37Mn5 steel thermal refining process for high-steel-grade oil well pipe

Abstract

The invention discloses a 37Mn5 steel thermal refining process for a high-steel-grade oil well pipe. The 37Mn5 steel thermal refining process for the high-steel-grade oil well pipe comprises the following steps of: cleaning up the surface of an oil well pipe manufactured by 37Mn5 steel; quenching, namely, conveying the oil well pipe to a quenching furnace and heating the oil well pipe to 790+ / -10 DEG C, and performing water quenching on the whole workpiece at the water temperature of between 25 and 35 DEG C after taking out the workpiece from the quenching furnace, wherein the quenching hardness reaches over 45.5 Rockwell hardness (HRC); and tempering, conveying the quenched oil well pipe to a tempering furnace and heating the oil well pipe to 630+ / -10 DEG C, tempering the oil well pipe, taking out the oil well pipe and then performing air cooling. The oil well pipe manufactured by the 37Mn5 steel material is quenched at the temperature of 790+ / -10 DEG C and is tempered at the temperature of 630+ / -10 DEG C by the thermal refining process, so the APISpec 5CT standard requirement can be met, quenching distortion is obviously reduced, a quenching cracking phenomenon is basically avoided, mechanical properties of the quenched oil well pipe are very close to those of the oil well pipe subjected to the conventional thermal treatment process, the quenching temperature is reduced by 80 to 90 DEG C, and natural gas energy consumption required by heating and cost are greatly reduced.

Description

technical field [0001] The invention relates to the technical field of heat treatment technology of medium carbon steel, in particular to a quenching and tempering treatment technology of 37Mn5 steel for high-grade oil well pipes. Background technique [0002] Medium-carbon alloy steel is an alloy steel commonly used in oil well pipes. Taking the grade 37Mn5 as an example, the outer thickened oil well pipes with specifications of Φ88.9×6.45mm and N80-Q steel grade are manufactured. During the production process, in order to make them mechanically If the performance meets the steel grade performance requirements specified in the API Spec 5CT standard, necessary heat treatment is required for the oil well pipe. At present, the conventional quenching and tempering process is generally used for heat treatment. The quenching heating temperature is 880±10°C and the heat preservation time is 45min. , the overall water quenching, tempering at 640±10°C, the workpiece is air-cooled af...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is: to overcome the deficiencies in the prior art, to provide a 37Mn5 steel quenching and tempering process for high-grade oil well pipes, to solve the quenching cracks that exist when the existing conventional heat treatment process heat treats 37Mn5 steel The problem of high proportion and large energy waste

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