The .26 Crmonbtib Steel Drill Pipe To Develop,

Drill pipe is one of the absolutely necessary instruments in exploitation of oil & natual gas. Dill pipes are classified into several steel grades as E75, X95, G105, and S135 according to API Spec 5D. API Standard also specified that Drill pipes of X95 and its above grade need to be quenched & tempered (Q+T) or normalized & tempered (N+T). Nowadays only few factories have capability of producing drill pipes with steel grade higher than G, and the remaining depends on import. There exists great market development potential.This article systemically introduced the market demand and properties requirements of the high steel grade drill pipes, analyzed the chemical compositions and properties of the drill pipes both in domestic and abroad, and compared their advantages and dis-advantages. Based on the today's development status of water-quenching process both in domestic and abroad, and considering the production conditions of Hengyang Valin Steel Tube Co., Ltd, a new low carbon steel named 26CrMoNbTiB is designed and applied. This article analyzed the functions of separate elements in the steel, specified process requirements in different stage as metallurgy, pipe rolling, and end upsetting. Through the experiences of industrial production, it demonstrate that quality of metallurgy, five-harm elements, and rolling quality can meet the expected requirements.Based on the heat-treatment characteristics of water-quenching steel, heat-treatment process parameters for 26CrMoNbTiB is carfully studied herein in this article. This include: the baice rules of how the tempering temperature and its time, Quenching tempetature and its time affect pipe's properties and its micro-structure, and finally worked out the system of heat-treatment process.i.e. For G105, Quenching tempetature is 900℃(30 min), tempering temperature is 650℃(40 min); For S135, Quenching tempetature is 900℃(30 min), tempering temperature is 590℃(40 min)The research result demonstrate that every machenical properties of 26CrMoNbTiB can be completely in accordance with API standard and it can be used to produce drill pipe of G105 and S135.