Microstructure And Mechanical Properties Of Vacuum Manufacturing Hot-Rolled Titanium/Steel Clad Plate

Titanium has excellent corrosion resistance,making it the first choice of marine engineering corrosion resistant materials,but its expensive price limits its wide range of applications.The composite plate can greatly reduce the cost and the Ti/Steel composite plate not only has better corrosion resistant,but also has excellent mechanical properties.Vacuum hot rolling composite method has higher bonding strength and has many advantages of high production efficiency,little environmental pollution,but the core technology of vacuum manufacturing billet hot-rolled is in the hands of only a few countries such as Japan.Therefore,in order to link international market,it is necessary to research of the technology of vacuum hot roll-cladding of Ti/Steel corrosion resistant composite plate.The main work and the research results of this thesis are as follows:(1)TA2/Q345R cladding plates were produced by vacuum hot roll-cladding,effect of rolling reduction ratio,heat treatment after rolling and assembly vacuum degree on interface inclusions and the TiC layer in Ti/Steel cladding plates were studied and analyzed,interfacial cladding properties was also analyzed.Results show that the higher rolling reduction rate is,the more serious the interface inclusion is crushed,and the less effect on the bonding properties is.Proper holding time is beneficial to the formation of TiC layer of the composite interface,the longer the heat preservation time is,the more Intermetallic Compounds are formed in the composite interface,eventually leading the combination strength of the composite plate presents the tendency of going up firstly and going down secondly.Vacuum degree of the interface directly affects the quantity and size of cladding interface oxide and nitride,on the one hand,the existence of these compounds affects the continuity of TiC layer,on the other hand,they will be the source of crack during the rolling process and infact the mechanical properties of the interface.With the increase of the vacuum degree of the interface,the number and size of the impurities and oxides are decreased,and the combination property of the composite interface is improved.(2)The experience of composite TA2 and X65 pipeline steel was achived by the thermal simulation test machine.Results show that the thickness of intermetallic compounds(IMC)increases when the temperature rises.When the heating temperature below 850? the softening degree of titanium and steel is not enough,so the plastic deformation and high temperature creep can not be fully performed during the composite;when the temperature is 900?,the composite interface appears a lot of Fe-Ti brittle compounds.(3)TA2/X65 pipeline steel cladding plates were produced by vacuum hot roll cladding,impact of rolling reduction ratio and first pass reduction ratio on interface inclusions and the TiC layer in TA2/X65 steel cladding plates was researched.Results show that the higher the total compression rate is,the more closely the interface contact is,the more smooth the the diffusion of elements is and the the higher interface shear strength is.When the reduction ratio is more than 50%,the interface strength can meet ASTM standard requirements.With the first reduction rate increase,the number and the size of the interfacial strips or granular inclusions becomes small,and the interface generates more TiC,and TiC layer is more and more continuous.(4)In Nanjing Steel Group,TA2/Q235R steel cladding plates were produced by vacuum hot roll-cladding,through testing its mechanical properties systematic,the interfacial bonding strength and mechanical properties of the base material all meet the requirements of technical specifications,so the design of Ti/steel hot rolling composite technology is reasonable.