A method and device for forming 625 alloy pipe

Abstract

The present invention relates to a method and device for forming a 625 alloy pipe, and the device includes pre-processing equipment, a resistance furnace, an induction furnace, a hole expander, an extruder, a hot rolling mill, a pickling tank, a grinding machine, a cold rolling mill, a continuous roller bottom heat treatment furnace, a finished product refining inspection equipment and a finished product warehouse. The forming process is: (1) blank preparation, (2) blank preheating, (3) heating hole expansion, (4) heating extrusion, (5) insulation recrystallization, (6) hot rolling, (7) insulation recrystallization, (8) pickling, grinding, (9) cold rolling, (10) solution treatment and (11) refining inspection. The present invention adopts a production process of hot extrusion + induction furnace insulation + hot rolling + induction furnace insulation, which reduces the number of cold rolling passes in the cold deformation process, has good product quality, is conducive to shortening the production cycle, reduces production costs, and improves comprehensive economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing production, relates to a seamless nickel-based alloy pipe production technology, and in particular to a 625 alloy pipe forming method and device. Background Art

[0002] Alloy 625 is a grade in the standard ASTM B444, which is a kind of solid solution strengthened nickel-based high alloy, usually called Inconel Alloy 625. Since the alloy contains a large amount of Ni, Cr, Mo and other elements, and has a single-phase austenite structure, it has good corrosion resistance in both oxidizing and reducing media, so it is often used in special environments with high temperature and strong corrosion.

[0003] Due to the high alloy content and great difficulty in deformation, the mature production process of 625 alloy seamless pipes is hot extrusion + cold rolling. Especially for some 625 alloy seamless pipes with high dimensional accuracy requirements, they are generally produced by multi-pass cold rolling.

[0004] Analysis of existing technical conditions: From the perspective of deformation characteristics, the extrusion process has the characteristics of three-dimensional stress compression, which greatly exerts the plastic deformation of the metal and obtains a large deformation amount. Extrusion deformation can improve the organization of metal materials and improve their mechanical properties. The overall quality of the product is high, which is very suitable for the manufacture of high-end products such as stainless steel and nickel-based alloys. The cold rolling or cold drawing process belongs to finishing, which can produce products with high dimensional accuracy and good surface quality. However, in the hot extrusion + multi-pass cold rolling forming process, the rough pipe after extrusion often requires multiple passes of cold rolling to reach the finished product. Each cold rolling requires solution + pickling treatment, which has a long production cycle, a low yield rate, and a high overall cost. Summary of the invention

[0005] The purpose of the present invention is to provide a method for forming a 625 alloy tube, so as to overcome the problems of many cold rolling passes, long production cycle, low yield rate and high comprehensive cost in the existing hot extrusion + cold rolling forming process, improve product quality, shorten production cycle and improve comprehensive economic benefits. Another purpose of the present invention is to provide a device for forming a 625 alloy tube.

[0006] The technical solution of the present invention is: a method for forming a 625 alloy tube, and the forming process is as follows:

[0007] ⑴ Billet preparation: including billet inspection and billet processing. Billet processing includes sawing, peeling, polishing, drilling, bell mouth processing, inspection, grinding and cleaning;

[0008] ⑵ Preheating of blanks: The processed blanks are preheated in a resistance furnace at a temperature of 930-960°C;

[0009] ⑶ Heating and hole expansion: After preheating, the blank is heated to 1160-1180℃ in an induction furnace, and a 2500T vertical hole expansion machine is used for hole expansion. The inner and outer surfaces of the blank are lubricated with glass powder before hot hole expansion. The hot hole expansion speed is 160-220mm / s, and the hole expansion extension coefficient is 1.05-1.33;

[0010] (4) Heating and extruding: After hole expansion, the blank is heated to 1170-1200℃ in an induction furnace and extruded using a 6300T horizontal extruder. The inner and outer surfaces of the blank are lubricated with glass powder before extrusion.

[0011] ⑸ Insulation recrystallization: After hot extrusion, the alloy tube is sent into the induction furnace while hot and kept at 1120-1160℃ for 10-60min to complete recrystallization;

[0012] (6) Hot rolling: Multi-frame forming is used to perform hot rolling longitudinal deformation on alloy pipes. The overall hot rolling elongation coefficient is 2.0-4.5, and the elongation coefficient of each frame is 1.01-1.60;

[0013] ⑺ Insulation recrystallization: The alloy tube after hot rolling is sent into the induction furnace while hot, and kept at 1120-1160℃ for 10-60min. After recrystallization, it is sent into water at high temperature and cooled to room temperature;

[0014] ⑻ Pickling and grinding: Pickle the alloy pipe after continuous rolling to remove the oxide scale; inspect and grind the alloy pipe after pickling to remove surface cracks, folds and pits;

[0015] ⑼Cold rolling: The alloy pipe is cold rolled once or twice to the final specification, and the elongation coefficient of single cold rolling is 1.45-1.95;

[0016] ⑽Solution treatment: The alloy pipe is subjected to solution treatment in a continuous roller bottom heat treatment furnace. The holding temperature of the solution treatment is 1140-1160°C, the holding time is 40-60 minutes, and then sprayed with water to cool to room temperature;

[0017] ⑾Refining inspection: The alloy pipes after solid solution treatment are straightened, pickled, inspected and ground, ultrasonically inspected and finished, and cut into finished 625 alloy pipes, which are then put into storage.

[0018] The extrusion speed of heating extrusion is 100-160mm / s, and the extrusion elongation coefficient is 2.2-5.8. The heat preservation recrystallization adopts online heating and heat preservation while hot after extrusion or reheating and heat preservation after extrusion cooling. The chemical composition of the alloy to be inspected for the billet must meet the requirements of ASTM B444, and the inspection quality of 625 alloy pipe products must meet the ASTM B444 standard. Step ⑴ After polishing, the outer surface is smooth and defect-free, with a roughness of ≤1.6μm, and the head of the processed billet has an outer arc angle of R30-40mm.

[0019] The device for forming 625 alloy pipes of the present invention comprises pre-processing equipment, a resistance furnace, an induction furnace, a reamer, an extruder, a hot rolling mill, a pickling tank, a grinding machine, a cold rolling mill, a continuous roller bottom heat treatment furnace, a finished product refining inspection equipment and a finished product warehouse. The pre-processing equipment, the resistance furnace, the induction furnace, the reamer, the extruder, the hot rolling mill, the pickling tank, the grinding machine, the cold rolling mill, the continuous roller bottom heat treatment furnace, the finished product refining inspection equipment and the finished product warehouse are arranged in sequence.

[0020] The pre-processing equipment includes sawing equipment, peeling equipment, polishing machine, drilling machine, bell mouth processing machine, inspection equipment, grinding machine and cleaning machine. The finished product refining inspection equipment includes straightening machine, pickling machine, inspection grinding machine, ultrasonic flaw detector and finishing inspection and cutting equipment. The extruder is a 6300T horizontal extruder, the reamer is a 2500T vertical reamer, and the hot rolling mill is a multi-frame forming hot rolling mill. The resistance furnace is equipped with an observation hole, a furnace door, a thermocouple, a furnace shell, an electric heating element, a refractory material, a thermal insulation material and a leg. The extruder includes a base, a die-die pad-die base assembly, an extrusion barrel jacket, an extrusion barrel, an extrusion barrel liner, an extrusion pad, a core rod, a needle support and an extrusion rod.

[0021] The method and device for forming 625 alloy pipes of the present invention utilize multi-frame hot rolling, each frame is designed with a small elongation coefficient of 1.01-1.60, and the overall hot rolling elongation coefficient is 2.0-4.5. After the 625 alloy is extruded, the pipe is longitudinally deformed during hot rolling to achieve a large deformation amount, and then one or two passes of cold rolling are performed to the final specification. Compared with the prior art, the present invention adopts a production process of hot extrusion + induction furnace insulation + hot rolling + induction furnace insulation, reduces the number of cold rolling passes in the cold deformation process, produces good product quality, is conducive to shortening the production cycle, reducing production costs, and improving comprehensive economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The schematic diagram of the process of forming the 625 alloy tube of the present invention;

[0023] Figure 2 It is the structural schematic diagram of the resistance furnace;

[0024] Figure 3 It is a structural schematic diagram of a horizontal extruder;

[0025] Among them: 1-pre-processing equipment, 2-resistance furnace, 3-induction furnace, 4-vertical reamer, 5-horizontal extruder, 6-hot rolling mill, 7-pickling tank, 8-grinding machine, 9-cold rolling mill, 10-continuous roller bottom heat treatment furnace, 11-finished product refining inspection equipment, 12-finished product warehouse. 13-observation hole, 14-furnace door, 15-thermocouple, 16-furnace shell, 17-electric heating element, 18 refractory material, 19-insulating material, 20-support leg, 21-base, 22-mold-mold pad-mold base assembly, 23-extrusion cylinder jacket, 24-extrusion cylinder, 25-extrusion cylinder lining, 26-extrusion pad, 27-core rod, 28-needle support, 29-extrusion rod. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with the embodiments and drawings. The protection scope of the present invention is not limited to the embodiments, and any changes made by those skilled in the art within the scope defined by the claims also fall within the protection scope of the present invention.

[0027] The device for forming the 625 alloy tube of the present invention is as follows Figure 1 As shown, it includes pre-processing equipment 1, resistance furnace 2, induction furnace 3, reaming machine 4, extruder 5, hot rolling mill 6, pickling tank 7, grinding machine 8, cold rolling mill 9, continuous roller bottom heat treatment furnace 10, finished product refining inspection equipment 11 and finished product warehouse 12. The pre-processing equipment includes sawing equipment, peeling equipment, polishing machine, drilling machine, bell mouth processor, inspection equipment, grinding machine and cleaning machine. The pre-processing equipment, resistance furnace, induction furnace, reaming machine, extruder, hot rolling mill, pickling tank, grinding machine, cold rolling mill, continuous roller bottom heat treatment furnace, finished product refining inspection equipment and finished product warehouse are arranged in sequence. The finished product refining inspection equipment includes straightening machine, pickling machine, inspection grinding machine, ultrasonic flaw detector and finishing inspection and cutting equipment. The extruder 5 is a 6300T horizontal extruder, the reaming machine is a 2500T vertical reaming machine, and the hot rolling mill is a multi-frame forming hot rolling mill. As shown in FIG. Figure 2 As shown, the resistance furnace is provided with an observation hole 13, a furnace door 14, a thermocouple 15, a furnace shell 16, an electric heating element 17, a refractory material 18, a heat-insulating material 19 and a support leg 20. Figure 3 As shown, the extruder includes a base 21, a die-die pad-die holder assembly 22, an extrusion barrel outer sleeve 23, an extrusion barrel 24, an extrusion barrel liner 25, an extrusion pad 26, a core rod 27, a needle support 28 and an extrusion rod 29.

[0028] The process steps for forming 625 alloy pipes are: billet inspection → billet processing → billet cleaning → resistance furnace preheating → hole expansion induction heating → lubrication → hot hole expansion → extrusion induction heating → lubrication → hot extrusion → heating and insulation → hot rolling → heating and insulation → water cooling → pickling → inspection and grinding → cold rolling → solution treatment → straightening → pickling → inspection and grinding → ultrasonic flaw detection → finishing inspection and cutting → warehousing.

[0029] Example 1

[0030] The production specification is φ168.3mm×10.97mm 625 alloy pipe, and the alloy chemical composition meets the requirements of ASTM B444. The differentiation test data of 625 alloy pipe are shown in Table 1:

[0031] Table 1. 625 alloy tube composition test data / (mass percentage %)

[0032]

[0033] The traditional process of deformation is: billet φ435 / φ165mm→extrusion φ273×25mm→first cold rolling φ245×17mm→second cold rolling φ219×13mm→third cold rolling φ168.3×10.97mm. The method of forming the 625 alloy pipe of the present invention has the following specific steps:

[0034] ⑴ Billet preparation: The billet is a forging billet with a specification of φ435 / φ165×600mm. The billet is inspected and processed, including sawing, peeling, polishing, drilling, bell mouth processing, inspection, grinding and cleaning. Process requirements: After processing and polishing, the outer surface is smooth and defect-free, with a roughness of ≤1.6μm, and the outer arc angle of the billet head after lathe processing is R40mm.

[0035] ⑵ Preheating of blanks: The processed blanks are preheated in a resistance furnace at a preheating temperature of 930-960°C.

[0036] ⑶ Heating and expanding: After preheating, the blank is heated to 1160-1180℃ in an induction furnace, and a 2500T vertical expanding machine is used for hole expansion. The inner and outer surfaces of the blank are lubricated with glass powder before hot hole expansion. The diameter of the expanding head is 240mm, the hot hole expansion speed is 160-220mm / s, and the hole expansion extension coefficient is about 1.33.

[0037] (4) Heating and extrusion: After hole expansion, the blank is heated to 1170-1200℃ in an induction furnace and extruded by a 6300T horizontal extruder. The inner and outer surfaces of the blank are lubricated with glass powder before extrusion; the core rod diameter is 230mm, the inner diameter of the extrusion die is 280mm, the inner diameter of the extrusion barrel is 375mm, the extrusion speed is 100-160mm / s, and the extrusion elongation coefficient is about 3.4.

[0038] ⑸ Insulation recrystallization: After hot extrusion, the alloy tube is sent into the induction furnace while hot and kept at 1120-1160℃ for 10-60min to complete recrystallization.

[0039] (6) Hot rolling: Multi-frame forming is used to perform hot rolling longitudinal deformation on the alloy pipe. The overall hot rolling elongation coefficient is 2.0-4.5, and the elongation coefficient of each frame is 1.01-1.60. The alloy pipe specification is φ219×13mm.

[0040] ⑺ Insulation recrystallization: The alloy tube after hot rolling is sent into the induction furnace while hot, and kept at 1120-1160℃ for 10-60min. After recrystallization, it is sent into water at high temperature and cooled to room temperature.

[0041] ⑻ Pickling and grinding: Pickle the alloy pipes after continuous rolling to remove the oxide scale; inspect and grind the alloy pipes after pickling to remove surface cracks, folds and pits.

[0042] ⑼Cold rolling: cold rolling is performed once to the final specification of 625 alloy pipe of φ168.3×10.97mm, and the cold rolling elongation coefficient is 1.55-1.65.

[0043] ⑽Solution treatment: The 625 alloy pipe is solution treated in a continuous roller bottom heat treatment furnace. The holding temperature of the solution treatment is 1140-1160℃, the holding time is 40-60 minutes, and then sprayed with water to cool to room temperature.

[0044] ⑾Refining inspection: The 625 alloy pipe after solid solution treatment is straightened, pickled, inspected and ground, ultrasonically inspected and finished to make finished 625 alloy pipe. The product quality meets the ASTM B444 standard and is then put into storage. The performance test data of 625 alloy pipe after refinement inspection is shown in Table 2.

[0045] Table 2. Performance test results of 625 alloy tube after refining inspection

[0046]

[0047] Example 2

[0048] The product specification is φ60mm×6mm 625 alloy pipe, and the alloy chemical composition meets the requirements of ASTM B444. The differentiation test data of 625 alloy pipe are shown in Table 3:

[0049] Table 3. 625 alloy tube composition test data / (mass percentage %)

[0050]

[0051] The traditional process of deformation is: billet φ242 / φ65mm→extrusion φ161×18mm→first cold rolling φ133×12mm→second cold rolling φ114×10mm→third cold rolling φ90×7.5mm→fourth cold rolling φ60×6mm. The method of forming 625 alloy pipe of the present invention has the following specific steps:

[0052] ⑴ Billet preparation: The billet is a forging billet with a specification of φ242 / φ65×600mm. The billet is inspected and processed, including sawing, peeling, polishing, drilling, bell mouth processing, inspection, grinding and cleaning. After processing and polishing, the outer surface is smooth and defect-free, with a roughness of ≤1.6μm. The outer arc angle of the billet head after lathe processing is R30mm.

[0053] ⑵ Preheating of blanks: The processed blanks are preheated in a resistance furnace at a preheating temperature of 930-960°C.

[0054] ⑶ Heating and expanding: After preheating, the blank is heated to 1160-1180℃ in an induction furnace, and a 2500T vertical expanding machine is used for hole expansion. The inner and outer surfaces of the blank are lubricated with glass powder before hot expansion. The diameter of the expanding head is 138mm, the hot expansion speed is 160-220mm / s, and the expansion extension coefficient is 1.30.

[0055] (4) Heating and extrusion: After hole expansion, the blank is heated to 1170-1200℃ in an induction furnace and extruded by a 6300T horizontal extruder. The inner and outer surfaces of the blank are lubricated with glass powder before extrusion; the core rod diameter is 127.2mm, the inner diameter of the extrusion die is 164.7mm, the inner diameter of the extrusion barrel is 255mm, the extrusion speed is 100-150mm / s, and the extrusion elongation coefficient is about 4.46.

[0056] ⑸ Insulation recrystallization: After hot extrusion, the alloy tube is sent into the induction furnace while hot and kept at 1120-1160℃ for 10-60min to complete recrystallization.

[0057] ⑹ Hot rolling: Multi-frame forming is used to perform hot rolling longitudinal deformation on the alloy pipe. The overall hot rolling elongation coefficient is 2.0-4.5, and the elongation coefficient of each frame is 1.01-1.60. The alloy pipe specification is φ114×10mm.

[0058] ⑺ Insulation recrystallization: The alloy tube after hot rolling is sent into the induction furnace while hot, and kept at 1120-1160℃ for 10-60min. After recrystallization, it is sent into water at high temperature and cooled to room temperature.

[0059] ⑻ Pickling and grinding: Pickle the alloy pipe after continuous rolling to remove the oxide scale; inspect and grind the alloy pipe after pickling to remove surface cracks, folds and pits;

[0060] ⑼Cold rolling: The alloy pipe is subjected to two passes of cold rolling, and the elongation coefficient of a single pass of cold rolling is 1.45-1.95, to obtain a 625 alloy pipe with a specification of φ60×6mm.

[0061] ⑽Solution treatment: The 625 alloy pipe is solution treated in a continuous roller bottom heat treatment furnace. The holding temperature of the solution treatment is 1140-1160℃, the holding time is 40-60 minutes, and then sprayed with water to cool to room temperature.

[0062] ⑾Refined inspection: The 625 alloy pipe after solution treatment is straightened, pickled, inspected, ground, ultrasonically inspected, and finished and inspected to make finished 625 alloy pipes, and then put into storage. The performance test data of 625 alloy pipe after refined inspection is shown in Table 4.

[0063] Table 4. Performance test results of 625 alloy tube after refining inspection

[0064]

[0065]

Claims

1. A method for forming a 625 alloy tube, characterized in that: The molding process is as follows: (1) Billet preparation: including billet inspection and billet processing, the billet processing includes sawing, peeling, polishing, drilling, bell mouth processing, inspection, grinding and cleaning; ⑵ Preheating of blanks: The processed blanks are preheated in a resistance furnace at a preheating temperature of 930-960°C; ⑶ Heating and hole expansion: After preheating, the blank is heated to 1160-1180℃ in an induction furnace, and a 2500T vertical hole expansion machine is used for hole expansion. The inner and outer surfaces of the blank are lubricated with glass powder before hot hole expansion. The hot hole expansion speed is 160-220mm / s, and the hole expansion extension coefficient is 1.05-1.33; (4) Heating and extruding: After hole expansion, the blank is heated to 1170-1200℃ in an induction furnace and extruded using a 6300T horizontal extruder. The inner and outer surfaces of the blank are lubricated with glass powder before extrusion. ⑸ Insulation recrystallization: After hot extrusion, the alloy tube is sent into the induction furnace while hot and kept at 1120-1160℃ for 10-60min to complete recrystallization; (6) Hot rolling: Multi-frame forming is used to perform hot rolling longitudinal deformation on alloy pipes. The overall hot rolling elongation coefficient is 2.0-4.5, and the elongation coefficient of each frame is 1.01-1.60; ⑺ Insulation recrystallization: The alloy tube after hot rolling is sent into the induction furnace while hot, and kept at 1120-1160℃ for 10-60min. After recrystallization, it is sent into water at high temperature and cooled to room temperature; ⑻ Pickling and grinding: Pickle the alloy pipe after continuous rolling to remove the oxide scale; inspect and grind the alloy pipe after pickling to remove surface cracks, folds and pits; ⑼Cold rolling: The alloy pipe is cold rolled once or twice to the final specification, and the elongation coefficient of single cold rolling is 1.45-1.95; ⑽Solution treatment: The alloy pipe is subjected to solution treatment in a continuous roller bottom heat treatment furnace. The holding temperature of the solution treatment is 1140-1160°C, the holding time is 40-60 minutes, and then sprayed with water to cool to room temperature; ⑾Refining inspection: The alloy pipes after solid solution treatment are straightened, pickled, inspected and ground, ultrasonically inspected and finished to make finished 625 alloy pipes. The products are tested and the quality meets the ASTM B444 standard before being put into storage.

2. The method for forming a 625 alloy tube according to claim 1, characterized in that: The extrusion speed of the heated extrusion is 100-160 mm / s, and the extrusion extension coefficient is 2.2-5.

8.

3. The method for forming a 625 alloy tube according to claim 1, characterized in that: The heat preservation and recrystallization after extrusion molding can be carried out by online heating while hot after extrusion or by reheating after extrusion cooling. The heating and heat preservation after hot rolling can be carried out by online heating while hot after continuous rolling or by reheating after continuous rolling cooling.

4. The method for forming a 625 alloy tube according to claim 1, characterized in that: The chemical composition of the alloy to be inspected for billets must meet the requirements of ASTM B444, and the quality of 625 alloy pipe products must comply with ASTM B444 standards.

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