Microstructure And Properties Of Hot-rolled Stainless Steel Clad Steel Bars

Stainless steel rebar has excellent corrosion resistance and is suitable for marine construction and other highly corrosive environments.However,the high cost and poor mechanical properties make the application of stainless steel rebar limited.On this basis,stainless steel composite steel bar came into being.Composite steel bar not only has excellent corrosion resistance of stainless steel,but also has good mechanical properties of carbon steel.This solves the problem of poor cost and mechanical properties.The hot-rolled stainless steel composite steel can obtain composite steel with excellent bonding quality by controlling variables such as vacuum degree and cooling rate.This is mainly through the control of the type and number of interface inclusions to ensure the combined effect,through the cooling rate to ensure adequate element diffusion.The main research results of this paper are as follows:?1?When carbon steel is compounded by hot rolling,different oxidation reactions occur depending on the vacuum environment.At 1Pa,the elements with strong affinity for oxygen,such as Al in carbon steel,react with oxygen first,and selective oxidation occurs to generate Al₂O₃,which is less than 1?m.At atmospheric pressure,Si and Mn,which are abundant in carbon steel,easily form Fe-Si-Mn-based oxides with oxygen,the oxide can reach about 5?m;?2?When the stainless steel carbon steel is hot rolled and compounded,element diffusion occurs in addition to the oxidation reaction.Alloy elements such as Cr and Ni diffuse under the concentration gradient to form a stable transition layer.Among them,after the C element is diffused,C will form a ferrite band on the side of the carbon steel,and its thickness will decrease as the cooling rate increases.when cooling rate reach0.1?/S,the decarburization layer thickness up to 130?m;when cooling rate reach22?/S,bainite transformation occurs in this area without decarburization;?3?Under the effect of cooling rate and compression deformation,phase transformation occurs in the carbon steel side deformation zone.Close to the stainless steel part,austenite is formed due to the large diffusion flux of the alloy element and the basic element content of the stainless steel,the thickness of this area is about 4?m.In the area farther away from stainless steel,bainite is formed under the condition that the alloy element diffuses into the area with less content and the cooling rate is faster and the deformation amount is larger,that makes the area is above 0.33mm.Among them,a small amount of martensite is formed at a position with a high content of some alloy elements;...