CN117181839A - Titanium alloy pipe for petroleum drill pipe and processing method thereof - Google Patents

Abstract

The invention discloses a processing method of a titanium alloy pipe for a petroleum drill rod, which comprises the following steps: heating the ingot blank to 20-30 ℃ below the material phase transition point, preserving heat for 1-2h, and extruding to obtain a titanium alloy tube blank; performing inner and outer surface treatment on the tube blank; preheating a pass of a rolling mill for rolling a pipe blank and a core rod by adopting acetylene flame gun blank rolling, wherein the preheating temperature is 450-500 ℃; preheating a rolled tube blank at a position of 1000mm and heating the rolled tube blank at a position of 300mm at a feeding end, and ensuring that the rolling temperature of the final tube blank is controlled to be 400-700 ℃ and the rolling deformation is controlled to be 40-45%; oil removal, acid washing and high-temperature vacuum annealing treatment are carried out on the rolled tube blank; and (3) pickling and checking the tube blank to obtain the titanium alloy tube for the petroleum drill rod with the grade of 120ksi and above. The processing method of the titanium alloy pipe for the petroleum drill rod solves the problems of large section structure property difference and uneven radial property caused by insufficient radial deformation in cold rolling processing of thick-wall large-specification titanium alloy pipes.

Description

Titanium alloy pipe for petroleum drill pipe and processing method thereof

Technical Field

The invention relates to the technical field of new material processing, in particular to a titanium alloy pipe for a petroleum drill pipe and a processing method thereof.

Background

Currently, in the development of titanium alloy pipes for petroleum drill pipes, the initially established process comprises the steps of oblique rolling perforation blank making, multi-pass cold rolling, oblique rolling perforation in a steel mill, hot continuous rolling and radial forging. The piercing temperature is above the transformation point of the titanium alloy when the piercing blank is made by the oblique rolling piercing and the multipass cold rolling process, so that microscopic grains are coarse, the titanium alloy is difficult to cold-roll deformation, and the requirement on the capability of rolling equipment is high. The titanium alloy pipe for the petroleum drill pipe has the characteristics of high strength and wall thickness, and the small deformation multi-pass cold rolling method is adopted to produce the titanium alloy pipe which is easy to form uneven radial structure performance, and the pipe is continuously twisted to fail and break in the petroleum drilling process. The method is suitable for production of single-specification metal pipes with stable process and low requirements by adopting a steel mill inclined rolling perforation and hot continuous rolling mode, and aims at production of high-strength titanium alloy pipes for petroleum drill pipes, pipe blank defects caused by inclined rolling perforation cannot be removed in time in hot continuous rolling, the quality of the whole pipe is low, the temperature during hot continuous rolling is too high, the final regulation and control of the tissue performance is difficult, the oxidation of the inner surface and the outer surface of the produced titanium alloy pipe is serious, special equipment is required for inner surface treatment and outer surface treatment, the uniformity of the wall thickness cannot be guaranteed, the investment of the whole equipment is high, the efficiency is low, and the comprehensive cost is high. Radial forging has limited production length at present, and can only produce shorter samples in the face of high heating temperature like hot continuous rolling, difficult regulation and control of tissue performance, defect removal of the inner surface and the outer surface of a finished pipe and uneven wall thickness.

In view of the above, it is necessary to provide a new process for solving the above technical problems.

Disclosure of Invention

The invention aims to solve the technical problems of large difference in section tissue performance and uneven radial performance caused by insufficient radial deformation in cold rolling processing of thick-wall large-specification titanium alloy pipes by combining a hot rolling process and a vacuum heat treatment process at a time of temperature extrusion lower than a phase transition point, and simultaneously, the hot rolling process with large deformation obviously improves the quality and comprehensive performance of the inner surface and the outer surface of the pipes, the rolled titanium alloy pipes are uniform in tissue, good in impact toughness, high in nondestructive inspection level and excellent in surface quality, and the prepared petroleum drill pipes meet the index requirements of the high-strength high-toughness thick-wall large-specification titanium alloy pipes.

The technical scheme of the invention is as follows:

a processing method of a titanium alloy pipe for a petroleum drill rod comprises the following steps:

step S1, heating an ingot blank to 20-30 ℃ below the phase transition point of the material, preserving heat for 1-2 hours, and extruding by using a horizontal extruder to obtain a titanium alloy tube blank;

step S2, performing internal and external surface treatment on the tube blank prepared in the step S1;

s3, preheating a pass of a rolling mill for rolling a pipe blank and a core rod by adopting an acetylene flame gun blank, wherein the preheating temperature is 450-500 ℃;

specifically, the preheating temperature may be 450 ℃, 480 ℃ or 500 ℃, or may be other temperature values within the range.

Step S4, loading the tube blank to be rolled in the step S2 on the preheated rolling mill in the step S3 for rolling deformation, preheating the rolled tube blank at a position of 1000mm at a feeding end and heating the rolled tube blank at a position of 300mm, ensuring that the rolling temperature of the final tube blank is controlled between 400 and 700 ℃, controlling the rolling deformation to be 40 to 45 percent, and carrying out surface lubrication and roller temperature control on a hole pattern and spraying a molybdenum disulfide water agent on the surface of the tube blank during rolling; the rolling temperature may be 400 ℃, 500 ℃ or 700 ℃, or other values within the range;

step S5, oil removal, acid washing and high-temperature vacuum annealing treatment are carried out on the tube blank rolled in the step S4;

and S6, pickling and inspecting the pipe blank to obtain the titanium alloy pipe for the petroleum drill pipe with the grade of 120ksi and above.

Further, in the step S4, the rolling feed amount is less than or equal to 5 mm/time.

Preferably, in step S4, the rolling temperature is controlled to 500-550 ℃, such as 500 ℃, 510 ℃, 520 ℃, 530 ℃, 540 ℃ or 550 ℃, or other temperature values within the range.

Further, in step S4, the preheating temperature for preheating the rolled tube blank at 1000mm of the feed end is 300-500 ℃, for example, 300 ℃, 350 ℃, 400 ℃, 450 ℃ or 500 ℃, or other values within the range; the heating temperature for heating the rolled tube blank at 300mm of the feed end is 500-700 ℃, such as 500 ℃, 550 ℃, 600 ℃, 650 ℃ or 700 ℃, or other values within the range. The preheating temperature of the rolled tube blank at the position of 1000mm and the heating temperature of the rolled tube blank at the position of 300mm at the feeding end are set so as to control the final rolling temperature of the tube blank.

Further, in step S5, the high-temperature vacuum annealing temperature is 700-950 ℃, for example, 700 ℃, 750 ℃, 800 ℃, 820 ℃, 850 ℃, 900 ℃ or 950 ℃, or other temperature values within the range are also possible.

Further, in step S2, the inner and outer surface treatment of the pipe blank includes:

firstly, mechanically repairing the inner surface and the outer surface of a pipe blank, and removing the defect of extruding the pipe blank on the inner surface and the outer surface;

then, the inner surface and the outer surface of the pipe blank are subjected to pickling inspection;

then brushing graphite emulsion on the inner and outer surfaces, and naturally airing.

The invention also provides a titanium alloy pipe for the petroleum drill pipe, which is processed by the method.

Compared with the prior art, the titanium alloy pipe for the petroleum drill pipe and the processing method thereof have the beneficial effects that:

1. the invention provides a processing method of a titanium alloy pipe for a petroleum drill rod, which adopts a process of extrusion at a temperature lower than a phase transition point, hot rolling for one time and vacuum annealing, wherein the extrusion temperature is controlled to be 20-30 ℃ below the phase transition point, the extruded pipe blank deformation structure is a typical equiaxed structure, and an equiaxed alpha phase is distributed on a transition beta substrate. In the prior art, the extruded tube blank microstructure is a lamellar structure after being heated to above the phase transition point, and is characterized in that original beta grains are broken, and lamellar alpha phases are distributed in the beta grains in a staggered manner to form the lamellar structure. The equiaxed tissue material has lower strength and good plasticity compared with lamellar tissue, is beneficial to plastic deformation of the material and is beneficial to improving the dimensional accuracy, the surface quality control and the tissue uniformity of the pipe. In the hot rolling process, firstly, a rolling mill pass and a core rod are preheated, then the 1000mm position and the 300mm position of the feeding end of a pipe blank are preheated (the preheating and heating positions are in front of a rolling deformation zone), and as the heat conductivity coefficient lambda=15.24W (mK) of a titanium alloy material is about 1/4 of that of nickel, about 1/5 of that of iron and about 1/14 of that of aluminum, the heat conductivity is poor, if direct high-temperature heating is adopted, the heating temperature in the wall thickness direction of a pipe blank is uneven, the internal stress of the material is easily caused to be overlarge, the deformation is uneven during rolling, the internal cracks of the pipe are easily caused, and the like; the method of one-pass hot rolling with large deformation is adopted, the capability of the existing rolling equipment and the metal deformation capability are utilized to the maximum extent, the problems of large difference of section tissue performance and uneven radial performance caused by insufficient radial deformation in cold rolling processing of thick-wall large-specification titanium alloy pipes are thoroughly solved, meanwhile, the quality and comprehensive performance of the inner surface and the outer surface of the pipes are remarkably improved by hot rolling with large deformation, the rolled titanium alloy pipes are uniform in tissue, good in impact toughness, high in nondestructive inspection level and excellent in surface quality. The vacuum annealing is carried out after rolling, so that the surface oxidation of the material can be prevented, the phenomenon that the material is subjected to brittle fracture due to microcrack is prevented, and the performance of the pipe is improved. Therefore, the processing technology of the invention achieves the aim of improving the material performance by preparing a two-phase region (alpha+beta) tissue blank, rolling and refining tissues, and adjusting the tissue morphology and the quantity of the two phases through vacuum heat treatment, thereby obtaining the high-strength high-toughness large-wall-thickness titanium alloy pipe.

2. According to the processing method of the titanium alloy pipe for the petroleum drill rod, provided by the invention, the rolling temperature is below the titanium alloy transformation point, the structure performance of the produced titanium alloy pipe is convenient to regulate and control, the inner surface and the outer surface are lubricated and protected by graphite emulsion during hot rolling, the oxidation phenomenon during hot continuous rolling is avoided, the quality of the inner surface and the outer surface is good, the deformation capacity of the heated titanium alloy is utilized to the maximum extent, the pass deformation is large, the radial deformation is more sufficient, and the uniformity of the radial performance is good. The processing method can realize the production of the high-strength high-toughness large-specification thick-wall titanium alloy pipe for the petroleum drill pipe with the yield strength of more than 827 MPa.

3. The processing method of the titanium alloy pipe for the petroleum drill pipe provided by the invention has the advantages of simple production process, fewer rolling passes, high production efficiency and low comprehensive cost, and is suitable for large-scale industrialized popularization.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a photograph showing the longitudinal and transverse microstructure of a titanium alloy pipe of example 1 and example 2 after heat treatment;

FIG. 2 is a schematic diagram of the dimension test points of the titanium alloy pipes of example 1 and example 2.

Detailed Description

In order to better understand the technical solution in the embodiments of the present invention and make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the present invention will be further described.

The description of these embodiments is provided to assist understanding of the present invention, but is not intended to limit the present invention. In addition, technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Example 1

Petroleum drill pipeThe processing method of the titanium alloy pipe comprises the following steps:

step S1, heating the extruded ingot blank to 950 ℃ by using a 6300 ton horizontal extruder, and extrudingThe brand is TC4 titanium alloy tube blank;

step S2, after pickling the inner and outer surfaces of the titanium alloy tube blank prepared in the step S1, machining and repairing the extrusion defect on the inner and outer surfaces, brushing a graphite emulsion coating on the inner and outer surfaces after strong acid washing and coating, and airing and rolling;

s3, preheating the rolling hole pattern and the core rod to 400-450 ℃ by acetylene flame;

step S4, loading the tube blank to be rolled in the step S2 on the preheated rolling mill in the step S3 for rolling deformation, preheating and heating the tube blank at 1000mm and 300mm positions of a rolling feeding end by adopting a special heating system, controlling the temperature to be 500-550 ℃ when the final tube blank is rolled, controlling the rolling deformation to be 40-45% and the rolling feeding amount to be less than or equal to 5 mm/time by adjusting the flow rate of a torch gun in a preheating zone and the feeding speed of the tube blank, and carrying out surface lubrication and roller temperature control on a hole pattern and the surface of the tube blank by spraying molybdenum disulfide water agent in rolling to ensure good rolling lubrication and avoid surface adhesion caused by hole pattern overheating;

step S5, carrying out oil removal and acid washing treatment on the titanium alloy pipe prepared in the step S4, and carrying out annealing treatment;

step S6, carrying out vacuum heat treatment on the titanium alloy pipe prepared in the step S5 for 1.5 hours at the temperature of 820 ℃, and carrying out three-point compressive stress temperature straightening on a local bending area after annealing is finished;

step S7, performing longitudinal and transverse wave flaw detection on the titanium alloy pipe obtained in the step S6 by adopting a water immersion ultrasonic flaw detection method, and performing size surface and performance inspection on the qualified pipe after pickling to obtain the steel pipe for the petroleum drill pipeTitanium alloy hot rolled pipe.

Example 2

Petroleum drill pipeThe processing method of the titanium alloy pipe comprises the following steps:

step S1, heating the extruded ingot blank to 950 ℃ by using a 6300 ton horizontal extruder, and extrudingThe brand is TC4 titanium alloy tube blank;

step S2, after pickling the inner and outer surfaces of the titanium alloy tube blank prepared in the step S1, machining and repairing the extrusion defect on the inner and outer surfaces, brushing a graphite emulsion coating on the inner and outer surfaces after strong acid washing and coating, and airing and rolling;

s3, preheating the rolling hole pattern and the core rod to 400-450 ℃ by acetylene flame;

step S4, loading the tube blank to be rolled in the step S2 on the preheated rolling mill in the step S3 for rolling deformation, preheating and heating the tube blank at 1000mm and 300mm positions of a rolling feeding end by adopting a special propane heating torch device, controlling the temperature to be 500-550 ℃ when the final tube blank is rolled, controlling the rolling deformation to be 40-45% and the rolling feeding amount to be less than or equal to 5 mm/time by adjusting the flow rate of a torch gun in a preheating area and the feeding speed of the tube blank, and carrying out surface lubrication and roller temperature control on a hole pattern and a tube blank surface by spraying molybdenum disulfide water agent during rolling to ensure good rolling lubrication and avoid surface adhesion caused by hole pattern overheating;

step S5, carrying out oil removal and acid washing treatment on the titanium alloy pipe prepared in the step S4, and carrying out annealing treatment;

step S6, carrying out vacuum heat treatment on the titanium alloy pipe prepared in the step S5 at 900 ℃ for 1h, and carrying out three-point compressive stress warm straightening on the local bending region after annealing is finished;

step S7, performing longitudinal and transverse wave flaw detection on the titanium alloy pipe obtained in the step S6 by adopting a water immersion ultrasonic flaw detection method, and performing size surface and performance inspection on the qualified pipe after pickling to obtain the steel pipe for the petroleum drill pipeTitanium alloy hot rolled pipe.

Referring to fig. 1, a photograph of a longitudinal and transverse microstructure of a titanium alloy tube after heat treatment in example 1 and example 2 is shown in fig. 1, wherein the titanium alloy tube is a typical α+β two-phase titanium alloy structure after heat treatment, an original β grain boundary is completely broken, and an initial α phase and a secondary needle-like α phase are distributed on the β grain, and the morphology and the number of each structure are adjusted by heat treatment, so that the comprehensive mechanical properties of the titanium alloy tube meet the standard requirements.

The pipes processed in examples 1-2 were tested for mechanical properties and process properties and for dimensions, with the following results:

table 1: phi 88.9X9.35X110000 mm room temperature mechanical property

Table 2: phi 101.6X19.7X19700 mm room temperature mechanical property

Table 3: phi 88.9X19.35X110000 mm room temperature impact test

Table 4: phi 101.6X19.7X19700 mm room temperature impact test

The test points of the pipe are subjected to size detection, as shown in fig. 2, the cross section is symmetrically divided into 6 equal parts from two ends of the pipe, each equal part is axially marked (1-6 points in fig. 2) along the pipe, each equal part is axially circled along the pipe at intervals of 1 meter from one end of the pipe, as shown in fig. 2, a, b, c, d and the like, the longitudinal lines and the transverse lines form grids, and a wall thickness value and 2 outer diameter values are measured at the intersection point of each grid. Dimensional accuracy measurement data are shown in tables 5-8:

table 5: phi 88.9x9.35x10000 mm pipe outside diameter dimension unit: mm (mm)

Table 6: phi 88.9x9.35x10000 mm tubing wall thickness dimension unit: mm (mm)

Table 7: Φ101.6x9.7x9700 mm pipe outside diameter dimension unit: mm (mm)

Table 8: Φ101.6x9.7x9700 mm tubing wall thickness dimension unit: mm (mm)

As can be seen from tables 5-8, the pipe processed by the processing method provided by the invention has good dimensional accuracy and can meet the index requirements.

Meanwhile, the pipes processed in the embodiment 1-2 are subjected to ultrasonic longitudinal and transverse inspection one by one, and all the ultrasonic inspection standard requirements of the third part of the non-destructive inspection of the pressure equipment of NB/T47013.3 are met.

The processing method can realize continuous production of the pipe so as to produce the ultra-long pipe.

The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims (7)

1. The processing method of the titanium alloy pipe for the petroleum drill rod is characterized by comprising the following steps of:

step S1, heating an ingot blank to 20-30 ℃ below the phase transition point of the material, preserving heat for 1-2 hours, and extruding by using a horizontal extruder to obtain a titanium alloy tube blank;

step S2, performing internal and external surface treatment on the tube blank prepared in the step S1;

s3, preheating a pass of a rolling mill for rolling a pipe blank and a core rod by adopting an acetylene flame gun blank, wherein the preheating temperature is 450-500 ℃;

step S4, loading the tube blank to be rolled in the step S2 on the preheated rolling mill in the step S3 for rolling deformation, preheating the rolled tube blank at a position of 1000mm at a feeding end and heating the rolled tube blank at a position of 300mm, ensuring that the rolling temperature of the final tube blank is controlled between 400 and 700 ℃, controlling the rolling deformation to be 40 to 45 percent, and carrying out surface lubrication and roller temperature control on a hole pattern and spraying a molybdenum disulfide water agent on the surface of the tube blank during rolling;

step S5, oil removal, acid washing and high-temperature vacuum annealing treatment are carried out on the tube blank rolled in the step S4;

and S6, pickling and inspecting the pipe blank to obtain the titanium alloy pipe for the petroleum drill pipe with the grade of 120ksi and above.

2. The method for producing a titanium alloy pipe for a drill pipe for petroleum according to claim 1, wherein in step S4, the rolling feed amount is 5 mm/time or less.

3. The method for processing a titanium alloy pipe for a drill pipe for petroleum according to claim 1, wherein in step S4, the rolling temperature is controlled to 500-550 ℃.

4. The method for producing a titanium alloy tube for a drill pipe for petroleum according to claim 1, wherein in step S4, the preheating temperature for preheating the rolled tube blank at 1000mm of the feed end is 300 to 500 ℃ and the heating temperature for heating the rolled tube blank at 300mm of the feed end is 500 to 700 ℃.

5. The method for processing a titanium alloy pipe for a drill pipe for petroleum according to claim 1, wherein in step S5, the high-temperature vacuum annealing temperature is 700 to 950 ℃.

6. The method for processing a titanium alloy pipe for a drill pipe for petroleum according to claim 1, wherein in step S2, the inner and outer surface treatment of the pipe blank comprises:

firstly, mechanically repairing the inner surface and the outer surface of a pipe blank, and removing the defect of extruding the pipe blank on the inner surface and the outer surface;

then, the inner surface and the outer surface of the pipe blank are subjected to pickling inspection;

then brushing graphite emulsion on the inner and outer surfaces, and naturally airing.

7. A titanium alloy pipe for petroleum drill pipes, characterized by being processed by the method of any one of claims 1-6.