Papers by Keyword: Bimetal

Abstract: Interaction at the interface during the production of functional steel-aluminum compositions by arc processes has been investigated. Regularities and mechanisms of the diffusion zone formation have been proposed upon contact of a melt based on aluminum, alloyed with 11-13 wt% Si, with the steel substrate or Al-Fe system intermetallic compounds. It was found that the presence of Si in the composition of filler material leads to diffusion mobility of Al and Fe decreasing due to the replacement of Al, as well as the occupation of structural vacancies in double Fe_xAl_y intermetallics and ternary intermetallic phases with different stoichiometric composition Fe_xAl_ySi_z formation. It was determined that during the arc cladding process using as substrate the steel with intermediate zinc coating, a diffusion zone with an average thickness of 7 μm is formed, while in the presence of an intermediate coating from aluminum deposited by the “cold metal transfer” process, its average thickness is 18 μm.

Abstract: Contact surfaces preparation before cold cladding is one of the most important technological operations. A joint plastic components deformation of the of bimetal 1 according to OST 3-6648-91 and bimetal 3 according to OST 3-6649-91 CuZn10 brass - C22E steel - CuZn10 brass (according to EN standard) should be performed with the strongest possible compression to obtain the required layers connection strength, ensuring strip winding into a roll without delamination. We investigated influence of some factors on the bond strength of bimetal layers: surface hardening of contact surfaces, presence of an underlayer on a steel base, contact surfaces micro geometry, components heating temperature in the deformation zone, diffusion annealing after cladding and a bimetal layers thicknesses ratio effect. Cold cladding technological recommendations have been developed for manufacturing of bimetal 1 according to OST 3-6648-91 and bimetal 3 according to OST 3-6649-91 (CuZn10 brass - C22E steel - CuZn10 brass).

Abstract: Properties of cast iron on the bimetallic part depend on the initial structural state of the cladded cast iron and technological parameters of its induction cladding process. Methodology of predicting the properties of the cast iron in the bimetallic valve tappets ICE largest hardness billets was used for cladding, the silicon content in the alloy cladding and the technological parameters of the process, as well. A hereditary relationship between the initial state of the cast iron of the semi-finished product, used for induction cladding, and the structural state of the layer of weld on the steel base of the part, has been established.

Abstract: Combining copper alloy with steel back to make bearing bush can not only improve the strength of bearing bush, but also prolong the life of bearing bush, which is called bimetallic bearing. In this paper, the development status of copper alloy materials in bimetallic bearing bushes and the manufacturing principle and characteristics of copper alloy-steel bimetallic bearing bushes are summarized, and the defects of several manufacturing processes are analyzed. This paper summarizes the research on improving the performance of copper-steel bimetallic bearing bush. Finally, the development direction of the preparation process of copper alloy-steel bimetal is prospected.

Abstract: Fluxing and tinning processes are usually used to improve the adhesion of the Al bearing layer on steel substrate. Commonly after grinding the surface of the steel substrate, it is briefly immersed in flux solution followed by coating steel surface with either pure Sn (in a process known as tinning process) to promote adhesion between the bearing alloys and the steel. The current work is designated to investigate the influence of tinning material for carbon steel substrate using simultaneous fluxing and tinning mixture technique. The influence of three different tinning materials on the interface structure and shear strength of cast Al-Sn bearing alloy/steel bimetal composite is evaluated for compound casting technique. Sn pure, Sn-3Cu alloy and Sn-7.5Sb-3Cu powder alloys mixed individually with flux are used as tinning materials. It was found that using of different tinning materials have a significant effect on the bonding of interface area and the shear strength of interface as well. The shear strength of the bimetal fabricated using tinning mixture contains Sn+3% Cu with flux significantly increases by 59% compared to that fabricated using tinning mixture contains pure Sn. This increment is mainly due to the improvements of the interface bond structure and lower percentage of tin oxides. Such kind of phenomena can be explained in the fact that Cu minimizes the possibility of Sn oxidation during tinning process and during preheating of tinned steel substrate before casting of Al12Sn4Si1Cu bearing alloy as well.

Abstract: The processes of structure formation in the bimetal М1 + VТ1-0 after laser treatment from the side of copper are studied. The structure, phase and chemical composition of the interaction zone was investigated, the factors influencing the change in its hardness were determined.

Abstract: The paper presents a new technological scheme for obtaining bimetallic materials of the composition "aluminum casting alloy - sintered iron powder" by the method of joint stamping. The results of experimental studies of the effect of process conditions on the physicomechanical properties of the starting materials and the adhesive strength of the final bimetal blank are presented.

Abstract: Manufacturing of bimetallic brass-aluminum-brass strips is connected with a number of technological features. The features under consideration are cladding (welding) of the primary components, annealing of metal compositions and strain modes assignment. The purpose of the studies upon the development of bimetallic brass-aluminum-brass strips production technologies in SUSU is to analyze the modes, as well as to elaborate recommendations for the primary components thickness selection, strain modes assignment and annealing using bell-type furnace and strand-type furnace. The performed studies resulted in recommendations dealing with annealing cycles. The studies have also delivered the regression ratio between the thickness selection of primary components during the cladding operation, and the supreme total strain. A correct ratio prevents from the surface ruptures on the bimetallic brass-aluminum-brass strips surface while rolling.

Abstract: Joint plastic deformation of the components of bimetal 1 according to OST 3-6648-91 brass L90-steel 18JUA-brass L90 should be produced with the greatest possible compression to obtain the necessary strength of the joining of the layers, ensuring the strip looking into a roll without stratification. Preparation of contact surfaces before cold cladding is one of the most important technological operations. The influence of such factors on the strength of the bonding of bimetal layers as the surface hardening of contact surfaces, the microgeometry of contact surfaces, the temperature of diffusion annealing after cladding, the influence of the ratio of the thicknesses of bimetal layers was investigated. Technological recommendations for the production of bimetal 1 on OST 3-6648-91 brass L90-steel 18JUA-brass L90 by the method of cold cladding are developed.

Abstract: The present study is undertaken to investigate the influence of annealing and normalizing heat treatment on the bimetallic interface microstructures of 304 stainless steel and gray cast iron. The current work is aim to control the bimetal interface microstructures by different types of heat treatment processes to improve performance of the bimetallic castings performance. For low temperature annealing, specimens are heated to 760 0C for 60 min in an electrical heating furnace. For high temperature annealing and normalizing, specimens are heated to 920 0C for 120 and 240 min. A different interface structures are obained for all heat treated samples. Annealing and normalizing induce a significant effect on the diffusion of C and Cr elements and slightly effect on the diffusion of Ni element. Thickness of interface layer 1 (austenite + carbide) increases by increasingthe annealing temperature.