阅读说明：本技术 一种钻杆焊区热处理工艺 (Heat treatment process for drill rod welding area ) 是由 舒志强 欧阳志英 余世杰 陈猛 罗小俊 姚挺 于 2021-08-19 设计创作，主要内容包括：本发明公开了一种钻杆焊区热处理工艺,钻杆焊区由材质26CrMo,强度等级105ksi的钻杆管体和材质37CrMnMo,强度等级130ksi的钻杆接头经惯性摩擦焊接形成,钻杆焊区热处理包括淬火步骤和回火步骤,对钻杆焊区进行淬火时,将淬火加热线圈的中心对准焊缝线偏钻杆管体侧3～8mm处；对钻杆焊区进行回火时,将回火加热线圈的中心对准焊缝线偏钻杆接头侧5～10mm处。本发明有利于降低焊缝线偏钻杆接头侧硬度,提高焊缝线偏钻杆管体侧硬度,使整个焊缝线区域硬度不均匀问题改善,拉伸强度和伸长率、冲击韧性更好,避免焊缝线区域成为整个焊区最薄弱的位置,同时,批量生产合格率高。(The invention discloses a drill rod welding area heat treatment process, wherein a drill rod welding area is formed by a drill rod pipe body made of 26CrMo with a strength grade of 105ksi and a drill rod joint made of 37CrMnMo with a strength grade of 130ksi through inertia friction welding, the drill rod welding area heat treatment comprises a quenching step and a tempering step, and when the drill rod welding area is quenched, the center of a quenching heating coil is aligned to a welding line and deviates 3-8 mm from the drill rod pipe body side; when the drill rod welding area is tempered, the center of the tempering heating coil is aligned to the position 5-10 mm away from the joint side of the welding line eccentric rod. The method is beneficial to reducing the hardness of the joint side of the welding line partial drill rod, improving the hardness of the tube body side of the welding line partial drill rod, improving the problem of uneven hardness of the whole welding line area, ensuring better tensile strength, elongation and impact toughness, avoiding the welding line area from becoming the weakest position of the whole welding area, and having high batch production qualification rate.)

1. The heat treatment process for the welding zone of the drill rod comprises the welding zone of the drill rod formed by welding a drill rod pipe body (1) and a drill rod joint (2) through inertia friction welding, wherein the heat treatment of the welding zone of the drill rod comprises quenching treatment and tempering treatment, and is characterized in that: when a drill rod welding area between the drill rod pipe body (1) and the drill rod joint (2) is quenched, the center of a quenching heating coil (5) is aligned to a position where a welding line (3) deviates 3-8 mm from the drill rod pipe body (1); when a drill rod welding area between the drill rod pipe body (1) and the drill rod joint (2) is tempered, the center of the tempering heating coil (6) is aligned to the position, 5-10 mm away from the drill rod joint (2), of a welding line (3).

2. The drill pipe weld heat treatment process according to claim 1, wherein: the quenching treatment process comprises the following steps:

firstly, conveying a drill rod welding area to a quenching heating coil (5), and aligning the center of the quenching heating coil (5) to a welding line (3) to be 3-8 mm away from the drill rod pipe body (1);

step two, increasing the temperature of a welding area to 830-900 ℃ by using 55-75 s, and preserving the heat for 95-115 s;

and step three, spraying a water-soluble PAG medium with the concentration of 12.5% externally and spraying compressed air internally for quenching and cooling.

3. The drill pipe weld heat treatment process according to claim 1, wherein: the tempering process specifically comprises:

firstly, conveying a drill rod welding area to a tempering heating coil (6), and aligning the center of the tempering heating coil (6) to the side of a welding line (3) deviated from a drill rod joint (2) by 5-10 mm;

step two, increasing the temperature of the welding area to 640-690 ℃ by using 55-75 s, and preserving the heat for 145-165 s;

and step three, cooling the air to room temperature.

4. A drill pipe weld heat treatment process as claimed in any one of claims 1 to 3, wherein: when a drill rod welding area between the drill rod pipe body (1) and the drill rod joint (2) is quenched, the center of a quenching heating coil (5) is aligned to the position of a welding line (3) which is 3mm away from the drill rod pipe body (1); raising the temperature of the welding area to 830 ℃ by 55s, and keeping the temperature for 95 s; the quenching cooling adopts the water-soluble PAG medium with the external spraying concentration of 12.5 percent and the compressed air is sprayed in; when a drill pipe welding area between the drill pipe body (1) and the drill pipe joint (2) is tempered, aligning the center of a tempering heating coil (6) to a position 5mm away from the drill pipe joint (2) side of a welding line (3); raising the temperature of the welding area to 640 ℃ by 55s, and preserving the temperature for 145 s; the air was cooled to room temperature.

Technical Field

The invention belongs to the technical field of petroleum drill rods, and particularly relates to a heat treatment process for a drill rod welding zone.

Background

The oil drill pipe consists of a drill pipe male joint, a drill pipe female joint and a drill pipe body, and the drill pipe body and the drill pipe female joint are different in chemical composition, steel grade, matrix structure performance state and the like of selected materials due to different wall thicknesses, so that the connection of the male joint and the female joint with the pipe body is particularly important.

At present, the most effective and reliable connection method of a drill pipe body and a drill pipe joint is inertia friction welding, each drill pipe is provided with two welding areas after welding, a weld line (fusion surface) of the drill pipe body and the drill pipe joint is the weakest position of the mechanical property of the whole drill pipe, the mechanical property and the metallographic structure of a weld area of the drill pipe are directly determined by the weld area heat treatment process, the hardness difference of the weld line area of the drill pipe is large due to the improper heat treatment process, the comprehensive mechanical property of the weld line area is reduced, and the weld area failure accident occurs in the application process.

Therefore, when the drill rod welding area is subjected to heat treatment, the content of main alloy elements of the material is different, the quenching property of the material is different, and the mechanical properties of the material are different.

According to experience, in the heat treatment process of the welding zone of the drill rod, the higher the quenching temperature is, the higher the hardness of the welding zone is, the higher the tempering temperature is, and the lower the strength and hardness of the welding zone is. In addition, for the 26CrMo drill pipe body and the 37CrMnMo drill pipe joint, in the actual heat treatment process, the tempering heating temperature required by the drill pipe joint is higher and the tempering heating temperature required by the drill pipe body is lower to achieve similar strength and hardness.

In the prior art, when a welded area of a drill rod formed by friction welding a 26CrMo drill rod pipe body and a 37CrMnMo drill rod joint is subjected to heat treatment, a quenching heating coil and a tempering heating coil are both aligned to a weld line, the relative hardness of the welded seam inclined drill rod pipe body side and the pipe body heat affected area is lower after the heat treatment, the hardness difference between the welded seam inclined joint area and the inclined drill rod pipe body area is very large, when the welded area is subjected to a tensile test, a fracture position may occur on the welded seam inclined drill rod pipe body side, namely the weld line area may become the weakest position of the whole welded area, which should be avoided in the design and manufacture of the drill rod.

Disclosure of Invention

Technical problem to be solved

The invention aims to provide a drill rod welding area heat treatment process aiming at the defects in the prior art, the problem of uneven hardness of the whole welding line area after a 26CrMo drill rod pipe body is welded with a 37CrMnMo drill rod joint is solved, the welding line area is prevented from becoming the weakest position of the whole welding area, the drill rod produced by the area heat treatment process disclosed by the invention is better in tensile strength, elongation and impact toughness, and meanwhile, the qualification rate of batch production can be improved.

(II) technical scheme

In order to achieve the purpose, the invention adopts the following technical scheme:

a heat treatment process for a drill rod welding area comprises the steps that a drill rod welding area is formed by welding a drill rod pipe body and a drill rod joint through inertia friction welding, the heat treatment for the drill rod welding area comprises quenching treatment and tempering treatment, and when the drill rod welding area between the drill rod pipe body and the drill rod joint is quenched, the center of a quenching heating coil is aligned to a welding line and deviates 3-8 mm from the drill rod pipe body side; when a drill rod welding area between a drill rod pipe body and a drill rod joint is tempered, the center of the tempering heating coil is aligned to the position 5-10 mm away from the joint side of the drill rod joint of the welding line.

Preferably, the quenching treatment process comprises:

step one, conveying a drill rod welding area to a quenching heating coil, and aligning the center of the quenching heating coil to a weld line to deviate from the drill rod pipe body side by 3-8 mm;

step two, increasing the temperature of a welding area to 830-900 ℃ by using 55-75 s, and preserving the heat for 95-115 s;

and step three, adopting a water-soluble PAG medium with the external spraying concentration of 12.5% for quenching and cooling, and internally spraying compressed air, wherein the external spraying time and the internal spraying time exceed 50 s.

Preferably, the tempering process specifically includes:

firstly, conveying a drill rod welding area to a tempering heating coil, and aligning the center of the tempering heating coil to the joint side of a welding seam eccentric drill rod by 5-10 mm;

step two, increasing the temperature of the welding area to 640-690 ℃ by using 55-75 s, and preserving the heat for 145-165 s;

and step three, cooling the air to room temperature.

Preferably, the material of the drill pipe body is 26CrMo, and the strength grade is 105 ksi; the drill rod joint is made of 37CrMnMo and has the strength grade of 130 ksi.

According to the invention, the main alloy elements of the drill pipe body comprise 0.24-0.30% of C, 0.250-0.35% of Si, 1.0-1.20% of Mn, 0.75-1.0% of Cr, 0.15-0.25% of Mo, less than or equal to 0.008% of P, less than or equal to 0.005% of S and the balance of Fe, the yield strength of the drill pipe body is not less than 724MPa, and the hardness is 24-30 HRC.

Preferably, the main alloy elements of the drill rod joint comprise 0.35-0.4% of C, 0.30-0.40% of Si, 0.80-1.0% of Mn, 0.9-1.2% of Cr, 0.28-0.33% of Mo, less than or equal to 0.008% of P, less than or equal to 0.005% of S and the balance of Fe, the yield strength of the drill rod joint is not less than 896MPa, and the hardness of the drill rod joint is 31-36 HRC.

It can be seen that the drill rod joint has high main alloy element proportion and drill rod pipe body, especially C content, that is, the hardenability and hardenability of the drill rod joint are superior to those of the drill rod pipe body, and under the same quenching process, the drill rod joint has sufficient microstructure change and higher hardenability. Further, the drill pipe joint may have a strength rating of 130ksi and the drill pipe body may have a strength rating of 105ksi, the former having a higher strength and hardness than the latter.

Tests prove that the invention most preferably adopts the drill rod welding area heat treatment process, and when the drill rod welding area between the drill rod pipe body and the drill rod joint is quenched, the center of the quenching heating coil is aligned to the position 3mm away from the drill rod pipe body side of the weld line; raising the temperature of the welding area to 830 ℃ by 55s, and keeping the temperature for 95 s; the quenching cooling adopts the water-soluble PAG medium with the external spraying concentration of 12.5 percent and the compressed air is sprayed in; when a drill rod welding area between the drill rod pipe body and the drill rod joint is tempered, aligning the center of a tempering heating coil to the position 5mm away from the drill rod joint side of a welding line; raising the temperature of the welding area to 640 ℃ by 55s, and preserving the temperature for 145 s; the air was cooled to room temperature.

(III) advantageous effects

Compared with the prior art, the invention provides a drill rod welding zone heat treatment process, which has the following beneficial effects:

(1) the invention provides a drill rod welding zone heat treatment process, wherein a drill rod pipe body is made of 26CrMo, the strength grade is 105ksi, a drill rod joint is made of 37CrMnMo, the strength grade is 130ksi, and when the welding zone is subjected to heat treatment after friction welding, the heating temperature is gradually reduced when the welding zone is farther away from the center of a heating coil in the quenching and heating process, the center of the quenching and heating coil is aligned to the side of the weld seam eccentric drill rod pipe body by 3-8 mm, so that the heating temperature of the weld seam eccentric drill rod pipe body side is higher than the position of the weld seam, the position of the weld seam is higher than the position of the weld seam eccentric drill rod joint side, the hardness of the weld seam eccentric drill rod pipe body side is ensured not to be very low, and the hardness of the weld seam and the weld seam eccentric drill rod joint side is not very high;

(2) in the tempering heating process, the center of the tempering heating coil is aligned to the weld line inclined drill rod pipe body side by 5-10 mm, so that the heating temperature of the weld line inclined drill rod joint side is higher than the position of the weld line, the temperature of the weld line position is higher than the position of the weld line inclined drill rod pipe body side, the higher the return temperature is, the lower the hardness is, the hardness of the weld line inclined drill rod pipe body side can be further ensured not to be very low, and the hardness of the weld line and the weld line inclined drill rod joint side can not be very high.

(3) The yield strength of the welding area of the drill rod obtained by the method is not less than 690MPa, the tensile strength is not less than 758MPa, and the hardness of the welding area is uniform and is not more than 37 HRC.

(4) Compared with the prior art, the method is beneficial to reducing the hardness of the joint side of the welding line partial drill rod and improving the hardness of the tube body side of the welding line partial drill rod, so that the problem of uneven hardness of the whole welding line area is solved, the tensile strength, the elongation and the impact toughness are better, the welding line area is prevented from becoming the weakest position of the whole welding area, and meanwhile, the yield of batch production is high.

Drawings

FIG. 1 is a schematic view of a drill pipe weld zone and quenching heating in the present invention.

FIG. 2 is a schematic view of the drill pipe weld zone and tempering heating of the present invention.

FIG. 3 is a schematic diagram of a drill pipe weld zone full wall thickness hardness test point in the invention.

In the figure: 1-drill pipe body, 2-drill pipe joint, 3-weld line, 4-inertia friction welding heat affected zone, 5-quenching heating coil, 6-tempering heating coil, 7-pipe body side heat affected zone, 8-joint side heat affected zone and 9-weld zone full wall thickness hardness test point.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A heat treatment process for a drill rod welding area comprises the drill rod welding area formed by welding a drill rod pipe body 1 and a drill rod joint 2 through inertia friction welding, wherein the heat treatment for the drill rod welding area comprises quenching treatment and tempering treatment, and when the drill rod welding area between the drill rod pipe body 1 and the drill rod joint 2 is quenched, the center of a quenching heating coil 5 is aligned to a welding line 3 and deviates from the side of the drill rod pipe body 1 by 3-8 mm; when a drill rod welding area between the drill rod pipe body 1 and the drill rod joint 2 is tempered, the center of the tempering heating coil 6 is aligned to a welding line 3 and is 5-10 mm away from the drill rod joint 2 side.

The quenching treatment process comprises the following steps:

firstly, conveying a drill rod welding area to a position of a quenching heating coil 5, and aligning the center of the quenching heating coil 5 to a weld line 3 to be 3-8 mm away from the side 1 of a drill rod pipe body;

step two, increasing the temperature of a welding area to 830-900 ℃ by using 55-75 s, and preserving the heat for 95-115 s;

and step three, spraying a water-soluble PAG medium with the concentration of 12.5% externally and spraying compressed air internally for quenching and cooling.

The tempering process specifically comprises the following steps:

firstly, conveying a drill rod welding area to a tempering heating coil 6, and aligning the center of the tempering heating coil 6 to a weld line 3 to be 5-10 mm away from the side of a drill rod joint 2;

step two, increasing the temperature of the welding area to 640-690 ℃ by using 55-75 s, and preserving the heat for 145-165 s;

and step three, cooling the air to room temperature.

Description of selected materials: the main alloy elements of the drill pipe body 1 made of 26CrMo and having the strength grade of 105ksi comprise 0.24-0.30% of C, 0.250-0.35% of Si, 1.0-1.20% of Mn, 0.75-1.0% of Cr0, 0.15-0.25% of Mo0, less than or equal to 0.008% of P, less than or equal to 0.005% of S and the balance of Fe, the yield strength of the pipe body is not less than 724MPa, and the hardness of the pipe body is 24-30 HRC;

the material 37CrMnMo, the drill pipe joint 2 with the strength grade of 130ksi, mainly comprises alloy elements of 0.35-0.4% of C, 0.30-0.40% of Si, 0.80-1.0% of Mn, 0.9-1.2% of Cr, 0.28-0.33% of Mo, less than or equal to 0.008% of P, less than or equal to 0.005% of S and the balance of Fe, the yield strength of the joint is not less than 896MPa, and the hardness is 31-36 HRC.

Example 1

A heat treatment process for a welding zone of a drill rod comprises the welding zone of the drill rod formed by welding a drill rod pipe body 1 and a drill rod joint 2 through inertia friction welding, wherein the heat treatment process for the welding zone of the drill rod comprises quenching treatment and tempering treatment, and when the welding zone of the drill rod between the drill rod pipe body 1 and the drill rod joint 2 is quenched, the heat treatment process for the welding zone is adopted:

step one, quenching heat treatment is carried out on a welding area of the drill rod, the welding area of the drill rod is sent to a position of a quenching heating coil 5, and the center of the quenching heating coil 5 is aligned to a weld line 3 and deviates 3mm from the pipe body side; raising the temperature of the welding area to 830 ℃ within 55s, and keeping the temperature for 95 s; immediately quenching and cooling the welding area after heating, adopting a water-soluble PAG medium with the concentration of 12.5% sprayed externally, wherein the temperature of the cooling medium is not more than 45 ℃, internally spraying compressed air, cooling for 70s, and cooling to 52 ℃ after the welding area is cooled;

secondly, tempering heat treatment is carried out on the welding area of the drill rod, the welding area of the drill rod is sent to a position of a tempering heating coil 6, and the center of the tempering heating coil 6 is aligned to the side of the weld joint 3, which is 5mm away from the joint; raising the temperature of the welding area to 640 ℃ in 55s, and preserving the temperature for 145 s; and after heating, air cooling to room temperature.

Example 2

A heat treatment process for a welding zone of a drill rod comprises the welding zone of the drill rod formed by welding a drill rod pipe body 1 and a drill rod joint 2 through inertia friction welding, wherein the heat treatment process for the welding zone of the drill rod comprises quenching treatment and tempering treatment, and when the welding zone of the drill rod between the drill rod pipe body 1 and the drill rod joint 2 is quenched, the heat treatment process for the welding zone is adopted:

step one, quenching heat treatment is carried out on a welding area of the drill rod, the welding area of the drill rod is sent to a position of a quenching heating coil 5, and the center of the quenching heating coil 5 is aligned to a weld seam line 3 and is 8mm away from the pipe body side; raising the temperature of the welding area to 900 ℃ in 75s, and keeping the temperature for 115 s; immediately quenching and cooling the welding area after heating, adopting a water-soluble PAG medium with the concentration of 12.5% sprayed externally, wherein the temperature of the cooling medium is not more than 45 ℃, internally spraying compressed air, cooling for 70s, and cooling to 48 ℃ after the welding area is cooled;

secondly, tempering heat treatment is carried out on the welding area of the drill rod, the welding area of the drill rod is sent to a position of a tempering heating coil 6, and the center of the tempering heating coil 6 is aligned to the joint side of the welding seam line 3 by 10 mm; increasing the temperature of the welding area to 690 ℃ in 75s, and keeping the temperature for 165 s; and after heating, air cooling to room temperature.

Example 3

A heat treatment process for a welding zone of a drill rod comprises the welding zone of the drill rod formed by welding a drill rod pipe body 1 and a drill rod joint 2 through inertia friction welding, wherein the heat treatment process for the welding zone of the drill rod comprises quenching treatment and tempering treatment, and when the welding zone of the drill rod between the drill rod pipe body 1 and the drill rod joint 2 is quenched, the heat treatment process for the welding zone is adopted:

step one, quenching heat treatment is carried out on a welding area of the drill rod, the welding area of the drill rod is sent to a position of a quenching heating coil 5, and the center of the quenching heating coil 5 is aligned to a weld line 3 and is 5mm away from the pipe body side; increasing the temperature of the welding area to 865 ℃ within 65s, and preserving the temperature for 105 s; immediately quenching and cooling the welding area after heating, adopting a water-soluble PAG medium with the concentration of 12.5 percent sprayed externally, wherein the temperature of the cooling medium is not more than 45 ℃, internally spraying compressed air, cooling for 70s, and cooling to 50 ℃ after the welding area is cooled;

secondly, tempering heat treatment is carried out on the welding area of the drill rod, the welding area of the drill rod is sent to a position of a tempering heating coil 6, and the center of the tempering heating coil 6 is aligned to the side, 7mm away from the joint, of the welding seam line 3; increasing the temperature of the welding area to 670 ℃ within 65s, and preserving the heat for 155 s; and after heating, air cooling to room temperature.

Example 4 (control group)

In the comparative example, the heat treatment process for the welding zone of the drill rod comprises the welding zone of the drill rod formed by welding the drill rod pipe body 1 and the drill rod joint 2 through inertia friction welding, wherein the heat treatment process for the welding zone of the drill rod comprises quenching treatment and tempering treatment, and when the welding zone of the drill rod between the drill rod pipe body 1 and the drill rod joint 2 is quenched, the heat treatment process for the welding zone is carried out by adopting a conventional process, and specifically comprises the following steps:

step one, quenching heat treatment is carried out on a welding area of the drill rod, the welding area of the drill rod is sent to a position of a quenching heating coil 5, and the center of the quenching heating coil 5 is aligned to a welding line 3; increasing the temperature of the welding area to 860 ℃ within 65s, and preserving the temperature for 105 s; immediately quenching and cooling the welding area after heating, adopting a water-soluble PAG medium with the concentration of 12.5 percent sprayed externally, wherein the temperature of the cooling medium is not more than 45 ℃, internally spraying compressed air, cooling for 70s, and cooling to 50 ℃ after the welding area is cooled;

secondly, tempering heat treatment is carried out on the welding area of the drill rod, the welding area of the drill rod is sent to a position of a tempering heating coil 6, and the center of the tempering heating coil 6 is aligned to the welding seam line 3; increasing the temperature of the welding area to 670 ℃ within 65s, and preserving the heat for 155 s; and after heating, air cooling to room temperature.

Mechanical property tests are carried out on the drill rod welding zone samples after heat treatment is carried out on the drill rod welding zones in the process examples 1, 2 and 3 and the example 4 (comparison group), the test results are shown in the tables 1 and 2, and the data of the measurement data of the side heat affected zone of the pipe body in the table 2 are acquired at 3 optional positions.

TABLE 1 weld zone mechanical test Performance results

TABLE 2 weld Total section Hardness (HRC)

It can be seen from the comparison that when the process (examples 1, 2 and 3) of the invention is used for heat treatment of the welded area of the drill rod, compared with the conventional process (example 4), the tensile strength of the welded area is not reduced, the plastic elongation and the impact toughness are obviously improved, the hardness of the welded line 3 is improved on the side of the drill rod pipe body 1 after the new process is adopted, the hardness of the welded line 3 and the side of the drill rod joint 2 is reduced, the problem of large difference of the hardness on the two sides of the welded line 3 is obviously improved, meanwhile, the hardness value of the heat affected zone 8 on the side of the joint is not obviously changed, the heat affected zone 7 on the side of the pipe body is still the weakest position of the whole welded area, but compared with the conventional process, the hardness value of the zone is improved. Compared with the prior art, the method is beneficial to reducing the hardness of the weld line 3 on the side of the drill rod joint 2 and improving the hardness of the weld line 3 on the side of the drill rod pipe body 1, so that the problem of uneven hardness of the whole weld line area is solved, the tensile strength, the elongation and the impact toughness are better, the weld line area is prevented from becoming the weakest position of the whole welding area, and meanwhile, the mass production yield is high.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.