Browse Topic: Silicon alloys

Items (53)
The bearing performance of steel backed half bearings, bushings, and washers is dependent on the properties and thickness of the lining alloy, the strength and dimensional stability of the steel backing (usually SAE 1010) and the strength of the bond between the lining alloy and the backing. This SAE Information Report is primarily concerned with the properties of the lining alloys used in automotive applications, in particular, the crankshaft bearings of the internal combustion engine.
Metals Technical Committee
For convenience, this SAE Information Report is presented in two parts as shown below. To avoid repetition, however, data applicable to both wrought and cast alloys is included only in Part 1. Part I—Wrought Copper and Copper Alloys Types of Copper (Table 1) General Characteristics (Table 3) Electrical Conductivity Thermal Conductivity General Mechanical Properties (Table 10) Yield Strength Fatigue Strength Physical Properties (Table 2) General Fabricating Properties (Table 3) Formability Bending Hot Forming Machinability Joining Surface Finishing Color Corrosion Resistance Effect of Temperature Typical Uses (Table 3) Part II—Cast Copper Alloys Types of Casting Alloys Effects of Alloy Elements and Impurities General Characteristics (Table 11) Physical Properties (Table 12) Typical Uses (Table 11)
Metals Technical Committee
High Performance Aluminum Casting Alloys for Engine Applications2016-32-001911/8/2016
In the early 1980's, some promising research and development efforts focused on powder metallurgy revealed that aluminum alloys containing 4 wt% cerium exhibit high temperature mechanical properties exceeding those of the best commercial aluminum casting alloys currently in production. Cerium oxide is an abundant rare earth oxide that is often discarded during the refining of more valuable rare earths such as Nd and Dy. Therefore, the economics are compelling for cerium as an alloy additive. In this paper, we report select results obtained during an investigation of the castability of aluminum-cerium alloys and determine compositional modifications that may be required to ensure the compatibility of the alloy with near net shape casting methods such as advanced sand casting, die casting, permanent mold casting and squeeze casting. Al-Ce alloys were cast in binary composition of 6-16 wt% Ce. Commercially pure aluminum ingots were melted and held at approximately 785°C. Ternary and quaternary alloys with Si and Mg additions were also investigated. Test bars were cast to establish mechanical properties and step plates and hot tear molds were used to determine sensitivity to solidification conditions and hot tearing sensitivity respectively. Finally, air cooled engine cylinder heads were cast in sand molds to get a sense of castability in complicated shape castings.
Weiss, David
Aluminium Piston Alloy to Retard Age Softening Characteristics in Motorcycle Engines2006-32-003011/13/2006
Pistons for high power output demand its material to possess the properties of low thermal expansion, anti-seizure, wear resistance, high thermal conductivity, high creep and fatigue strength and high strength to weight ratio. Aluminium silicon alloys has excellent characteristics as a piston material. Due to design constraints in engines for heat dissipation and engine temperatures upto 300 ° C, the need for the study on the effect of thermal behaviour of the piston alloy during engine operation becomes important. However a piston operating at 150° C with aluminum silicon alloy gradually loses its attained hardness in T6 condition and is not a constant during engine operation. This decrease in hardness of the alloy due to exposure to temperature and time is due to the phenomena called “age softening”. This phenomena occurs if the equilibrium phase diagram reveals partial solid solubility of the alloying element, at a higher temperature than at lower temperature. Large decrease in hardness of the piston leads to piston wear and seizure. In order to retain hardness during softening, copper was added to the existing aluminium silicon alloy. Though maximum hardening effect can be obtained by addition of 3 to 6 weight %, the amount of copper addition is optimized to 3.4 weight percent, due to reasons discussed in the paper. The age hardening and softening behaviour data is determined and in the heat-treated condition the new alloy reveal peak hardness significantly higher than the existing alloy substantiated by presence of phases in scanning electron micrographs. As the time to attain peak hardness and the peak hardness of the new alloy is found to be higher than the existing alloy, the onset of age softening behaviour is delayed and also the hardness at the offset of the age softening is increased. Effect of softening of alloys at different temperatures was studied and master curves are plotted for hardness versus time at constant temperature. It was found that the hardness of the new alloy was higher at all the temperatures, the hardness decreasing with increasing temperatures. Pistons made of new and existing alloy were heat treated for engine endurance. Hardness of the piston was measured at number of locations across the cross section of the piston before and after the engine test. There was a drop in hardness of the piston alloy at all locations and the hardness is minimum in the top center of the piston. This hardness decrease data is very important to estimate the piston temperature during operation. The temperatures during operation of the piston can be determined from the master curves of hardness versus time plotted. The hardness profile of the engine tested piston with new alloy is about 25 percent higher than the existing alloy, thus the age softening is retarded.
Jayamathy, M.Vasanth, R.
Heat Treatment Cycle Time Reduction of Cylinder Head by Microalloying Aluminium Alloy2006-32-002911/13/2006
Aluminium finds diverse applications in the automotive industry. However, owing to its somewhat poor mechanical properties, the metal is unsuitable for structural applications. The problem is overcome by addition of alloying elements like zinc, copper, silicon, etc. and these alloys on proper heat-treatment show substantial improvement in the mechanical properties. Further enhancement of their mechanical properties can be brought about by the addition of small percentages of zirconium, which helps in the grain refinement of the cast alloy ingots. At present for cylinder head the aluminium alloy used requires to be heat treated for a cycle time of about 15 hours (T6 condition) to achieve the desired mechanical properties. The proposed aluminium alloy, which contain microalloying element, Zirconium of about 0.12 weight %, can achieve the required mechanical properties with about five times reduced cycle time (T5 condition) only. All other properties viz., castability, machinability, wear resistance, high temperature tensile properties etc., were studied for the microalloyed alloy and found to be superior than the aluminium alloy being used at present. Cylinder head manufactured using the microalloyed alloy, tested for performance related tests is found to be comparable to the present alloy. As the cycle time for heat treatment is reduced the productivity is increased and cost of manufacture is reduced. Distortion of the component due to heat treatment is decreased significantly as solution treatment is eliminated. Most importantly as the wear resistance of the part is increased due to microalloying, the regions of high wear in cylinder head can be free from valve inserts. This leads to reduction in number of parts to be assembled and thus ease of assembly and manufacturing.
Jayamathy, M.Vasanth, R.
For convenience, this SAE Information Report is presented in two parts as shown below. To avoid repetition, however, data applicable to both wrought and cast alloys is included only in Part 1. Part I—Wrought Copper and Copper Alloys Types of Copper (Table 1) General Characteristics (Table 3) Electrical Conductivity Thermal Conductivity General Mechanical Properties (Table 10) Yield Strength Fatigue Strength Physical Properties (Table 2) General Fabricating Properties (Table 3) Formability Bending Hot Forming Machinability Joining Surface Finishing Color Corrosion Resistance Effect of Temperature Typical Uses (Table 3) Part II—Cast Copper Alloys Types of Casting Alloys Effects of Alloy Elements and Impurities General Characteristics (Table 11) Physical Properties (Table 12) Typical Uses (Table 11)
Metals Technical Committee
Influence of Microstructure on the Static and Thermal Fatigue Properties of 319 Alloys9707052/24/1997
Modern architectures for diesel cylinder heads, especially high performance, direct injection heads for passenger cars and light trucks, require an optimized combination of design and material properties. In aluminium castings, microstructural gradients and associated fatigue and mechanical properties can result from the process selection, e. g. gravity or low pressure, and from the variable cooling rates which have to be applied to the different parts of the casting in order to get a progressive solidification and a sound part. It is thus essential to understand the relationship between the microstructure resulting from the combination of process, material choice and heat treatment, and the properties of the material. As the most widely used material for aluminium diesel as well as gasoline cylinder heads, the 319 alloy has been selected for its superior strength. We have carried out tensile testing and thermo - mechanical fatigue testing on a range of materials. The effect of parameters such as impurity levels (further refered as grade), DAS (secondary Dendritic Arm Space), and heat treatment has been investigated. The thermo - mechanical fatigue experienced by the inter valve seats areas has been simulated on a specific rig developped by Montupet. The thermal cycle applied to the sample was chosen between 20 to 250° C. Also the material evolution in a running engine has been simulated by soaking the specimens 200 h at 200°C. The results show that the cooling rate, which influences directly the DAS and the size of intermetallic compounds is of prime importance for the static and dynamic behavior of the material. It is observed that a very fine DAS can even compensate for a lower grade of the alloy by reducing the size and harmfulness of intermetallic compounds. In this paper also, the effect of alloy grade and soak will be discussed in terms of microstructure changes, in correlation with the mechanical properties.
Meyer, Ph.Massinon, D.Guerin, Ph.
Prefluxed Aluminum Tube for Brazed Automotive Heat Exchangers9501162/1/1995
Provision of a thin layer of zinc on aluminium to provide the fillets during brazing has been described previously [1]. The process for zinc coating of the extruded aluminium multiport tubes has been further enhanced by utilisation of the zinc layer to carry flux for subsequent brazing operations, thereby making it possible to produce brazed heat exchanger assemblies utilising the thin zinc layer, without the need for a separate fluxing operation prior to brazing. The flux is applied directly onto the molten zinc coating where it becomes mechanically locked in position when the zinc freezes. Because of this action, the flux cannot be easily dislodged, unlike other techniques where powdered flux has been sprayed directly upon the aluminium tube surface or a fused flux has been applied to the tube surface. The prefluxed product can readily be handled and subjected to simple forming operations without dislodging the flux. Flux can be adhered to zinc coatings as thin as two micrometers and below, which is somewhat lower than required for the zinc-based joining process but, in this form, the flux layer is suitable for enhancement of conventional Al: Si brazing technology. In this case, the zinc is diffused into the aluminium tube wall during brazing to provide enhanced corrosion resistance. When the flux is applied to a heavier zinc coating, the need for Al:Si brazing is avoided, with the zinc providing the braze fillets through diffusion and partial melting of the diffused layer at normal braze temperatures. The technology also offers potential for brazing in normal air rather than nitrogen atmospheres and more simplified braze cycles can be used, where the need to drive off water from the flux is reduced. It also has the added advantage that the flux is carried directly into the joint area where it will melt and act in situ obviating the requirement to melt and flow into the joints to become effective during brazing. Furthermore, the need to apply extra flux to certain joint areas can be eliminated.
Morley, E. J.Börjeson, R.
Low Water Tolerant Brake FluidsJ1705_199412 (Historical)12/1/1994
This SAE Recommended Practice was prepared by the Motor Vehicle Brake Fluids Subcommittee of the SAE Hydraulic Brake Systems Actuating Committee to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance standards in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTF) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with existing motor vehicle brake fluids conforming to SAE J1703 and with braking systems designed for such fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J 1703 are not known to have any adverse effects on performance, but all combinations have not been tested. Vehicle manufacturer's recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of –50 °C (–58 °F). Brake fluids covered under this document are not required to tolerate water and extreme caution should be exercised to prevent LWTFs with fluids meeting SAE J 1703 are not known to have any adverse effects on performance, but all combinations have not been tested. Vehicle manufacturer's recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of –50 °C (–58 °F). Brake fluids covered under this document are not required to tolerate water and extreme caution should be exercised to prevent accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTFs not covered in this document are discussed in Appendix A.
Brake Fluids Standards Committee
The bearing performance of steel backed half bearings, bushings, and washers is dependent on the properties and thickness of the lining alloy, the strength and dimensional stability of the steel backing (usually SAE 1010) and the strength of the bond between the lining alloy and the backing. This SAE Information Report is primarily concerned with the properties of the lining alloys used in automotive applications, in particular, the crankshaft bearings of the internal combustion engine.
Metals Technical Committee
Low Water Tolerant Brake FluidsJ1705_198810 (Historical)10/1/1988
This SAE Recommended Practice was prepared by the Motor Vehicle Brake Fluids Subcommittee of the SAE Hydraulic Brake Systems Actuating Committee to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance standards in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTF) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with existing motor vehicle brake fluids conforming to SAE J1703 and with braking systems designed for such fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J 1703 are not known to have any adverse effects on performance, but all combinations have not been tested. Vehicle manufacturer's recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of –50 °C (–58 °F). Brake fluids covered under this document are not required to tolerate water and extreme caution should be exercised to prevent accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTFs not covered in this document are discussed in Appendix A.accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTFs not covered in this document are discussed in Appendix A.
Brake Fluids Standards Committee
Low Water Tolerant Brake FluidsJ1705_198503 (Historical)3/1/1985
This SAE Recommended Practice was prepared by the Motor Vehicle Brake Fluids Subcommittee of the SAE Hydraulic Brake Systems Actuating Committee to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance standards in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTF) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with existing motor vehicle brake fluids conforming to SAE J1703 and with braking systems designed for such fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J 1703 are not known to have any adverse effects on performance, but all combinations have not been tested. Vehicle manufacturer's recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of –50 °C (–58 °F). Brake fluids covered under this recommended practice are not required to tolerate water and extreme caution should be exercised to prevent accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTF's not covered in this recommended practice are discussed in the Appendix.
Brake Fluids Standards Committee
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