The Influence Of Heat Treatment On Structure And Properties Of The Composite Interface Of The Bimetal Tube Made By High Chromium Cast Iron And Steel

As industrial production capacity improves rapid,the requirements of the product are also more and more strict.Fluid transport pipeline was not exceptional pass away.in the past most of pipeline to the use of a single homogeneous while composite pipes can be seen everywhere nowadays.From shipping,marine,aerospace and other resource extraction to daily household supplies,such as tap water,heat pipe.The composite pipes are occupying the mainstream of the market step by step now,and a single homogeneous material of pipe is to be eliminated.The excellent properties of materials can be integrated to the composite pipes for meeting the requirements of increasingly stringent conditions,such reducing the cost of the production,improving the benefit of assets and taken the attention by manufacturers.Bimetal tubes usually can integrate the excellent properties of two kinds of material while not necessarily can give full play to the excellent properties of the material.However,a single homogeneous material can often improve the mechanical properties of materials to another level through heat treatment and other means.To the bimetal tubes,it is difficult to improve comprehensive mechanical properties of materials by means of heat treatment.On the one hand,the best heat treatment methods of the two kinds of materials used to compound the bimetal tubes are not necessarily the same,so it's really hard to choose what kind of heat treatments to use.On the other hand,the physical properties of the two materials(thermal expansion rate and the cooling shrinkage rate,etc.)often tend to be different,it will causes the different heating expansion and cooling contraction of the composite interface of two materials in the process of heat treatments,thus the stress concentration and crack initiation and propagation will be easily occurred near the interface and the interface bonding strength will be reduced greatly.This is not what we want to see.The study mainly in view of the two kinds of bimetal tubes compounded by high chromium cast iron and stainless steel,high chromium cast iron and carbon steel.In order to give full play to the wear-resisting performance of the high chromium cast iron,we have adopted several typical ways of heat treatment.To explore the impact on the interface bonding strength while using different heat treatment methods to improve the mechanical properties of high chromium cast iron,so as to find a suitableheat treatment made to improve the performance of high chromium cast iron while the bonding strength of bimetal tubes are not be affected too lot.Using sands-wearing experiment machine to make sand-wear experiments on high chromium cast iron of heat treatments,aims to explore heat treatment influence on the wear properties of high chromium cast iron;Using the macro hardness tester,micro hardness tester,universal testing machine to test macro hardness,micro hardness and interfacial shear strength of the interface,aims to explore the heat treatments influence on the bimetal tubes mechanical properties and bonding strength of interface,Using scanning electron microscope to scan the interface of bimetal tubes microstructure morphology and the shear fracture morphology analysis,to observe the effects of heat treatment on microstructure morphology and influence on the interfacial fracture mode near the interface.By using electron probe scan technology to test the alloy elements and quantitative scanning the area near the interface,designed to understand the influence of heat treatment on alloy elements diffusion near the interface.The result found that the heat treatments can greatly improving the wear properties of high chromium cast iron,the mechanical properties of the interface and the bonding strength.The heat treatments also have some effects on alloying elements diffusion near the interface.Compared with heat treatment on the mechanical behavior of interface organization and the comprehensive influence,quenching and high temperature tempering is more suitable for heat treatment on bimetal tubes because of having the best comprehensive mechanical properties of bimetal tubes,and the interface bonding strength maximum increase.