Heat treatment process of welded type weighted drill rod joint

Abstract

The invention discloses a heat treatment process of a welded type weighted drill rod joint. The heat treatment process comprises the following steps of: sequentially placing workpieces into a box type quenching furnace, vertically placing in a large-space mode, heating the furnace to 860 to 890 DEG C, preserving heat for at least 60 minutes, and stirring quenching oil before discharging the workpieces out of the furnace, wherein the oil temperature is controlled to be 80+ / -1 DEG C; taking the workpieces out of the furnace, throwing the workpieces into the quenching oil at once, quenching, and cooling the workpieces in the quenching oil for at least 10 minutes; performing tempering treatment on the workpieces within 3.5 hours after the workpieces are quenched, heating a tempering furnace to 600 to 630 DEG C, preserving heat for at least 120 minutes, taking the workpieces out of the tempering furnace, throwing the workpieces into a water channel at once, and cooling to normal temperature. By adopting the heat treatment process, the quenching quality is improved mainly by taking a series of technology measures of reducing the quenching upper limit temperature, increasing the heat-preserving time and the like, so that the cracking phenomenon is avoided.

Description

technical field [0001] The invention relates to a metal heat treatment process, in particular to a heat treatment process for a welded heavy drill pipe joint made of AISI4145 material. Background technique [0002] Welded heavy-duty drill pipe joint is a thick-walled pipe with inner and outer pipe threaded joints at both ends. After connecting with the drill pipe, it forms a direct connection structure between the upper and lower joints. The working conditions of the drill pipe joint during drilling are very complicated. It not only plays the role of connecting the upper and lower joints, but also directly transmits the torque and bears the impact force. Therefore, the drill pipe joint must have sufficient strength and good toughness. The industry generally uses AISI4145 steel to manufacture welded heavy drill pipe joints. AISI4145 steel is a high-quality high-strength alloy steel, and its mechanical properties can be greatly improved after quenching. However, this material...

AI Technical Summary

Problems solved by technology

[0003] The present invention mainly aims at the problem that AISI4145 material is easily cracked by applying conventional heat treatment process, and proposes a heat treatment process of welded heavy drill pipe joint with reasonable process parameters, standardization and easy operation. The process mainly reduces the quenching upper limit temperature and increases the holding time and Select the appropriate cooling medium, control the cooling rate and a series of technical measures to achieve the purpose of improving the quality of quenching

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