Mechanical properties and microstructural evaluation of heat-treated aluminum alloy using formulated bio-quenchants

Heat treatment industries require various quenching media to improve the properties of the materials to be quenched. Petroleum based mineral (PBM) oil, a non-biodegradable oil, is popular amongst others quenchants in heat treatment processes. Recently, biodegradable oils mostly in their raw, unblended and unbleached forms have been employed for quenching of various engineering materials. Therefore, the present study examined the effects of some selected bio-quenchants in blended raw (BR) and blended bleached (BB) forms on the mechanical properties and microstructure of solution heat treated aluminum (Al)-alloy. Edible vegetable oil (70% by volume) was blended with 30% by volume of jatropha oil to form the bio-quenchant oils. Another set of bio-quenchants were formed by bleaching the raw oils before mixing so as to reduce the oxidation level and contaminations in the oil. The Al-alloy is solution heat treated at 500 °C and soaked for 15 min in an electric muffle furnace before quenching in the various established bio-quenchants. Results showed that samples treated in blended raw melon (BRM) oil have higher tensile strength of 151.76 N/mm2 while samples quenched in blended bleached melon (BBM) oil have higher hardness value of 61.00 HRC. In accordance to the results obtained the bio-quenchants were found to be effective replacement to the PBM oil.

Applying of Automatic Laser Particle Counter as Technique to Morphology Assessment and Distribution of Wear Particles during Lifetime of Transmission Oils

Vast part of environment pollution is caused by the lubricants. Lubricants are mostly of mineral origin. They are toxic and not easily biodegradable. Transition to biodegradable oils involves several technical issues. During the operation of machines and equipment wear occurs due to formation of particles that pollute the lubricant fillings. Cleanliness of the oils in lubrication systems is an important prerequisite for maintaining the operating conditions of machines and equipment.The aim of this article is to evaluate distribution of wear particles of tested transmission oil samples via automatic laser particle counter and classifier LaserNet Fines-C which is highly accurate and a fully automated tribotechnical diagnostics device.

Effect of Particles on the AC Breakdown Voltage of Palm Oil and Coconut Oil

Under current scenario of regulation on the safety and environment, biodegradable oils are gaining interest as dielectric insulating fluid in transformers. There are different types of biodegradable oils that are currently examined and among them are Palm Oil (PO) and Coconut Oil (CO). It is important to carry out extensive examination on these oils at laboratory level since the failure in-service could be costly. Among the important studies are the AC breakdown strength properties under the influence of particles. In this paper, a study is carried out to examine the influence of particles on the AC breakdown voltage of POand CO. The PO used in this study is Refined Bleached and Deodorized (RBDPO) Olein type. Two types of particles are used for the investigations which are cellulose and copper particles.Four different weights of particles are added on each of the samples and tested with the AC breakdown tester at a gap distance of 1 mm using VDE electrodes. It was found that copper particles have more significant effect on the AC breakdown strength of RBDPO and CO than cellulose particles.

Results of the development of biodegradable oils suitable for forest machines

The paper is a response to the problem of the environment pollution by oil product spills from mechanisms of forest and agricultural machines. The problem can be dealt with through the replacement of mineral oils by biodegradable oils. Information concerning the measurement of parameters of these oils was published by the author. It has been demonstrated that the parameters are broadly suitable with the exception of thermooxidation stability. The paper is, therefore, aimed at improving the thermooxidation stability of biodegradable oils of HETG type. Oil raffinates based on rape oil, methyl esters are delivered in various quality, mostly with a service life of 600 to 2,000 service hours at a temperature of max. 70^oC. Methods of testing are based on monitoring the change in acid value, viscosity, water content and peroxide number during the service life test. It has been proved that peroxide number characterizes very well thermooxidation stability which is nearly unsatisfactory in raffinates. A method for improving the thermooxidation stability has been proposed using high superheating of oils at the beginning of use and their subsequent treatment. Thus, deep-frying oils (HETG) characterized by a short-term thermal stress appear to be suitable. Through filtration and other treatment three types of samples were developed and tested. The advantage of the procedure consists in the fact that esterification does not occur. Results of the tests are evaluated and compared with properties of traditional raffinates. It is possible to conclude that thermooxidizing stability of the oils has been substantially improved, other parameters in additivated samples are comparable with raffinates.