Papers Posted on - Feb / 2019


Author Name Jatinder Kaur
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DOI http://dx.doi.org/10.11127/ijammc 2019.02.01
Paper Title Explosive welding of Aluminium Alloy With Low Carbon Steel Plates and Weld Interface Characteristics
Abstract
In the present paper joining of aluminium alloy-AA1100 and low carbon steel (LCS) plates has been carried out using explosive welding methodology. Optical and scanning electron microscope (SEM) were used to observe the morphology and microstructure at the interface boundary. Mechanical properties of weld joints have been evaluated by carrying out, chisel test, Ram tensile and hardness tests. After successful joining of plates, the bonding interface had laminar morphology free from voids/cracks. No separation was observed at the interface of the welded plates after conduct of chisel test indicating good quality weld.
Keywords
Low carbon steel, AA1100, explosive welding, interface
Author Name Ali Mohamadinia
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DOI http://dx.doi.org/10.11127/ijammc 2019.02.02
Paper Title Bonds Strength of St37 to SKF-Cu by Using Diffusion Welding
Abstract
Different methods are used to produce bronze bearings with steel backing and bronze coatings. Technically, success of each method is dependent on the bonds strength and economically, production method is important. Temperature and pressure are two important variables in producing such bearings with appropriate bonds strength. This paper aims at studying temperature and pressure effects on the bonds strength of structural steel (St37) to pure commercial copper (SKF Cu), which has been produced using diffusion welding method. So, 18 sample pairs were used in 9 groups, each group containing 2 sample pairs. Diffusion was done in this way: 3 groups without any pressure, 3 groups with 1 MPa pressure, and 3 groups with 2 MPa pressure and 2 sample pairs of each group were diffused at boiling points 700, 850 and 920 C, respectively. Results show that there were no bonds in non- pressure condition at any temperature and also at 700C on all pressures conditions, while average bonds strength for 850C and 920C conditions were 2.2 and 5.4 MPa, respectively. So, for bonds between general structural steel and pure commercial copper, pressure is required with temperatures above 850 C.
Keywords
Bond’s length; Bearing; Pressure; Temperature
Author Name Sina Karimifar
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DOI http://dx.doi.org/10.11127/ijammc 2019.02.04
Paper Title Effect of Pouring Temperature on the Hardness and Wear Resistance of Bronze CuPb10Sn8Zn2
Abstract
In the production of engineering parts by casting method, the pouring temperature is an important variable. In this research, the effect of the pouring temperature on the two important characteristics, including the hardness and wear resistance of bronze bearing CuPb10Sn8Zn2 is studied. For this purpose, the melt is produced in a transistor induction furnace and, in the end, the microstructure (by using scanning electron microscope), hardness test (by using Brinell test device) and wear resistance (by using pin-on-disc at 440m and 10N force) of the bronze of CuPb10Sn8Zn2 bearings are compared in sandy mold at pouring temperatures of 950C and 1200C. The results indicated that at high pouring temperatures (1200C); the wear resistance is almost doubled, because the contents of intermetallic compound and solid solution were more and the content of lead was less.
Keywords
Microstructure; Bearing; Pouring; Casting
Author Name Seyed Ebrahim Vahdat1
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DOI http://dx.doi.org/10.11127/ijammc 2019.02.04
Paper Title Correlation between Mechanical Properties and Microstructure of Aluminium 2024 and 7075 after Deep Cryogenic Treatment
Abstract
Aluminium 2024 and 7075 are common airplane body alloys and they are affected by cooling to subzero temperatures. In this research, the effect of sub-zero treatment at temperature of -196C (deep cryogenic treatment or DCT) and 4 hours on the precipitation hardening of aluminium 2024 and 7075 is studied. For this purpose, scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) were used studying the microstructure. Also, tensile and hardness tests have been used to study mechanical properties. The results have shown that by performing DCT, the formation of precipitation in the vicinity of the particles in the matrix especially for iron particles is facilitated, because at -196C, the difference in the coefficient of iron contraction with the aluminium matrix causes at aging temperature of 100C, elements (such as copper in 2024 and magnesium in 7075) are easier to absorb the areas around iron particles. The new particles increased the yield strength of aluminium 2024 and 7075 compared to the control specimen. While in both specimens, the change of hardness was not noticeable.
Keywords
Hardness; Liquid nitrogen; Population density of particles; Tensile properties
Author Name Saeed Nosratabadi
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DOI Doi: http://dx.doi.org/10.11127/ijammc 2019.02.05
Paper Title Effect of Sn and Pouring Temperature on the Hardness and Wear Resistance of CuSn7Pb7Zn3
Abstract
Although the bearings are part of the assembly in the set of moving parts, they must endure a variety of axial and radial forces. In this way, their hardness and wear resistance should be suitable. On the other hand, the chemical composition and the pouring temperature of the casting are two important factors for the formation of proper microstructure and, therefore, favorable properties. The purpose of this study was to study the effect of tin and pouring temperature (casting temperature) on microstructure and total hardness and weight loss due to wear of CuSn7Pb7Zn3 bronze for use in the bearing. For this purpose, first, the CuSn7Pb7Zn3 bronze was melted in a transistor induction furnace and then the microstructure, hardness and wear resistance in sand mold in four different casting conditions including casting temperatures of 950C and 1200C, and tin values of 2.5 and 7.0 Wt% compared. The results indicate that the sample that is pouring at 950C and its tin content is 7.0% by weight, with a hardness of 77 Brinell and a weight loss of 2.9 mg is most appropriate because the contents of solid solution phase and lead phase, and intermetallic compounds, are more and more comparable in dispersed distribution.
Keywords
Bearing, Bronze, Casting temperature, Overheating, Tin