Heavy extruder, small-size core rod structure and preparation method

Abstract

The invention discloses a small-size core rod structure which comprises a core rod body, a tail part and a working part, the tail part and the working part are arranged at the two ends of the core rod body, a longitudinal blind hole and a transverse through hole are formed in the tail part, the transverse through hole transversely penetrates through the tail part and is communicated with the longitudinal blind hole, and a chromium coating is arranged on the surface of the working part. The invention further discloses a heavy extruder and a preparation method of the small-size core rod structure. According to the invention, lateral displacement and breakage of the core rod are avoided, and the extrusion metal reflux accident can be reduced.

Description

Technical Field

[0001] The invention belongs to the field of seamless steel pipe extrusion manufacturing, and in particular relates to a heavy-duty extruder, a small-size core rod structure and a preparation method. Background Art

[0002] The molds required for the seamless steel pipe extrusion process include an extrusion cylinder, an extrusion shaft, an extrusion pad, an extrusion die and a mandrel. The extrusion cylinder accommodates the extruded billet, the extrusion shaft provides the force required for extrusion, and the extrusion pad is connected to the extrusion shaft and acts directly on the billet; the extrusion die determines the hot outer diameter of the steel pipe, and the metal billet is extruded from it; the mandrel determines the hot inner hole size of the steel pipe, the mandrel is installed in the extrusion shaft, and the tail is connected to the cylinder. During extrusion, the mandrel passes through the extrusion pad, the hollow billet and the extrusion die, and the metal is extruded from the annular gap formed by the extrusion die and the mandrel to form a seamless steel pipe. After extrusion, the mandrel is retracted into the extrusion shaft and the extrusion pad.

[0003] The inner diameter specifications of seamless steel pipes extruded by heavy-duty extruders are generally larger. For example, the inner diameter specifications of seamless steel pipes produced by 36,000-ton ferrous metal vertical extruders are generally Φ230~Φ1000mm. The inner diameter of the steel pipe is determined by the mandrel in extrusion production. The smaller the inner diameter of the steel pipe, the smaller the size of the mandrel. During the extrusion process, the mandrel is subjected to the compressive stress of the metal under high temperature conditions and the tensile stress generated by strong friction. The mandrel often fails due to severe bending or dimensional wear, and the more serious case is the mandrel breakage. The smaller the size of the mandrel, the lower the service life. When preparing certain special seamless steel pipes with an inner diameter of ≤200mm, the mandrel is in a more demanding working state. In order to increase the service life of small-sized mandrels, it is necessary to design and optimize the structure and manufacturing method of the mandrel. Summary of the invention

[0004] The object of the present invention is to provide a heavy-duty extruder, a small-size core rod structure and a preparation method, which can avoid the lateral displacement and breakage of the core rod and reduce the accident of extruded metal backflow.

[0005] To achieve the above purpose, the technical solution used in the present invention is:

[0006] The small-size mandrel structure comprises: a mandrel body, a tail, and a working part. The tail and the working part are arranged at two ends of the mandrel body. The tail is provided with a longitudinal blind hole and a transverse through hole. The transverse through hole transversely penetrates the tail, and the transverse through hole is connected with the longitudinal blind hole. A chrome-plated layer is arranged on the surface of the working part.

[0007] Furthermore, the two transverse through holes intersect each other perpendicularly, and the opening of the transverse through hole is stepped, with a diameter of 60-100 mm and a center line 80-150 mm from the bottom.

[0008] Furthermore, the core rod is a rotating body structure and is made of heat-resistant die steel H13.

[0009] Furthermore, the diameter of the longitudinal blind hole is 360-500 mm, the height is 200-400 mm, the depth of the longitudinal blind hole below the transverse through hole is 150-250 mm, and the wall thickness of the tail is 120-180 mm.

[0010] Furthermore, the connection between the tail and the core rod body is connected by an arc transition, and the fillet radius is 10-20mm.

[0011] Furthermore, the rear end diameter of the working part is 80-200 mm, the length is 1600-2200 mm, and the slope of the working part 3 is 1:500-1:600.

[0012] Furthermore, a working portion threaded hole is provided at the end of the working portion.

[0013] Furthermore, the connection between the core rod body and the working part is transitionally connected, the angle of the connection part is 120°-150°, the angle is transitionally connected with the fillet of the working part, and the fillet radius is 20-30.

[0014] A heavy-duty extruder comprises: an extrusion barrel, an extrusion pad, an extrusion shaft, an extrusion die, a connecting device, a connecting pin and a small-sized core rod structure. The extrusion pad and the small-sized core rod structure are located in the extrusion barrel, the extrusion die is located on the side of the extrusion barrel, and the extrusion die is provided with an extrusion die through hole; the core rod body is passed through the extrusion pad inner hole of the extrusion pad, the tail is located outside the extrusion pad, and the working part extends out of the extrusion barrel and the extrusion die through hole; the end of the connecting device is provided with a pin hole, the end of the connecting device is inserted in the longitudinal blind hole, the connecting pin is passed through the transverse through hole and the pin hole, and the tail and the end of the connecting device are connected together; the end of the connecting device and the tail are located in the inner hole of the extrusion shaft.

[0015] A method for manufacturing a small-size mandrel structure, comprising:

[0016] H13 steel is smelted in an electric furnace, and then refined outside the furnace, vacuum degassed, and cast to obtain electrode blanks;

[0017] The electrode blank is electroslag remelted to obtain an electroslag ingot, with gas content: [H]≤2ppm, [O]≤30ppm, and the amount of electroslag ingot tail removed is 50mm;

[0018] After the electroslag ingot is heated, it is forged to obtain a forging, with a forging ratio of ≥4, and annealing is performed immediately after forging;

[0019] The forging is first rough-machined to obtain the core rod, and then quenched and tempered after retaining a 5-10mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, KV2 = 17J;

[0020] The core rod is finely processed to the finished product size, and the surface of the working part of the core rod is chrome-plated with a thickness of 0.10-0.12 mm to obtain a small-sized core rod structure.

[0021] The technical effects of the present invention include:

[0022] 1. In the small-size mandrel structure of the present invention, the tail and middle of the mandrel are positioned and guided with the extrusion shaft and the extrusion pad respectively, thereby preventing the mandrel from shifting sideways. The transition between the chamfer and fillet of the middle of the mandrel and the working part not only avoids the risk of the mandrel being broken by the lateral force during the mandrel extrusion process, but also reduces the accident of extruded metal backflow.

[0023] 2. The surface chrome plating of the small-size mandrel structure of the present invention reduces the mandrel withdrawal force after the mandrel is extruded, and at the same time increases the service life, which is more than 3 times that before chrome plating. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the core rod 1 in the present invention;

[0025] Figure 2 It is a usage state diagram of the small-sized mandrel structure of the present invention. DETAILED DESCRIPTION

[0026] The following description sufficiently illustrates specific embodiments of the invention to enable those skilled in the art to practice and reproduce the invention.

[0027] like Figure 1 , which is a structural diagram of the core rod 1 in the present invention.

[0028] The small-size mandrel structure includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected with the longitudinal blind hole 21. The tail 2 is used to be connected to the oil cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0029] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 60-100mm (preferably 90mm), and the center line is 80-150mm (preferably 100mm) from the bottom.

[0030] The diameter D1 of the longitudinal blind hole 21 is 360-500 mm (preferably 480 mm), the height is 200-400 mm (preferably 250 mm), the depth of the lower part of the transverse through hole 22 is 150-250 mm, and the wall thickness of the tail 2 is 120-180 mm (preferably 150 mm).

[0031] The diameter D2 of the core rod body 1 = the inner hole diameter d1-5mm of the extrusion pad (preferably 260mm). When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is equal to the inner hole height of the extrusion pad 5 (300mm). The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the radius is R10-R20mm.

[0032] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 80-200mm (preferably 160mm), the length is 1600-2200mm (preferably 2000mm), the slope of the working part 3 is 1:500-1:600, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 120°-150° (preferably 135°), the angle is transitioned with the fillet of the working part, and the fillet radius is R20-R30mm.

[0033] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0034] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0035] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0036] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0037] (4) The forging is first rough-machined to obtain the core rod, and then quenched and tempered after leaving a 5-10mm finishing allowance. The mechanical properties after heat treatment are Rp 0.2 =1095MPa, Rm=1258MPa, KV2=17J;

[0038] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0039] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0040] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10-0.12 mm and a hardness of 800 HV.

[0041] The service life of the small-size mandrel structure is increased by 3.5 times, which improves the mandrel manufacturing technology level while reducing production costs.

[0042] like Figure 2 The figure shows the use state of the small-sized mandrel structure of the present invention.

[0043] A heavy extruder, comprising: an extrusion barrel 4, an extrusion pad 5, an extrusion shaft 6, an extrusion die 7, a connecting device 8, a connecting pin 9 and a small-sized core rod structure,

[0044] The extrusion pad 5 and the small-size core rod structure are located in the extrusion barrel 4, the extrusion die 7 is located on the side of the extrusion barrel 4, and the extrusion die 7 is provided with an extrusion die through hole; the core rod body 1 is passed through the extrusion pad inner hole of the extrusion pad 5, the tail 2 is located outside the extrusion pad 5, and the working part 3 extends out of the extrusion barrel 4 and the extrusion die through hole; the end of the connecting device 8 is provided with a pin hole, and the end of the connecting device 8 is inserted into the longitudinal blind hole 21, and the connecting pin 9 is passed through the transverse through hole 22 and the pin hole to connect the tail 2 and the end of the connecting device 8 together; the end of the connecting device 8 and the tail 2 are located in the inner hole of the extrusion shaft 6.

[0045] The billet is placed in the extrusion barrel 4, the extrusion shaft 6 provides extrusion force, the extrusion pad 5 contacts the extrusion shaft 6, and together pushes the billet. The billet is extruded from the annular gap between the through hole of the extrusion die and the working part 3 to form a seamless steel pipe. After the extrusion is completed, the core rod is retracted into the extrusion barrel 4.

[0046] Example 1

[0047] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0048] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0049] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0050] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0051] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving a 5-10mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0052] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0053] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0054] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.12 mm and a hardness of 800 HV.

[0055] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0056] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 90mm, and the center line is 100mm from the bottom.

[0057] The diameter D1 of the longitudinal blind hole 21 is 480 mm, the height is 250 mm, the depth of the lower part of the transverse through hole 22 is 150, and the wall thickness of the tail 2 is 150 mm.

[0058] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R10mm.

[0059] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 160 mm, the length is 2000 mm, the slope of the working part 3 is 1:500, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 135°, the angle is transitioned with the fillet of the working part, and the fillet radius is R20 mm.

[0060] Example 2

[0061] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0062] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0063] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0064] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0065] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving a 5-10mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0066] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0067] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0068] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 mm and a hardness of 800 HV.

[0069] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0070] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 60, and the center line is 80 from the bottom.

[0071] The diameter D1 of the longitudinal blind hole 21 is 360, the height is 200, the depth of the lower part of the transverse through hole 22 is 150, and the wall thickness of the tail 2 is 120.

[0072] The core rod body 1 has a diameter of 260 mm and is used in conjunction with a squeeze pad 5 . The inner hole diameter d1 of the squeeze pad is 265 mm and the height is 300 mm higher than the inner hole height of the squeeze pad 5 . The connection between the tail 2 and the core rod body 1 is connected by an arc transition with a fillet of R10.

[0073] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 80, the length is 1600, the slope of the working part 3 is 1:600, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 120°, and the angle transitions with the fillet of the working part, and the fillet radius is R20.

[0074] Example 3

[0075] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0076] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 100 mm, and the center line is 150 mm from the bottom.

[0077] The diameter D1 of the longitudinal blind hole 21 is 500 mm, the height is 400 mm, the depth of the lower part of the transverse through hole 22 is 250 mm, and the wall thickness of the tail 2 is 180 mm.

[0078] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R20mm.

[0079] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 200mm, the length is 2200mm, the slope of the working part 3 is 1:500, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 150°, and the angle transitions with the fillet of the working part, and the fillet radius R30mm.

[0080] Example 4

[0081] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0082] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0083] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0084] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0085] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving a 5% finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0086] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0087] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0088] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 to 0.12 mm and a hardness of 800 HV.

[0089] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0090] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 70mm, and the center line is 90 from the bottom.

[0091] The diameter D1 of the longitudinal blind hole 21 is 400 mm, the height is 250 mm, the depth of the lower part of the transverse through hole 22 is 200 mm, and the wall thickness of the tail 2 is 150 mm.

[0092] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R15mm.

[0093] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 90, the length is 1800mm, the slope of the working part 3 is 1:500-1:550, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 135°, the angle is transitioned with the fillet of the working part, and the fillet radius is R20.

[0094] Example 5

[0095] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0096] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0097] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0098] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0099] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving a 10mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0100] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0101] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0102] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.11 mm and a hardness of 800 HV.

[0103] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0104] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 90mm, and the center line is 140 from the bottom.

[0105] The diameter D1 of the longitudinal blind hole 21 is 500 mm, the height is 300 mm, the depth of the lower part of the transverse through hole 22 is 200 mm, and the wall thickness of the tail 2 is 180 mm.

[0106] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R15mm.

[0107] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 160 mm, the length is 2000 mm, the slope of the working part 3 is 1:500, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 135°, the angle is transitioned with the fillet of the working part, and the fillet radius is R30 mm.

[0108] Example 6

[0109] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0110] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0111] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0112] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0113] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving an 8mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0114] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0115] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0116] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 and a hardness of 800 HV.

[0117] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0118] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 60, and the center line is 150mm from the bottom.

[0119] The diameter D1 of the longitudinal blind hole 21 is 500 mm, the height is 200, the depth of the lower part of the transverse through hole 22 is 150, and the wall thickness of the tail 2 is 150 mm.

[0120] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R20mm.

[0121] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 80, the length is 2200mm, the slope of the working part 3 is 1:600, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 135°, and the angle transitions with the fillet of the working part, and the fillet radius R30mm.

[0122] Example 7

[0123] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0124] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0125] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0126] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0127] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving an 8mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0128] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0129] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0130] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 and a hardness of 800 HV.

[0131] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0132] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 100mm, and the center line is 80 from the bottom.

[0133] The diameter D1 of the longitudinal blind hole 21 is 450 mm, the height is 300 mm, the depth of the lower part of the transverse through hole 22 is 150, and the wall thickness of the tail 2 is 140 mm.

[0134] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R10.

[0135] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 100mm, the length is 1600, the slope of the working part 3 is 1:600, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 150°, and the angle transitions with the fillet of the working part, and the fillet radius is R20mm.

[0136] Example 8

[0137] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0138] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0139] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0140] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0141] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving an 8mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0142] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0143] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0144] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 and a hardness of 800 HV.

[0145] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0146] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 90 mm, and the center line is 120 mm from the bottom.

[0147] The diameter D1 of the longitudinal blind hole 21 is 500 mm, the height is 400 mm, the depth of the lower part of the transverse through hole 22 is 250 mm, and the wall thickness of the tail 2 is 180 mm.

[0148] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R20mm.

[0149] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 200mm, the length is 1600-2200mm, the slope of the working part 3 is 1:500, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 120°, the angle is transitioned with the fillet of the working part, and the fillet radius is R30mm.

[0150] Example 9

[0151] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0152] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0153] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0154] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0155] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving an 8mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0156] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0157] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0158] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 and a hardness of 800 HV.

[0159] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0160] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 95mm, and the center line is 120mm from the bottom.

[0161] The diameter D1 of the longitudinal blind hole 21 is 360480 mm, the height is 20, the depth of the lower part of the transverse through hole 22 is 150, and the wall thickness of the tail 2 is 120.

[0162] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R10.

[0163] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 80, the length is 2000mm, the slope of the working part 3 is 1:550, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 140°, and the angle transitions with the fillet of the working part, and the fillet radius is R20.

[0164] Example 10

[0165] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0166] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0167] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0168] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0169] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving an 8mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0170] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0171] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0172] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 and a hardness of 800 HV.

[0173] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0174] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 100 mm, and the center line is 150 mm from the bottom.

[0175] The diameter D1 of the longitudinal blind hole 21 is 480 mm, the height is 400 mm, the depth of the lower part of the transverse through hole 22 is 250 mm, and the wall thickness of the tail 2 is 120.

[0176] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R10.

[0177] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 160 mm, the length is 2200 mm (preferably 2000 mm, the slope of the working part 3 is 1:500, and the end of the working part 3 is provided with a working part threaded hole. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 150°, the angle is transitioned with the rounded corner of the working part, and the rounded corner radius is R25 mm.

[0178] Embodiment 11

[0179] The manufacturing method of the small-size core rod structure includes: smelting, forging, heat treatment, machining and surface treatment.

[0180] (1) Smelting H13 steel in an electric furnace, refining outside the furnace, vacuum degassing, and casting to obtain electrode blanks;

[0181] (2) Electroslag remelting of the electrode blank to obtain an electroslag ingot, with gas content of [H]≤2ppm, [O]≤30ppm, and a removal amount of 50mm at the tail of the electroslag ingot;

[0182] (3) After the electroslag ingot is heated, the forging is forged, the forging ratio is ≥4, and annealing is performed immediately after forging;

[0183] (4) The forging is first rough-machined to obtain a core rod, and then quenched and tempered after leaving an 8mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, and KV2 = 17J;

[0184] (5) The mandrel is finely processed to the finished product size, and the roughness Ra of the working part is better than 1.6μm;

[0185] (6) The surface of the mandrel working part is chrome plated to obtain a small-sized mandrel structure;

[0186] The chrome plating layer on the surface of the working part 3 of the small-size mandrel structure has a thickness of 0.10 and a hardness of 800 HV.

[0187] A small-size mandrel structure for a heavy-duty extruder includes: a mandrel body 1, a tail 2, and a working part 3. The tail 2 and the working part 3 are arranged at both ends of the mandrel body 1. The tail 2 is provided with a longitudinal blind hole 21 and a transverse through hole 22. The transverse through hole 22 transversely penetrates the tail 2 and is connected to the longitudinal blind hole 21. The tail 2 is used to be connected to the cylinder, the mandrel body 1 is used to cooperate with the extrusion pad 5, and the working part 3 participates in the extrusion deformation of the metal.

[0188] The two transverse through holes 22 intersect each other perpendicularly. The core rod is a rotating body structure, and the material is heat-resistant mold steel H13. The opening of the transverse through hole 22 is stepped, the diameter of the transverse through hole 22 is 60, and the center line is 80 from the bottom.

[0189] The diameter D1 of the longitudinal blind hole 21 is 480 mm, the height is 270 mm, the depth of the lower part of the transverse through hole 22 is 200 mm, and the wall thickness of the tail 2 is 180 mm.

[0190] The diameter D2 of the core rod body 1 is equal to the inner hole diameter of the extrusion pad 260mm. When used in conjunction with the extrusion pad 5, the inner hole diameter d1 of the extrusion pad is 265mm, and the height is 300mm the same as the inner hole height of the extrusion pad 5. The connection between the tail 2 and the core rod body 1 is connected by an arc transition, and the fillet is R10.

[0191] The rear end diameter D3 of the working part 3 of the mandrel body 1 is 180 mm, the length is 2000 mm, the slope of the working part 3 is 1:550, and a working part threaded hole is provided at the end of the working part 3. The connection between the mandrel body 1 and the working part 3 is transitionally connected, the angle of the connection part is 135°, the angle is transitioned with the fillet of the working part, and the fillet radius is R30 mm.

[0192] The terms used in the present invention are illustrative and exemplary, rather than restrictive. Since the present invention can be implemented in various forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the aforementioned details, but should be widely interpreted within the spirit and scope defined by the attached claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the attached claims.

Claims

1. A small-size mandrel structure, characterized in that: include: The core rod body, the tail part and the working part are arranged at both ends of the core rod body. The tail part is provided with a longitudinal blind hole and a transverse through hole. The transverse through hole transversely penetrates the tail part. The transverse through hole is connected with the longitudinal blind hole. The surface of the working part is provided with a chrome plating layer.

2. The small-size mandrel structure according to claim 1, characterized in that: The two transverse through holes cross each other perpendicularly, and the opening of the transverse through hole is stepped, with a diameter of 60-100 mm and a center line 80-150 mm from the bottom.

3. The small-size mandrel structure according to claim 1, characterized in that: The core rod is a rotating body structure and is made of heat-resistant die steel H13.

4. The small-size mandrel structure according to claim 1, characterized in that: The diameter of the longitudinal blind hole is 360-500mm, the height is 200-400mm, the depth of the longitudinal blind hole below the transverse through hole is 150-250mm, and the wall thickness of the tail is 120-180mm.

5. The small-size mandrel structure according to claim 1, characterized in that: The connection between the tail and the core rod body is connected by an arc transition, and the fillet radius is 10-20mm.

6. The small-size mandrel structure according to claim 1, characterized in that: The rear end diameter of the working part is 80-200mm, the length is 1600-2200mm, and the slope of the working part 3 is 1:500-1:

600.

7. The small-size mandrel structure according to claim 1, characterized in that: A working part threaded hole is provided at the end of the working part.

8. The small-size mandrel structure according to claim 1, characterized in that: The connection between the core rod body and the working part is transitionally connected, the angle of the connection part is 120°-150°, the angle is transitionally connected with the fillet of the working part, and the fillet radius is 20-30.

9. A heavy extruder, comprising: An extrusion barrel, an extrusion pad, an extrusion shaft, an extrusion die, a connecting device, and a connecting pin, characterized in that they also include the small-size core rod structure described in any one of claims 1 to 8, the extrusion pad and the small-size core rod structure are located in the extrusion barrel, the extrusion die is located on the side of the extrusion barrel, and the extrusion die is provided with an extrusion die through hole; the core rod body is passed through the extrusion pad inner hole of the extrusion pad, the tail is located outside the extrusion pad, and the working part extends out of the extrusion barrel and the extrusion die through hole; the end of the connecting device is provided with a pin hole, the end of the connecting device is inserted into the longitudinal blind hole, the connecting pin is passed through the transverse through hole and the pin hole, and the tail and the end of the connecting device are connected together; the end and tail of the connecting device are located in the inner hole of the extrusion shaft.

10. The method for manufacturing a small-size mandrel structure according to any one of claims 1 to 8, characterized in that: include: H13 steel is smelted in an electric furnace, and then refined outside the furnace, vacuum degassed, and cast to obtain electrode blanks; The electrode blank is electroslag remelted to obtain an electroslag ingot, with gas content: [H]≤2ppm, [O]≤30ppm, and the amount of electroslag ingot tail removed is 50mm; After the electroslag ingot is heated, it is forged to obtain a forging, with a forging ratio of ≥4, and annealing is performed immediately after forging; The forging is first rough-machined to obtain the core rod, and then quenched and tempered after retaining a 5-10mm finishing allowance. The mechanical properties after heat treatment are Rp0.2 = 1095MPa, Rm = 1258MPa, KV2 = 17J; The core rod is finely processed to the finished product size, and the surface of the working part of the core rod is chrome-plated with a thickness of 0.10-0.12 mm to obtain a small-sized core rod structure.

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