Development Of J55Hot Rolled Wide Strip For Oil Casing Pipe

In recent years, with the improvement of our living standard, the demand for petroleum and gas is increasing. By2012, China’s annual petroleum output had reached205million tons and annual natural gas output had run up to106.76billion cubic meters. At present, China is still in a critical period of rapid development of urbanization and industrialization and over the next few years the average annual growth rate of our oil and gas demand is expected to be about4%. The increasing production stimulates the demand of oil well pipe market so that by2015it is expected to be6million tons, of which oil casing tube demand is about4.2million tons.The development of smelting technology, micro alloying technology, control rolling technology and control cooling technology worldwide help develop the hot rolled steel strip with excellent comprehensive performance successfully. In the1970s, ERW oil casing tube manufactured by hot rolled strip took the place of traditional seamless steel pipe at abroad. Because of the advantages of high quality, low price, material saving and environmental protection, ERW oil casing tube is gradually replacing some of the market of seamless oil casing pipe. In the oil casing tube market in developed countries,50%of oil casing tube is J55grade oil casing tube and more than60%of total oil casing tube is ERW oil casing tube. But the ERW oil casing tube is only about10%in domestic. According to the level of developed countries, China’s ERW oil casing tube demand will reach more than2.5million tons by2015. Therefore, there is a huge potential to apply hot rolled wide strip to the ERW oil casing tube.In order to cope with the downturn market situation and seek new point of efficiency, in November of2012, Tonghua Steel Corporation successfully reached a cooperation with Huludao Steel Tube Co. Ltd. and Shenzhoutong Tianjin Steel Pipe Co., and considered that ERW oil casing tube steel J55has higher profit space than high strength steel with low alloy Q345B. In the current market, considering the ERW oil casing tube’s good market situation, relying on the technology advantages of FTSR compact strip production line, to develop oil casing tube steel J55has great significance to Tonghua Steel Coporation in promoting product’s additional value and adjusting product structure.This paper is based on the research of micro alloying technology, compact strip production and controlled rolling and cooling of niobium microalloyed steel’s compact strip production. The effect and harm of the alloying elements on J55oil casing steel was analysed and the chemical composition of J55was designed by referring to the J55products chemical composition of the similar steelmaking enterprises. The designed composition was optimized by calculating the mechanical properties with empirical formula and theory. According to the designed components,we made the general technical scheme and determined the key point in smelting,continuous casting and rolling. Then we made the scheme to be specific and took the industrial production practice and tracked the production situation of users. The problems during the production and using were analysed particularly and the optimization schemes were raised. Tonghua Steel developed the petroleum casing J55wide strip sucessfully. In2013, the output of petroleum casing pipe steel J55is more than200hundred tons and product qualification rate has reached98.5%that has brought good economic benefit to Tonghua Steel.