Heat treatment method of weld seam of welding weighted drill pipe

Abstract

The invention relates to a heat treatment method of a weld seam of a welding weighted drill pipe. The method comprises the following steps: 1) heating the weld seam of the weighted drill pipe to 880-900 DEG C under 320V, keeping the temperature for 180+ / -20S, cooling in 9-12% quenching fluid of which temperature is 20-40 DEG C for 100S+ / -20S, discharging, sending the weighted drill pipe in a tempering furnace; 2) placing a heating coil in a place 30+ / -2mm away from the weld seam excentric shaft connection, heating to 705-715 DEG C under 220V, keeping the temperature for 540-990S, then aligning the heating coil with the weld seam, heating to 695-705 DEG C under 220V, keeping the temperature for 420-540 seconds, discharging to place in water for cooling; and 3) reducing the temperature to no more than 100 DEG C, wherein water cooling is performed when the temperature of the weld seam is not reduced to 650 DEG C. Two tempering treatments in different positions and with different temperatures are performed so as to ensure the hardnesses of the connection and the tube, reduce the brittlenesses of the connection and the tube and reach better tensile strength and yield strength.

Description

technical field [0001] The invention relates to a heat treatment method, in particular to a heat treatment method for welding seams of welded heavy drill pipes. Background technique [0002] The wall thickness of the weighted drill pipe is between the drill pipe and the drill collar, and its structure is similar to that of the drill pipe. It can withstand tensile loads and also allows compression loads. Connecting it between the drill pipe and the drill collar can prevent the sudden change of the section modulus of the drill string and reduce the fatigue damage of the drill pipe. It can replace a part of the drill collar, reduce the lifting load and increase the drilling depth capability of the drilling rig. It can replace most of the drill collars in directional wells, and can drill at high speeds with low torque, improving the ability to change the direction of the wellbore. Since the rigidity of the heavier drill pipe and the contact area with the borehole wall are sma...

AI Technical Summary

Problems solved by technology

[0003] In the API7-1 standard of the American Petroleum Institute, the mechanical properties of welded heavy drill pipes only include the tensile requirements, hardness requirements, and impact strength requirements of the weighted joints, and only the minimum tensile strength and minimum yield are required for the weighted pipe body. Strength and minimum elongation, and the requirements for the weld are only the strength of the weld (the cross-sectional area of ​​the weld multiplied by the minimum yield strength of the weld) and the strength of the part exceeding the pipe body (the minimum cross-sectional area of ​​the pipe Multiplied by the minimum yield strength of the pipe body), the hardness test requirement in the welded heat-affected zone is that the surface hardness is less than 37HRC. The existing welded heavy drill pipe does not require the bending test of the weld, and the bending test can be very Good detection of differences in material quality and surface strength of parts with surface treatment such as high-frequency induction heating and quenching, so the existing welded heavy-duty drill pipe has poor safety and reliability in use

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