMgSi-Fe12% Hasil Pengecoran terhadap Kekerasan

Wardoyo

2018

The purpose of this research is to know the effect of Heat Treatment Hardening-Tempering Alloy AlMgSi–Fe12% foundry result to hardness and toughness. The test was carried out on raw material and material test specimen after obtaining Hardening heat treatment at 600℃ and quenching with SAE 20 oil medium. While Tempering variation at temperature 200℃, temperature 250℃ and temperature 300℃ with detention time for 15 min at each temperature, each heat treatment. Hardness testing method is done by standard micro Vickers test method with 100 gf loading. The result of raw material testing for hardness value is 60,92 VHN. Test results after heat treatment process at temperature 200℃ cause hardness value increased by 63,50 VHN. At temperature 250℃ cause hardness value decreased to 59,94 VHN. At temperature 300℃ cause hardness value increase to 76,98 VHN

Pengaruh Paduan Serbuk Fe12% pada Aluminium terhadap Porositas dan Struktur Mikro dengan Metode Gravity Casting

2017

The purpose of this research is to know the effect of Fe12% powder alloy on aluminum to porosity and micro structure by gravity casting method. Metal Matrix Composite (MMC) is an engineering material formed from the combination of two or more materials to obtain new materials with better properties. Making of composite material with aluminum matrix or metal matrix composite (MMC) can be done by casting method. The composite forming elements are called boosters (fibers or particles) and binders (matrices). In the process of casting metal can occur porosity In the casting process with sand molds usually occur porosity, causing the mechanical properties of casting objects decreased. Porosity is caused by bubbles of gas, gas released by the core when exposed to metal liquid heat, resulting in pores or perforated defects.The process of smelting was carried out at the metal foundry laboratory of Mechanical Engineering UP 45 Yogyakarta. The smelting process uses a krusible furnace with coke fuel, on which it is placed kowi to place aluminum and iron powder to be melted. Aluminum and 12% iron powder are weighed in accordance with the volume of the pattern, so that the melt does not suffer from metal deficiency. Observation of porosity is done by looking visually on each side of the outer part of the casting object. Observation of microstructure using optical microscope is done by taking three samples of specimen castings that have been in the preparation of polishing machine and etching. The effect of Fe 12% alloys on porosity is the average porosity occurring on specimens A, B and C of 2,766 gr / cm3. The effect of Fe 12% alloys on micro structure is the spreading of Fe, Si and Mg elements evenly, but for the C specimens of Fe and Si bersenyawa, while the Al and Mg elements are separate.

Analisa Kekerasan dan Keausan Cylinder Sleeve dari Besi Cor Kelabu FC250 Hasil Sand Mold Casting

Sukarjo

Wardoyo

et al. 2021

The Cylinder sleeve is an engine component that is mounted on the cylinder block which functions as a piston glide base. The cylinder sleeve is made of FC250 gray cast iron. FC250 is a gray cast iron that has lamellar graphite with a tensile strength of at least 250 MPa. This study aims to determine the mechanical properties of hardness and wear of the Cylinder Sleeve made of gray cast iron FC250. The method used in this research is gray cast iron which is cut with a length of 5.5cm, thickness 0.7cm, height 0.7cm which is formed according to the standard size of the hardness and wear test. The tests carried out include testing brinell hardness and wear. The results showed that the lowest hardness value was 134.63BHN and the highest hardness value was 191.43BHN. The increase in hardness values is influenced by the carbon content that cannot be spread evenly, which is followed by a fast cooling rate. The results of the wear test obtained the lowest price of 0.00017mm³/kg.m and the highest wear price of 0.00028 mm³/kg.m.