Papers by Keyword: Buttress Thread

Abstract: The force of each API standard buttress casing thread teeth under axial tension is uneven, so the bearing capacity of this kind of thread is seriously restricted. On the basis of structural characteristics, mechanical model of the casing thread under axial tension is established and the loading and deforming features of thread teeth are analyzed. Based on this, to improve force distribution of casing thread, the designing method of multi-segment variable pitch thread is put forward and NC machining method of variable pitch thread with equal tooth thickness is presented.

Abstract: This article is taking 5.5"special thread petroleum casing-pipe as example, using nonlinear technology of Ansys FEA software to analyze characteristics of threading up and unload of the petroleum casing-pipe. The result of FEA is conformed to the experiment. It provides strong help for the enterprises using research data to instruct practice further.

Abstract: At present, offshore drilling operations often use buttress thread casing as surface casing. The design conception of buttress thread casing comes from the offshore drilling’s demands and this kind of casing is mainly used as surface casing. This paper has taken material mechanical experiment, numerical simulation analysis and field test, the research results show that the various parameters of buttress thread casing fully complies with the drilling design requirements and the offshore oilfield production demands. This product can reduce drilling cost effectively, improve working efficiency and safety, and realize manufacture domestically. Meanwhile, the development of this project will fill the blank of the ERW (Electrical Resistance Weld) casing in CNOOC (China National Offshore Oil Corporation), and have a broad prospect of application.

Abstract: 13%Cr stainless steel has good comprehensive performance, which makes it suitable to work under the condition of high temperature, high pressure and corrosive environment, such as petroleum industry. It can be used as materials of petroleum pipes with buttress thread. Buttress thread turning is a heavy-load machining, which places high requirement on the cutting tool. Based on the cutting characteristics of buttress thread, the machinability of 13%Cr stainless steel is studied by turning experiments. Two kinds of inserts with different geometries were employed in buttress thread turning experiments. Experimental results show that less cutting force, longer tool life, better chip curling effect and surface quality was acquired for the insert with rake angle of 12° , clearance angle of 3° and chip-curling groove during 13%Cr stainless steel buttress thread turning process.

Abstract: Stainless 2Cr13 is used as petroleum pipe material for its good performance in condition of high temperature, high pressure and corrosive environment. Buttress thread turning is a type of heavy machining, which has a great influence on the residual stress of workpiece. Residual stress is usually determined by cutting parameters and tool geometries. Experiments with different geometrical tools were carried out and a finite element model was used to study the influence of tool geometries on the residual stress. Experimental and simulated results showed that relatively bigger rake angle and smaller corner radius make a relatively lower tensile residual stress of workpiece surface in dry turning buttress thread.