Punching needle for hot extrusion of copper and copper alloy and method for manufacturing the same

Abstract

The present invention relates to a piercing needle for hot extrusion of copper and copper alloys and a method for manufacturing the same. The piercing needle comprises an extrusion section, a working section, a connecting section, and an assembly section, coaxially connected from left to right. The rightmost end of the working section has a transition section. Deep holes are formed in the working section, connecting section, and assembly section along their axes. The manufacturing method comprises the following steps: smelting and casting a solid H13 billet, homogenizing annealing, forging, rough turning, austempering, oil cooling and air cooling, high-temperature tempering and air cooling, first overall tempering and air cooling, second overall tempering and air cooling, finish turning, grinding, polishing, and testing. The present invention exhibits excellent hardness stability, a long service life, and high safety.

Description

Technical Field

[0001] The invention belongs to the technical field of copper and copper alloy tube manufacturing, in particular to a piercing needle for hot extrusion of copper and copper alloy and a manufacturing method thereof. Background Art

[0002] Hot extrusion is a common process in the field of copper and copper alloy tube manufacturing technology, and piercing needles are essential molds in this process. Currently, there are two problems with piercing needles used in hot extrusion of copper and copper alloys during use:

[0003] 1) Short service life. Frequent replacement of piercing needles also reduces the efficiency of hot extrusion and disrupts the production cycle. The quality of the tube billet during the heating process is difficult to guarantee during the subsequent extrusion process.

[0004] 2) The piercing needle breaks. The piercing needle is subjected to huge tensile stress under high temperature during use. Once it breaks, the piercing needle will fly out of the extruder, posing a huge safety hazard. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a copper and copper alloy hot extrusion piercing needle having good hardness stability, long service life and high safety, and a method for manufacturing the same.

[0006] According to the technical solution provided by the present invention, the piercing needle for hot extrusion of copper and copper alloys comprises an extrusion section, a working section, a connecting section and an assembly section coaxially connected in sequence from left to right, the rightmost end of the working section having a transition section, and deep holes are opened in the working section, the connecting section and the assembly section along their axes;

[0007] In the direction from left to right, the diameter of the extrusion section is gradually increased, the working section is a cylindrical section, and the diameter of the right end of the extrusion section is equal to the diameter of the working section, the diameter of the connecting section is smaller than the diameter of the working section, and the assembly section is an external thread section, and the outer diameter of the assembly section is smaller than the diameter of the working section;

[0008] The sum of the length L5 of the extrusion section, the length L1 of the working section, the length L2 of the connecting section and the length L3 of the assembly section is 630~680mm; the length L5 of the extrusion section is 28~32mm, the surface roughness Ra is 0.3~0.5mm, and the hardness is 48~52HRC, the diameter of the working section is 63.9~64.0mm, the surface roughness Ra is 0.3~0.5mm, and the hardness is 48~52HRC, the length L2 of the connecting section is 20~30mm, the length L3 of the assembly section is 90~95mm, the outer diameter of the thread is 55.9~56mm, the inner diameter of the thread is 49.9~50mm, and the hardness is 30~40HRC, the remaining part is the length of the working section, and the rightmost end of the working section is the transition section, the length L1-1 of the transition section is 40~60mm, and the diameter of the deep hole is φ24~25mm.

[0009] The method for manufacturing the above-mentioned copper and copper alloy hot extrusion piercing needle comprises the following steps:

[0010] S1. A solid billet with a material of H13 and a specification of φ100*2000~6000 mm is obtained by melting and casting, wherein the Si content is 0.85~0.95 wt%, the Mn content is 0.30~0.45 wt%, the V content is 0.85~0.95 wt%, the Mo content is 1.50~1.70 wt%, the Cr content is 4.90~5.30 wt%, the C content is 0.39~0.43 wt%, the P content does not exceed 0.025 wt%, the S content does not exceed 0.010 wt%, and the balance is Fe;

[0011] S2, homogenizing annealing the solid billet of S1 at a temperature of 1225-1250°C for 1-1.5 hours;

[0012] S3, forging the solid billet obtained in S2 to φ74~76mm;

[0013] S4. Rough-turn the blank obtained in S3 to φ67.5~68mm*630~680mm, mark the positions of the punching and extrusion section, working section, connecting section, and assembly section, and mark the position of the transition section in the working section. Drill deep holes with a diameter of φ24~25mm in the working section, connecting section, and assembly section along their axes;

[0014] S5, firstly subjecting the blank obtained in S4 to isothermal quenching treatment in a salt bath furnace at a quenching temperature of 1030-1040°C and a holding time of 40-50 minutes, and then cooling the blank in quenching oil at 60-70°C for 25-35 minutes, and finally removing the blank from the quenching oil and cooling it in air;

[0015] S6. Perform high-temperature tempering treatment on half the transition section, the connecting section, and the assembly section of the blank obtained in S5 in a salt bath furnace at a tempering temperature of 650-680° C. for 60-80 min, and then air cool the blank after exiting the salt bath furnace.

[0016] S7, subjecting the blank obtained in S6 to a first overall tempering treatment at a tempering temperature of 580-590°C for a holding time of 300-360 minutes, and air cooling after being taken out of the furnace;

[0017] S8, subjecting the blank obtained in S7 to a second overall tempering treatment at a tempering temperature of 560-570°C for a holding time of 300-360 minutes, and air cooling after being taken out of the furnace;

[0018] S9, performing fine turning, grinding and polishing on the blank obtained in S8 to obtain a piercing needle;

[0019] S10, inspecting and testing the punching needle obtained in S9.

[0020] Preferably, in step S5, the punching needle blank is suspended in a non-contact manner and sequentially subjected to austempering, oil cooling and air cooling.

[0021] Preferably, in step S6, the punching needle blanks are suspended in a non-contact manner and subjected to high-temperature tempering treatment and air cooling in sequence.

[0022] Preferably, in step S7, the punching needle blanks are suspended in a non-contact manner and sequentially subjected to a first overall tempering treatment and air cooling.

[0023] Preferably, in step S8, the punching needle blanks are suspended in a non-contact manner and sequentially subjected to a second overall tempering treatment and air cooling.

[0024] The present invention has the following advantages:

[0025] 1. The piercing needle for hot extrusion of copper and copper alloys and its manufacturing method have a simple manufacturing process and good hardness stability, avoiding the problem of unstable bearing capacity when used at high temperatures. Combined with the performance and shape design of the piercing needle, its service life is improved and its use safety is high.

[0026] 2. Through the scientific design and control of alloy elements and impurity elements, the toughness and hardenability of the material are improved, and the service life and safety of the piercing needle are improved.

[0027] 3. Through homogenization annealing after melting and casting, material segregation is eliminated, the forging quality is improved, and a good reserve is made for the performance stability of subsequent quenching and tempering. The setting of this process also cancels the subsequent common spheroidizing annealing process, thereby improving the manufacturing efficiency of the piercing needle.

[0028] 4. Through the step-by-step cooling annealing process, combined with the non-contact hanging heat treatment of the piercing needles, the stability of the final performance after tempering is guaranteed.

[0029] 5. By setting the length of the transition section, the hardness of the non-working section is reduced, the toughness is improved, and the brittle fracture of the threaded section when the piercing needle is in use is avoided; the traditional threaded section is extended to the non-threaded section as a transition section, so that when the piercing needle is in use, the working section and the transition section are seamlessly connected, avoiding brittle fracture at the connection between the threaded section, the working section and the transition section, and also improving the service life of the piercing needle.

[0030] 6. The length of the piercing needle is designed to be the shortest, which increases the stability during use, extends the service life, and is less likely to break.

[0031] 7. The inside of the piercing needle adopts a deep hole design, which is cooled by water during use, greatly improving its service life.

[0032] 8. By reducing the surface roughness of the punching needle, the tensile stress on the punching needle during use is greatly reduced, and the service life and safety are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific embodiments.

[0035] Example 1

[0036] A method for manufacturing a piercing needle for hot extrusion of copper and copper alloys, the method comprising the following steps:

[0037] S1, melt casting to obtain a solid billet with a material of H13 and a specification of φ100*4000mm, with a Si content of 0.91 wt%, a Mn content of 0.33 wt%, a V content of 0.89 wt%, a Mo content of 1.62 wt%, a Cr content of 5.18 wt%, a C content of 0.41 wt%, a P content of 0.009 wt%, a S content of 0.006 wt%, and the balance of Fe;

[0038] S2, homogenizing annealing the solid billet of S1 at a temperature of 1225°C for 1.5 hours;

[0039] S3, forging the solid billet obtained in S2 to φ74mm;

[0040] S4. Rough-turn the blank obtained in S3 to φ67.5*645mm, mark the positions of the punching section 5, working section 1, connecting section 2, and assembly section 3, and mark the position of the transition section 1-1 in the working section 1. Drill deep holes 4 with a diameter of φ24mm in the working section 1, connecting section 2, and assembly section 3 along their axes;

[0041] S5, the billet obtained in S4 is first subjected to austempering treatment in a salt bath furnace in a non-contact hanging manner, the quenching temperature is 1030° C., the holding time is 50 min, and then the billet is subjected to oil cooling in quenching oil at 70° C. in a non-contact hanging manner for 25 min, and finally the billet is subjected to air cooling in a non-contact hanging manner;

[0042] S6. The half length of the transition section 1-1, the connecting section 2, and the assembly section 3 of the blank obtained in S5 are suspended together in a salt bath furnace without contact with each other for high-temperature tempering treatment at a tempering temperature of 650° C. for 80 minutes. After being taken out of the furnace, they are suspended without contact with each other for air cooling.

[0043] S7, the blanks obtained in S6 are subjected to a first overall tempering treatment by hanging them in a non-contact manner, with a tempering temperature of 580° C. and a holding time of 360 min. After being taken out of the furnace, they are hung in a non-contact manner for air cooling;

[0044] S8, subjecting the blanks obtained in S7 to a second overall tempering treatment in a non-contact hanging manner, with a tempering temperature of 560° C. and a holding time of 360 min, and then subjecting them to air cooling in a non-contact hanging manner after being taken out of the furnace;

[0045] S9, performing fine turning, grinding and polishing on the blank obtained in S8 to obtain a piercing needle;

[0046] S10, inspecting and testing the punching needle obtained in S9.

[0047] The obtained copper and copper alloy hot extrusion piercing needle comprises an extrusion section 5, a working section 1, a connecting section 2, and an assembly section 3 coaxially connected from left to right. The rightmost end of the working section 1 has a transition section 1-1. Deep holes 4 are formed in the working section 1, the connecting section 2, and the assembly section 3 along their axes.

[0048] From left to right, the diameter of the extrusion section 5 is gradually increased. The working section 1 is a cylindrical section, and the diameter of the right end of the extrusion section 5 is equal to the diameter of the working section 1. The diameter of the connecting section 2 is smaller than the diameter of the working section 1. The assembly section 3 is an external threaded section, and the outer diameter of the assembly section 3 is smaller than the diameter of the working section 1.

[0049] The sum of the length L5 of the extrusion section 5, the length L1 of the working section 1, the length L2 of the connecting section 2 and the length L3 of the assembly section 3 is 640 mm; the length L5 of the extrusion section 5 is 28 mm, the surface roughness Ra is 0.461 mm, and the hardness is 50 HRC, the diameter of the working section 1 is 63.92 mm, the surface roughness Ra is 0.33 mm, and the hardness is 51 HRC, the length L2 of the connecting section 2 is 20 mm, the length L3 of the assembly section 3 is 90.4 mm, the outer diameter of the thread is 55.90 mm, the inner diameter of the thread is 49.92 mm, and the hardness is 35 HRC, the remaining part is the length L1 of the working section 1, and the rightmost end of the working section 1 is the transition section 1-1, the length L1-1 of the transition section 1-1 is 40 mm, and the diameter of the deep hole 4 is φ24 mm.

[0050] The 60 copper and copper alloy hot extrusion piercing needles manufactured in this embodiment were used to extrude solid white copper alloy tubes made of BFe10-1-1 and with specifications of φ180×230mm into hollow tubes of φ84×10mm. On average, each piercing needle extruded 1,319 tubes. The average service life of each piercing needle was increased by 83.3% compared with the previous ones, and none of the piercing needles had problems of brittle fracture or flying out.

[0051] Example 2

[0052] A method for manufacturing a piercing needle for hot extrusion of copper and copper alloys, the method comprising the following steps:

[0053] S1. A solid billet with a material of H13 and a specification of φ100*5000 mm is obtained by melting and casting, wherein the Si content is 0.88 wt%, the Mn content is 0.41 wt%, the V content is 0.89 wt%, the Mo content is 1.62 wt%, the Cr content is 5.10 wt%, the C content is 0.42 wt%, the P content is 0.012 wt%, the S content does not exceed 0.007 wt%, and the balance is Fe;

[0054] S2, homogenizing annealing the solid billet of S1 at 1250°C for 1.0h;

[0055] S3, forging the solid billet obtained in S2 to φ76mm;

[0056] S4. Rough-turn the blank obtained in S3 to φ58*685mm, mark the positions of the punching section 5, working section 1, connecting section 2, and assembly section 3, and mark the position of the transition section 1-1 in the working section 1. Drill deep holes 4 with a diameter of φ25mm in the working section 1, connecting section 2, and assembly section 3 along their axes;

[0057] S5, the billet obtained in S4 is first subjected to austempering treatment in a salt bath furnace in a non-contact hanging manner, the quenching temperature is 1040° C., the holding time is 40 min, and then the billet is subjected to oil cooling in a quenching oil at 60° C. in a non-contact hanging manner for 35 min, and finally the billet is subjected to air cooling in a non-contact hanging manner;

[0058] S6. The half length of the transition section 1-1, the connecting section 2, and the assembly section 3 of the blank obtained in S5 are suspended together in a salt bath furnace without contact with each other for high-temperature tempering treatment at a tempering temperature of 680° C. for a holding time of 60 min. After being taken out of the furnace, they are suspended without contact with each other for air cooling.

[0059] S7, the blanks obtained in S6 are subjected to a first overall tempering treatment by hanging them in a non-contact manner, the tempering temperature is 590° C., the holding time is 300 min, and the blanks are taken out of the furnace and hung in a non-contact manner for air cooling;

[0060] S8, subjecting the blanks obtained in S7 to a second overall tempering treatment in a non-contact hanging manner, with a tempering temperature of 570° C. and a holding time of 300 min, and then subjecting the blanks to air cooling in a non-contact hanging manner after being taken out of the furnace;

[0061] S9, performing fine turning, grinding and polishing on the blank obtained in S8 to obtain a piercing needle;

[0062] S10, inspecting and testing the punching needle obtained in S9.

[0063] The obtained copper and copper alloy hot extrusion piercing needle comprises an extrusion section 5, a working section 1, a connecting section 2, and an assembly section 3 coaxially connected from left to right. The rightmost end of the working section 1 has a transition section 1-1. Deep holes 4 are formed in the working section 1, the connecting section 2, and the assembly section 3 along their axes.

[0064] From left to right, the diameter of the extrusion section 5 is gradually increased. The working section 1 is a cylindrical section, and the diameter of the right end of the extrusion section 5 is equal to the diameter of the working section 1. The diameter of the connecting section 2 is smaller than the diameter of the working section 1. The assembly section 3 is an external threaded section, and the outer diameter of the assembly section 3 is smaller than the diameter of the working section 1.

[0065] The sum of the length L5 of the extrusion section 5, the length L1 of the working section 1, the length L2 of the connecting section 2 and the length L3 of the assembly section 3 is 680 mm; the length L5 of the extrusion section 5 is 32 mm, the surface roughness Ra is 0.455 mm, and the hardness is 51 HRC; the diameter of the working section 1 is 63.98 mm, the surface roughness Ra is 0.41 mm, and the hardness is 50 HRC; the length L2 of the connecting section 2 is 30 mm; the length L3 of the assembly section 3 is 94.6 mm, the outer diameter of the thread is 55.98 mm, the inner diameter of the thread is 49.94 mm, and the hardness is 37 HRC; the remaining part is the length L1 of the working section 1, and the rightmost end of the working section 1 is the transition section 1-1, the length L1-1 of the transition section 1-1 is 60 mm, and the diameter of the deep hole 4 is φ25 mm.

[0066] The 60 copper and copper alloy hot extrusion piercing needles manufactured in this embodiment are used to extrude solid white copper alloy tubes made of BFe30-1-1 and with specifications of φ180×230mm into hollow tubes of φ84×10mm; each piercing needle extrude an average of 42 tubes; the average service life of each piercing needle is increased by 85.6% compared with the previous ones, and none of the piercing needles have the problem of brittle fracture or flying out.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment according to the essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A piercing needle for hot extrusion of copper and copper alloys, characterized by: It comprises an extrusion section (5), a working section (1), a connecting section (2) and an assembly section (3) which are coaxially connected in sequence from left to right. The rightmost end of the working section (1) has a transition section (1-1). Deep holes (4) are provided in the working section (1), the connecting section (2) and the assembly section (3) along their axes. In the direction from left to right, the diameter of the extrusion section (5) is gradually increased, the working section (1) is a cylindrical section, and the diameter of the right end of the extrusion section (5) is equal to the diameter of the working section (1), the diameter of the connecting section (2) is smaller than the diameter of the working section (1), and the assembly section (3) is an external thread section, and the outer diameter of the assembly section (3) is smaller than the diameter of the working section (1); The sum of the length L5 of the extrusion section (5), the length L1 of the working section (1), the length L2 of the connecting section (2) and the length L3 of the assembly section (3) is 630-680 mm; the length L5 of the extrusion section (5) is 28-32 mm, the surface roughness Ra is 0.3-0.5 mm, and the hardness is 48-52 HRC; the diameter of the working section (1) is 63.9-64.0 mm, the surface roughness Ra is 0.3-0.5 mm, and the hardness is 48-52 HRC. C, the length of the connecting section (2) is L2 = 20 ~ 30 mm, the length of the assembly section (3) is L3 = 90 ~ 95 mm, the outer diameter of the thread is 55.9 ~ 56 mm, the inner diameter of the thread is 49.9 ~ 50 mm, the hardness is 30 ~ 40 HRC, the remaining part is the length of the working section (1), and the rightmost end of the working section (1) is the transition section (1-1), the length of the transition section (1-1) is L1-1 = 40 ~ 60 mm, and the diameter of the deep hole (4) is φ24 ~ 25 mm; The method for manufacturing the piercing needle for hot extrusion of copper and copper alloys comprises the following steps: S1. A solid billet with a material of H13 and a specification of φ100*2000~6000 mm is obtained by melting and casting, wherein the Si content is 0.85~0.95 wt%, the Mn content is 0.30~0.45 wt%, the V content is 0.85~0.95 wt%, the Mo content is 1.50~1.70 wt%, the Cr content is 4.90~5.30 wt%, the C content is 0.39~0.43 wt%, the P content does not exceed 0.025 wt%, the S content does not exceed 0.010 wt%, and the balance is Fe; S2, homogenizing annealing the solid billet of S1 at a temperature of 1225-1250°C for 1-1.5 hours; S3, forging the solid billet obtained in S2 to φ74~76mm; S4, rough turning the blank obtained in S3 to φ67.5~68mm*630~680mm, marking the positions of the punching section (5), the working section (1), the connecting section (2) and the assembly section (3), and marking the position of the transition section (1-1) in the working section (1), and punching a deep hole (4) with a diameter of φ24~25mm along the axis of the working section (1), the connecting section (2) and the assembly section (3); S5, firstly subjecting the blank obtained in S4 to isothermal quenching treatment in a salt bath furnace at a quenching temperature of 1030-1040°C and a holding time of 40-50 minutes, and then cooling the blank in quenching oil at 60-70°C for 25-35 minutes, and finally removing the blank from the quenching oil and cooling it in air; S6, subjecting half the length of the transition section (1-1), the connecting section (2) and the assembly section (3) of the blank obtained in S5 to high-temperature tempering treatment in a salt bath furnace, with the tempering temperature being 650-680°C and the holding time being 60-80 minutes, and then air cooling after exiting the salt bath furnace; S7, subjecting the blank obtained in S6 to a first overall tempering treatment at a tempering temperature of 580-590°C for a holding time of 300-360 minutes, and air cooling after being taken out of the furnace; S8, subjecting the blank obtained in S7 to a second overall tempering treatment at a tempering temperature of 560-570°C for a holding time of 300-360 minutes, and air cooling after being taken out of the furnace; S9, performing fine turning, grinding and polishing on the blank obtained in S8 to obtain a piercing needle; S10, inspecting and testing the punching needle obtained in S9.

2. The piercing needle for hot extrusion of copper and copper alloys according to claim 1, characterized in that: In step S5, the punching needle blanks are suspended in a non-contact manner and sequentially subjected to austempering, oil cooling, and air cooling.

3. The piercing needle for hot extrusion of copper and copper alloys according to claim 1, characterized in that: In step S6, the punching needle blanks are suspended in a non-contact manner and sequentially subjected to high-temperature tempering treatment and air cooling.

4. The piercing needle for hot extrusion of copper and copper alloys according to claim 1, characterized in that: In step S7, the punching needle blanks are suspended in a non-contact manner and sequentially subjected to a first overall tempering treatment and air cooling.

5. The piercing needle for hot extrusion of copper and copper alloys according to claim 1, characterized in that: In step S8, the punching needle blanks are suspended in a non-contact manner and sequentially subjected to a second overall tempering treatment and air cooling.

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