Short-process low-cost preparation method of pure titanium plate

Abstract

The invention discloses a short-process low-cost preparation method of a pure titanium plate, and belongs to the field of nonferrous metal processing.The preparation method comprises the steps that sponge titanium is subjected to vacuum ball milling to obtain powder with the specific particle size, then the powder is subjected to hot pressing sintering blank making and hot isostatic pressing treatment, and the density of a pure titanium blank is further improved; and finally, rolling and forming to obtain the target pure titanium plate. According to the method, the problems of long flow, low yield and high cost of a traditional process route of smelting and ingot casting, blank forging and plate rolling are solved, the yield can reach 88% or above, and the obtained target pure titanium plate has excellent structure uniformity and performance uniformity, meets market requirements and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of non-ferrous metal processing, and particularly relates to a short-process low-cost pure titanium plate preparation method. BACKGROUND

[0002] Titanium and titanium alloy have a series of advantages such as small density, high strength, high temperature resistance, etc., and are widely used in aerospace, marine engineering, medical treatment, chemical industry and other fields, and are also called "space metal" and "marine metal". Among them, the pure titanium plate is one of the most widely used categories in titanium and titanium alloy materials due to its high strength and excellent plasticity, toughness and corrosion resistance. There are two traditional process flows for preparing the pure titanium plate: the first one is to melt the sponge titanium into an ingot by a vacuum self-consumption arc furnace, then prepare a forged blank by multiple upsetting and drawing, and finally prepare the plate by multiple passes of rolling; the second one is to melt the sponge titanium into a slab by an electron beam cold bed furnace, and then prepare the plate by multiple passes of rolling. The above two methods both need to go through the links of ingot melting, hot forging, hot rolling, etc., especially need to go through the links of ingot skinning, cutting riser, polishing and cleaning defects, slab machine adding, etc. in the production process, and the process flow is long, the material loss is large, and the yield from raw materials to plate is generally less than 78%, the cost is extremely high, which indirectly affects the mass application of the pure titanium plate.

[0003] At present, the reduction of the production cost of the pure titanium plate is mainly through optimizing the existing production process flow and improving the yield: patent CN116511246A discloses a preparation method of an ultra-thin large-width titanium plate one-fire finished product, which shortens the rolling passes of the plate and improves the yield by optimizing the process flow. Patent CN108356088A discloses a processing method of a large-specification pure titanium plate, which prepares a pure titanium slab by an EB electron beam cold bed melting furnace, and then performs large-deformation rolling in a rolling mill to prepare a large-width pure titanium plate. The above improvements are all based on the traditional ingot melting-plate rolling process flow, and the cost is reduced by optimizing the process, reducing the processing passes and improving the yield, but the problem of long process flow and high cost is not fundamentally solved.

[0004] Therefore, a pure titanium plate preparation method starting from raw materials and optimizing the whole process is needed, which can effectively reduce the production cost of the pure titanium plate. In view of this, the present application is proposed. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a short-process low-cost pure titanium plate preparation method. The method can effectively shorten the production process flow of the plate and improve the yield by the process mode of sponge titanium powder preparation, hot pressing sintering and hot isostatic pressing, and plate rolling. At the same time, the pure titanium plate with good uniformity of microstructure is prepared by controlling the density of the titanium blank and the deformation amount of the plate rolling.

[0006] Referring to Figure 1 To achieve the above object, the present application adopts the following technical scheme: comprising the following steps: Step 1, put the titanium sponge into a container for ball milling to obtain a powder with a specific particle size; Step 2, sinter the powder obtained in step 1 to obtain a first-stage pure titanium blank; Step 3, hot isostatic pressing the first-stage pure titanium blank to obtain a second-stage pure titanium blank with a specific density; Step 4, rolling the second-stage pure titanium blank to obtain a target pure titanium plate.

[0007] Further, the titanium sponge in step 1 has a particle size of 0.83mm-12.7mm, and the ball milling is carried out in a vacuum environment with a vacuum degree less than 1×10 -2 Pa.

[0008] Specifically, the specific particle size in step 1 is 50μm-200μm, and the powder is stored by vacuum sealing for standby.

[0009] Further, the specific parameters of sintering in step 2 are as follows: the sintering temperature is 1000℃-1200℃, the pressure is 90MPa-150MPa, and argon protection is carried out during the sintering process.

[0010] Specifically, the thickness H of the first-stage pure titanium blank in step 2 is 150mm-250mm, the width W is 800mm-1000mm, and the length L is 1000mm-1500mm.

[0011] Further, the specific parameters of hot isostatic pressing in step 3 are as follows: the pressure is 300MPa-500MPa, the holding temperature is 500℃-700℃, and the holding time is 6h-10h. The second-stage pure titanium blank is cooled to room temperature for standby.

[0012] Specifically, the specific density in step 3 is greater than 99.7%.

[0013] Further, during rolling in step 4: rolling is divided into 2-3 times, the temperature is controlled below 30℃-60℃ below the beta phase transition point of pure titanium, the holding time is calculated according to the holding coefficient of 1.2-1.6×(minimum thickness size / mm) / min, the rolling speed is 1.5m / s-2.5m / s, the deformation amount from the second-stage pure titanium blank to the target pure titanium plate is greater than 80%, and the thickness H of the target pure titanium plate is ≤30mm.

[0014] Compared with the prior art, the present application has the following beneficial effects: 1) The present application selects small particle size titanium sponge, which is ball milled to prepare powder, hot pressed to sinter blanks, and the blanks are rolled, which optimizes the traditional process flow and shortens the preparation time; 2) The present application adopts hot isostatic pressing process to further improve the density of the titanium blanks prepared by hot pressing sintering, so that the target pure titanium plate prepared has excellent microstructure uniformity and performance uniformity; In summary, the present application provides a short process low cost pure titanium plate process route of "titanium sponge powder preparation + hot pressing sintering + hot isostatic pressing + blank rolling", which solves the problems of long process flow, low yield and high cost of the traditional "melting ingot + blank forging + plate rolling" process route. The plate yield can reach more than 88%, and the prepared pure titanium plate meets the market demand and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings, which are incorporated into and form part of the specification, together with the specification, serve to explain the principles of the present application.

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0017] Figure 1 The preparation method flow chart of the short process low cost pure titanium plate of the present application; Figure 2 The microstructure diagram of the target pure titanium plate with thickness H=30mm of Example 1; Figure 3 The microstructure diagram of the target pure titanium plate with thickness H=20mm of Example 2; Figure 4 The microstructure diagram of the target pure titanium plate with thickness H=15mm of Example 3. DETAILED DESCRIPTION

[0018] Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples consistent with some aspects of the present application, as detailed in the appended claims.

[0019] Example 1 The present application provides a short process low cost titanium plate preparation method, which comprises the following steps: Step 1, Preparation of sponge titanium powder: 0-grade small particle sponge titanium with a particle size of 0.83 mm to 12.7 mm is selected and loaded into a steel container for ball milling under vacuum, with a vacuum degree less than 1 x 10 -2 Pa, and a powder with a particle size of 90 μm to 180 μm is prepared. After ball milling, the powder is vacuum sealed for storage.

[0020] Step 2, Hot-pressing sintering: The prepared powder is placed in a hot-pressing sintering tank for sintering, with a sintering temperature of 1150℃ and a pressure of 100 MPa. The sintering process is protected by argon gas, and a first-stage pure titanium blank with a size of 250 mm x 900 mm x 1200 mm (H x W x L) is prepared.

[0021] Step 3, Hot isostatic pressing: The first-stage pure titanium blank is subjected to hot isostatic pressing at a pressure of 450 MPa and a holding temperature of 650℃ for 8 h, further improving the density of the first-stage pure titanium blank to more than 99.7% to obtain a second-stage pure titanium blank. The second-stage pure titanium blank is cooled to room temperature for standby.

[0022] Step 4, Blank rolling: The cooled second-stage pure titanium blank is rolled, with a rolling heating temperature of 50℃ below the beta phase transition point of pure titanium, and a holding time calculated according to 1.4 x 230 (minimum thickness size / mm) / min, with an actual holding time of 322 min to ensure sufficient heating and uniformity of the blank. Three times of rolling are performed at a rolling speed of 2.2 m / s to ensure a deformation of 87% from the second-stage pure titanium blank to the target pure titanium plate, and a pure titanium plate with a thickness H = 30 mm is prepared (as shown in FIG. 1). Figure 2

[0023] Specifically, the pure titanium plate prepared in Example 1 is annealed and subjected to room temperature tensile property testing according to GB / T 228.1-2021, and the related mechanical property characterization results are shown in the following table: Table 1: Mechanical properties of H = 30 mm plate Example 2 The preparation method of the short-process low-cost titanium plate provided in this embodiment includes the following steps: Step 1, Preparation of sponge titanium powder: 0-grade small particle sponge titanium with a particle size of 0.83 mm to 12.7 mm is selected and loaded into a steel container for ball milling under vacuum, with a vacuum degree less than 1 x 10 -2 Pa, and a powder with a particle size of 60 μm to 150 μm is prepared. After ball milling, the powder is vacuum sealed for storage.

[0024] ​Step 2, hot-press sintering: the prepared powder is placed in a hot-press sintering tank for sintering, the sintering temperature is 1000°C, the pressure is 150 MPa, the sintering process is protected by argon, and a first-stage pure titanium blank with a specification of 180mmx1000mmx1500mm (HxWxL) is prepared.

[0025] Step 3, hot isostatic pressing: the first-stage pure titanium blank is subjected to hot isostatic pressing, the pressure is 300 MPa, the holding temperature is 500°C, and the holding time is 6h, so as to further improve the density of the first-stage pure titanium blank to more than 99.7% to obtain a second-stage pure titanium blank. The second-stage pure titanium blank is cooled to room temperature for standby.

[0026] Step 4, plate rolling: the cooled second-stage pure titanium blank is rolled, the rolling heating temperature is 30°C below the beta phase transition point of pure titanium, the holding time is calculated according to 1.2x180 (minimum thickness / mm) / min, the actual holding time is 216min, the blank is fully heated and uniformly, 2 times of rolling are performed, the rolling rate is selected to be 1.5m / s, and the deformation amount from the second-stage pure titanium blank to the target pure titanium plate is ensured to be 89%, and a pure titanium plate with a thickness H=20mm is prepared (as shown in FIG. 1). Figure 3

[0027] Specifically, the pure titanium plate prepared in Example 2 is subjected to room temperature tensile property test after annealing according to GB / T 228.1-2021, and the related mechanical property characterization results are shown in the following table: Table 2: Mechanical properties of H=20mm plate Example 3 Referring to Figure 1 , the preparation method of the short-process low-cost titanium plate provided in the embodiment includes the following steps: Step 1, sponge titanium powder preparation: 0-grade small particle sponge titanium with a particle size of 0.83mm-12.7mm is selected and loaded into a steel container, and is subjected to ball milling in a vacuum environment, the vacuum degree is required to be less than 1x10 -2 Pa, and a powder with a particle size of 50μm-200μm is prepared. After ball milling, the powder is vacuum sealed and stored for standby.

[0028] Step 2, hot-press sintering: the prepared powder is placed in a hot-press sintering tank for sintering, the sintering temperature is 1200°C, the pressure is 90 MPa, the sintering process is protected by argon, and a first-stage pure titanium blank with a specification of 150mmx800mmx1000mm (HxWxL) is prepared.

[0029] ​Step 3, hot isostatic pressing: the first-stage pure titanium blank is subjected to hot isostatic pressing, the pressure is 500 MPa, the holding temperature is 700 DEG C, and the holding and pressure maintaining time is selected as 10 h, so as to further improve the density of the first-stage pure titanium blank to more than 99.7% to obtain a second-stage pure titanium blank, and the second-stage pure titanium blank is cooled to room temperature for standby.

[0030] Step 4, plate rolling: the cooled second-stage pure titanium blank is rolled, the rolling heating temperature is 60 DEG C below the beta phase transition point of pure titanium, the holding time is calculated according to 1.6 x 150 (minimum size of thickness) / min, the actual holding time is 240 min, the blank is fully heated and uniformly, 2 times of rolling are formed, the rolling rate is selected as 2.5 m / s, and the deformation amount from the second-stage pure titanium blank to the target pure titanium plate is 86%, and the pure titanium plate with a thickness of H = 15 mm is prepared (as shown in FIG. 2). Figure 4

[0031] Specifically, the pure titanium plate prepared in the embodiment 3 is subjected to room temperature tensile property test after annealing according to GB / T 228.1-2021, and the related mechanical property characterization results are shown in the following table: Table 3: mechanical properties of H = 15 mm plate It should be noted that in the above embodiments, the high-magnification structure of the H = 30 mm, H = 20 mm and H = 15 mm plate is small and uniform, the grain size is about 6, complete recrystallization is achieved, and the mechanical property results in different directions show that the plate is uniform in transverse and longitudinal directions, and the yield rate can be more than 88%.

[0032] The above description is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application.

[0033] It should be understood that the present application is not limited to the above described and that various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.​

Claims

1. A short-process, low-cost method for preparing pure titanium plates, characterized in that, Includes the following steps: Step 1: Place the sponge titanium into a container and ball mill it to obtain powder with a specific particle size; Step 2: Sinter the powder obtained in Step 1 to obtain a first-order pure titanium billet; Step 3: Hot isostatic pressing is applied to the first-order pure titanium billet to obtain a second-order pure titanium billet with a specific density. Step 4: Roll the second-order pure titanium billet into shape to obtain the target pure titanium sheet.

2. The preparation method according to claim 1, characterized in that, The sponge titanium in step 1 is grade 0 sponge titanium with a particle size of 0.83 mm to 12.7 mm. The ball milling is carried out under vacuum, with a vacuum degree of less than 1 × 10⁻⁶. -2 Pa.

3. The preparation method according to claim 1, characterized in that, The specific particle size in step 1 is 50μm~200μm, and the powder is stored in a vacuum-sealed container for later use.

4. The preparation method according to claim 1, characterized in that, The specific parameters for sintering in step 2 are as follows: sintering temperature is 1000℃~1200℃, pressure is 90MPa~150MPa, and argon gas protection is provided during the sintering process.

5. The preparation method according to claim 1, characterized in that, The thickness H of the first-order pure titanium billet in step 2 is 150mm~250mm, the width W is 800mm~1000mm, and the length L is 1000mm~1500mm.

6. The preparation method according to claim 1, characterized in that, The specific parameters for hot isostatic pressing in step 3 are as follows: pressure is 300MPa~500MPa, holding temperature is 500℃~700℃, holding time is 6h~10h, and the second-order pure titanium billet is cooled to room temperature for later use.

7. The preparation method according to claim 1, characterized in that, The specific density in step 3 is >99.7%.

8. The preparation method according to claim 1, characterized in that, During rolling in step 4, the rolling process is carried out in 2 to 3 passes, with the temperature controlled at 30°C to 60°C below the β phase transformation point of pure titanium. The holding time is calculated as 1.2 to 1.6 × (minimum thickness / mm) / min, and the rolling speed is 1.5 m / s to 2.5 m / s.

9. The preparation method according to claim 1, characterized in that, The deformation from the second-order pure titanium billet to the target pure titanium plate is >80%, and the thickness H of the target pure titanium plate is ≤30mm.

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