Cast Iron Rings Research Articles

Radiological evaluation approach for oversized radioactive waste resulted from VVR-S Nuclear Reactor decommissioning

The management of radioactive waste is a costly process that involves several activities, including radiological characterization, treatment, conditioning, intermediate storage, and final storage. It is crucial to optimize these activities to reduce costs. Proper radiological characterization is essential to ensure correct classification of the waste and rational use of storage and final storage facilities. Overestimating the waste's activity reduces storage capacity, while underestimating it creates nuclear security issues. This paper describes the methodology used in the predisposal stage to evaluate the activity resulting from activation or contamination of a cast iron plate used to support the cast iron rings of the VVR-S nuclear research reactor block's biological protection. The reactor was decommissioned between 2010 and 2020, and the evaluation aimed to treat the piece as oversized radioactive waste within the Radioactive Waste Management Department at IFIN-HH.

The use of Selected Lean Management Tools for Analyzing Defects in Pistons for Internal Combustion Engines

The article presents the most significant material defects found in pistons for internal combustion engines, along with a graphical method of categorization using a Pareto-Lorenz chart. For the top three defects (constituting approximately 80% of all issues), a slightly different Ishikawa chart was employed to identify the causes behind their occurrence. Remedial actions were proposed, to be implemented primarily within the interoperative quality control of piston casting. It was concluded that it is crucial to prevent the excessive iron content in the alloy used for alfin inserts (AS9 alloy), particularly for cast iron ring carriers. The research was conducted in collaboration with Federal-Mogul company in Gorzyce (F-MG), one of the largest piston foundries in Poland.

Improving the Sealing Efficiency of Compressor Cylinders of Gas Engine Compressors in the System of Gas-Lift Production of Offshore Fields

An increase in the efficiency of gland seals in compressor cylinders with cast iron rings pressed against the contact surface of the piston rod using a steel spring in reciprocating compressors used in offshore oil and gas-condensate fields for gas-lift oil production systems is considered. Studies of a gas engine reciprocating compressor working directly on the operating gas-lift system have shown that in order to increase the time of normal operation of gland seals, it is necessary to adjust the clearance using lubricant up to 0.1 mm. After increasing the spring stiffness, the serviceability and number of working hours of the gland seal increased twofold, from 850 to 1700 h.

TRIBOLOGICAL PROPERTIES OF PISTON RINGS DESIGNEDFOR SLIDING AGAINST COMPOSITE MATERIALSIN LUBRICATED CONTACTS

The paper presents basic information on the production, structure and tribological properties of a compositechromium-ceramic coating deposited electrolytically on a cast-iron piston ring for a combustion enginedesigned for sliding against a composite cylinder liner. The results of comparative tests of two contacts,i.e. cast-iron GJL-250/AlMC and GJL250+Cr-Al2O3/AlMC, are described. The deposition of the Cr-Al2O3coating on the cast-iron piston ring reduces almost trifold the wear of the piston ring and about 20% thefriction resistance in the contact due to the presence of aluminium oxide particles and fibres. The reinforcingphase removed from the chromium layer polishes the chromium and composite sliding surfaces. The placesleft by the removed particles serve as depots for oil, which reduces the friction forces and minimises oilconsumption. The Al2O3 wear debris decreases the roughness of the surfaces in contact, which additionallyreduces the friction forces according to the friction hypothesis of Ernst and Merchant.

Influence of the Duration and Temperature of the Al-Fin Process for the Cast Iron Insert on the Microstructure of the Bimetallic Joint Obtained in the Piston Casting Process

The aim of this work was to determine the effect of the duration and temperature of the Al-Fin process for casting the bimetallic joint on the formation of the metallurgical bond between the AlSi9 aluminium alloy piston and the cast iron insert. Knowledge about the formation of individual bonding layers has a direct impact on the bonding strength between the aluminium alloy and the EN-GJLA-XNiCuCr15-6-2 austenitic cast iron ring. In the performed tests, the Al-Fin casting process was carried out for different temperatures of the liquid AlSi9 alloy. The temperature of the AlSi9 aluminium alloy varied in the range 700–950 °C in steps of 50 °C. The duration of the Al-Fin process ranged from 1 to 10 min. An optical microscope and a scanning electron microscope were used to study the microstructure of the bimetallic joints. The analysis of the microstructure of the bimetallic bond showed that characteristic layers are formed between the aluminium alloy piston and the cast iron insert: a transition layer, in which iron and aluminium atoms from both joined materials are mixed, and a diffusion layer, in which aluminium and silicon atoms penetrate the surface layer of the joined metals. The thickness of the intermetallic diffusion layer formed between the aluminium alloy and the cast iron insert is thinner and does not depend on the heating time of the aluminium insert in the bath. However, there is a significant effect of both the annealing time and the temperature of the AlSi9 aluminium alloy on the thickness of the transition zone.

Heat-treating and nano-reinforcing improvements on fretting fatigue properties and fracture behaviors of cylinder head aluminum alloys

The presence of cyclic loading alongside the wear increases the probability of fretting fatigue phenomenon in the cylinder head of automobiles. In the current study, the nano-reinforcing and the T6 heat-treating impact on the fretting fatigue behavior of the cylinder head aluminum alloy were studied. Fretting fatigue tests were performed in the high-cycle fatigue regime, under 15 N contact load and four different stress levels (75, 100, 125, and 150 MPa). According to the test results, the fretting fatigue lifetime of heat-treated nano-composites under the lowest stress level increased by about 621%. Furthermore, the fracture surface of the studied aluminum alloys, the worn surface of the cast-iron ring used as fretting pads, and the derbies obtained during the fretting test were investigated with the help of field emission scanning electron microscopy. The failure behavior of the cylinder head materials concerning the presence of the quasi-cleavage and cleavage marks were brittle in all cases. In addition, as it is observed the wear mechanism of fretting pads was adhesive.

The influence of initial deflection angle on the tribological properties of gray cast iron rings with curve distributed pits under dry sliding

This study presents the influence of initial deflection angle (IDA) on the tribological properties of gray cast iron (GCI) rings with curve distributed pits in the radial direction (CDPRD). The thermal behavior of pits textured GCI rings with different initial deflection angles (0°, 30°, 45°, 60°, 75°) and fixed deflexional angle of adjacent pits (DAAP, 10°) were researched, through APDL programming. A pin-on-disc wear test rig was used to reveal the anti-wear performance of samples under dry sliding, at a rotating speed of 200 rpm, with a normal load of 70 N. An electronic balance and an optical microscope (OM) were used to obtain their wear losses and worn surfaces, respectively. The results show that: comparing with the smooth GCI ring, there are evident high temperature regions between two adjacent pits groups, called “temperature barrier and separation effect”. Among all textured samples, the von Mise’s stress of IDA45 is the most stable, and its temperature is almost the lowest. The friction coefficient curve and the wear loss of IDA45 are also the lowest, and much lower than the loss of smooth GCI ring, indicating the excellent anti-wear performance. This work can provide a valuable reference for the surface design of journal bearings.

Wear behavior of pits textured grey cast iron rings with Zr/ZrN coatings under dry sliding

This study presents the influence of Zr/ZrN coatings on the tribological performance of pits textured grey cast iron parts under dry sliding. A laser marking system and a physical vapor deposition equipment were applied to manufacture pits textured grey cast iron rings combined with Zr/ZrN coatings. A pin-on-disc wear test rig was used to reveal the wear behavior of samples under dry wear condition, at a rotating speed of 200 r/min, with a normal load of 70 N. The wear losses and the worn surfaces of all rings were obtained by an electronic balance and a three-dimensional surface profilometer, respectively. The results show that Zr/ZrN coatings can significantly increase the surface roughness and surface hardness of grey cast iron rings. As a result, Zr/ZrN coatings increase the friction coefficients of all coated GCI rings, and reduce the wear losses of some ones. In this work, when surface texturing combines with Zr/ZrN coatings, the final tribological properties of coated grey cast iron rings may be either improved or deteriorated, depending on surface characteristics, texturing parameters and loads. Compared with the uncoated smooth grey cast iron ring, Zr/ZrN coatings cannot effectively improve the wear behavior of pits textured samples. Among all coated grey cast iron rings, when the diameter of the pit is 0.8 mm, and the distance between pits is 1.25 mm, the pits textured grey cast iron ring can provide the optimal anti-wear performance. This work would provide a valuable reference for the surface design of journal bearings and roller bearings.

The Manganese Influence on the AlSi12 Alloy Alfinal Bath Mechanical Properties Change

The experiment described in this article deals with the possibility of AlSi12 alloy alfinal bath mechanical properties change used in the manufacture of the compression ignition engines pistons by the addition of manganese. The alfinal bath is intended for the aluminium layer deposition which provides more convenient connection of the carrier with the aluminum alloy after casting in the mold. The analysis performed in the experiment were focused on the assessment of the manganese addition influence in the form of the AlMn20 master alloy on the resulting mechanical properties of the AlSi12 alloy in which the iron content gradually changes (up to 7 wt. %). The iron is released from inserting cast iron rings. The research is primarily focused on assessing of strength and hardness of the alloy which is affected by the occurrence of intermetallic phases excluded in the microstructure depending on the ratio of iron to manganese content. The alloy with the high Fe content was subjected to the static tensile test and Brinell hardnes test measurement after the manganese addition.

Study of Distortion on the Example of the Rings from Ductile Iron and Cast Steel

Abstract The paper attempts to analyze distortions of cast iron and cast steel rings, after heat treatment cycles. The factors influencing distortion are: chemical composition of material, sample geometry, manufacturing process, hardenability, temperature and heat treatment method. Standard distortion tests are performed on C-ring samples. We selected a ring-model, which approximate the actual part, so that findings apply to gear rings. Because distortion depends on so many variables, this study followed strictly defined procedures. The research was started by specifying the appropriate geometry of the samples. Then, the heat treatment was conducted and samples were measured again. The obtained results allow to determine the value of the resulting distortion and their admissibility. The research will be used to evaluate the possibility of using the material to produce parts of equipment operated under extreme load conditions.

Thermo-mixed lubrication analysis of coated compression rings with worn cylinder profiles

PurposeCompression rings are the main sources of frictional losses in internal combustion engines. The present paper aims to present a thermo-mixed hydrodynamic analysis for coated top compression rings. To understand the coating effects, the main tribological parameters are investigated into a ring-cylinder conjunction in a motorbike engine. Furthermore, flow simulations have been carried out on how different worn profiles on the cylinder inner liner affects friction, lubricant film and localized contact deformation of the coated compression rings.Design/methodology/approachIn this paper, the basic geometrical dimensions of the top compression ring-cylinder system are obtained from a real motorbike engine. A 2D axisymmetric CFD/FLOTRAN model is created for coated compression rings. Flow simulations are performed by solving the Navier-Stokes and the energy equations. The load capacity of the asperities is also taken into account by Greenwood and Tripp contact model. Realistic boundary conditions are imposed to simulate the in-plane ring motion. The simulation model is validated with analytical and experimental data from the literature. Under thermal considerations, the contribution of worn cylinder profiles in conjunction with different coated compression rings is presented.FindingsThis research shows that because of thermal effects, the boundary friction is higher at reversals and the viscous friction is lower because of reduced oil viscosity. As regards to the isothermal case, the viscous friction is greater because of a higher lubricant viscosity. In the case of chromium-plated ring, boundary friction was 16 per cent lower than a grey cast iron ring taking into account thermal effects. Regarding the localized contact deformation, the coated compression rings showed lower values under different worn cylinder shapes. In particular, hard wear-resistant (Ni-Cr-Mo) coating showed the slighter local deformation. Therefore, the worn cylinder profiles promote boundary/mixed lubrication regime, whereas the lobed profile of cylinder inner liner becomes more wavy.Originality/valueThe solution of the thermo-mixed lubrication model, concerning the piston ring and worn cylinder tribo pair by taking into account the coating of the top compression ring.

Влияние материала контактных пар на износ электрических щеток электрических машин в отсутствие токовой нагрузки

The performance of electrical machine slip ring units is considered for the case when the brushes operate under no-load conditions. The article presents the results from investigations aimed at determining the effect the slip ring material has on the wear of electric brushes with and without using the lubricating brushes made on the basis of molybdenum disulfide. It has been found that the minimal brush wear is achieved in case of using “EG-4 brush—steel ring” contact pairs. It has also been determined that the highest brush film resistance is obtained in case of using cast iron rings. The use of lubricating brushes allows the wear of main brush es to be decreased by more than a factor of two with simultaneously making their wear more uniformly distributed in time. Physical models have been developed that allow the wear of EG-61A and MGS-7 brushes to be predicted at the design and operation stages for their operation on a steel slip ring in combination with lubricating brushes.

Behaviour of cast-iron bolted tunnels and their modelling

The behaviour of cast-iron bolted tunnels in London underground railway network was investigated using the 3-D finite element (FE) method. A series of numerical simulations on a cast-iron segmental ring were conducted and its performance was compared against the analytical assessment used by London Underground Limited (LUL). Unlike the 2D plane model used in the LUL standard, the proposed FE model considered the 3D lining structural features (i.e. the geometry of the tunnel segment and the bolted joint) in a detailed manner. The behaviour of a cast-iron tunnel primarily goes through three stages: tunnel construction, soil loading and structural deterioration. At each stage, the influences on the tunnel behaviour such as external loading, soil-tunnel interaction were examined. Considering that, the proposed model thus resulted in more realistically structural performance in agreement with the field measurements.

Effect of surface treatment to inserted ring on Al-Fe bonding layer of aluminium piston with reinforced cast iron ring

In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring, the different methods of the surface treatments (shot blasting and sand blasting) to the cast iron ring are experimented. The optical micrograph shows that an intermetallic layer and a ligulate shaped structure are formed between piston alloys and cast iron base ring. After sand blasting treatment, the ring surface is non-metal shiny, matte-like and has no obvious pits. The intermetallic layer thickness formed between piston alloys and cast iron is thinner and more equally distributed after sand blasting to the ring. The content of the graphite distributed the interfacial zone after the shot blasting treatment is little. With the increase of time by sand blasting, the hardness starts to slightly descend. The bonding strength of the sample by sand blasting is obviously higher than that by shot blasting and increases from 9.32 MPa to 19.53 MPa.

Detailed mechanical design of the LIPAc beam dump radiological shielding

The LIPAc is a 9MeV, D+ linear prototype accelerator for the validation of the IFMIF accelerator design. The high intensity, 125mA CW beam is stopped in a copper cone involving a high production of neutrons and gamma radiation and activation of its surface.The beam stopper is surrounded by a shielding to attenuate the resulting radiation so that dose rate values comply with the limits at the different zones of the installation. The shielding includes for that purpose polyethylene rings, water tanks and gray cast iron rings. A lead shutter has also been designed to shield the gamma radiation that comes through the beam tube when the linear accelerator is not in operation, in order to allow access inside the building for maintenance tasks.The present work summarizes the detailed mechanical design of the beam dump shielding and the lead shutter taking into account the design constraints, such as working conditions and other external loads, as well as including provisions for dismantling.

Study on Wear Mechanism of Chromium Carbide Coating Reinforced Cast Iron Cylinder Sleeve

In tribological system of internal combustion engine, cylinders and pistons were in high temperature, pressure and load working status. An SRV IV wear tester was used to measure dynamic coefficient of friction by simulating working condition of cylinder liner and piston ring. The worn surface topography was observed through scanning electron microscope and metallography. The results show that loads had little effect on the friction coefficient under oil lubrication. Cylinder with the high-chromium carburizing ring in pairs displayed wear in the form of plastic deformation, while cylinder with the phosphide cast iron ring in pairs displayed adhesive wear. The piston ring was subjected to shear stress and tensile force under dry friction condition and deformed into tapering burr. Lubricants played a bearer role under lubrication condition; therefore, surface borderline of piston ring was relatively flat.

The influence of start–stop transient velocity on the friction and wear behaviour of a hyper-eutectic Al–Si automotive alloy

As worldwide automotive ownership is set to exceed 2 billion vehicles by 2030 (Dargay et al., 2007 [1]), environmental and economical pressures on the automotive industry mean there is a trend to reduce harmful greenhouse gas emissions whilst simultaneously improving fuel economy. The use of electrical hybrid, start–stop idling and materials light-weighting are some of the technological solutions which can offer efficiency savings, however their combined use in a tribological context is less well understood. Interruption of piston sliding as a result of start–stop technology will simultaneously interrupt fluid film lubrication at the ring/liner interface. This could have implications on the friction and wear behaviour of Al–Si cylinder blocks, where scuffing can be an issue. In order to determine the effect of a start–stop velocity cycles on the lubricated friction and wear behaviour of a hyper-eutectic Al–Si liner, an interrupted reciprocating laboratory tribometer test programme was developed based upon the European Urban Cycle standard. Refined cast iron piston ring segments were slid at 23Hz frequency, 4MPa nominal contact pressure and 25mm stroke length against a conformal honed Alusil cylinder liner segment. Regular velocity interruptions at 60s intervals did not significantly inhibit the dynamic friction behaviour between the liner and the cast-iron piston ring segment, indicating that lubricant additive function was not significantly inhibited. However contact potential and FIB–SIMS depth profiles indicated that anti-wear tribo-film thickness was reduced as a result of start–stop cycling. Mass loss from the piston ring was also notably higher as a result of the interruption of elasto-hydrodynamic lubrication causing boundary conditions at re-start and subsequent 2-body abrasion by harder protruding Si particles. Specific wear rates for the Al–Si liner as a result of start–stop velocities were surprisingly lower compared to uninterrupted tests and was believed to be due to faster running-in of the piston ring surface. These results are discussed in terms of the viability of Al–Si as engine materials running start–stop technology.

Effect of Si content in hot dipping aluminium bath on Al–Fe bonding layer of aluminium piston with reinforced cast iron ring

Pistons with reinforced cast iron ring are produced to meet the increasing performance requirement of internal combustion engines with high power. The intermetallic bonding between piston alloys and cast iron ring must be able to withstand the high pressure and high temperature environment of internal combustion engines. Consequently, the quality and strength of the intermetallic bonding are very important in piston manufacturing. In the present work, the effects of Si content variation in the hot dipping aluminium bath on interface reaction and the intermetallic bonding strength between the cast iron ring and the piston alloys are investigated. The results indicate that bonding strength increases with the increase in Si in the hot dipping aluminium bath to eutectic composition and decreases with excess Si. The mechanism for the variation of bonding strength is also discussed.

Microstructure and Mechanical Behavior of in Situ Primary Si/Mg2Si Locally Reinforced Aluminum Matrix Composites Piston by Centrifugal Casting

Al-Si pistons are frequently damaged by burning piston top surface due to elevated combustion temperature, and by rubbing the first ring groove against the engine cylinder liner. To prevent piston from these damages, some technologies were invented, such as mounting high Ni cast iron ring around the first ring groove in Al alloy piston body and thermal resistant steel on piston top surface, and fabricating Al composite pistons by squeeze casting for enhancing the whole or local piston performance. In this paper, composite pistons locally reinforced with in situ primary Si and primary Mg2Si particles are fabricated by centrifugal casting. The microstructure characteristics, hardness and wear resistance of the composite piston are investigated and the motion characteristic of the in situ particles in centrifugal field is analyzed. The results of the experiments show that primary Si and Mg2Si particles mix up with each other in melt and segregate at the regions of piston top and piston ring grooves under the effect of centrifugal force. Particulate reinforced regions have a higher hardness and better wear resistance compared with the unreinforced regions and this performance increases after heat treatment. The analysis result of particle movement shows that, primary Si and primary Mg2Si particles move at approximately the same velocity in the centrifugal field, because of the growth of primary Si and fusion after colliding between primary Si particles, which compromised the velocity difference of primary Si and primary Mg2Si particles caused by the difference of their densities. Research results have some theory significance and applicative value of project in development of new aluminum matrix composites piston products.

An experimental study on interaction of nodular cast iron with CRT glass

In the manufacturing of glass components of cathode ray tubes, ductile cast iron rings are commonly used as an integral part of the mold assembly. The thermo-chemical interaction of molten glass with cast iron therefore becomes critical as far as the mold life and productivity is concerned. In this perspective, the present study is carried out to understand and analyze the chemical interaction of cast iron when immersed in molten glass. The experiments were conducted in the temperature range of 700°C to 900°C for selected time duration of 0 to 100 hours. The important observations include the formation of diffusion zone at the glass metal interface. SEM-EDS analysis revealed that diffusion of silicon and lead from glass takes place in diffusion zone with varying degree, depending on temperature and time. The hardness variation across the interface correlates well with the measured compositional changes. The plausible reasons for the measured hardness increase in the diffusion zone are also discussed.