Experimental Study On Rolling Seamless Billet By Multi-layer Metal Strips

The seamless tube is one of the national pillar products,and the total demand of the seamless tube blanks is large.With the growth of the national economy,the number of seamless tubes used for import and export trade is huge.However,the import price of seamless tube blanks is several times higher than the export price.With the increasing demand for seamless tubes with excellent performance,the processing methods for seamless tube blanks with excellent performance are gradually being paid attention to by researchers.In the process of producting seamless tube blanks,there are problems such as complicated processing steps and difficulty in processing,especially in the process of producting small-diameter seamless tubes.In order to solve the problems in the process of producting seamless tube blanks,independently developing a processing technology for rolling seamless blanks using multi-layer metal strips.The method has the advantages of easy availability of raw materials,high precision of processed samples and low preparation cost,and has good application prospects especially in the preparation of composite pipes.In order to facilitate the smooth implementation of the rolling composite process,independently designing and developing a three-roll drawing device,and using the equipment to verify the feasibility of the processing technology for rolling seamless tube blanks using multi-layer metal strips.The main research contents are:(1)A processing technology for producting the seamless tube blanks using multi-layer metal strips is independently developed.The specific steps of the process include preparing the ultra-thin strips,rolling the ultra-thin strips onto the core rod,and then deforming the ultra-thin strips.After the core rod is withdrawn,the seamless billet obtained by the process is annealed to obtain the seamless tube blank with good composite condition.The seamless tube after annealing is subjected to a fixed mold drawing to obtain the target size.(2)In order to facilitate the smooth implementation of the rolling composite process,this paper introduces the three-roller drawing equipment independently.After designing and manufacturing the three-roller drawing equipment,in order to achieve stable operation of the equipment,the equipment is adjusted several times to ensure the smooth operation of the equipment.(3)The feasibility of the above process was verified by using pure aluminum strips of different thicknesses,and the optimal process was proposed.The composite interface of the processed seamless tubes is experimentally studied,and the metallographic observation,line scanning,hardness test and tensile test are carried out on the processed seamless tube blanks respectively,and the fracture morphology of the seamless tube blank after the fracture is observed,which is combined with the existing composite theory.