From the standpoint of processing, hard chromium layer plate may be applied to steels, CAST IRON, aluminum and nickel base alloys. CAST IRON can be plated provided that the surface is capable of conducting the required current and is reasonably free of voids, pits, gross silicate inclusions, and massive segregation. There are many difficulties arising from graphite phase and deposition of hydrogen on the surface of GRAY CAST IRON (G.C.J). To obtain desired hard chromium coating with acceptable adhesion, special pretreatments should be used. In this paper the surfaces of G.C.I. were prepared in sulphuric acid, chromic acid + S04-- by anodic etching phosphoric acid + sulphuric acid solution by electro polishing and sulphuric acid + fluoridric solution by dipping in the different conditions. The best results for removal of graphite from the surface of specimens are obtained after anodic etching in 60% H2S04 solution.

GRAY CAST IRON is among the most common and important engineering material that plays a significant role and has many applications in various industries, including the automotive and machinery manufacturing. It still attracts researchers’ interest to improve its properties and maintain its position among the engineering materials. In this research, the microstructure of plain CAST IRON as well as those containing 4 wt% aluminum with different amounts of silicon, 1 to 4 wt%, was studied. Pin-on disc method was used to evaluate the wear resistance of the CAST IRONs. The results showed that the addition of aluminum to GRAY CAST IRON brings about the formation of ferrite phase, which accompanies a decrease in hardness value. In addition, the increase in silicon content in aluminum bearing CAST IRON up to 2wt% intensifies the formation of ferrite phase, while further increase to 3 wt% results in emerging a Fe-Al-Si intermetallic compound. In GRAY CAST IRON with constant 4 wt% aluminum, increasing silicon content to 3 wt% and 4 wt% leads to improve the hardness value due to the increased percentage of intermetallic phase. Confirming microstructure evolution as well as hardness values, the results of wear experiment approved lower wear rate in CAST IRONs containing intermetallic phase. In contrast, the lowest wear resistance was observed in aluminum bearing CAST IRON containing 2 wt% silicon.

An investigation of the friction and sliding wear of GRAY CAST IRON against chromium plated CAST IRONs was carried out on a newly constructed reciprocating friction and wear tester. The tests were the first to be done on the test rig under dry conditions and at the speed of 170 cm/mm and variable loads of 20-260 N for duration of 15 min to 3 hours. The GRAY CAST IRON surfaces worn by a process of plastic deformation at the subsurface, crack nucleation, and crack growth leading to formation of plate like debris and therefore the delamination theory applies. No evidence of adhesion was observed. This could be due to formation of oxides on the wear surface which prevent adhesion. Channel type chromium plating picked up CAST IRON from the counter body surfaces by mechanically trapping CAST IRON debris on and within the cracks. The removal of the plated chromium left a pitted surface on the CAST IRON.

The vehicle braking system is considered to be one of the most fundamental safety-critical systems in modern vehicles, as its main purpose is to stop or decelerate the vehicle. The frictional heat generated during braking application can cause numerous negative effects on the brake assembly, such as brake fade, premature wear, thermal cracks and disc thickness variation. In the past, surface roughness and wear at the pad interface have rarely been considered in studies of the thermal analysis of a disc brake assembly using the finite element method. The ventilated pad-disc brake assembly is built by a three-dimensional model with a thermo mechanical coupling boundary condition and multi-body model technique. The numerical simulation for the coupled transient thermal field and stress field is carried out sequentially with the thermal-structural coupled method, based on ANSYS software, to evaluate the stress fields of deformations that are established in the disc with the pressure of the pads and in the conditions of tightening of the disc; thus, the contact pressure distributions field in the pads is obtained, which is another significant aspect in this research. The results obtained by the simulation are satisfactorily compared with those of the specialized literature.

Lost foam CASTing has been used as a production method since 1950. This process has the capability to put different types of fiber and particles inside the polystyrene pattern before starting to CAST. The process utilized in this research can be also regarded as a promising approach for production composite and bimetals. Furthermore, this process can be used for studying interface reactions between a given melt and supposed solid insert. In this research, Aluminum wire with a diameter of 3 mm inserted in polystyrene pattern and then GRAY CAST IRON was poured. States of melting Aluminum insert, different Fe/Al intermetallic phases and effect of Aluminum on the graphite in interface were studied by Scanning Electron Microscopy. Results showed that formation of different intermetallic components such as FeAl3, FeAl2, FeAl and Fe3AlCx at Fe/Al/C interface.

IRON-based metal matrix composites containing hard particles have good resistance to abrasive wear. One of their production methods is infiltration-CASTing, which has the ability to produce surface composites reinforced parts. In this Article, the infiltration of molten GRAY CAST IRON into a porous skeleton of compacted swarfs of 304 stainless steel has been investigated. The molten CAST IRON was pulled into the porous skeleton by capillary forces. At the infiltration temperature of the molten GRAY CAST IRON, it was in contact with the solid skeleton of 304 steel. Due to the diffusion of chromium as a carbide-maker element and nickel element into the molten GRAY CAST IRON, its chemical composition changed and became similar to the composition of white Ni-Hard CAST IRONs. By diffusion and exchange of alloying elements, an IRON matrix with hard chromium-IRON carbide (M7C3) particles and a ferritic-austenitic matrix were obtained. The microstructure formation, type, and hardness of different phases were examined with light and electron microscopy, XRD, and microhardness measurement. Due to the relatively low price of GRAY CAST IRON and the waste stainless steel turning chips, it can be said that a method has been proposed to produce economical parts reinforced with surface composites.

Gears are the most significant element of mechanical systems. In this paper, Hertzian contact stress is studied which is one of the main failure causes of gears. As it is known, the rotation motion of meshing gears as a result of torque creates repeated contact stress on the surface of the teeth, and this stress creates fatigue stress in the contact area of the material over a certain period of time. This type of stress is considered as one of the most serious problems of gears, and its optimization is important for increasing the gears’ stability. There are many factors affecting contact stress. In this study, as the most important factors, the contact stress values were measured which modify with the varying values of temperature. Taking into account that contact stress is a theoretical value and cannot be measured practically, the analysis was done by the Finite Element Analysis method using Solidworks simulation software. The contact stress values are measured by means of two gears modeled by applying a high mesh density in contact with each other. The process is repeated in several stages, and the teeth surfaces of each gear in contact are exposed to different temperatures.

In this study, the effects of adding of alumina particles and carbon monoxide gas bubbles through the runner system on graphite morphology and microstructure of GRAY CAST IRON was studied. To add alumina particles, thermite reaction of aluminum and IRON oxide powders in runner was used and for production of carbon monoxide gas bubbles in runner, reduction reaction of IRON oxide by carbon was carried out. Light microscopy, scanning electron microscopy and XRD were investigated. The burning of sand in chamber of powders provided that reactions were performed in according with the expected and their heat caused the sand burning of Microscopic evaluation showed that the addition of alumina particles has great influence on the graphite morphology. The presence of these particles in the liquid was cased heterogeneous nucleation of graphite and as a result, B type of graphite and Kish-graphite were produced. Alumina particles have no affected microstructure. Bubbles of carbon monoxide have no effect on the graphite morphology and microstructure.