Thermal insulation coating for hot rolling of titanium alloy and high temperature alloy seamless rings and its application method

Abstract

The present invention provides a thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys and an application method thereof. In parts by weight, the thermal insulation coating comprises: 10 to 15 parts of glass powder A, 2 to 6 parts of glass powder B, 8 to 15 parts of TiO2, 5 to 15 parts of SiO2, 2 to 6 parts of TiN, 5 to 15 parts of Cr2O3, 1 to 3 parts of dolomite, 3 to 6 parts of forsterite, 1 to 5 parts of potassium feldspar, 25 to 35 parts of a dispersing solvent and 5 to 10 parts of an acrylic emulsion. The present invention effectively solves the problems of poor thermal insulation effect and easy falling off of thermal insulation materials in the hot rolling process of seamless rings of titanium alloys and high-temperature alloys in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, and in particular to a thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys and an application method thereof. Background Art

[0002] Titanium alloys can be divided into four categories according to the organizational characteristics after annealing: α, near α, α+β and β. Titanium alloys have significant comprehensive performance advantages such as low density, high specific strength, high specific fatigue strength and corrosion resistance in the temperature range of 60-600℃. They have been widely used in important components such as aircraft engines. At present, the amount of titanium alloys used in advanced aircraft engines has accounted for 25-40% of the total weight of the whole machine. There are about 20 common alloying elements in high-temperature alloys, which can be divided into iron-based, nickel-based and cobalt-based high-temperature alloys. High-temperature alloys have good oxidation resistance and corrosion resistance at high temperatures, and have good resistance to plastic deformation and fracture damage at high temperatures. They have also been widely used in important components such as aircraft engines.

[0003] Seamless ring hot rolling technology is a plastic hot processing process that uses a ring rolling machine to reduce the wall thickness, expand the diameter, and form the cross-sectional profile of the ring at high temperature. At present, the hot rolling technology of rings has gradually replaced the technology of producing rings through free forging, and has become an irreplaceable low-consumption, high-efficiency, and high-performance manufacturing technology for various high-performance seamless rings. High-performance seamless rings such as titanium alloys, high-temperature alloy casings, mounting edges, missile cabin joint rings, spacecraft reinforcement rings, artillery, tank seat rings, etc., have gradually replaced heat-resistant steel rings with their excellent performance and are widely used in aerospace, shipbuilding, nuclear power, high-speed rail, high-end engineering machinery and other fields.

[0004] However, due to the particularity of titanium alloy and high-temperature alloy materials themselves, that is, the poor plasticity of hot processing technology and the narrow hot processing temperature window, cracks are easily generated during the hot rolling process of seamless rings as the temperature of the metal rings drops, especially at the edges and corners of the rings, where the cracks are more obvious. Therefore, it is particularly important to take insulation measures during the hot rolling process for the hot rolling process of titanium alloy and high-temperature alloy seamless rings. At present, when taking insulation measures, domestic related enterprises mostly use soft packaging to insulate difficult-to-deform titanium alloy and high-temperature alloy billets. The specific operation method is: wrap the high-temperature resistant fiber felt on the outer surface of the billet at room temperature, and tie it with fine iron wire, and then heat the billet in the furnace to ensure that the fiber felt is not easy to fall off during the transfer process. However, during rolling, since the fiber felt becomes more brittle after high-temperature heating, it will gradually fall off as the metal ring is rolled and deformed, which seriously affects the insulation effect. At the same time, the process of wrapping and bundling fiber felt with iron wire is relatively complicated and time-consuming, which will reduce the production efficiency of seamless rings; high-quality filament fiber felts are generally more expensive; the detached fiber felt will affect the workshop environment, and the fiber filaments are easily broken to produce tiny filaments, which are easily inhaled by the human body and deposited in the lungs to cause damage to the respiratory system; fiber felt cannot prevent the oxidation of titanium alloys and high-temperature alloys at high temperatures, and the formed oxide layer will directly affect the quality of the rings after rolling, and will also reduce the utilization rate of metal materials.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The main purpose of the present invention is to provide a thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys and an application method thereof, so as to solve the problems in the prior art of poor thermal insulation effects and easy falling off of thermal insulation materials during hot rolling of seamless rings of titanium alloys and high-temperature alloys, resulting in obvious cracks in the rings after rolling.

[0007] In order to achieve the above-mentioned object, according to one aspect of the present invention, a thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys is provided. The thermal insulation coating comprises, by weight, 10 to 15 parts of glass powder A, 2 to 6 parts of glass powder B, 8 to 15 parts of TiO2, 5 to 15 parts of SiO2, 2 to 6 parts of TiN, 5 to 15 parts of Cr2O3, 1 to 3 parts of dolomite, 3 to 6 parts of forsterite, 1 to 5 parts of potassium feldspar, 25 to 35 parts of dispersing solvent and 5-10 parts of acrylic emulsion; wherein, by weight, glass powder A comprises 20-30 parts of SiO2, 8-15 parts of Al2O3, 5-10 parts of B2O3, 2-5 parts of Na2O and 5-8 parts of K2O; glass powder B comprises 10-15 parts of SiO2, 3-5 parts of Al2O3, 1-5 parts of B2O3, 8-15 parts of Na2O, 3-8 parts of MgO and 6-12 parts of CaO.

[0008] Furthermore, the total weight of the glass powder A and the glass powder B accounts for 14-20% of the total weight of the thermal insulation coating, preferably 16-18%.

[0009] Furthermore, the weight percentage of TiN in the thermal insulation coating is 2-6%, preferably 3-5%.

[0010] Furthermore, the weight ratio of dolomite, forsterite and potassium feldspar is (1-2):(3-5):(1-5).

[0011] Furthermore, when the thermal insulation coating is used for hot rolling of a high-temperature alloy seamless ring, the thermal insulation coating comprises, by weight: 10 to 15 parts of glass powder A, 2 to 5 parts of glass powder B, 8 to 12 parts of TiO2, 5 to 10 parts of SiO2, 2 to 6 parts of TiN, 5 to 8 parts of Cr2O3, 1 to 2 parts of dolomite, 3 to 4 parts of forsterite, 1 to 3 parts of potassium feldspar, 25 to 30 parts of a dispersing solvent and 5 to 1 0 parts of acrylic emulsion; wherein, by weight, glass powder A comprises 20-25 parts of SiO2, 10-13 parts of Al2O3, 5-8 parts of B2O3, 3-5 parts of Na2O and 6-8 parts of K2O; glass powder B comprises 11-13 parts of SiO2, 3-4 parts of Al2O3, 3-5 parts of B2O3, 8-11 parts of Na2O, 6-8 parts of MgO and 7-10 parts of C aO; when the thermal insulation coating is used for hot rolling of titanium alloy seamless rings, the thermal insulation coating includes, by weight: 10 to 12 parts of glass powder A, 3 to 6 parts of glass powder B, 8 to 10 parts of TiO2, 5 to 10 parts of SiO2, 2 to 6 parts of TiN, 5 to 10 parts of Cr2O3, 2 to 3 parts of dolomite, 4 to 6 parts of forsterite, 3 to 5 parts of potassium feldspar, 25 to 30 parts of dispersing solvent and 5 to 10 parts of acrylic emulsion; wherein, by weight, glass powder A includes 26-30 parts of SiO2, 9-11 parts of Al2O3, 6-9 parts of B2O3, 2-4 parts of Na2O and 5-7 parts of K2O; glass powder B includes 13-15 parts of SiO2, 3-5 parts of Al2O3, 2-5 parts of B2O3, 10-15 parts of Na2O, 4-6 parts of MgO and 8-11 parts of CaO.

[0012] Furthermore, the dispersion solvent is water.

[0013] Furthermore, except for the dispersed solvent and the acrylic emulsion, all materials in the thermal insulation coating are solid particles with a particle size of 200 to 400 meshes.

[0014] According to another aspect of the present invention, a hot rolling method for seamless rings of titanium alloys and high-temperature alloys is also provided, which comprises the following steps: providing a ring-shaped blank of titanium alloy or high-temperature alloy; applying the above-mentioned thermal insulation coating on the inner and outer surfaces of the ring-shaped blank, and after drying, sending it into a heating furnace for heating to obtain a hot billet; hot rolling the hot billet to obtain a seamless ring.

[0015] Furthermore, the coating amount of the thermal insulation coating on the inner and outer surfaces of the annular blank is 0.2-0.3 kg / m 2 , the coating thickness is 0.2~0.4mm.

[0016] Furthermore, the titanium alloy is TC4 titanium alloy, the high-temperature alloy is GH141 high-temperature alloy or GH718 high-temperature alloy, and the seamless ring is an engine casing, an engine mounting edge, a missile cabin connecting ring, a spacecraft reinforcement ring, a gun seat ring or a tank seat ring.

[0017] The thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys provided by the present invention can perfectly replace the soft-packing process, and can better solve the protection and insulation problems of the blanks in the hot rolling process of seamless rings of titanium alloys and high-temperature alloys, reduce the surface cracks of the blanks after rolling, and make it easier to obtain uniform and fine microstructures. Compared with the soft-packing process, the use of the above-mentioned thermal insulation coating can also simplify the production process, reduce labor intensity, reduce the damage to human health caused by construction, and improve the on-site environment of the workshop. In addition, the thermal insulation coating of the present invention can be used in the hot rolling process of other difficult-to-deform alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 A photo showing the hot rolling process of a GH141 high temperature alloy seamless ring according to Example 1 of the present invention is shown;

[0020] Figure 2 Another photo showing the hot rolling process of the GH141 high temperature alloy seamless ring according to Example 1 of the present invention;

[0021] Figure 3 A photo showing the hot rolling process of a GH141 high temperature alloy seamless ring according to Comparative Example 1 of the present invention is shown;

[0022] Figure 4 Another photo showing the hot rolling process of the GH141 high temperature alloy seamless ring according to Comparative Example 1 of the present invention;

[0023] Figure 5A photo of a ring formed by hot rolling of a GH141 high temperature alloy seamless ring according to Comparative Example 1 of the present invention is shown;

[0024] Figure 6 A photo of a GH141 high temperature alloy seamless ring formed by hot rolling according to Example 1 of the present invention is shown;

[0025] Figure 7 A photo of a GH141 high temperature alloy seamless ring formed by hot rolling according to Example 2 of the present invention is shown;

[0026] Figure 8 A photo of a GH141 high temperature alloy seamless ring formed by hot rolling according to Example 3 of the present invention is shown;

[0027] Fig. 9 A photo of a GH141 high temperature alloy seamless ring formed by hot rolling according to Example 4 of the present invention is shown;

[0028] Fig.10 A photo of a GH141 high temperature alloy seamless ring formed by hot rolling according to Example 5 of the present invention is shown;

[0029] Fig.11 A photo of a TC4 titanium alloy seamless ring formed by hot rolling according to Example 6 of the present invention is shown;

[0030] Fig.12 A photo of a TC4 titanium alloy seamless ring formed by hot rolling according to Example 7 of the present invention is shown;

[0031] Fig.13 A photo of a TC4 titanium alloy seamless ring formed by hot rolling according to Example 8 of the present invention is shown;

[0032] Fig.14 A photo of an integral ring formed by hot rolling of a TC4 titanium alloy seamless ring according to Comparative Example 2 of the present invention is shown;

[0033] Fig.15 A photo of a partial ring formed by hot rolling of a TC4 titanium alloy seamless ring according to Comparative Example 2 of the present invention is shown;

[0034] Fig.16 The scanning electron microscope photograph of the TC4 titanium alloy after the thermal history according to Comparative Example 3 of the present invention is shown;

[0035] Fig.17 The scanning electron microscope photograph of the TC4 titanium alloy after the thermal history according to Example 9 of the present invention is shown;

[0036] Fig.18 The scanning electron microscope photograph of the GH141 high temperature alloy after the thermal history according to Comparative Example 4 of the present invention is shown;

[0037] Fig.19 The scanning electron microscope photograph of the GH141 high temperature alloy after the thermal history according to Example 10 of the present invention is shown;

[0038] Fig. 20 A comparison diagram of the cooling curves of the GH141 high-temperature alloy samples in Example 11 according to the present invention and Comparative Example 5 is shown. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] Terminology explanation:

[0041] Thermal insulation coating: A suspension made of a variety of amorphous composite glass and high temperature resistant fillers as the main solid base materials, and a certain amount of adhesive, additives and water. Before the blank is put into the furnace for heating, the coating is stirred evenly and brushed, sprayed or dipped on the surface of the blank so that the coating is evenly covered on the surface of the blank, and a coating is formed after drying.

[0042] As described in the background technology section, in the prior art, there are problems such as poor insulation effect and easy falling off of insulation materials during hot rolling of seamless rings of titanium alloys and high-temperature alloys.

[0043] In addition to the many defects of the soft-coating process mentioned above, the inventors also found that traditional glass protective coatings are not suitable for titanium alloys and high-temperature alloys due to the particularity of the materials and the particularity of the hot rolling process. On the one hand, during the hot rolling process of titanium alloy and high-temperature alloy seamless rings, the thermal expansion coefficient of traditional glass protective coatings is poorly compatible with the material, and uneven problems are prone to occur during the hot rolling process, thus affecting the surface morphology of the final product; on the other hand, unlike other heat treatment processes, the hot rolling process is different from other heat treatment processes due to the particularity of steps such as hole expansion, and the lubricity of traditional glass protective coatings is too high, which directly affects the processing process. Based on this, the present invention provides a thermal insulation coating specifically suitable for the hot rolling process of titanium alloy and high-temperature alloy seamless rings, which is introduced in detail below.

[0044] The present invention provides a typical thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys. The thermal insulation coating comprises, by weight, 10 to 15 parts of glass powder A, 2 to 6 parts of glass powder B, 8 to 15 parts of TiO2, 5 to 15 parts of SiO2, 2 to 6 parts of TiN, 5 to 15 parts of Cr2O3, 1 to 3 parts of dolomite, 3 to 6 parts of forsterite, 1 to 5 parts of potassium feldspar, 25 to 35 parts of a dispersing solvent and 5 to 10 parts of acrylic emulsion; wherein, by weight, glass powder A includes 20 to 30 parts of SiO2, 8 to 15 parts of Al2O3, 5 to 10 parts of B2O3, 2 to 5 parts of Na2O and 5 to 8 parts of K2O; glass powder B includes 10 to 15 parts of SiO2, 3 to 5 parts of Al2O3, 1 to 5 parts of B2O3, 8 to 15 parts of Na2O, 3 to 8 parts of MgO and 6 to 12 parts of CaO.

[0045] The content of glass powder in the above-mentioned thermal insulation coating is appropriate, so that a stable thermal insulation protective layer can be formed on the inner and outer surfaces of the titanium alloy and high-temperature alloy seamless ring blanks during the application process, and its lubricity is very low, which will not affect the hot rolling process. At the same time, the above-mentioned thermal insulation coating is composed of the above components, and its thermal expansion coefficient is more suitable for the thermal expansion coefficient of titanium alloy and high-temperature alloy, and the thermal insulation performance is better. For example, SiO2 is the most abundant oxide in the earth's crust, with low cost, and its low expansion coefficient can cause the coating to peel off by itself during the cooling process of the metal out of the furnace. At the same time, at high temperatures, SiO2 can form a dense glass state, which enhances the airtightness of the coating and is conducive to isolating the high-temperature corrosion of harmful gases to the metal. The addition of TiN has an important influence on the thermal expansion performance of the coating to adapt to the thermal expansion of titanium alloy and high-temperature alloy. Cr2O3 exists stably at high temperatures, which can further enhance the high-temperature stability of the coating. Acrylic emulsion, as a binder, can cooperate with solvents and other components to form a thermal insulation coating with a more suitable viscosity, which can play a better role in thermal insulation protection during the hot rolling of seamless rings of titanium alloys and high-temperature alloys. The components are used according to the above ratios. The thermal insulation coating has good compatibility with the specific process of hot rolling of titanium alloy and high-temperature alloy seamless rings, namely heating temperature, insulation time, furnace atmosphere, rolling conditions, etc., and can provide good protection and insulation for metals at high temperatures.

[0046] In short, the above-mentioned thermal insulation coating can perfectly replace the soft-packing process, and can better solve the protection and insulation problems of the blanks in the hot rolling process of titanium alloy and high-temperature alloy seamless rings, reduce the surface cracks of the blanks after rolling, and make it easier to obtain uniform and fine microstructures. Compared with the soft-packing process, the use of the above-mentioned thermal insulation coating can also simplify the production process, reduce labor intensity, reduce the damage to human health during construction, and improve the on-site environment of the workshop.

[0047] In the specific application process, the above-mentioned thermal insulation coating can be applied to the inner and outer surfaces of the titanium alloy and high-temperature alloy seamless ring blank, and then melted in the subsequent heating process to form a dense, uniform, continuous film layer to isolate the high-temperature corrosion of the titanium alloy and the high-temperature alloy by harmful gases such as O2. Considering further improving the high-temperature protection performance of the coating and minimizing its lubricity, in a preferred embodiment, the sum of the weights of the above-mentioned glass powder A and glass powder B accounts for 14-20% of the total weight of the thermal insulation coating, preferably 16-18%.

[0048] The addition of TiN plays a more important role in adapting the thermal expansion properties of the coating to the thermal expansion properties of titanium alloys and high-temperature alloys. In order to better play this role and further improve the high-temperature protection performance of the coating, so that it can stably spread on the surface of titanium alloy and high-temperature alloy seamless ring blanks during hot rolling, in a preferred embodiment, the weight percentage of the above-mentioned TiN in the thermal insulation coating is 2-6%, preferably 3-5%.

[0049] In a preferred embodiment, the weight ratio of dolomite, forsterite and potassium feldspar is (1-2): (3-5): (1-5). Controlling the ratio of the above three components within the above range is conducive to further improving the coating performance and stability of the thermal insulation coating, especially in the hot rolling process, it can further enhance the high-temperature adhesion of the coating, and further prevent the coating from being too lubricated, which has a better promoting effect on the smooth and stable progress of the hot rolling process.

[0050] In a preferred embodiment, when the thermal insulation coating is used for hot rolling of high-temperature alloy seamless rings, the thermal insulation coating includes, by weight: 10 to 15 parts of glass powder A, 2 to 5 parts of glass powder B, 8 to 12 parts of TiO2, 5 to 10 parts of SiO2, 2 to 6 parts of TiN, 5 to 8 parts of Cr2O3, 1 to 2 parts of dolomite, 3 to 4 parts of forsterite, 1 to 3 parts of potassium feldspar, 25 to 30 parts of dispersed solvent agent and 5-10 parts of acrylic emulsion; wherein, by weight, glass powder A comprises 20-25 parts of SiO2, 10-13 parts of Al2O3, 5-8 parts of B2O3, 3-5 parts of Na2O and 6-8 parts of K2O; glass powder B comprises 11-13 parts of SiO2, 3-4 parts of Al2O3, 3-5 parts of B2O3, 8-11 parts of Na2O, 6-8 parts of MgO and 7-10 When the thermal insulation coating is used for hot rolling of titanium alloy seamless rings, the thermal insulation coating includes, by weight: 10 to 12 parts of glass powder A, 3 to 6 parts of glass powder B, 8 to 10 parts of TiO2, 5 to 10 parts of SiO2, 2 to 6 parts of TiN, 5 to 10 parts of Cr2O3, 2 to 3 parts of dolomite, 4 to 5 parts of forsterite, 3 to 5 parts of potassium feldspar, 25 to 30 parts of dispersing solvent and 5 to 10 parts of acrylic emulsion; wherein, by weight, glass powder A includes 26-30 parts of SiO2, 9-11 parts of Al2O3, 6-9 parts of B2O3, 2-4 parts of Na2O and 5-7 parts of K2O; glass powder B includes 13-15 parts of SiO2, 3-5 parts of Al2O3, 2-5 parts of B2O3, 10-15 parts of Na2O, 4-6 parts of MgO and 8-11 parts of CaO. The hot rolling process of titanium alloy seamless rings and the hot rolling process of high-temperature alloy seamless rings are more suitable for using the above-mentioned thermal insulation coatings, which have better protective and thermal insulation performance in the hot rolling process.

[0051] In a preferred embodiment, the above-mentioned dispersion solvent is water. More preferably, in addition to the dispersion solvent and the acrylic emulsion, the materials in the thermal insulation coating are all solid particles with a particle size of 200 to 400 mesh. Controlling the particle size of the solid particles within the above range is conducive to quickly forming a stable thermal insulation protective layer during the heating process after coating.

[0052] In actual use, the above coating can be weighed according to the ingredients and then put into a ball mill for ball milling, and the ball-to-material ratio, ball milling speed and ball milling time are determined (for example, the ball-to-material ratio is 2-3:1, the ball milling speed is 50-70 rpm, and the ball milling time is 5-30h). After ball milling, pour out the coating, and after aging for one day, it can be sprayed or brushed on the surface of titanium alloy and high-temperature alloy. After the coating is dry, it can be heated in the furnace with the mold. This coating should be sealed and stored in a cool and dry place. There will be slight precipitation after long-term storage. It can be used after stirring evenly.

[0053] According to another aspect of the present invention, a hot rolling method for seamless rings of titanium alloys and high-temperature alloys is also provided, which comprises the following steps: providing a ring-shaped blank of titanium alloy or high-temperature alloy; applying the above-mentioned thermal insulation coating on the inner and outer surfaces of the ring-shaped blank, and after drying, sending it into a heating furnace for heating to obtain a hot billet; hot rolling the hot billet to obtain a seamless ring.

[0054] The content of glass powder in the above-mentioned thermal insulation coating is appropriate, so that a stable thermal insulation protective layer can be formed on the inner and outer surfaces of the titanium alloy and high-temperature alloy seamless ring blanks during the application process, and its lubricity is very low and will not affect the hot rolling process. At the same time, the above-mentioned thermal insulation coating is composed of the above components, and its thermal expansion coefficient is more suitable for the thermal expansion coefficient of titanium alloy and high-temperature alloy, and the thermal insulation performance is better. Based on this, the thermal insulation coating can perfectly replace the soft-packing process, and can better solve the protection and insulation problems of the blanks in the hot rolling process of titanium alloy and high-temperature alloy seamless rings, reduce the surface cracks of the blanks after rolling, and make it easier to obtain uniform and fine microstructures. Compared with the soft-packing process, the use of the above-mentioned thermal insulation coating can also simplify the production process, reduce labor intensity, reduce the damage to human health caused by construction, and improve the on-site environment of the workshop.

[0055] In order to better provide thermal insulation protection during specific application, in a preferred embodiment, the coating amount of the thermal insulation coating on the inner and outer surfaces of the annular blank is 0.2-0.3 kg / m 2 , the coating thickness is 0.2~0.4mm.

[0056] The hot rolling method provided by the present invention is suitable for hot rolling seamless rings of titanium alloys and high-temperature alloys, especially TC4 titanium alloy, GH141 high-temperature alloy, GH718 high-temperature alloy, etc. Preferably, the seamless rings include but are not limited to engine casings, engine mounting edges, missile cabin joint rings, spacecraft reinforcement rings, artillery seat rings or tank seat rings.

[0057] In actual use, most of the thermal insulation coating will peel off in the later stage of rolling of titanium alloy and high-temperature alloy seamless rings. The unpeeled parts can be removed by sand blasting, acid pickling and alkaline washing.

[0058] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0059] Hot rolling test of metal rings

[0060] Example 1

[0061] GH141 high temperature alloy seamless ring hot rolling

[0062] Heating system: The metal ring billet is directly put into a 1010℃ furnace, kept warm for 3 hours, rolled out of the furnace, and air-cooled to room temperature after rolling.

[0063] The raw material ratio of the thermal insulation coating used in the hot rolling process is (by weight):

[0064] Glass powder A: 15 parts, glass powder B: 4 parts, TiO2: 9 parts, SiO2: 6 parts, TiN: 3 parts, Cr2O3: 6 parts, dolomite: 1 part, forsterite: 5 parts, potassium feldspar: 1 part, water: 25 parts, acrylic emulsion: 10 parts. By weight, glass powder A includes 20 parts of SiO2, 10 parts of Al2O3, 8 parts of B2O3, 5 parts of Na2O and 6 parts of K2O; glass powder B includes 11 parts of SiO2, 3 parts of Al2O3, 5 parts of B2O3, 11 parts of Na2O, 6 parts of MgO and 7 parts of CaO.

[0065] The particle size of the above solid components is controlled at 200-400 meshes.

[0066] Weigh the above components in proportion and put them into a ball mill, and use a roller ball mill to grind them. The ball-to-material ratio is 3:1, the ball mill speed is 55 rpm, and the ball milling time is 12 hours. After ball milling, pour out the coating, and after aging for 1 day, spray or brush it on the surface of the high-temperature alloy ring billet. After the coating is dry, it can be heated in the furnace and then hot rolled (the hot rolling process is as follows Figure 1 and Figure 2 shown).

[0067] Example 2

[0068] The difference from Example 1 is that the raw material ratio of the thermal insulation coating is as follows (by weight): glass powder A: 10 parts, glass powder B: 5 parts, TiO2: 8 parts, SiO2: 10 parts, TiN: 6 parts, Cr2O3: 5 parts, dolomite: 2 parts, forsterite: 4 parts, potassium feldspar: 3 parts, water: 30 parts, and acrylic emulsion: 5 parts.

[0069] Example 3

[0070] The difference from Example 1 is that the raw material ratio of the thermal insulation coating is (by weight): glass powder A: 12 parts, glass powder B: 2 parts, TiO2: 12 parts, SiO2: 5 parts, TiN: 2 parts, Cr2O3: 8 parts, dolomite: 1 part, forsterite: 3 parts, potassium feldspar: 1 part, water: 25 parts, and acrylic emulsion: 8 parts.

[0071] Example 4

[0072] The difference from Example 1 is that the thermal insulation coating has the following raw material ratios (by weight): glass powder A: 15 parts, glass powder B: 6 parts, TiO2: 15 parts, SiO2: 5 parts, TiN: 6 parts, Cr2O3: 15 parts, dolomite: 3 parts, forsterite: 3 parts, potassium feldspar: 5 parts, water: 35 parts, and acrylic emulsion: 10 parts.

[0073] Example 5

[0074] The difference from Example 1 is that, in parts by weight, glass powder A includes 25 parts of SiO2, 13 parts of Al2O3, 5 parts of B2O3, 3 parts of Na2O and 8 parts of K2O; glass powder B includes 13 parts of SiO2, 4 parts of Al2O3, 3 parts of B2O3, 8 parts of Na2O, 8 parts of MgO and 10 parts of CaO.

[0075] Comparative Example 1

[0076] The difference from Example 1 is that no heat-insulating coating is used for hot rolling (the hot rolling process is as follows Figure 3 and Figure 4 shown).

[0077] It has been verified that the coating has good protection and thermal insulation properties. In Comparative Example 1, the surface cracks of the uncoated GH141 high-temperature alloy are more (the photo of the ring after hot rolling is shown in Figure 2). Figure 5 As shown in the figure, the inner diameter cracks of the ring after rolling are obvious), and no obvious cracks are found on the surface of the GH141 high-temperature alloy with coating in Example 1 (the photo of the ring after hot rolling is shown in the figure Figure 6 As shown, no obvious cracks were observed in the ring after rolling).

[0078] In addition, the photo of the hot-rolled ring of GH141 high-temperature alloy coated in Example 2 is shown in Figure 7 The coating in Example 3 is used for the hot-rolled ring of GH141 high-temperature alloy. Figure 8 The coating in Example 4 is used for the hot-rolled ring of GH141 high-temperature alloy. Fig. 9 The coating in Example 5 is used for the hot-rolled ring of GH141 high-temperature alloy. Fig.10 The hot-rolled rings in Examples 2 to 5 did not produce obvious cracks. Compared with Example 4, the hot-rolled rings in Examples 1 to 3 had better quality.

[0079] Example 6

[0080] TC4 Titanium Alloy Seamless Ring Hot Rolling

[0081] Heating system: The metal ring blank is directly put into a 950℃ furnace, kept warm for 4 hours, rolled out of the furnace, and air-cooled to room temperature after rolling.

[0082] The raw material ratio of the thermal insulation coating used in the hot rolling process is (by weight): glass powder A: 10 parts, glass powder B: 6 parts, TiO2: 10 parts, SiO2: 8 parts, TiN: 4 parts, Cr2O3: 5 parts, dolomite: 2 parts, forsterite: 6 parts, potassium feldspar: 5 parts, water: 30 parts, acrylic emulsion: 5 parts. By weight, glass powder A includes 26 parts of SiO2, 9 parts of Al2O3, 9 parts of B2O3, 4 parts of Na2O and 5 parts of K2O; glass powder B includes 13 parts of SiO2, 3 parts of Al2O3, 5 parts of B2O3, 15 parts of Na2O, 4 parts of MgO and 8 parts of CaO.

[0083] The particle size of the above solid components is controlled at 200-400 meshes.

[0084] Weigh the above components in proportion and put them into a ball mill, and use a roller ball mill to mill the materials, with a ball-to-material ratio of 3:1, a ball milling speed of 55 rpm, and a ball milling time of 12 hours. Pour out the coating after ball milling, and after aging for 1 day, spray or brush it on the surface of the TC4 titanium alloy ring blank. After the coating is dry, it can be heated with the furnace, and then hot rolling is completed.

[0085] Example 7

[0086] The difference from Example 6 is that the raw material ratio of the thermal insulation coating is (by weight): glass powder A: 12 parts, glass powder B: 3 parts, TiO2: 8 parts, SiO2: 10 parts, TiN: 2 parts, Cr2O3: 10 parts, dolomite: 3 parts, forsterite: 6 parts, potassium feldspar: 3 parts, water: 25 parts, and acrylic emulsion: 10 parts.

[0087] Example 8

[0088] The difference from Example 6 is that the raw material ratio of the thermal insulation coating is as follows (by weight): glass powder A: 15 parts, glass powder B: 2 parts, TiO2: 15 parts, SiO2: 15 parts, TiN: 6 parts, Cr2O3: 15 parts, dolomite: 1 part, forsterite: 3 parts, potassium feldspar: 5 parts, water: 25 parts, and acrylic emulsion: 10 parts.

[0089] Comparative Example 2

[0090] The difference from Example 6 is that no thermal insulation coating is used for hot rolling.

[0091] It has been verified that the coating has good protection and thermal insulation properties. In Comparative Example 2, the TC4 titanium alloy without coating has more surface cracks (the photo of the ring after hot rolling is shown in Figure 2). Fig.14 and 15 As shown, Fig.14 This is a photo of the entire ring. Fig.15The photo is a partial enlarged photo. It can be seen that the inner diameter cracks of the ring after rolling are serious). No obvious cracks are found on the surface of the TC4 titanium alloy with coating in Example 6 (the photo of the ring after hot rolling is as shown in FIG. Fig.11 As shown, no obvious cracks were observed in the ring after rolling).

[0092] In addition, the photo of the hot-rolled ring of TC4 titanium alloy coated in Example 7 is shown in Fig.12 The photo of the hot-rolled ring of TC4 titanium alloy coated in Example 8 is shown in Fig.13 The hot-rolled rings in Examples 7 to 8 did not produce obvious cracks. Compared with Example 8, the hot-rolled rings in Examples 6 and 7 had better quality.

[0093] Verification test of anti-oxidation effect and thermal insulation effect of thermal insulation coating

[0094] 1. Anti-oxidation effect

[0095] Example 9

[0096] The selected size is The TC4 titanium alloy was sprayed with the thermal insulation coating in Example 6 on its surface, and then put into a furnace at 1150°C and kept warm for 3 hours. After being taken out of the furnace and air-cooled to room temperature, the longitudinal section of the test block was polished, and then the oxide layer thickness of the test block was observed and measured through a metallographic microscope.

[0097] Comparative Example 3

[0098] The difference from Example 9 is that the thermal insulation coating is not sprayed and the thermal process is directly carried out.

[0099] The scanning electron microscope photo of the TC4 titanium alloy after the thermal history in Comparative Example 3 is as follows: Fig.16 As shown, the scanning electron microscope photo of the TC4 titanium alloy after the thermal history in Example 9 is as follows Fig.17 The uncoated TC4 titanium alloy in Comparative Example 3 produced an oxide layer of about 112 microns, while no oxide layer was observed in the coated TC4 titanium alloy in Example 9.

[0100] Example 10

[0101] The selected size is A GH141 high-temperature alloy sample was sprayed with the thermal insulation coating in Example 1 on its surface, and then placed in a 1150°C furnace and kept warm for 3 hours. After being taken out of the furnace and air-cooled to room temperature, the longitudinal section of the test block was polished, and the oxide layer thickness of the test block was observed and measured through a metallographic microscope.

[0102] Comparative Example 4

[0103] The difference from Example 4 is that the thermal insulation coating is not sprayed and the thermal process is directly carried out.

[0104] The scanning electron microscope photograph of the GH141 high temperature alloy after the thermal history in Comparative Example 4 is as follows: Fig.18 As shown, the scanning electron microscope photo of the GH141 high temperature alloy after the thermal history in Example 10 is as follows Fig.19 The uncoated GH141 high temperature alloy in Comparative Example 4 produced an oxide layer of about 72 microns, while no oxide layer was observed in the coated GH141 high temperature alloy in Example 10.

[0105] 2. Thermal insulation effect

[0106] Embodiment 11

[0107] The selected size is A GH141 high-temperature alloy sample was sprayed with the thermal insulation coating of Example 1 on its surface, and then placed in a 1150°C furnace for 3 hours. After being taken out of the furnace, the temperature change of the sample was continuously measured with an infrared temperature measuring gun, and the sample state was recorded by taking photos every 0.5 to 1 minute. The temperature of the sample was identified by observing the color of the sample, and finally a cooling curve was formed, as shown in FIG. Fig. 20 .

[0108] Comparative Example 5

[0109] The difference from Example 11 is that the thermal insulation coating is not sprayed, and the sample is placed in a furnace at 1150°C for 3 hours. After being taken out of the furnace, the temperature change of the sample is continuously measured with an infrared temperature measuring gun, and the sample state is recorded by taking photos every 0.5 to 1 minute. The temperature of the sample is identified by observing the color of the sample, and finally a cooling curve is formed. Fig. 20 .

[0110] Depend on Fig. 20 It can be seen that the thermal insulation coating provided by the present invention has a very significant thermal insulation effect on the alloy.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A thermal insulation coating for hot rolling of seamless rings of titanium alloys and high-temperature alloys, characterized in that: In parts by weight, the thermal insulation coating comprises: 10 to 15 parts of glass powder A, 2 to 6 parts of glass powder B, 8 to 15 parts of TiO2, 5 to 15 parts of SiO2, 2 to 6 parts of TiN, 5 to 15 parts of Cr2O3, 1 to 3 parts of dolomite, 3 to 6 parts of forsterite, 1 to 5 parts of potassium feldspar, 25 to 35 parts of a dispersing solvent and 5 to 10 parts of an acrylic emulsion; the weight percentage of the TiN in the thermal insulation coating is 2 to 6%; the weight ratio of the dolomite, the forsterite and the potassium feldspar is (1 to 2):(3 to 5): (1～5)； Among them, in parts by weight, the glass powder A includes 20 to 30 parts of SiO2, 8 to 15 parts of Al2O3, 5 to 10 parts of B2O3, 2 to 5 parts of Na2O and 5 to 8 parts of K2O; the glass powder B includes 10 to 15 parts of SiO2, 3 to 5 parts of Al2O3, 1 to 5 parts of B2O3, 8 to 15 parts of Na2O, 3 to 8 parts of MgO and 6 to 12 parts of CaO.

2. The thermal insulation coating for hot rolling of titanium alloy and high-temperature alloy seamless rings according to claim 1 is characterized in that: The total weight of the glass powder A and the glass powder B accounts for 14-20% of the total weight of the thermal insulation coating.

3. The thermal insulation coating for hot rolling of titanium alloy and high-temperature alloy seamless rings according to claim 2 is characterized in that: The total weight of the glass powder A and the glass powder B accounts for 16-18% of the total weight of the thermal insulation coating.

4. The thermal insulation coating for hot rolling of titanium alloy and high-temperature alloy seamless rings according to any one of claims 1 to 3, characterized in that: The weight percentage of the TiN in the thermal insulation coating is 3-5%.

5. The thermal insulation coating for hot rolling of titanium alloy and high temperature alloy seamless rings according to any one of claims 1 to 3, characterized in that: When the thermal insulation coating is used for hot rolling of the high-temperature alloy seamless ring, the thermal insulation coating includes, by weight: 10 to 15 parts of glass powder A, 2 to 5 parts of glass powder B, 8 to 12 parts of TiO2, 5 to 10 parts of SiO2, 2 to 6 parts of TiN, 5 to 8 parts of Cr2O3, 1 to 2 parts of dolomite, 3 to 4 parts of forsterite, 1 to 3 parts of potassium feldspar, 25 to 30 parts of a dispersing solvent and 5 to 10 parts of Acrylic emulsion; wherein, by weight, the glass powder A comprises 20 to 25 parts of SiO2, 10 to 13 parts of Al2O3, 5 to 8 parts of B2O3, 3 to 5 parts of Na2O and 6 to 8 parts of K2O; the glass powder B comprises 11 to 13 parts of SiO2, 3 to 4 parts of Al2O3, 3 to 5 parts of B2O3, 8 to 11 parts of Na2O, 6 to 8 parts of MgO and 7 to 10 parts of CaO; When the thermal insulation coating is used for hot rolling of the titanium alloy seamless ring, the thermal insulation coating includes, by weight: 10 to 12 parts of glass powder A, 3 to 6 parts of glass powder B, 8 to 10 parts of TiO2, 5 to 10 parts of SiO2, 2 to 6 parts of TiN, 5 to 10 parts of Cr2O3, 2 to 3 parts of dolomite, 4 to 6 parts of forsterite, 3 to 5 parts of potassium feldspar, 25 to 30 parts of a dispersing solvent and 5 to 10 parts of Acrylic emulsion; wherein, by weight, the glass powder A comprises 26-30 parts of SiO2, 9-11 parts of Al2O3, 6-9 parts of B2O3, 2-4 parts of Na2O and 5-7 parts of K2O; the glass powder B comprises 13-15 parts of SiO2, 3-5 parts of Al2O3, 2-5 parts of B2O3, 10-15 parts of Na2O, 4-6 parts of MgO and 8-11 parts of CaO.

6. The thermal insulation coating for hot rolling of titanium alloy and high temperature alloy seamless rings according to any one of claims 1 to 3, characterized in that: The dispersing solvent is water.

7. The thermal insulation coating for hot rolling of titanium alloy and high temperature alloy seamless rings according to any one of claims 1 to 3, characterized in that: Except for the dispersion solvent and the acrylic emulsion, all materials in the thermal insulation coating are solid particles with a particle size of 200 to 400 meshes.

8. A hot rolling method for titanium alloy and high temperature alloy seamless rings, characterized in that: The following steps are involved: Providing a ring-shaped blank of the titanium alloy or the high-temperature alloy; Apply the thermal insulation coating according to any one of claims 1 to 7 on the inner and outer surfaces of the annular blank, and after drying, send it into a heating furnace for heating to obtain a hot blank; The hot billet is hot rolled to obtain a seamless ring.

9. The hot rolling method according to claim 8, characterized in that: The coating amount of the thermal insulation coating on the inner and outer surfaces of the annular blank is 0.2-0.3 kg / m 2 , the coating thickness is 0.2~0.4mm.

10. The hot rolling method according to claim 8, characterized in that: The titanium alloy is TC4 titanium alloy, the high-temperature alloy is GH141 high-temperature alloy or GH718 high-temperature alloy, and the seamless ring is an engine casing, an engine mounting edge, a missile cabin connecting ring, a spacecraft reinforcement ring, a gun seat ring or a tank seat ring.

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