Production process of large-diameter pure nickel pipe

Abstract

The invention provides a production process of a large-diameter pure nickel pipe, and relates to the technical field of pipe processing, the process comprises the following steps: S1, material preparation: weighing raw materials according to the components of the pure nickel pipe; s2, casting: adding the raw materials into a smelting furnace for vacuum induction smelting, and remelting electroslag to obtain a cast ingot; s3, forging is conducted, specifically, the cast ingot is heated and forged into a solid billet; s4, perforating: heating the solid billet ingot, and extruding and perforating the solid billet ingot into a hollow pipe billet; s5, deformation is conducted, specifically, the hollow pipe blank is drawn and rolled to the target size, and a semi-finished product is obtained; and S6, the semi-finished product is subjected to heat treatment and coping, and the pure nickel pipe is obtained. According to the method, the pretreated raw materials are subjected to vacuum induction melting and electroslag remelting to obtain the cast ingot, the cast ingot is forged and perforated to obtain the hollow pipe blank, a reasonable deformation and heat treatment process system is designed, the purpose of producing the large-diameter pure nickel pipe is achieved, and the large-diameter pure nickel pipe is uniform in chemical component, low in impurity content and uniform in mechanical property.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal processing, in particular to a production process of a large-caliber pure nickel pipe. Background Art

[0002] Pure nickel pipes are widely used in industrial production and scientific research, especially in aerospace, shipbuilding, automobile manufacturing, chemical industry and oil extraction. Due to its excellent corrosion resistance and high temperature performance, pure nickel pipes have become an important raw material for manufacturing various alloy materials and chemical equipment.

[0003] With the development of industry, especially the continuous advancement of large-scale chemical equipment, the demand for large-diameter pure nickel pipes is increasing; traditional production processes face many technical challenges in the preparation of large-diameter pipes, such as low material utilization, high production costs, and difficult to control product quality; therefore, it is particularly important to develop an efficient, low-cost, high-quality production process for large-diameter large-diameter pure nickel pipes.

[0004] Due to the complex deformation process of large-diameter pure nickel tubes and high requirements for alloy purification, there are some technical difficulties in production, mainly including the following aspects: 1. Due to the limitation of production equipment, the manufacturing capacity of large-size nickel tubes is limited; 2. Multiple deformations during the production process make it difficult to control product quality; 3. The requirements for the purification of ingot alloy are high. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a production process for large-diameter pure nickel pipes. The raw materials are subjected to vacuum induction melting + electroslag remelting to obtain high-quality ingots. The ingot forging size is designed and perforated to obtain large-size hollow tube blanks. A reasonable deformation + heat treatment process system is designed to achieve the purpose of producing large-diameter pure nickel pipes.

[0006] The technical solution adopted by the present invention is:

[0007] A production process for large-caliber pure nickel pipes, comprising the following steps:

[0008] Step S1. Ingredients: In terms of mass percentage, the pure nickel pipe includes the following components: Si: 0.02-0.03%, Mn: 0.10-0.30%, Al: 0.015-0.025%, Ti: 0.1-0.2%, Ni-Mg: 0.07-0.10%, and the rest are electrolytic nickel and unavoidable impurity elements, the total of which is 100%.

[0009] According to the above components, Si powder, Mn powder, Al powder, Ti powder, Ni-Mg alloy, and electrolytic nickel raw material are weighed;

[0010] Step S2. Melting and casting: adding the raw materials weighed in step S1 into a melting furnace for vacuum induction melting, and then electroslag remelting to obtain an ingot with a diameter of φ508-700 mm;

[0011] Step S3. Forging: heating the ingot and forging it into a solid billet with a diameter of Φ250 mm to 350 mm;

[0012] Step S4. Punching: The solid billet forged in step S3 is heated and extruded to be punched into a hollow tube with a diameter of Φ250 mm to 350 mm and a wall thickness of 10 mm to 25 mm;

[0013] Step S5. Deformation: The hollow tube blank is subjected to multiple drawing, expansion and multiple rolling to obtain a semi-finished product to a target size, and heat treatment, grinding and water cooling are performed in sequence after each drawing and each rolling;

[0014] Step S6: heat-treating the semi-finished product and then grinding it to obtain a pure nickel pipe.

[0015] Preferably, in the production process of the large-diameter pure nickel pipe, the temperature of the vacuum induction melting in step S2 is 1500-1550° C., and the current of the electroslag remelting is 9000-9500A.

[0016] Preferably, in the production process of the large-diameter pure nickel pipe, the heating temperature of the ingot in step S3 is 1100-1150° C., and the holding time is 50-90 min.

[0017] Preferably, in the production process of the large-diameter pure nickel tube, the heating temperature of the solid billet in step S4 is 980-1030° C., and the holding time is 20-40 min.

[0018] Preferably, in the production process of the large-diameter pure nickel tube, the drawing speed in step S5 is 1 m / min to 1.5 m / min, and the inner hole of the tube is smeared with lime for lubrication before drawing.

[0019] Preferably, in the production process of the large-diameter pure nickel tube, the outer diameter increase of the tube in a single drawing and expanding pass in step S5 is ≤35 mm, the tube is continuously expanded for a maximum of 5 times before rolling, and the deformation rate of a single rolling pass is ≤40%.

[0020] Preferably, in the production process of the large-diameter pure nickel pipe, the heat treatment temperature in step S5 is 820° C. to 850° C., and the heat treatment time is 40 min to 60 min.

[0021] Preferably, in the production process of the large-diameter pure nickel pipe, in step S5, after each grinding, color flaw detection is performed inside and outside the pipe, and the defect positions are marked.

[0022] Preferably, in the production process of the large-diameter pure nickel pipe, the heat treatment temperature in step S6 is 800° C. to 820° C., and the heat treatment time is 30 min to 40 min.

[0023] Advantages of the present invention:

[0024] The production process of the large-diameter pure nickel pipe of the present invention comprises the following steps: subjecting the pretreated raw materials to vacuum induction melting+electroslag remelting to obtain high-quality ingots, designing the forging size of the ingots and punching them to obtain large-size hollow tube blanks, and designing reasonable deformation and heat treatment process systems to achieve the purpose of producing a large-diameter pure nickel pipe. The large-diameter pure nickel pipe has uniform chemical composition and low impurity content, which meets the chemical composition requirements of GB / T 5235 for corresponding grades, and uniform mechanical properties, which meets the mechanical property requirements of GB / T 2882 for corresponding grades. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific embodiments.

[0026] Example 1

[0027] A production process for a Φ377*10 large-diameter N5 pure nickel pipe comprises the following steps:

[0028] Step S1. Ingredients: In terms of mass percentage, the pure nickel pipe includes the following components: Si: 0.02-0.03%, Mn: 0.10-0.30%, Al: 0.015-0.025%, Ti: 0.1-0.2%, Ni-Mg: 0.07-0.10%, and the rest are electrolytic nickel and unavoidable impurity elements, the total of which is 100%. According to the above components, Si powder, Mn powder, Al powder, Ti powder, Ni-Mg alloy, and electrolytic nickel raw material are weighed;

[0029] Step S2. Melting and casting: adding the raw materials weighed in step S1 into a melting furnace for vacuum induction melting at a temperature of 1520°C, and then performing electroslag remelting at a current of 9250A to obtain an ingot with a diameter of φ700mm; wherein samples are taken from the head and tail of the electroslag ingot to test non-metallic inclusions according to ASTM E45, and the DS inclusions are not greater than level 1.0, and the A+B+C+D level is ≤2.5;

[0030] Step S3. Forging: heating the ingot at a heating temperature of 1150° C. for a holding time of 60 min, and forging the ingot into a solid ingot with a diameter of Φ310 mm;

[0031] Step S4. Punching: The solid billet forged in step S3 is heated to a temperature of 1000°C for a holding time of 30 min, and is extruded and punched into a hollow tube billet with a diameter of Φ310 mm and a wall thickness of 25 mm;

[0032] Step S5. Deformation: The hollow tube blank is drawn and rolled multiple times to a target size to obtain a semi-finished product. After each drawing and each rolling, heat treatment, grinding and water cooling are performed in sequence. The multiple drawing and multiple rolling are specifically: Φ310*25mm drawing→340*17mm drawing→360*26mm drawing→Φ370*26mm drawing→Φ400*25mm→356*16mm rolling→385*15mm drawing→377*14mm rolling→400*13mm drawing→392*13mm Drawing → 385*12.5mm drawing → Φ377*10mm rolling, drawing speed is 1.5m / min, lime is applied to the inner hole of the tube before drawing for lubrication, the increase of the outer diameter of the tube expansion in a single drawing pass is ≤35mm, and the tube is expanded continuously for up to 5 times before rolling, and the deformation rate of a single rolling pass is ≤40%; the heat treatment temperature is 850℃, and the heat treatment time is 60min; after each grinding, the tube is color-checked inside and outside, the defect position is marked, the defect is eliminated in a targeted manner, and the grinding is thorough to eliminate the deformation defects of the previous pass and ensure the quality of subsequent deformation;

[0033] Step S6. The semi-finished product is heat treated at a temperature of 820° C. for 30 min, and then ground to eliminate the previous deformation defects and surface oxides to obtain a pure nickel tube.

[0034] The chemical composition and mechanical properties of the pure nickel tube prepared in Example 1 were tested, and the results are shown in Tables 1 and 2.

[0035] Table 1

[0036]

[0037] Table 2

[0038]

[0039] It can be seen from Table 1 above that the Φ377*10 large-diameter N5 pure nickel pipe prepared in Example 1 has uniform chemical composition and low impurity content, which meets the requirements of GB / T 5235 for the chemical composition of grade N5; it can be seen from Table 2 above that the mechanical properties of the Φ377*10 N02201 prepared in Example 1 are uniform, which meets the requirements of GB / T 2882 for the mechanical properties of grade N5.

[0040] Example 2

[0041] A Φ273*8 large-caliber N7 pure nickel pipe production process comprises the following steps:

[0042] Step S1. Ingredients: In terms of mass percentage, the pure nickel pipe includes the following raw materials: Si: 0.02%, Mn: 0.15%, Al: 0.018%, Ti: 0.12%, Ni-Mg: 0.078%, and the rest is electrolytic nickel and unavoidable impurity elements, the total of which is 100%. According to the above components, Si powder, Mn powder, Al powder, Ti powder, Ni-Mg alloy, and electrolytic nickel raw materials are weighed;

[0043] Step S2. Melting and casting: adding the raw materials weighed in step S1 into a melting furnace for vacuum induction melting at a temperature of 1500°C, and then electroslag remelting at a current of 9200A to obtain an ingot with a diameter of φ508 mm, wherein samples are taken from the head and tail of the ingot electroslag ingot to test non-metallic inclusions according to ASTM E45, and DS inclusions are not greater than level 1.0, and A+B+C+D≤2.5;

[0044] Step S3. Forging: heating the ingot at a heating temperature of 1130° C. for a holding time of 60 min, and forging the ingot into a solid ingot with a diameter of Φ250 mm;

[0045] Step S4. Punching: The solid billet forged in step S3 is heated to a temperature of 1020°C for a holding time of 30 min, and is extruded and punched into a hollow tube billet with a diameter of Φ250 mm and a wall thickness of 20 mm;

[0046] Step S5. deformation: the hollow tube blank is drawn and rolled multiple times to a target size to obtain a semi-finished product, and heat treatment, grinding and water cooling are performed in sequence after each drawing and each rolling. The multiple drawing and multiple rolling are specifically: Φ250*20 drawing→285*19 drawing→305*18 drawing→Φ310*18 drawing→Φ273*14 rolling→290*13 drawing→310*12 drawing→Φ273*8 rolling, the drawing speed is 1m / min, the inner hole of the tube is smeared with lime for lubrication before drawing, the outer diameter increase of the single-pass drawing and expanding tube is ≤35mm, the tube is continuously expanded for a maximum of 5 times before rolling, the deformation rate of a single-pass rolling is ≤40%, the heat treatment temperature is 850℃, the heat treatment time is 60min, and the tube is color-checked inside and outside after each grinding, the defect position is marked, the grinding is thorough, the deformation defects of the previous pass are eliminated, and the quality of subsequent deformation is guaranteed;

[0047] Step S6. The semi-finished product is heat treated at a temperature of 830° C. for 35 min, and then ground to eliminate the previous deformation defects and surface oxides to obtain a pure nickel tube.

[0048] The chemical composition and mechanical properties of the pure nickel tube prepared in Example 2 were tested, and the results are shown in Tables 3 and 4.

[0049] Table 3

[0050]

[0051] Table 4

[0052]

[0053] It can be seen from Table 3 above that the Φ273*8 large-diameter N7 pure nickel pipe prepared in Example 2 has uniform chemical composition and low impurity content, which meets the requirements of GB / T 5235 for the chemical composition of grade N7; it can be seen from Table 4 above that the mechanical properties of the Φ273*8 N7 prepared in Example 2 are uniform, which meets the requirements of GB / T 2882 for the mechanical properties of grade N7.

[0054] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A production process for large-caliber pure nickel pipes, characterized in that: The following steps are involved: Step S1. Ingredients: In terms of mass percentage, the pure nickel tube includes the following components: Si: 0.02-0.03%, Mn: 0.10-0.30%, Al: 0.015-0.025%, Ti: 0.1-0.2%, Ni-Mg: 0.07-0.10%, and the rest are electrolytic nickel and unavoidable impurity elements, the total of which is 100%. According to the above components, Si powder, Mn powder, Al powder, Ti powder, Ni-Mg alloy, and electrolytic nickel raw material are weighed; Step S2. Melting and casting: adding the raw materials weighed in step S1 into a melting furnace for vacuum induction melting, and then electroslag remelting to obtain an ingot with a diameter of φ508-700 mm; Step S3. Forging: heating the ingot and forging it into a solid billet with a diameter of Φ250 mm to 350 mm; Step S4. Punching: The solid billet forged in step S3 is heated and extruded to be punched into a hollow tube with a diameter of Φ250 mm to 350 mm and a wall thickness of 10 mm to 25 mm; Step S5. Deformation: The hollow tube blank is subjected to multiple drawing, expansion and multiple rolling to obtain a semi-finished product to a target size, and heat treatment, grinding and water cooling are performed in sequence after each drawing and each rolling; Step S6: heat-treating the semi-finished product and then grinding it to obtain a pure nickel pipe.

2. The production process of large-diameter pure nickel pipe according to claim 1, characterized in that: In step S2, the temperature of vacuum induction melting is 1500-1550°C, and the current of electroslag remelting is 9000-9500A.

3. The production process of large-diameter pure nickel pipe according to claim 1, characterized in that: In step S3, the heating temperature of the ingot is 1100-1150° C., and the holding time is 50-90 minutes.

4. The production process of large-diameter pure nickel pipe according to claim 1, characterized in that: In step S4, the heating temperature of the solid ingot is 980-1030° C., and the holding time is 20-40 minutes.

5. The production process of large-caliber pure nickel pipe according to claim 1, characterized in that: The drawing speed in step S5 is 1 m / min to 1.5 m / min, and the inner hole of the tube is smeared with lime for lubrication before drawing.

6. The production process of large-caliber pure nickel pipe according to claim 1, characterized in that: In step S5, the increase in outer diameter of the tube by drawing and expanding in a single pass is ≤35 mm, and the tube is expanded continuously for a maximum of 5 times before rolling, and the deformation rate of the rolling in a single pass is ≤40%.

7. The production process of large-diameter pure nickel pipe according to claim 1, characterized in that: The heat treatment temperature in step S5 is 820° C. to 850° C., and the heat treatment time is 40 min to 60 min.

8. The production process of large-diameter pure nickel pipe according to claim 1, characterized in that: In step S5, after each grinding, color flaw detection is performed inside and outside the pipe, and the defect positions are marked.

9. The production process of large-diameter pure nickel pipe according to claim 1, characterized in that: In step S6, the heat treatment temperature is 800° C. to 820° C., and the heat treatment time is 30 min to 40 min.

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