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This work consists of evaluating the influence of heat treatment on sintered valve seat insert (VSI) obtained with two different high-speed steels powders and one tool steel: AISI M3:2, AISI M2 and AISI D2, respectively. The high-speed / tool steel powders were mixed with iron powders and additives such as manganese sulphide, zinc stearate, graphite and niobium carbide. All the high-speed / tool steel powders had its particle size distribution and morphology analyzed. The heat treatment of the VSI consisted of air quenching followed by double tempering it in seven different and equidistant temperatures, ranging from 100 °C until 700 °C. A data acquisition system with a thermocouple type k attached to the samples was used to determine the air-quenching cooling rate. The mechanical and physical properties measurements were carried out, i.e., apparent density, apparent hardness and crush radial strength.

Studying the formation and distribution of residual stress fields will improve the wheel safety operational criteria among other gains. Many engineering specifications, manufacturing procedures, inspection and quality control have begun to require that the residual stress of a particular component to be evaluated. It is known that these residual stress fields could be added to the effects of a system load (tare weight plus occupation of vehicle, traction, braking and torque combined). The mathematical tools for modeling and simulations using finite elements had evolved following the increasing computing power and hardware cost reduction. On the other hand, the experimental testing, offers specific physical component behavior and with the use of statistical tools, it is possible to predict the real behavior of the component when in operation. The experiments undertaken used the X-ray diffraction technique and the drilling method with rosette type strain gages.

This paper reports the experimental efforts in recording the 2-dimensional temperature distribution on autogenous thin plates of UNS S32304 steel during welding. The butt-welded autogenous joints were experimentally performed by the GTAW (Gas Tungsten Arc Welding) process with either argon or argon-2%nitrogen atmospheres. The temperatures cycles were recorded by means of thermocouples embedded by spot welding on the plate's surfaces and connected to a multi-channel data acquisition system. The laser flash method (LFM) was also used for the determination thermal diffusivity of the material in the thickness direction. The temperature curves suggest a relationship between the microstructures in the solidified and the heat affected zone with the diffusivity variation. This is a region where there had been a major incidence of heat. The obtained results validate the reliability of the experimental used apparatus.

This article shows some fabrication aspects related to the obtention of sintered valve seat insert. The insert was made of a mixture of high-speed steel powders and iron powders. The physical properties, mechanical properties and machining behaviour are discussed. The machining characteristics of the insert were compared to available commercial insert. The results indicate that the material under development has potential for commercial application and shows good machining evidences.

In this study, the corrosion resistance of four Al-Si hypereutectic alloys has been investigated in a solution of chemical composition typical of the condensed solution from automotive fuel combustion products - here named automotive synthetic condensed solution. The significance of the undertaken study was in the evaluation of materials used for cylinder liners fabrication in relation to the Brazilian motor fuel. Three commercial Al-Si alloys that have been used for cylinder liners and a laboratory made alloy (Osprey Process) were evaluated by electrochemical impedance spectroscopy measurements at increasing times of immersion in this solution. The surfaces of the alloys were evaluated before and after corrosion test by scanning electron microscopy and.

The importance of powder technology to the automotive industry is well known, mainly due to its growing potential. This work presents aspects related to high-speed steels for valve seat inserts application. Four series of materials were evaluated: high speed steel M3/2 infiltrated with copper during sintering; high speed steel M3/2 with Cu3P addition; high speed steel M3/2 with Cu3P addition and further copper infiltrated during sintering; high speed steel M3/2 mixed with iron powder. The main material selection topics such as cost, performance, reliability, and environmental aspects were considered. The physical and mechanical properties of the evaluated high-speed steels are presented in terms of densification, hardness, and radial mechanical strength.