Cold working pipe making method capable of controlling inner wall surface roughness of high temperature alloy seamless pipe

Abstract

A cold working pipe making method capable of controlling the inner wall surface roughness of high-temperature alloy seamless pipes utilizes a combined two-roll and three-roll process to produce billets, ensuring an inner wall roughness Ra ≤ 1.2 μm for the Φ12×0.4 mm product. The process then proceeds through a combined process of finishing rolling with a three-roll mill, four passes of small-deformation mandrel-free drawing, and a single pass of long-mandrel cold drawing to produce finished GH4169 high-temperature alloy thin-diameter seamless steel pipes with a specification of Φ3×0.35 mm. This method addresses the specificity of small-diameter pipes and the characteristics of nickel-based high-temperature alloy steel grades. The method utilizes finishing rolling with a three-roll cold rolling mill to promptly address the potential longitudinal streaks during billeting with a two-roll cold rolling mill and the adverse effects of inner wall roughness caused by mandrel-free drawing, thereby improving inner wall roughness quality. The method utilizes a combined long-mandrel drawing and drawing process. During long-mandrel drawing, the mandrel inner die and the billet tube move synchronously, minimizing frictional resistance and improving the inner wall surface roughness of the cold-drawn pipe.

Description

Technical Field

[0001] The present invention relates to a cold working pipe making process for producing seamless steel pipes in the metallurgical and steel production industries, and in particular to a cold working pipe making method capable of controlling the surface roughness of the inner wall of a high-temperature alloy seamless pipe. The method is particularly suitable for the cold working pipe making process of a high-temperature alloy seamless thin-diameter pipe with a finished product outer diameter not greater than 4 mm. Background Art

[0002] High-temperature alloys are metal materials based on iron, nickel, and chromium, capable of long-term operation within a temperature range of -253°C to 700°C under certain stresses. These alloys, also known as "superalloys," possess a single austenitic structure and a high degree of alloying. They exhibit excellent structural stability and operational reliability across a wide range of temperatures. They are particularly well-known for their high high-temperature strength, excellent oxidation and corrosion resistance, and excellent overall properties such as fatigue resistance and fracture toughness, leading to their widespread application in the aerospace and energy sectors.

[0003] Seamless steel pipes are common metallurgical metal products. In recent years, high-grade seamless steel pipes represented by high-temperature alloys have become the production trend of the seamless steel pipe industry at home and abroad. Among them, cold working pipe making under normal temperature conditions is a key process in the entire seamless steel pipe production. The cold working pipe making process is a key factor in ensuring the production capacity and efficiency, quality and production cost of seamless steel pipes. At present, the cold working pipe making of seamless steel pipes is mainly done by cold rolling and cold drawing. In order to improve the quality and production capacity of cold-worked seamless steel pipes, enterprises with a certain production scale and equipment conditions often adopt a composite cold rolling production mode of two-roll periodic rolling mill for initial rolling and three-roll periodic rolling mill for finishing, as follows:

[0004] Seamless steel tube billets are rolled and deformed at room temperature using a cyclic cold rolling mill. These mills are categorized by the number of rolls into two-roll and multi-roll types, with the three-roll type being the most commonly used. The resulting seamless cold-rolled tubes are characterized by strong wall reduction, large per-pass reduction, good machining accuracy, high yield, minimal metal loss, and high yield. However, these methods suffer from slow production speeds, inconvenience in changing specifications, and high tooling and processing costs. Furthermore, cyclic cold rolling mills are complex in structure, resulting in high equipment investment and ongoing maintenance costs. They are primarily used for the production of seamless steel tubes made from stainless steel, alloy steel, and other materials.

[0005] In addition to the above description, the two-roll periodic cold rolling mill and the three-roll periodic cold rolling mill are structurally different, as follows:

[0006] 1. A two-roll cyclic cold rolling mill consists of a rolling mechanism, a feed and rotary mechanism, a transmission mechanism, a mandrel chuck mechanism, a bed support mechanism, a feeding and blanking mechanism, a hydraulic system, a process lubrication system, an electrical automation control system, a pneumatic system, and auxiliary mechanisms. The rolling mechanism's function is to cold-deform the seamless steel pipe billet at room temperature using a deformation tool consisting of a plug and a pass. The rolling principle is that the depth of the semicircular groove in the center of a single pass varies continuously and evenly from deep to shallow along the entire circumference of the pass. During rolling, the passes are used in pairs according to the rolling specifications, with the circular holes formed by the two passes decreasing from large to small, thereby reducing the pipe diameter, thinning the pipe wall, and extending the pipe material. When the rollers rotate one revolution, the groove installed in the middle of the rollers synchronously completes a change cycle. Within this change cycle, the billet tube completes a feed amount and a synchronous rotation amount, and then, driven by the rollers, performs a reverse rolling motion... This cycle repeats over and over again to complete the tube rolling (diameter reduction, wall thickness reduction, and elongation) process. During seamless steel tube rolling, when the groove contacts the billet tube, the diameter of the contacted section gradually decreases, and the wall thickness is reduced all at once. When the rollers rotate one revolution, the billet tube of that section passes through the groove of the groove, completing forging, finishing, and sizing in one go. The high rolling speed, high rolling force, large deformation per pass, few processing passes, and short production cycles make it suitable for the cold rolling production of seamless steel tubes with high deformation resistance and large wall and diameter reduction.

[0007] 2. A three-roll cyclic cold mill consists of a rolling mechanism, a feed and rotary mechanism, a transmission mechanism, a mandrel chuck mechanism, a bed support mechanism, a feeding and blanking mechanism, a hydraulic system, a process lubrication system, an electrical automation control system, a pneumatic system, and auxiliary mechanisms. Its rolling mechanism is completely different from that of a two-roll cyclic cold mill. Three rolls with equal-diameter grooves in the middle of the trunnions at both ends replace the pass, and together with a mandrel, a deformation tool performs cold deformation processing on the seamless steel tube billet at room temperature. The rolling principle is as follows: the three rolls are symmetrically arranged at the vertices of an equilateral triangle centered on the rolling centerline. The roll axis and the rolling centerline are inclined at two different angles: one for the feed angle and the other for the rolling angle. The billet tube is reduced in diameter, wall thickness, and length in the closed annular ring formed by the three rolls and a mandrel. The three-roll cyclic cold rolling mill produces less deformation for reducing the diameter than the two-roll cyclic cold rolling mill, but a relatively larger deformation for reducing the wall thickness. This improves the inner surface quality of seamless steel pipes and is considered a finishing deformation process. The high rolling precision and excellent surface quality make it suitable for finishing rolling of seamless steel pipes requiring high inner surface quality. It is also commonly used for cold rolling of thinner-walled seamless steel pipes.

[0008] The cold drawing of seamless steel pipes is a process in which a cold drawing machine is used to draw and deform the seamless steel pipe billet under normal temperature conditions through an annular circular hole composed of a core rod inner die and an outer die. The cold drawing machine is divided into two categories: single chain and double chain according to the transmission mechanism. It consists of a drawing mechanism, a transmission mechanism, a bed support mechanism, a material feeding and blanking mechanism, a pneumatic and hydraulic system, an electrical control system and auxiliary mechanisms.

[0009] There are currently five main methods for cold drawing pipe making, as follows:

[0010] 1) Mandrelless cold drawing: It is empty drawing, which is used to only reduce the outer diameter of the pipe (reducing the diameter).

[0011] 2) Cold drawing of tubes with fixed short mandrel: the mandrel and the outer die are fixed at the same time. The drawing force is large, the deformation per pass is small, and the friction resistance between the blank tube and the deformation tool is large. It is used to draw tubes to reduce the outer diameter of the tube (diameter reduction) and the wall thickness (wall reduction) at the same time. Because its drawing method is simple and practical, it is widely used.

[0012] 3) Floating mandrel cold drawing: Due to the floating mandrel structure, the drawing force is small, which can increase the deformation of diameter reduction and wall reduction in each pass; since there is no restriction of the pull rod, seamless steel pipes with small diameters can be drawn with a mandrel. It is often used for reel cold drawing and can produce seamless steel pipes of very long lengths.

[0013] 4) Long mandrel cold drawing: During cold drawing, the mandrel moves horizontally synchronously with the seamless steel pipe, which basically eliminates the friction resistance between the core inner die and the blank pipe. Therefore, the deformation of the diameter reduction and wall reduction can be increased on the basis of reducing the drawing force. At the same time, due to the synchronous horizontal movement of the mandrel inner die during cold drawing, the surface roughness accuracy of the inner wall of the seamless steel pipe can also be improved. However, the accuracy requirements of the mandrel inner die are strict, and the mandrel inner die needs to be removed in time after cold drawing (the mandrel inner die is separated from the finished pipe), which is labor-consuming and time-consuming.

[0014] 5) Expansion cold drawing: During expansion cold drawing, the blank tube is fixed and the pull rod drives the core rod inner die to pass through the inner hole of the seamless steel tube, so that the wall thickness of the seamless steel tube is reduced, the diameter is increased, and the length is shortened.

[0015] In production practice, the cold-drawn pipe making process has good surface roughness accuracy, fast production speed, convenient specification changes, and convenient production process organization. The cold-drawing machine and deformation tooling have a simple structure, are easy to manufacture and process, require low investment and low cost. For some small batches of seamless steel pipes with special specifications, cold-drawn pipe making is more suitable. However, cold-drawn pipes have a small deformation amount, many processing passes, and a long production cycle. The "heading" cutting of the ends leads to large metal loss and low yield. The precision and surface quality of cold-drawn seamless steel pipes are lower than those of cold-rolled seamless steel pipes. Therefore, cold-rolled seamless steel pipes are currently the mainstream cold-processing method for seamless steel pipes.

[0016] Due to differences in equipment manufacturing costs and limitations on production specifications, cold-drawn pipe making can be used to achieve deformation processing for products that are not suitable for or cannot be produced using cold-rolled pipe making. Taking into account the characteristics of cold-rolled and cold-drawn pipe making processes, and leveraging their strengths to overcome their weaknesses, a combination of cold-rolled and cold-drawn pipe making can be used in the current industrial-scale production of seamless steel pipes to meet the technical requirements for high-grade seamless steel pipe production.

[0017] However, during the long production process, on-site workers discovered that although the existing technology adjusted the cold drawing (air drawing) pass and added a three-roll finishing pass, the last two passes of coreless air drawing pipe making were not adjusted and optimized. The surface roughness of the inner wall of the last two drawing pipes was still affected to a certain extent. The surface roughness of the inner wall of the final finished product was Ra = 1.7~2.1μm or even higher, which did not meet the technical requirement of Ra≤1.6μm.

[0018] Due to the steel grade characteristics and special requirements for inner wall roughness of finished specification seamless steel pipes, both the conventional cold working pipe making process for the same steel grade and the cold working pipe making process after targeted optimization and adjustment cannot meet the technical requirements of inner wall roughness accuracy Ra≤1.6μm for finished pipes with small diameters (such as Φ12×0.4mm). Therefore, it is urgent to optimize and improve the process technology and invent a new pipe making method that can control the inner wall surface roughness of the pipe, improve the adverse effects of inner wall surface roughness caused by air drawing pipe making, and meet the technical requirements of cold working pipe making production of nickel-based high-temperature alloy small diameter pipes. Summary of the Invention

[0019] To address the problem of tube inner wall surface roughness failing to meet requirements in existing cold working pipe-making processes, the present invention optimizes the cold working deformation process for nickel-based superalloy seamless steel tubes, providing a cold working pipe-making method capable of controlling the inner wall surface roughness of superalloy seamless tubes. By optimizing and integrating the advantages of two-roll and multi-roll cold rolling, the present invention first utilizes a combined two-roll and three-roll process to produce the blank. After the blank tube undergoes large deformation through two-roll cold rolling, it undergoes multiple passes of small deformation through three-roll finishing rolling to repair the inner wall quality, improving the inner wall roughness and ensuring an inner wall roughness Ra ≤ 1.2μm for the finished product, thus providing the necessary inner wall roughness quality margin for subsequent cold working pipe-making.

[0020] The cold working pipe making method of the present invention capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe comprises the following specific steps:

[0021] A cold working pipe making method capable of controlling the inner surface roughness of a high-temperature alloy seamless pipe includes a blank pipe, and the specific steps are as follows:

[0022] 1) The billet tube is rolled using a two-roller or three-roller combined process:

[0023] The billet tube is cold rolled with two rollers at a large deformation amount, and then subjected to multiple passes of three-roll finishing rolling with small deformation amounts to repair the inner wall roughness problem caused by the large deformation amount of two-roll rolling. The intermediate product tube with a diameter of 12×0.4mm is obtained, and the inner wall roughness Ra at this time is confirmed to be ≤1.2μm;

[0024] 2) Using 8T single-chain cold drawing machine to draw the tube:

[0025] The Φ12×0.4 mm intermediate product tube obtained in step 1) is drawn and deformed to form an intermediate product tube with a specification of Φ8.8×0.45 mm. In this step, the drawing speed is 0.1 to 0.35 m / s;

[0026] 3) Using 3T single chain cold drawing machine to draw the tube:

[0027] The intermediate product tube of Φ8.8×0.45 mm obtained in step 2) is drawn and deformed to produce an intermediate product tube of Φ6.6×0.50 mm. In this step, the drawing speed is 0.1-0.35 m / s;

[0028] 4) Using LD3~8 three-roll mill to roll the pipe:

[0029] The Φ6.6×0.50 mm intermediate product tube obtained in step 3) is rolled and deformed to form an intermediate product tube with a specification of Φ6×0.40 mm. In this step, the rolling speed is 65 to 105 times / min and the rolling feed rate is 1.5 to 3.0 mm / time;

[0030] 5) Using 1T single-chain cold drawing machine to draw pipes without mandrel:

[0031] The Φ6×0.40 mm intermediate product tube obtained in step 4) is drawn and deformed to form an intermediate product tube with a specification of Φ4×0.40 mm. In this step, the drawing speed is 0.10-0.35 m / s;

[0032] 6) Use 1T single-chain cold drawing machine with long mandrel to draw the tube:

[0033] The Φ4×0.40 mm intermediate product tube obtained in step 5) is drawn and deformed to form an intermediate product tube with a specification of Φ3.5×0.35 mm. In this step, the drawing speed is 0.10-0.35 m / s, the mandrel diameter is 2.8 mm, and the mandrel length is 3.5-7.5 m.

[0034] 7) A 1T single-chain cold drawing machine is used to draw the tube without a mandrel to produce a final product with a specification of Φ3×0.35mm. In this step, the drawing speed is 0.10-0.35m / s.

[0035] The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to the present invention is characterized in that the lubrication method used in the drawing process of step 2), step 3) and step 5) is applying tallow lime + baking lubrication.

[0036] The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to the present invention is characterized in that the lubrication method used in the rolling process of step 4) is thin oil online lubrication.

[0037] The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to the present invention is characterized in that the lubrication method used in the drawing process of step 6) and step 7) is thin oil + paraffin lubrication.

[0038] The cold working pipe making method of the present invention capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe has the following main implementation principles:

[0039] The present invention realizes the cold processing pipe production of fine-diameter high-temperature alloy seamless steel pipes with finished product specifications through a combined process of one pass of three-roll mill finishing rolling + four passes of coreless empty drawing + one pass of long core rod cold drawing, and reasonably sets the relevant parameters of each process. In addition, the present invention takes into account the particularity of small specifications of fine-diameter pipes and the steel characteristics of nickel-based high-temperature alloys, and uses the three-roll cold rolling mill finishing rolling to timely repair the hidden dangers of longitudinal streaks in the blanking of the two-roll cold rolling mill and the adverse effects of inner wall roughness caused by coreless empty drawing, thereby further improving the quality of inner wall roughness. In addition, the present invention adopts a combined process of long core rod drawing + empty drawing, and utilizes the characteristics of synchronous movement of the core rod inner mold and the blank tube during long core rod drawing and small friction resistance to improve the inner wall surface roughness during cold drawing.

[0040] The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to the present invention has the following beneficial effects:

[0041] 1. The process of the present invention is rationally designed, safe, reliable, practical and efficient. It adopts a combined process of cogging on a two-roll cyclic cold rolling mill, finishing rolling on a three-roll cyclic cold rolling mill, mandrel-free drawing, and long mandrel drawing, meeting the technical requirements for cold working pipe making of GH4169 nickel-based high-temperature alloy small-diameter seamless steel pipes.

[0042] 2. This invention optimizes and integrates the advantages of two-roll and multi-roll cold rolling for pipe making. First, a two-roll and three-roll combined process is used to roll the blank. After the blank pipe is cold rolled with a large deformation amount by two rolls to open the blank, it is then subjected to multiple passes of three-roll finishing rolling with small deformation amounts to repair the inner wall quality, improve the inner wall roughness quality, and ensure that the inner wall roughness of fine-diameter products is Ra ≤ 1.2μm, providing the necessary inner wall roughness quality space for subsequent further cold working pipe making;

[0043] 3. This invention addresses the particularity of small diameter tubes and the characteristics of nickel-based high-temperature alloy steel grades. It utilizes a three-roll cold rolling mill for finishing rolling to promptly repair the potential longitudinal streaks during cogging on a two-roll cold rolling mill and the adverse effects of inner wall roughness caused by mandrel-free drawing, further improving the quality of inner wall roughness.

[0044] 4. The present invention adopts two passes of continuous air drawing with small deformation to replace one pass of air drawing with large deformation, which significantly improves the adverse effect of large deformation air drawing on the roughness of the inner wall surface.

[0045] 5. The present invention adopts a combined process of long mandrel drawing and air drawing based on the characteristics of cold-drawn tube making. The inner die of the mandrel and the blank tube move synchronously during long mandrel drawing, and the friction resistance is basically eliminated, thereby improving the inner wall surface roughness during cold-drawn tube making.

[0046] 6. The present invention enables the cold working production of GH4169 fine-diameter seamless steel pipes with a finished specification of Φ3×0.35mm to be achieved by rationally setting the relevant parameters of each process through a combination of three-roller finishing rolling, four mandrel-free drawing, and one long mandrel cold drawing process.

[0047] 7. The process organization of the present invention is smooth, and it realizes the effective control of the inner wall roughness of the high-temperature alloy thin-diameter tube in the cold working tube making process from the source, meeting the technical requirement of Ra≤1.6μm and having a high yield rate, ensuring the production capacity and quality of the enterprise's thin-diameter tube, and significantly reducing energy consumption and emissions.

[0048] 8. The present invention has strong versatility and has certain reference and application value for the research and development and industrial production of cold-processed thin-diameter seamless steel pipes made of other materials in the industry. It promotes the localization of key materials in the field of key domestic engineering equipment, has broad market application prospects, and considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a process flow chart of the cold working pipe making method of the present invention that can control the inner wall surface roughness of the high-temperature alloy seamless pipe DETAILED DESCRIPTION

[0050] The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0051] Example - Cold Working of GH4169 Alloy Seamless Pipe

[0052] The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe of the present invention is used on a seamless steel pipe cold working production line. SKW-75 two-roll rolling mill, LD-60 three-roll rolling mill, LD-30 three-roll rolling mill, LD3-8 three-roll rolling mill, 8T, 3T, and 1T cold drawing mills are used to produce GH4169 fine-diameter high-temperature alloy seamless steel pipes with a finished product specification of Φ3×0.35mm. The inner wall surface roughness Ra is required to be ≤1.6μm. The specific process is shown in Table 1:

[0053]

[0054]

[0055] Table 1- GH4169 alloy seamless pipe cold processing process

[0056] Pass 1: The blank is first rolled using a combined two-roll and three-roll process. After undergoing large deformation with two rolls, the blank tube undergoes multiple passes of three-roll finishing rolling to repair the inner wall quality and improve its inner wall roughness. Key technical points of this pass (for blank supply): A combination of two-roll cold rolling with large deformation and three-roll finishing rolling with multiple passes of smaller deformation is used. A sufficient number of three-roll finishing rolling passes is required to completely repair the inner wall roughness caused by the large deformation of two-roll rolling. The final inner wall roughness of the Φ12×0.4mm intermediate product tube is guaranteed to be Ra ≤ 1.2μm.

[0057] Pass 2: 8T single-strand cold drawing machine draws the tube in the air, with the deformation specification (intermediate product specification) being Φ8.8×0.45mm. Key technical points of this process include: a drawing speed of 0.1-0.35m / s is appropriate, and lubrication is applied with butter lime and baked lubrication.

[0058] Pass 3: 3T single-strand cold drawing machine draws the tube in the air, with the deformation specification (intermediate product specification) being Φ6.6×0.50mm. Key technical points of this process include: a drawing speed of 0.1-0.35m / s is appropriate, and the lubrication method is butter lime application followed by baking lubrication.

[0059] Pass 4: LD3-8 three-roll mill rolling tube, rolling deformation specifications (intermediate product specifications) is Φ6×0.40mm. The technical key points of this process include: rolling speed of 65-105 times / minute, rolling feed of 1.5-3.0mm / time, and thin oil online lubrication.

[0060] Pass 5: A 1T single-strand cold drawing machine draws tubes without a mandrel, with the final product specification being Φ4 x 0.40 mm. Key technical points for this process include a drawing speed of 0.10 to 0.35 m / s and lubrication using butter lime application followed by baking.

[0061] Pass 6: 1T single-strand cold drawing machine uses a long mandrel to draw tubes. The rolled deformation specification (intermediate product specification) is Φ3.5×0.35mm. Key technical points for this process include: a drawing speed of 0.10-0.35m / s, lubrication with thin oil and paraffin, a mandrel diameter of 2.8mm, and a mandrel length of 3.5-7.5m.

[0062] Pass 7: 1T single-strand cold drawing machine draws tubes without a mandrel. The rolled deformation specification (final product specification) is Φ3×0.35mm. Key technical points of this process include: the drawing speed should be 0.10-0.35m / s, and the lubrication method is thin oil + paraffin.

[0063] The final product is a nickel-based high-temperature alloy GH4169 thin-diameter seamless steel pipe with a specification of Φ3×0.35mm, which can fully meet the steel grade characteristics and technical requirements, and can complete cold processing pipe production under normal temperature conditions according to the production process. The inner wall surface roughness Ra=1.05~1.27μm is tested, which fully meets the technical requirement of Ra≤1.6μm.

[0064] It should be noted that the technical solution provided by this invention only covers the cold rolling and cold drawing processes involved in cold working pipe making. It does not include heat treatment, finishing (cutting to length, flattening, straightening), pickling (cleaning) and inspection, and the preparation and installation of deformation tools (die, rollers, inner and outer dies, mandrels, and plugs). Furthermore, the dimensions of the finished products are nominal.

[0065] In addition, those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present application and are not intended to limit the present application. As long as they are within the spirit of the present application, any changes or modifications to the above embodiments will fall within the scope of the claims of the present application.

Claims

1. A cold working pipe making method capable of controlling the inner surface roughness of a high-temperature alloy seamless pipe, comprising a billet pipe, wherein the specific steps are as follows: 1) The billet tube is rolled using a two-roller or three-roller combined process: The billet tube is cold rolled with two rollers at a large deformation amount, and then subjected to multiple passes of three-roll finishing rolling with small deformation amounts to repair the inner wall roughness problem caused by the large deformation amount of two-roll rolling. The intermediate product tube with a diameter of 12×0.4mm is obtained, and the inner wall roughness Ra at this time is confirmed to be ≤1.2μm; 2) Using 8T single-chain cold drawing machine to draw the tube: The Φ12×0.4 mm intermediate product tube obtained in step 1) is drawn and deformed to form an intermediate product tube with a specification of Φ8.8×0.45 mm. In this step, the drawing speed is 0.1 to 0.35 m / s; 3) Using 3T single chain cold drawing machine to draw the tube: The intermediate product tube of Φ8.8×0.45 mm obtained in step 2) is drawn and deformed to produce an intermediate product tube of Φ6.6×0.50 mm. In this step, the drawing speed is 0.1-0.35 m / s; 4) Using LD3~8 three-roll mill to roll the pipe: The Φ6.6×0.50 mm intermediate product tube obtained in step 3) is rolled and deformed to form an intermediate product tube with a specification of Φ6×0.40 mm. In this step, the rolling speed is 65 to 105 times / min and the rolling feed rate is 1.5 to 3.0 mm / time; 5) Using 1T single-chain cold drawing machine to draw pipes without mandrel: The Φ6×0.40 mm intermediate product tube obtained in step 4) is drawn and deformed to form an intermediate product tube with a specification of Φ4×0.40 mm. In this step, the drawing speed is 0.10-0.35 m / s; 6) Use 1T single-chain cold drawing machine with long mandrel to draw the tube: The Φ4×0.40 mm intermediate product tube obtained in step 5) is drawn and deformed to form an intermediate product tube with a specification of Φ3.5×0.35 mm. In this step, the drawing speed is 0.10-0.35 m / s, the mandrel diameter is 2.8 mm, and the mandrel length is 3.5-7.5 m. 7) A 1T single-chain cold drawing machine is used to draw the tube without a mandrel to produce a final product with a specification of Φ3×0.35mm. In this step, the drawing speed is 0.10-0.35m / s.

2. The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to claim 1, characterized in that: The lubrication method used in the drawing process of step 2), step 3) and step 5) is applying butter lime + baking lubrication.

3. The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to claim 1, characterized in that: The lubrication method used in the rolling process of step 4) is thin oil online lubrication.

4. The cold working pipe making method capable of controlling the inner wall surface roughness of a high-temperature alloy seamless pipe according to claim 1, wherein: The lubrication method used in the drawing process of step 6) and step 7) is thin oil + paraffin lubrication.

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