The Research Of Lightened Bar Of Steel Powder/steel Tube Fabricated By Hot Extrusion Process

About90%of the oil fields have adopted the way of sucker rod pumping in China, inwhich sucker rod is one of those main equipment. Working in wells thousands of meters deep,it causes greatly energy consuming and frequently accidents. Apparently, huge economicbenefits can be brought by making sucker rod less heavy without reducing its performance. Inthis article, porous composite bar shaping process using extrusion forming method under hightemperature after sintering are investigated and a new king of porous composite bar with steelshell are developed. Compared with solid bar, it is lighter and has higher tensile strength,having important theoretical and practical significance for further research and developmentof sucker rod.Based on sintering of metal powder and the theory of plastic forming extrusion,considering the present stage of porous metal materials production and research, shapingtechnology in character of hot punching directly after sintering used to manufacture porouscomposite bar are invented. A new porous composite bar center and shell made by porousmetal and shell and solid metal respectively are produced. Conclusions that porosity increasesfrom center to surface can be drowned by means of measuring and calculating its internalporosity. Its steady state deformation zone distributes uniformly on the longisection.Porous composite bar are trial-manufactured using steel powder, steel drop grain size of4mm,3mm and1.5mm or steel ball respectively. Experiment result shows that in terms ofporosity, steel ball made ones rank first with5%decrease.Treat shell thickness3mm,5mm and7mm as variables, the tensile testing result showsthat metallurgical bonding of the composite extrusion bar is obtained, and the tensile strength is higher than that of the solid bar with the same dimension. The tensile strength increaseswith the increase of the thickness of the shell, providing safety property for sucker rod.In one word, using composite blank made by large size steel ball and thick shell pipe andshaping process that directly hot punching after sintering, light and high tensile strengthporous composite bar, which has a wide usage and particularly in sucker rod can be produced.