A method for preparing Ti6Al4V titanium alloy wire for additive manufacturing with high straightness

Abstract

The application belongs to the field of titanium alloy material production and manufacturing, and discloses a preparation method of densely arranged Ti6Al4V titanium alloy wire for additive manufacturing powder production with high straightness. The method comprises the following steps: blank selection, heat treatment, cold drawing, skinning, roll die cold drawing and online annealing, polishing and densely arranged rewinding. Through multi-pass roll die cold drawing and atmosphere protection online annealing, the titanium alloy wire can realize full-surface brightness during the drawing process, which can effectively avoid defects such as pits, scratches and pitting on the surface of the wire, so that the surface quality of the final product wire is high. Through improvement of process arrangement and densely arranged rewinding equipment, the weight and straightness of the wire single coil can meet the corresponding technical standards.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of titanium alloy material production and manufacturing, and particularly relates to a preparation method of Ti6Al4V titanium alloy wire for high straightness additive manufacturing powder production. BACKGROUND

[0002] Titanium alloy has the advantages of small density, high temperature resistance, high yield ratio, strong corrosion resistance, etc., and is widely used in the fields of aerospace, warships, weapons and biomedicine. Ti6Al4V, as a typical alpha + beta two-phase titanium alloy, is mainly used as a raw material for the preparation of key structural parts in the above fields. The current manufacturing industry in China has gradually been fully transformed into digitalization and intelligentization. The key to the survival of enterprises in society and the core of production technology update is cost reduction and efficiency improvement. Therefore, the additive manufacturing technology based on metal wire has become a research and application hotspot at home and abroad in recent years due to its design flexibility, high material utilization rate, fast production speed, and small environmental pollution. At the same time, as the Ti6Al4V titanium alloy wire for manufacturing metal parts, the original powder production wire has the disadvantages of small single weight, low straightness, poor size consistency, etc. when facing the increasingly wide demand of the additive manufacturing industry and the increasingly stringent product standards. In order to solve these problems, the requirements for powder production equipment and raw materials are gradually improved, and new challenges are put forward for the wire production process. SUMMARY

[0003] Therefore, in view of the technical problems existing in the current Ti6Al4V titanium alloy wire, the purpose of the present application is to provide a preparation method of high straightness additive manufacturing powder production densely packed Ti6Al4V titanium alloy wire, so as to meet the technical requirement of keeping high straightness of titanium alloy wire in densely packed state.

[0004] In order to achieve the above purpose, the present application provides the following technical scheme.

[0005] On the one hand, the present application provides a preparation method of high straightness additive manufacturing powder production densely packed Ti6Al4V titanium alloy wire, which comprises the following steps:

[0006] (1) blank selection:

[0007] A black disc roll with good surface quality and chemical composition content meeting the standard requirements is selected;

[0008] (2) heat treatment:

[0009] The black disc roll is annealed by heating to 600-800 DEG C, holding, and air cooling after furnace discharge;

[0010] (3) cold drawing:

[0011] The black skin coil obtained in step (2) is cold-drawn, and the reduction ratio is controlled to be 10% to 40%;

[0012] (4) peeling:

[0013] The cold-drawn black skin coil obtained in step (3) is peeled, and the diameter reduction amount is 0.2mm to 1.5mm;

[0014] (5) roll die cold-drawing and on-line annealing:

[0015] The peeled black skin coil obtained in step (4) is subjected to multi-pass roll die cold-drawing and atmosphere protection on-line annealing cycle treatment, and the coil is processed to the target size;

[0016] (6) polishing:

[0017] The processed coil obtained in step (5) is polished;

[0018] (7) close-packed rewinding:

[0019] The polished coil obtained in step (6) is close-packed rewound to obtain the high straightness additive manufacturing Ti6Al4V titanium alloy wire for powder making.

[0020] Further, in step (1), the size of the black skin coil is Φ8.0mm.

[0021] Further, in step (2), the black skin coil is placed in a pit-type annealing furnace for annealing treatment.

[0022] Further, in step (2), the holding time is 60min.

[0023] Further, in step (4), after peeling the black skin coil, the coil surface quality is inspected and the defects are manually polished.

[0024] Further, in step (5), the reduction ratio of each pass of roll die cold-drawing is controlled to be 10% to 50%.

[0025] Further, in step (5), the number of passes is 2 to 5 passes.

[0026] Further, in step (5), the atmosphere protection on-line annealing cycle treatment adopts 730℃ to 760℃ through-type heating.

[0027] Further, in step (6), the polishing reduction is 0.02mm.

[0028] On the other hand, the application also provides a high straightness additive manufacturing Ti6Al4V titanium alloy wire for powder making, which is prepared by the above preparation method.

[0029] Compared with the prior production process, the technical solution provided by the present application has the following beneficial effects:

[0030] (1) Multi-pass roller die cold drawing and atmosphere protection online annealing can realize the full-surface brightness of titanium alloy wire during the drawing process, compared with vacuum annealing furnace annealing, which can effectively avoid defects such as pits, scratches, and pitting on the surface of the wire, so that the surface quality of the final product wire is high. Roller die cold drawing can realize rapid size reduction of the wire, greatly improving the actual production efficiency. The continuous online annealing production line can relieve the internal stress of the wire and improve the straightness of the finished product, while avoiding the abnormal growth of the grains that may occur under high temperature heating for a long time, so that the grain distribution of the wire after heat treatment is more uniform.

[0031] (2) By improving the close-packed rewinding equipment, adopting the process method of active pay-off + close-packed winding, the final product can still maintain good straightness after being payed off in a close-packed state. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Product diagram of Ti6Al4V titanium alloy wire prepared by the present application example 1;

[0033] Figure 2 Longitudinal metallographic structure diagram of Ti6Al4V titanium alloy wire prepared by the present application example 1;

[0034] Figure 3 Transverse metallographic structure diagram of Ti6Al4V titanium alloy wire prepared by the present application example 1;

[0035] Figure 4 Surface contamination layer test results of Ti6Al4V titanium alloy wire prepared by the present application example 1. DETAILED DESCRIPTION

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0037] In the present application, when a numerical interval (i.e. a numerical range) is involved, unless otherwise specified, the optional numerical distribution within the numerical interval is considered to be continuous, and includes both numerical end points (i.e. the minimum value and the maximum value) of the numerical range, and every numerical value between the two numerical end points. When a numerical interval refers only to integers within the numerical interval, unless otherwise specified, including both end point integers of the numerical range, and every integer between the two end points, in this document, it is equivalent to directly listing every integer, such as t is an integer selected from 1-10, which means that t is any one integer selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe a feature or characteristic, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all sub-ranges encompassed therein.

[0038] The temperature parameters in the present application, unless otherwise specified, allow both constant temperature treatment and variation within a certain temperature interval. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuation within a range such as ±5℃, ±4℃, ±3℃, ±2℃, ±1℃ is allowed.

[0039] For the purpose of clarity, the technical solutions and advantages of the present application, specific embodiments and the accompanying drawings will be described in detail below. The specific embodiments described herein are only used to explain the present application, and the present application is not limited thereto.

[0040] Example 1

[0041] The present embodiment provides a preparation method of high-straightness additive manufacturing powder-making densely packed Ti6Al4V titanium alloy wire, which comprises the following steps:

[0042] (1) Selection of blank:

[0043] A black skin coil with good surface quality and chemical composition content meeting the AMS 4930 and ASTM B 863 standards is selected, and the surface state of the coil is inspected to remove defects such as ears and cracks to prevent them from being brought into the next process. The size of the black skin coil used is Φ8.0mm.

[0044] (2) Heat treatment:

[0045] The black skin coil is annealed in a pit furnace, heated to 750℃, and held for 60min, and then air-cooled after discharge.

[0046] (3) Cold drawing:

[0047] The black skin coil obtained in step (2) is cold drawn at a drawing rate of 3-4m / min, and the area reduction is controlled at 10%-12%.

[0048] (4) Peeling:

[0049] The black-skinned coil obtained in step (3) is peeled off, and the diameter reduction is 0.4 mm to 0.6 mm. Finally, the surface quality of the coil is inspected and defects are manually repaired.

[0050] (5) Cold drawing and online annealing using rollers:

[0051] The peeled black wire coil obtained in step (4) is subjected to four rounds of cold drawing on a roller and then subjected to online annealing cycle treatment. The surface area reduction rate of each drawing is 15% to 25%, and the wire size after drawing is Φ4.2 (±0.03) mm.

[0052] Atmosphere-protected online annealing, 750°C through-feed heating.

[0053] (6) Polishing:

[0054] The disc obtained in step (5) is polished with a flap wheel to ensure that the surface of the disc is bright. The final product size is Φ4.2 (±0.05) mm.

[0055] Step (7), Close-packed rewinding:

[0056] The polished coil obtained in step (6) is rewound in close arrangement. After rewinding, a Ti6Al4V titanium alloy wire with a diameter between 550mm and 820mm and a single coil weight of 160kg is obtained.

[0057] Example 2

[0058] This embodiment provides a high-straightness additive manufacturing powder-making close-packed Ti6Al4V titanium alloy wire, which includes:

[0059] Step (1), Selection of billet:

[0060] Select black-coated coils with good surface quality and chemical composition that conforms to the standards of AMS 4930 and ASTM B 863. Inspect the surface condition of the coils to remove defects such as ears and cracks to prevent them from being carried into the next process. The size is Φ8.0mm.

[0061] Step (2), heat treatment:

[0062] The black-skinned coils are annealed in a pit furnace, heated to 750℃, held for 60 minutes, and then air-cooled after being removed from the furnace.

[0063] Step (3), cold drawing:

[0064] The black coil obtained in step (2) is cold-drawn at a rate of 3-4 m / min and the surface reduction rate is controlled at 12%-14%.

[0065] Step (4) Peeling

[0066] Peel the coil obtained in step (3) with a diameter reduction of 0.4 mm to 0.6 mm. Finally, inspect the surface quality of the coil and manually grind any defects.

[0067] Step (5), cold drawing with rollers + online annealing:

[0068] The peeled black wire coil obtained in step (4) is subjected to three rounds of cold drawing on a roller and then subjected to online annealing cycle treatment. The surface area reduction rate of each drawing is 25% to 35%, and the wire size after drawing is Φ3.6 (±0.03) mm.

[0069] Atmosphere-protected online annealing, 740°C through-feed heating.

[0070] Step (6), Polishing:

[0071] The disc obtained in step (5) is polished with a flap wheel to ensure that the surface of the disc is bright. The final product size is Φ3.6 (±0.05) mm.

[0072] Step (7), Close-packed rewinding:

[0073] The polished coil obtained in step (6) is rewound in close arrangement. The diameter of the rewound coil is between 550mm and 820mm, and the weight of a single coil is 160kg.

[0074] Example 3

[0075] This embodiment provides a high-straightness additive manufacturing powder-making close-packed Ti6Al4V titanium alloy wire, which includes:

[0076] Step (1), Selection of billet:

[0077] Select black-coated coils with good surface quality and chemical composition that conforms to the standards of AMS 4930 and ASTM B 863. Inspect the surface condition of the coils to remove defects such as ears and cracks to prevent them from being carried into the next process. The size is Φ8.0mm.

[0078] Step (2), heat treatment:

[0079] The black-skinned coils are annealed in a pit furnace, heated to 750℃, held for 60 minutes, and then air-cooled after being removed from the furnace.

[0080] Step (3), cold drawing:

[0081] The black coil obtained in step (2) is cold-drawn at a rate of 3-4 m / min and the surface reduction rate is controlled at 14%-16%.

[0082] Step (4) Peeling

[0083] Peel the coil obtained in step (3) with a diameter reduction of 0.4 mm to 0.6 mm. Finally, inspect the surface quality of the coil and manually grind any defects.

[0084] Step (5): Cold drawing and online annealing using rollers:

[0085] The peeled black wire coil obtained in step (4) is subjected to two passes of cold drawing on a roller and then subjected to online annealing cycle treatment. The surface area reduction rate of each drawing pass is 35% to 45%, and the wire size after drawing is Φ3.0 (±0.03) mm.

[0086] Atmosphere-protected online annealing, 730°C through-feed heating.

[0087] Step (6), Polishing:

[0088] The coil obtained in step (5) is polished with a flap wheel to ensure a bright surface. The final product size is Φ3.0 (±0.05) mm.

[0089] Step (7), Close-packed rewinding:

[0090] The polished coil obtained in step (6) is rewound in close arrangement. The diameter of the rewound coil is between 550mm and 820mm, and the weight of a single coil is 160kg.

[0091] Figure 1 The image shows a product diagram of the Ti6Al4V titanium alloy wire prepared in Example 1. Figure 2 and 3 The image shows longitudinal and transverse metallographic images of the Ti6Al4V titanium alloy wire prepared in Example 1. Figure 2 and 3 It is evident that the prepared titanium alloy wire exhibits α+β two-phase processing structure in both the transverse and longitudinal directions, and no other metallurgical defects such as cracks, shrinkage cavities, porosity, segregation, or metallic or non-metallic inclusions were found. Figure 4 The surface contamination layer test results show that the prepared Ti6Al4V titanium alloy wire has excellent surface quality and the finished product has no surface contamination layer.

[0092] Table 1 shows the bending test results of the finished Ti6Al4V titanium alloy wires prepared in Examples 1 to 3, respectively. As can be seen from Table 1, the wires did not show obvious bending after unwinding, which indicates that the Ti6Al4V titanium alloy wires prepared in the embodiments of the present invention still maintain a high degree of straightness in the close-packed winding state.

[0093] Table 1

[0094]

[0095] Table 2 shows the H content test results of the finished Ti6Al4V titanium alloy wires prepared in Examples 1 to 3. As can be seen from the test results in Table 2, the chemical composition of the finished Ti6Al4V titanium alloy wires is stable, and the H content is lower than the standard requirements.

[0096] Table 2

[0097]

[0098]

[0099] In summary, this invention uses black filament coils as raw materials and removes surface defects through annealing, drawing, peeling, and manual spot finishing of the intermediate material, ensuring a defect-free surface on the semi-finished product. The continuous annealing combined with roller cold drawing process ensures high straightness and good dimensional accuracy of the filament. Finally, polishing removes surface contaminants, guaranteeing the surface quality and roughness of the finished product. Improvements to the process arrangement and dense winding equipment ensure that the weight and straightness requirements of a single filament coil meet the corresponding technical standards.

[0100] The technical solution provided by this invention has a mature production process, stable finished product dimensions, excellent wire straightness, and uniform cross- and longitudinal metallographic structure, which can meet the different material requirements of current industrial production. Therefore, this high-straightness additive manufacturing powder-making Ti6Al4V titanium alloy wire has a very broad market application prospect.

[0101] It should be noted that the embodiments described above are merely preferred embodiments of the present invention. For those skilled in the art, various modifications, improvements, and equivalent substitutions can be made to the present invention without departing from its principles, and such modifications, improvements, and equivalent substitutions are also considered to fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a high-straightness additive manufacturing powder-making Ti6Al4V titanium alloy wire, characterized in that, Includes the following steps: (1) Selection of billet: Select black-coated coils with good surface quality and chemical composition that meets the requirements of AMS 4930 and ASTM B 863 standards; (2) Heat treatment: The black-skinned coils are annealed by heating to 600℃~800℃ and holding for 60 minutes, then air-cooled after removal from the oven. (3) Cold drawing: The black-skinned coils obtained in step (2) are cold-drawn, with the surface reduction rate controlled at 10% to 40%. (4) Peeling: Peel the black-skinned coil obtained in step (3) after cold drawing, and reduce the diameter by 0.2 mm to 1.5 mm; (5) Cold drawing and online annealing using rollers: The peeled black skin coils obtained in step (4) are subjected to 2 to 5 passes of cold drawing with rollers. The surface reduction rate of each pass of cold drawing with rollers is controlled at 10% to 50%. The coils are then subjected to an atmosphere-protected online annealing cycle to process them to the target size. The online annealing cycle uses a through-heating process at 730℃ to 760℃. (6) Polishing: Polish the processed coil obtained in step (5); (7) Densely packed and repeatedly wound: The polished coil obtained in step (6) is rewound in close arrangement using a process combining active unwinding and close-packed winding to obtain high straightness Ti6Al4V titanium alloy wire for additive manufacturing powder production.

2. The method for preparing high-straightness additive manufacturing powder-making Ti6Al4V titanium alloy wire according to claim 1, characterized in that, In step (1), the size of the black leather coil is Φ8.0mm.

3. The method for preparing high-straightness additive manufacturing powder-making Ti6Al4V titanium alloy wire according to claim 1, characterized in that, In step (2), the black leather coil is placed into a pit-type annealing furnace for annealing.

4. The method for preparing high-straightness additive manufacturing powder-making Ti6Al4V titanium alloy wire according to claim 1, characterized in that, In step (4), after peeling the black-skinned coil, the surface quality of the coil is inspected and defects are manually repaired.

5. The method for preparing high-straightness additive manufacturing powder-making Ti6Al4V titanium alloy wire according to claim 1, characterized in that, In step (6), the polishing depth is 0.02 mm.

6. A high-straightness Ti6Al4V titanium alloy wire for additive manufacturing powder production, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

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