Preparation method of TA1G large-disc round wire for fastener

Abstract

The invention relates to the technical field of processing of wires for fasteners, in particular to a preparation method of a TA1G large-disc round wire for a fastener. The method comprises the following steps: firstly, obtaining a TA1G cast ingot with the diameter of 500-700mm, then cogging and forging the TA1G cast ingot at the temperature of 1000-1100 DEG C into a bar billet with the diameter of 290-310mm, roughly forging the TA1G bar billet at the temperature of 900-1000 DEG C into a bar billet with the diameter of 130-150mm, precisely forging the TA1G bar billet at the temperature of 750-850 DEG C into a bar billet with the diameter of 95-105mm, continuously rolling the TA1G bar billet at the temperature of 750-850 DEG C to obtain a large disc round wire billet with the diameter of 7.5-15mm, drawing at room temperature, annealing, peeling, polishing and coating. The structure of the obtained TA1G wire material is a fine and uniform equiaxial structure, and the requirement of the TA1G material for a fastener is met.

Description

Technical Field

[0001] The invention relates to the technical field of wire processing for fasteners, and in particular to a method for preparing a TA1G large-coil round wire for fasteners. Background Art

[0002] Industrial pure titanium TA1G has high plasticity and excellent forming process performance, and has excellent corrosion resistance. TA1G is used in various fields with its excellent comprehensive performance, including aviation, aerospace, shipbuilding, chemical industry, biomedicine, construction, transportation, etc.

[0003] In recent years, bulge-type blind rivets have been used for single-sided connection of composite materials. They have excellent performance characteristics, mainly reflected in light weight, high specific strength, corrosion resistance, preload, locking, fatigue resistance, lightning protection, sealing and other aspects; they also solve the problems of potential compatibility, installation damage, low pull-off strength and other problems unique to composite materials. Blind rivets are mainly used for structural connection of composite materials in aircraft fairings, elevators, ailerons, wingtips, rear end of fuselage, leading and trailing edges, cargo floor, landing gear doors, passenger / crew doors, cabin doors and other parts. They have a large single-machine consumption and a large market. TA1G is used in the nail sleeve of bulge-type blind rivet assemblies, which can achieve a significant weight reduction effect and has great economic benefits.

[0004] At present, most of the TA1G wire used in domestic fasteners adopts small-batch processing technology, mainly rolling on horizontal rolling mills, and the finished products are mainly small single-weight round coils and straight bars. The consistency of product quality is difficult to ensure, resulting in large fluctuations in the mechanical properties of the prepared fasteners and difficulty in ensuring product quality stability.

[0005] Therefore, it is of great engineering significance to study the preparation process of large single weight round TA1G wire (specification Φ2~15mm, single roll weight ≥100kg) to prepare high-quality and high-uniformity large single weight round TA1G wire. Summary of the invention

[0006] Based on this, it is necessary to address the above technical problems. The present invention provides a method for preparing TA1G large-coil round wire for fasteners. The TA1G wire prepared by the method has fine and uniform microstructure, good consistency, high strength, good plasticity, and good surface quality and dimensional tolerance.

[0007] The technical solution of the present invention is:

[0008] A method for preparing TA1G large coiled round wire for fasteners, the specific steps are as follows:

[0009] Step 1, prepare ingot: take TA1G ingot with a diameter of 500-700 mm, the composition of TA1G ingot is as follows by weight percentage: matrix element is Ti, impurity element Fe≤0.20%, O≤0.18%, C≤0.08%, N≤0.03%, H≤0.015%, and the total impurity element is ≤0.40%;

[0010] Step 2, billet forging: heat the heating furnace to 800-900℃ to load the ingot, raise the temperature to 1000-1100℃, keep the temperature for 2-3h, and stretch the billet on the forging machine. After stretching, the diameter of the billet is 290-310mm, the total deformation is 70-80%, and the surface defects are repaired;

[0011] Step 3, rough forging: heat the heating furnace to 700-800℃ to load the billet, raise the temperature to 900-1000℃, keep it at temperature for 2-3h, take it out of the furnace and stretch it on the forging machine. After stretching, the diameter of the billet is 130-150mm, and the total deformation is 70-90%. The billet is rough forged and the surface defects are repaired;

[0012] Step 4, fine forging: heat the heating furnace to 600-700℃ to load the bar billet into the furnace, raise the temperature to 750-850℃, keep the temperature for 2-3h, take it out of the furnace and stretch it on the fine forging machine. After stretching, the diameter of the bar billet is 95-105mm, and the total deformation is 40-60%. The fine forged bar billet is obtained, and the surface defects are repaired;

[0013] Step 5, continuous rolling: the bar billet after fine forging is heated to 750-850°C by electromagnetic induction heating, and the temperature is kept for 5-10 minutes, and then rolled in a continuous rolling unit, and water-cooled to room temperature. The diameter of the round wire billet after rolling is 7.5-15 mm;

[0014] Step 6: Drawing: Drawing the rolled wire blank at room temperature, with each drawing deformation of 5-20% and a total deformation of 30-70%;

[0015] Step 7: Annealing: Anneal the drawn wire at a temperature of 550-650°C for 30-120 minutes, followed by air cooling to room temperature.

[0016] Step 8: Peeling: Peel the annealed wire with a peeling amount of more than 0.5 mm;

[0017] Step 9, polishing: polish the peeled wire, the surface roughness Ra of the polished wire is ≤1.2μm, and the out-of-roundness is ≤0.01mm;

[0018] Step 10: Coating: The polished wire is coated with a coating having a thickness of 1 to 15 μm.

[0019] The method for preparing the TA1G large-coil round wire for fasteners, preferably, in the step 1, the process of preparing the ingot is: pressing grade 1 or better than grade 1 sponge titanium into an electrode, and subjecting it to vacuum consumable arc melting for not less than 2 times to obtain a TA1G cylindrical ingot with a diameter of 550 to 650 mm.

[0020] In the method for preparing the TA1G large coiled round wire for fasteners, preferably, in the step 2, the blank forging is free forging, the holding temperature is 1025-1075° C., and the total deformation is 72-78%.

[0021] In the method for preparing the TA1G large coiled round wire for fasteners, preferably, in the step three, the rough forging is free forging, the holding temperature is 925-975° C., and the total deformation is 75-85%.

[0022] The method for preparing the TA1G large coiled round wire for fasteners, preferably, in the step 4, the fine forging temperature is 775-825°C, the total deformation is 45-55%, the cut length is 4500-5500mm, and the weight is 150-250kg.

[0023] The method for preparing TA1G large round wire for fasteners, preferably, in the step five, the continuous rolling temperature is 775-825°C, the total deformation is greater than or equal to 97%, the post-rolling cooling method is air cooling, and the weight of the round wire blank after rolling is 150-250kg.

[0024] In the method for preparing the TA1G large coiled round wire for fasteners, preferably, in step six, the drawing deformation amount in each pass is 5-15%, and the total drawing deformation amount is 40-60%.

[0025] In the method for preparing the TA1G large coiled round wire for fasteners, preferably, in step seven, the annealing temperature is 580-620° C., and the holding time is 60-120 min.

[0026] In the method for preparing the TA1G large coiled round wire for fasteners, preferably, in step eight, die peeling is adopted, and the peeling amount is greater than 0.5 mm.

[0027] The method for preparing the TA1G large round wire for fasteners, preferably, in the step 10, the coating is MoS 2 The coating made of the mixture of graphite and graphite is applied on the surface of the wire. The TA1G wire obtained after coating has a weight of 150 to 250 kg and a diameter of 2 to 12 mm.

[0028] The design concept of the present invention is:

[0029] The method of the present invention first obtains a TA1G ingot with a diameter of 500-700mm, then forges the TA1G ingot at 1000-1100°C into a rod blank with a diameter of 290-310mm, then rough forges the TA1G rod blank at 900-1000°C into a rod blank with a diameter of 130-150mm, then fine forges the TA1G rod blank at 750-850°C into a rod blank with a diameter of 95-105mm, then continuously rolls the TA1G rod blank at 750-850°C, quenches after rolling, obtains a large round wire blank with a diameter of 7.5-15mm, then draws at room temperature, then anneals, then peels, polishes and coats. Thus, through the overall technical solution of the present invention, a fine and uniform equiaxed α grain structure is obtained in the cross section, the surface is in a lubricating coating state, the wire coil weight is greater than 100kg, has excellent strength and plasticity, and meets the requirements of TA1G materials for fasteners.

[0030] The advantages and beneficial effects of the present invention are:

[0031] (1) In the composition design of the present invention, the content of O element is controlled below 0.08wt%, which can effectively improve the plasticity of TA1G.

[0032] (2) The total deformation of continuous rolling in the present invention is greater than or equal to 97%, the continuous rolling temperature is controlled, and the continuous rolling large deformation mode is adopted. The TA1G microstructure after rolling is a fine, uniform, equiaxed α grain structure.

[0033] (3) The present invention can obtain a large single weight TA1G wire for fasteners with uniform microstructure, excellent surface quality and excellent dimensional tolerance through continuous rolling, room temperature drawing and peeling processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a microstructure photograph of the TA1G rod with a diameter of 7.5 mm obtained in Example 1.

[0035] Figure 2 This is a microstructure photograph of the TA1G rod with a diameter of φ5.0 mm obtained in Example 2. DETAILED DESCRIPTION

[0036] In the specific implementation process, the present invention provides a method for preparing a high-quality microstructure TA1G large single weight round wire for fasteners, which is specifically implemented in the following steps:

[0037] Step 1, ingot preparation: Grade 1 or better titanium sponge is pressed into an electrode, and subjected to vacuum consumable arc melting for not less than 2 times to obtain a TA1G cylindrical ingot with a diameter of 500 to 700 mm (preferably 550 to 650 mm);

[0038] In terms of weight percentage, the matrix composition of the TA1G cylindrical ingot is Ti, and the impurity elements are: Fe≤0.20% (preferably Fe≤0.10%), O≤0.18% (preferably O≤0.08%), C≤0.08%, N≤0.03%, H≤0.015%, and the total impurity elements≤0.40%;

[0039] Step 2, billet forging: heat the box-type industrial resistance furnace to 800-900°C, heat it to 1000-1100°C (preferably 1025-1075°C), keep it warm for 2-3 hours, take it out of the furnace and stretch it on a free forging machine. After stretching, the diameter of the billet is 290-310mm, the total deformation is 70-80% (preferably 72-78%), and the surface defects are repaired;

[0040] Step 3, rough forging: heat the heating furnace to 700-800°C to load the billet into the furnace, raise the temperature to 900-1000°C (preferably 925-975°C), keep the temperature for 2-3 hours, take it out of the furnace and stretch it on a free forging machine. After stretching, the diameter of the billet is 130-150mm, the total deformation is 70-90% (preferably 75-85%), and the billet is obtained after rough forging, and the surface defects are repaired;

[0041] Step 4, precision forging: heat the box-type industrial resistance furnace to 600-700°C to load the bar billet into the furnace, raise the temperature to 750-850°C (preferably 775-825°C), keep the temperature for 2-3 hours, take it out of the furnace and stretch it on the precision forging machine, the diameter of the bar billet after stretching is 95-105mm, the total deformation is 40-60% (preferably 45-55%), cut it into a length of about 4500-5500mm, and the weight is 150-250kg, to obtain the bar billet after precision forging, and grind the surface defects;

[0042] Step 5, continuous rolling: the bar billet after fine forging is heated to 750-850°C by electromagnetic induction heating, and the temperature is kept for 5-10 minutes, and then rolled in a continuous rolling unit, and water-cooled to room temperature. After rolling, the weight of the round wire billet is 150-250kg, the diameter is 7.5-15mm, and the total rolling deformation is greater than or equal to 97%;

[0043] Step 6, drawing: drawing the rolled wire blank at room temperature, with each drawing deformation of 5-20% (preferably 5-15%) and a total deformation of 30-70% (preferably 40-60%);

[0044] Step 7, annealing: annealing the drawn wire at a temperature of 550-650°C (preferably 580-620°C) for a holding time of 30-120 min (preferably 60-120 min), followed by air cooling to room temperature;

[0045] Step 8: Peeling: Use a mold to peel the annealed wire, and the peeling amount is more than 0.5mm;

[0046] Step 9, polishing: polish the peeled wire, the surface roughness Ra of the polished wire is ≤1.2μm, and the out-of-roundness is ≤0.01mm;

[0047] Step 10: Coating: The polished wire is coated with a coating having a thickness of 1 to 15 μm. The obtained TA1G wire has a weight of 150 to 250 kg and a diameter of 2 to 12 mm.

[0048] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0049] Example 1

[0050] In this embodiment, a method for preparing a TA1G large coiled round wire for a fastener includes the following steps:

[0051] Step 1: Press the titanium sponge of grade 1 or better into 26 electrodes of 100 kg, and then melt them three times in vacuum consumable arc to obtain 2600 kg TA1G ingots with a size of about φ600mm×1950mm. The matrix composition of the TA1G ingot is Ti, and the impurity elements are: Fe 0.08%, O 0.06%, C 0.009%, N 0.008%, H 0.003% (wt%);

[0052] Step 2: Forging the blank. Heat the box-type industrial resistance furnace to 850℃ and heat it to 1050℃. Keep it at this temperature for 3h. Then, take it out of the furnace and stretch it on a free forging machine (such as a 10MN fast hydraulic forging machine). After stretching, the diameter of the blank is φ300mm, the forging deformation is 75%, and the surface defects are ground until the surface is bright (without cracks and oxide scale).

[0053] Step 3, rough forging, heat the box-type industrial resistance furnace to 750℃, heat it to 950℃, keep it at temperature for 2.5h, take it out of the furnace and stretch it on the free forging machine. After stretching, the diameter of the bar billet is 140mm, and the length is about 3000mm. The rough forging deformation is 78%, the weight is 207kg, and the surface defects are ground until the surface is bright (without cracks and oxide scale);

[0054] Step 4, fine forging, heat the box-type industrial resistance furnace to 650℃, heat it to 800℃, keep it at temperature for 2.5h, take it out of the furnace and stretch it on the fine forging machine. The diameter of the rod billet after stretching is 100mm, the fine forging deformation is 50%, the length is about 5000mm, the weight is 177kg, and the surface defects are repaired until the surface is bright (without cracks and oxide scale);

[0055] Step 5, continuous rolling, using induction heating to heat the fine forging billet to 800°C, holding time 5min, then rolling in a continuous rolling unit, water cooling to room temperature after rolling, the weight of the rolled round wire billet is 173kg, the diameter is 11mm, and the rolling deformation is 98.79%;

[0056] Step 6: Drawing: Drawing the rolled wire blank at room temperature for 4 times, with a diameter of φ8.1 mm after drawing, and a drawing deformation of about 10% in each time, with a total deformation of 45.7%;

[0057] Step 7: annealing: annealing the drawn wire at 600°C for 120 minutes, and air cooling to room temperature;

[0058] Step 8: peeling: peeling the drawn wire to obtain a wire with a diameter of φ7.5mm and a peeling amount of 0.6mm;

[0059] Step nine, polishing. After polishing, the surface roughness of the wire is Ra0.8μm and the out-of-roundness is 0.001mm;

[0060] Step 10: Coating treatment: Use MoS2 on the polished wire 2 The coating made of a mixture of MoS and graphite is coated, and the coating thickness is 6 μm. The coating composition of this embodiment is as follows by weight percentage: MoS 2 30%, graphite 40%, and the rest is resin binder.

[0061] like Figure 1 As shown in the figure, the microstructure photo of TA1G wire with a diameter of φ7.5mm shows that the microstructure is a fine and uniform equiaxed α grain structure.

[0062] Example 2

[0063] In this embodiment, a method for preparing a TA1G large coiled round wire for a fastener includes the following steps:

[0064] Step 1: Press the titanium sponge of grade 1 or better into 26 electrodes of 100 kg, and then melt them three times in vacuum consumable arc to obtain 2600 kg TA1G ingots with a size of about φ600mm×1950mm. The matrix composition of the TA1G ingot is Ti, and the impurity elements are: Fe 0.07%, O 0.07%, C 0.008%, N 0.009%, H 0.003% (wt%);

[0065] Step 2: Forging the blank. Heat the box-type industrial resistance furnace to 850℃ and heat it to 1050℃. Keep it at this temperature for 3h. Then, take it out of the furnace and stretch it on a free forging machine (such as a 10MN fast hydraulic forging machine). After stretching, the diameter of the blank is φ300mm, the forging deformation is 75%, and the surface defects are ground until the surface is bright (without cracks and oxide scale).

[0066] Step 3, rough forging, heat the box-type industrial resistance furnace to 750℃, heat it to 950℃, keep it at temperature for 2.5h, take it out of the furnace and stretch it on the free forging machine. After stretching, the diameter of the bar billet is 140mm, and the length is about 3000mm. The rough forging deformation is 78%, the weight is 207kg, and the surface defects are ground until the surface is bright (without cracks and oxide scale);

[0067] Step 4, fine forging, heat the box-type industrial resistance furnace to 650℃, heat it to 800℃, keep it at temperature for 2.5h, take it out of the furnace and stretch it on the fine forging machine. The diameter of the rod billet after stretching is 100mm, the fine forging deformation is 50%, the length is about 5000mm, the weight is 177kg, and the surface defects are repaired until the surface is bright (without cracks and oxide scale);

[0068] Step 5, continuous rolling, using induction heating to heat the fine forging billet to 800°C, holding time 5min, then rolling in a continuous rolling unit, water cooling to room temperature after rolling, the weight of the rolled round wire billet is 173kg, the diameter is 8mm, and the rolling deformation is 99.36%;

[0069] Step 6: Drawing: Drawing the rolled wire blank at room temperature for 5 times, with a diameter of φ5.6 mm after drawing, and a drawing deformation of about 10% in each time, with a total deformation of 50%;

[0070] Step 7: annealing: annealing the drawn wire at 600°C for 120 minutes, and air cooling to room temperature;

[0071] Step 8: peeling: peeling the drawn wire to obtain a wire with a diameter of φ5.0 mm and a peeling amount of 0.6 mm;

[0072] Step nine, polishing. After polishing, the surface roughness of the wire is Ra0.8μm and the out-of-roundness is 0.001mm;

[0073] Step 10: Coating treatment: Use MoS2 on the polished wire 2 The coating made of a mixture of MoS and graphite is coated, and the coating thickness is 6 μm. The coating composition of this embodiment is as follows by weight percentage: MoS 2 30%, graphite 40%, and the rest is resin binder.

[0074] like Figure 2 As shown in the figure, the microstructure photo of TA1G wire with a diameter of φ5.0 mm shows that the microstructure is a fine and uniform equiaxed α grain structure.

[0075] The test results of the mechanical properties of the TA1G wire obtained in Examples 1 to 2 are shown in Table 1.

[0076] Table 1

[0077]

[0078] From the mechanical property test results of Examples 1 and 2 in Table 1, it can be seen that the yield strength can reach 170-228 MPa, the tensile strength can reach 333-358 MPa, the elongation can reach 46.0-52.0%, and the cross-sectional shrinkage can reach 65-74%. Therefore, the TA1G wire obtained by the present invention has moderate tensile strength and good plasticity.

[0079] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing TA1G large round wire for fasteners, characterized in that: The specific steps are as follows: Step 1, prepare ingot: take TA1G ingot with a diameter of 500-700 mm, the composition of TA1G ingot is as follows by weight percentage: matrix element is Ti, impurity element Fe≤0.20%, O≤0.18%, C≤0.08%, N≤0.03%, H≤0.015%, and the total impurity element is ≤0.40%; Step 2, billet forging: heat the heating furnace to 800-900℃ to load the ingot, raise the temperature to 1000-1100℃, keep the temperature for 2-3h, and stretch the billet on the forging machine. After stretching, the diameter of the billet is 290-310mm, the total deformation is 70-80%, and the surface defects are repaired; Step 3, rough forging: heat the heating furnace to 700-800℃ to load the billet, raise the temperature to 900-1000℃, keep it at temperature for 2-3h, take it out of the furnace and stretch it on the forging machine. After stretching, the diameter of the billet is 130-150mm, and the total deformation is 70-90%. The billet is rough forged and the surface defects are repaired; Step 4, fine forging: heat the heating furnace to 600-700℃ to load the bar billet into the furnace, raise the temperature to 750-850℃, keep the temperature for 2-3h, take it out of the furnace and stretch it on the fine forging machine. After stretching, the diameter of the bar billet is 95-105mm, and the total deformation is 40-60%. The fine forged bar billet is obtained, and the surface defects are repaired; Step 5, continuous rolling: the bar billet after fine forging is heated to 750-850°C by electromagnetic induction heating, and the temperature is kept for 5-10 minutes, and then rolled in a continuous rolling unit, and water-cooled to room temperature. The diameter of the round wire billet after rolling is 7.5-15 mm; Step 6: Drawing: Drawing the rolled wire blank at room temperature, with each drawing deformation of 5-20% and a total deformation of 30-70%; Step 7: Annealing: Anneal the drawn wire at a temperature of 550-650°C for 30-120 minutes, followed by air cooling to room temperature. Step 8: Peeling: Peel the annealed wire with a peeling amount of more than 0.5 mm; Step 9, polishing: polish the peeled wire, the surface roughness Ra of the polished wire is ≤1.2μm, and the out-of-roundness is ≤0.01mm; Step 10: Coating: The polished wire is coated with a coating having a thickness of 1 to 15 μm.

2. The preparation method according to claim 1, characterized in that: Preferably, in step 1, the process of preparing the ingot is: pressing grade 1 or better than grade 1 titanium sponge into an electrode, and subjecting it to vacuum consumable arc melting for not less than 2 times to obtain a TA1G cylindrical ingot with a diameter of 550 to 650 mm.

3. The preparation method according to claim 1, characterized in that: Preferably, in the step 2, the blank forging is free forging, the holding temperature is 1025-1075° C., and the total deformation is 72-78%.

4. The preparation method according to claim 1, characterized in that: Preferably, in step three, the rough forging is free forging, the holding temperature is 925-975° C., and the total deformation is 75-85%.

5. The preparation method according to claim 1, characterized in that: Preferably, in step 4, the fine forging temperature is 775-825° C., the total deformation is 45-55%, the cut length is 4500-5500 mm, and the weight is 150-250 kg.

6. The preparation method according to claim 1, characterized in that: Preferably, in step five, the continuous rolling temperature is 775-825° C., the total deformation is greater than or equal to 97%, the cooling method after rolling is air cooling, and the weight of the coil round wire billet after rolling is 150-250 kg.

7. The preparation method according to claim 1, characterized in that: Preferably, in step six, the drawing deformation amount in each pass is 5-15%, and the total drawing deformation amount is 40-60%.

8. The preparation method according to claim 1, characterized in that: Preferably, in step seven, the annealing temperature is 580-620° C., and the holding time is 60-120 min.

9. The preparation method according to claim 1, characterized in that: Preferably, in step eight, mold peeling is adopted, and the peeling amount is greater than 0.5 mm.

10. The preparation method according to claim 1, characterized in that: Preferably, in the step ten, the surface of the wire is coated with a coating made of a mixture of MoS2 and graphite, and the TA1G wire obtained after coating weighs 150 to 250 kg and has a diameter of 2 to 12 mm.

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