Ratio of Fe-Al compound at interface of steel-backed Al-graphite semi-solid bonding plate

The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interfacial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interfacial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.     

Study on Bonding of Steel-mushy Al-7graphite

The bonding of steel-mushy Al-7graphite was studied. The relationship between interfacial shear strength of bonding plate and solid fraction of Al-7graphite mushy was obtained, and the interfacial structure of bonding plate was determined. The results showed that: under the condition of 500℃ for preheat temperature of steel plate and 10mm/s for rolling speed, the largest interfacial shear strength of bonding plate was 70.1 MPa when solid fraction of Al-7graphite mushy was 34.6%.     

The Influence of Preheat Temperature of Steel Plate on Steel-mushy Cu-graphite Bonding

The pressing bonding of steel plate to QTi3.5-3.5 graphite slurry was conducted. Under the conditions of 530 ℃ for the preheat temperature of dies, 45% for the solid fraction of QTi3.5- 3.5 graphite slurry, 50 MPa for the pressure and 2 min for the pressing time, the relationship between the preheat temperature of steel plate and interfacial mechanical property of bonding plate was studied. The results show that when the preheat temperature of steel plate is lower titan 618 ℃ , the interfacial shear strength of bonding plate increases with the increasing of the preheat temperature of steel plate. When the preheat temperature of steel plate is higher than 618 ℃ , the interfacial shear strength decreases with the increasing of the preheat temperature of steel plate. When the preheat temperature of steel plate is 618 ℃ , the highest interfacial shear strength of bonding plate of 127.8 MPa can be got.     

Interfacial mechanical property of steel-mushy Al-20Sn bonding

The bonding of a steel plate to Al-20Sn slurry was conducted using the casting rolling technique. The surface of the steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stored. Al-20Sn slurry was prepared using the electromagnetic mechanical stirring method. The interfacial mechanical property of the bonding plate was researched to determine the relationship between the diffusion time and the interfacial shear strength. In order to identify the mechanism of bonding, the interfacial structure of the bonding plate was studied. The results show that at a preheat temperature of the steel plate of 505℃ and a solid fraction of Al-20Sn slurry of 35%, the relationship between the interfacial shear strength S and the diffusion time t is S=28.8 4.3t-0.134t^2 0.0011t^3. When the diffusion time is 22 s, the largest interfacial shear strength is 70.3 MPa, and the corresponding interface is a new one which is made up of Fe-Al compound and Fe-Al solid solution alternatively and in a right proportion.In this interfacial structure, the interfacial embrittlement does not happen and Fe-Al compound can play its role in strong combination adequately.     

The Bonding Properties of Solid Steel to Liquid Aluminum

The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The relationship models of interfacial shear strength and thickness of interfacial layer of bonding plate vs bonding parameters ( such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time ) were respectively established by artificial neural networks perfectly. The bonding parameters for the largest interfacial shear strength were optimized with genetic algorithm successfully. They are 226℃ for preheating temperature of steel plate, 723℃ for temperature of aluminum liquid and 15.8s for bonding time, and the largest interfacial shear strength of bonding plate is 71.6MPa. Under these conditions, the corresponding reasonable thickness of interfacial layer (10.8μm) is gotten using the relationship model established by artificial neural networks.     

Thickness of compound layer in steel-aluminum solid to liquid bonding

The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The surface of solid steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. In order to determine the thickness of Fe-AI compound layer at the interface of steel-aluminum solid to liquid bonding under rapid solidification, the interface of bonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationship between bonding parameters (such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time) and thickness of Fe-AI compound layer at the interface was established by artificial neural networks (ANN) perfectly. The maximum of relative error between the output and the desired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacial shear strength of bonding plate (226℃for preheat temperature of steel plate, 723℃ for temperature of aluminum liquid and 15.8 s for bonding time), the reasona     

Influence of diffusion time on property of steel—aluminum solid to liquid bonding

The bonding of solid steel to liquid aluminum was conducted using rapid solidification.The influence of diffusion time on interfacial shear strength was studied.The results show that when the temperature of aluminum liquid is 700℃and the preheat temperature of steel plate is 250℃,the relationship between diffusion time(t) and interfacial shear strength(σ)is σ=15.1 8.14t-0.37t 0.005t^3,and the maximum interfacial shear strength is 71.1MPa.     

Immersing Treatment of Steel Plate Surface in Steel-Aluminum Solid to Liquid Bonding

The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and X-ray diffraction . The results showed that the layer of flux (the minimum thickness was 15 μm on the steel plate surface) could protect the steel plate surface from oxidizing effectively at high temperature in solid to liquid bonding. The melt temperatUre of the flux should be lower than 580 ℃ so that it could be melted and removed completely. No. 1 flux (patent product made by the author) made up of halogeindes could also force liquid aluminum to infiltrate into steel plate surface and thus the interfacial shear strength of the bonding plate was rather large.     

Experimental Study of Fluid Flow in Thin Slab Continuous Caster Mould with Water-Model

The interfacial status of the steel-alu-minum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and X-ray diffraction. The results showed that the layer of flux (the minimum thick-ness was 15 m on the steel plate surface) could protect the steel plate surface from oxidizing effectively at high temperature in solid to liquid bonding. The melt temperature of the flux should be lower than 580 ℃ so that it could be melted and removed completely. No.1 flux (patent product made by the author) made up of halogenides could also force liquid aluminum to infiltrate into steel plate surface and thus the interfacial shear strength of the bonding plate was rather large.     

Semi-solid slurry preparation and rolling of 1Cr18Ni9Ti stainless steel

The preparation and rolling of the semi-solid slurry 1Cr18Ni9Ti stainless steel were researched. The experimental results show that when stirred for 2-3 min under the given test condition, the semi-solid slurry with about 50%-60% (volume fraction) solid and the spherical primary austenitic grains in the size of 100-200μm can be obtained, and it is easy to be discharged from the bottom little hole of the stirring chamber. The semi-solid slurry of 1Cr18Ni9Ti stainless steel can be rolled into the given plate successfully. However, the solid phase and liquid phase are easily separated in the rolling process, so that the solid primary austenitic grains are concentrated in the center and the liquid phase is near the edge of the rolled plate. The strengths of the plate rolled in the semi-solid state are higher than that of the traditionally repeated hot-rolled plate of 1Cr18Ni9Ti stainless steel.     

Influence of aluminum solid fraction on property of steel-mushy aluminum bonding plate

The interfacial shear property of steel-mushy aluminum bonding plate was studied, and the relationship between aluminum solid fraction and the interfacial shear strength of bonding plate was determined. The results showed that when aluminum solid fraction is 34.3 %, the maximum interfacial shear strength of bonding plate is 71 .0 MPa.     

Effect of Interface on Mechanical Property of Steel-mushy Al-20Sn Bonding Plate

1 IntroductionSteel-Al-20Sn bonding plate is an ideal material ofneotype bearing[1-3].Almost one milliontons of this bond-ing plate are needed in machinery and automobile fieldannually[4-6].Forthis bonding plate ,theinterfacial struc-ture is very important .It determines the interfacial me-chanical property.Broadly,there are there kinds of inter-face for steel-Al-20Sn bonding plate .For solid steel plateto solid Al-20Sn bonding plate ,the interface is basicallymade upof Fe-Al solidsolution…     

Semi-solid Processing of Al-7Graghite Composite

Al-7graphite composite was processed using Al-7graphite mushy prepared by electromagnetic-mechanical stirring method, and the influence of solid fraction on the distributing of graphite particles in ingot was studied. The results shows that the relationship between solid fraction and stirring temperature of mushy is:fs=591.5-0.897 t(wherefs is the solid fraction, t is the stirring temperature). For Al-7graphite composite, with the increasing of solid fraction, the aggregation extent of graphite particles reduced gradually, and when solid fraction was larger than 30%, graphite particles could distribute evenly in ingot.