A wear-resistant surfacing flux-cored welding wire for fine-diameter oil drilling tools

Abstract

The invention provides a hardfacing flux-cored wire of a fine-diameter petroleum drilling tool. According to the flux-cored wire, a low-carbon steel H08A cold-rolled thin steel strip is adopted as theouter wrapper, high carbon ferro-chrome, ferrovanadium, ferromolybdenum, ferrotitanium, ferrosilicon, mid-carbon ferromanganese, super fine aluminum powder and atomized reduced iron powder are arranged in the wrapper to form a core, and a cellular structure composed of needle-type martensite and compound ferrovanadium carbide (Ti, V) C reinforced phase which is in in-situ dispersive precipitationfrom the martensite and a surfacing alloy of the organization structure of austenite in along-crystal distribution are formed. The hardfacing flux-cored wire has the advantages that the surfacing alloy toughness is greatly improved, and the wire can be applied to wear-resisting ring welding line strip surfacing manufacturing or repairing of the petroleum drilling tool, and also can be used for surface wear layer repair manufacturing of cold work die steel

Description

technical field [0001] The invention relates to the field of oil drilling tools, in particular to a wear-resistant surfacing flux-cored welding wire for oil drilling tools with a thin diameter. Background technique [0002] During oil exploration and development, especially during drilling operations, the wear and tear of drill strings and casings has always affected oilfield production and development. First of all, the wear of the drilling tool will lead to the decrease of its service life, and even the failure of the drilling tool, which will cause economic losses and waste of resources; Wear-through damage affects the quality and safety of subsequent drilling, well completion and mining operations, and also causes economic losses and waste of resources. [0003] At present, at home and abroad, most of the drill tools, especially the commonly used drill pipes, are surfacing with wear-resistant bands to reduce the wear of drill tools and casings. At present, there are tw...

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Problems solved by technology

At present, there are two types of wear-resistant belts commonly used on drill pipes: one is surfacing welding tungsten carbide wear-resistant belts, which are characterized by high hardness and good wear resistance, but poor friction reduction and serious wear to casings , high brittleness, poor weldability, many cracks, easy to drop blocks, which directly affects the rock-breaking efficiency of the drill bit; the second is the flux-cored welding wire surfacing wear-resistant belt, which is characterized by good friction reduction and moderate wear resistance. It not only protects the drill pipe, but also protects the casing, but the performance of this type of flux-cored welding wire produced in China is not ideal, mainly due to the low toughness of the surfacing alloy, and it is often found at the beginning and end of the wear-resistant surfacing welding girth weld zone. Cracks are generated at the lap joints, which are easy to expand and affect the strength of the drill pipe, which in turn seriously affects the operation progress and production efficiency of oil drilling tools

[0004] The reason is that the carbon content of the selected wear-resistant flux-cored wire is relatively high, and the carbon atoms are easily diffused to the grain boundary and other places where the atomic arrangement is relatively loose to form carbides distributed along the crystal network, which leads to the toughness of the alloy. The sharp drop makes it easy to initiate cracks at the lap joints of the surfacing strips

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