A difficult-to-combine metal layered composite material with high interface bonding quality and forming method

Abstract

The present invention discloses a difficult-to-combine metal layered composite material with high interface bonding quality and a forming method, and belongs to the technical field of metal layered composite material preparation. First, the blank is subjected to softening annealing, and then a rigid abrasive tool with a Mohs hardness of multi-sized hard particles on the surface of the blank is used to grind the surface to be composited of the blank, and a ridge-like protrusion is constructed on the surface to be composited, and then the blanks are stacked and cold-rolled for composite, and finally diffusion heat treatment is performed to obtain a metal layered composite material with high interface bonding quality. The advantage of the present invention is that by grinding the surface to be composited of the blank with a rigid abrasive tool with a multi-sized hard particles on the surface and constructing a ridge-like protrusion, a low-cost and efficient preparation of a metal layered composite material with high interface bonding quality using difficult-to-combine metals such as titanium, titanium alloy, carbon steel and alloy steel as components is achieved, and the advantages are short production cycle, low cost, high efficiency, energy saving and low carbon, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of metal layered composite materials, and in particular relates to a difficult-to-combine metal layered composite material with high interface bonding quality and a forming method thereof. Background Art

[0002] Metallic layered composite materials are composed of heterogeneous metals, which have the advantages of component metals and excellent comprehensive properties that single metals do not have. They have been widely used in the fields of marine ships, rail transportation, information and communication, aerospace, national defense and military industry, and daily life. Among them, the application fields of metallic layered composite materials with difficult-to-combine metals such as titanium, titanium alloy, carbon steel and alloy steel as components are extremely wide. However, due to the difficulty of the above-mentioned metal composites, the metal layered composite materials of the above-mentioned metals are currently mainly prepared by explosive composite method and hot rolling composite method. The explosive composite method uses the detonation wave generated by the explosion to achieve high-speed impact composite between metals, and can composite most metals. However, the explosive composite method has problems such as long production cycle, strict requirements on the production environment, large environmental pollution, potential safety hazards, inability to prepare continuously, and limited product size specifications, and has been gradually eliminated. The hot rolling composite method utilizes the high atomic activation state of metals at high temperature, combined with large reduction deformation, to achieve metal composite under high temperature and high pressure conditions. However, the surface of the metal blank to be composited is prone to severe oxidation at high temperature and is easy to react to form brittle intermetallic compounds. Therefore, before hot rolling composite, it is usually required to undergo a cumbersome welding vacuum sealing blanking process or hot rolling composite under inert atmosphere conditions. There are problems such as complex production process, high production cost, difficulty in ensuring interface bonding quality (low interface bonding strength, low interface composite rate), and limited matching of component metals.

[0003] The cold rolling composite method can achieve pre-compounding between metals by direct rolling under air atmosphere conditions, and then diffuse heat treatment to diffuse the atoms between the component metals to achieve metallurgical bonding, thereby obtaining a metal layered composite material with a certain interface bonding strength. It is a low-cost and efficient method for forming metal layered composite materials. It is widely used in the preparation of metal layered composite materials of easily composite metals such as copper and aluminum, and has generated great economic and social benefits. However, for high-strength and high-hardness difficult-to-combine metals such as titanium, titanium alloy, carbon steel and alloy steel, due to the existence of large resistance to cold working deformation, high hardness, high work hardening rate, poor thermal conductivity and other problems, when the traditional integral non-rigid grinding tool is used to mechanically grind the surface of these high-strength and high-hardness metals to be composited, the grinding tool will undergo large elastic deformation during the grinding process, weakening the unit grinding force, seriously reducing the removal efficiency of the oxide layer and pollutants on the metal surface to be composited, resulting in a significant extension of the required grinding time, and the metal surface to be composited is subjected to long-term high-speed friction and cutting by the grinding tool, which will generate a large amount of heat. At the same time, the work hardening caused by the metal during grinding will lead to an increase in hardness, further increasing the difficulty of grinding and generating more heat. In addition, the thermal conductivity of the above-mentioned metals is deviated, resulting in the severe deformation heat and friction heat generated by grinding, causing the temperature of the metal surface to be composited to rise sharply to thousands of degrees, and even reaching the melting point of the metal, causing the metal surface to be composited to oxidize and form built-up edge structure, seriously hindering the subsequent cold rolling composite effect, and easily forming inclusions at the interface, further reducing the bonding strength of the composite interface, and the composite rate of the composite interface is not high. Meanwhile, the surface of conventional grinding tools is abrasive particles of uniform size. When grinding the above-mentioned high-strength and high-hardness metal, the abrasive particles cannot be deeply cut, and it is difficult to construct a surface to be composited with a high surface roughness that is conducive to cold rolling composite, causing the critical deformation of required cold rolling composite to be larger. In addition, due to the large deformation resistance of the above-mentioned metal, very high requirements are also proposed for the performance of the rolling mill required for cold rolling composite, resulting in the difficulty of preparing such metal layered composite materials. Therefore, it is still difficult to adopt cold rolling composite method to prepare metal layered composite materials with difficult composite metals such as titanium, titanium alloy, carbon steel and alloy steel as components of high interface bonding quality (interface bonding strength and interface composite rate are both high).

[0004] Therefore, it is necessary to develop a new forming method for difficult-to-combine metal layered composite materials, so as to achieve low-cost and efficient preparation of metal layered composite materials with high interface bonding quality with difficult-to-combine metals such as titanium, titanium alloys, carbon steel and alloy steel as components. Summary of the invention

[0005] The purpose of the present invention is to provide a difficult-to-combine metal layered composite material with high interface bonding quality and a forming method. The surface of a metal blank to be composited is polished by a rigid grinding tool with a Mohs hardness of multi-sized hard particles on the surface of the grinding tool of ≥7, wherein the diameter of the multi-sized hard particles on the surface of the grinding tool is 2 to 2000 μm, the multi-sized hard particles are periodically distributed on the surface of the grinding tool, and periodically distributed ridge-like protrusions with a height of 2 to 2000 μm are constructed on the surface of the blank to be composited. The problems of low cleanliness of the surface of the blank to be composited, low exposure rate of fresh metal at the interface, high difficulty of extrusion and extrusion of fresh metal for composite, large critical deformation of rolling composite and low composite interface bonding quality during traditional cold rolling composite of difficult-to-combine metals are solved, and a metal layered composite material with high interface bonding quality and hard-to-combine metals such as titanium, titanium alloy, carbon steel and alloy steel as components can be prepared at low cost and high efficiency.

[0006] According to a first aspect of the technical solution of the present invention, a method for forming a difficult-to-combine metal layered composite material with high interface bonding quality is provided, comprising the following steps:

[0007] Step 1: Softening and annealing are performed on the metal blanks to be composited respectively to obtain the metal blanks in a soft state;

[0008] Step 2: using a rigid grinding tool with hard particles of multiple sizes on the surface and a Mohs hardness of ≥7 to mechanically grind the surfaces of the metal blanks to be composited, and constructing periodically distributed ridge-like protrusions with a height of 2 to 2000 μm on the surfaces to be composited;

[0009] Step 3: stacking the metal blanks to form metal layered blanks;

[0010] Step 4: cold-rolling and compounding the metal layered blank below the recrystallization temperature of the metal to obtain a metal layered composite blank, wherein the number of passes of the cold-rolling and compounding is 1 to 10, and the reduction rate of each pass of the cold-rolling and compounding is ≥30%;

[0011] Step 5: subjecting the metal layered composite blank to a diffusion heat treatment in an air atmosphere, wherein the heating temperature of the diffusion heat treatment is higher than the lowest recrystallization temperature of the metal;

[0012] Step 6: The metal layered composite blank is taken out of the furnace and air-cooled or cooled along with the furnace to obtain a metal layered composite material with high interface bonding quality.

[0013] Furthermore, the metal blank is in the shape of at least one of a wire, a rod, a tube, a plate, a strip, a foil or a profile, and is in the form of a single piece, a single block or a coil.

[0014] Furthermore, the mechanical polishing is off-line mechanical polishing or on-line mechanical polishing.

[0015] Furthermore, the multi-sized hard particles on the surface of the grinding tool are at least one of diamond, corundum, corundum or tungsten steel.

[0016] Furthermore, the diameter of the multi-sized hard particles on the surface of the grinding tool is 2 to 2000 μm, the diameter of the multi-sized hard particles on the surface is 2 or more sizes, the difference between at least 2 diameters of the multi-sized hard particles on the surface is ≥ 5 μm, the proportion of the hard particles of any one diameter is at least 1% of the multi-sized hard particles on the surface, and the multi-sized hard particles on the surface are periodically distributed on the surface of the grinding tool.

[0017] Furthermore, the ridge-like protrusions occupy 20% to 90% of the area of ​​the surface to be composited, and the angle between the extension direction of at least 50% of the ridge-like protrusions and the width direction of the metal blank is less than 15°.

[0018] Furthermore, the stacking and assembling of blanks is performed offline or online.

[0019] Furthermore, the diffusion heat treatment is an offline diffusion heat treatment or an online diffusion heat treatment, the heating method of the diffusion heat treatment is at least one of resistance heating, flame heating, induction heating, pulse heating, radiation heating or laser heating, and the atmosphere of the diffusion heat treatment is at least one of vacuum, reducing atmosphere or protective atmosphere.

[0020] Furthermore, the number of layers of the metal layered composite material is 2 to 10.

[0021] Furthermore, the metal is at least one of titanium, titanium alloy, carbon steel or alloy steel.

[0022] According to a second aspect of the technical solution of the present invention, there is provided a metal layered composite material with high interface bonding quality, wherein the metal layered composite material with high interface bonding quality is prepared by the method described in any one of the above aspects.

[0023] The main advantage of the present invention is that by using a rigid grinding tool with a Mohs hardness of multi-sized hard particles on the surface of the blank to be composited ≥7 to grind the surface of the blank to be composited, oxidation and formation of built-up edge structure due to drastic temperature rise on the surface of the blank to be composited are avoided, and ridge-shaped protrusions are constructed on the surface of the blank to be composited, the efficiency of rolling deformation at the interface is improved, and low-cost and high-efficiency preparation of metal layered composite materials with high interface bonding quality (high interface bonding strength and interface composite rate of 100%) with difficult-to-combine metals such as titanium, titanium alloy, carbon steel and alloy steel as components is achieved, and the problems existing in the preparation of such metal layered composite materials by traditional explosive composite method and hot rolling composite method are solved, and the method has the advantages of short production cycle, low cost, high efficiency, energy saving and low carbon, etc. The method can also be extended to the preparation of other metal layered composite materials, especially large-size and large-thickness high-performance metal layered composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of a method for forming a difficult-to-combine metal layered composite material with high interface bonding quality. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with the embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art may make non-essential improvements and adjustments based on the contents of the present invention.

[0026] According to the technical solution of the present invention, a forming method of a difficult-to-combine metal layered composite material with high interface bonding quality is provided. The surface to be composited of a metal blank is ground by using a rigid grinding tool with a Mohs hardness of multi-sized hard particles on the surface of the grinding tool of ≥7, wherein the diameter of the multi-sized hard particles on the surface of the grinding tool is 2 to 2000 μm, and the multi-sized hard particles are periodically distributed on the surface of the grinding tool. The rigid grinding tool as a whole does not undergo elastic deformation during grinding, which can ensure that the unit grinding force is not reduced. The multi-sized hard particles can further increase the unit grinding force and increase the cutting efficiency, thereby improving the cleaning efficiency of mechanical grinding, efficiently removing the oxide layer and contaminants on the surface of the blank to be composited, and avoiding a large amount of friction heat generated by long-term friction between the grinding tool and the blank. In addition, the high-speed detached chips can take away more than 90% of the grinding heat, avoiding oxidation and formation of built-up edge structure on the surface of the blank to be composited due to drastic temperature rise, which hinders the subsequent cold rolling composite effect and The formation of inclusions at the interface further reduces the bonding quality of the composite interface. At the same time, periodically distributed ridge-like protrusions with a height of 2 to 2000 μm are constructed on the surface of the blank to be composited. This layer of ridge-like protrusions undergoes strong plastic deformation and withstands ultra-high pressure stress during rolling composite, so as to improve the efficiency of rolling deformation at the interface and optimize the interface composite process, promote the maximum exposure and bonding of fresh metal at the interface, greatly reduce the critical deformation of cold-rolled composite and improve the bonding quality of the composite interface, and solve the problems of low cleanliness of the surface of the blank to be composited, low exposure rate of fresh metal at the interface, high difficulty in extrusion and extrusion of fresh metal, large critical deformation of rolling composite and low bonding quality of composite interface when conventional cold-rolled composite of difficult-to-combine metals is used. Combined with subsequent diffusion heat treatment, metal layered composite materials with high interface bonding quality and difficult-to-combine metals such as titanium, titanium alloy, carbon steel and alloy steel as components can be prepared at low cost and high efficiency.

[0027] like Figure 1 As shown, the forming method of the difficult-to-combine high-interface bonding quality metal layered composite material comprises the following steps:

[0028] Step 101: Softening annealing is performed on the metal blanks to be composited respectively to obtain soft metal blanks.

[0029] The metal blank is in the form of at least one of wire, rod, tube, plate, strip, foil or profile, and is in the form of a single piece, a single block or a coil.

[0030] Step 102: using a rigid grinding tool with multi-sized hard particles on the surface and a Mohs hardness of ≥7 to mechanically grind the surfaces of the metal blanks to be composited, and constructing periodically distributed ridge-like protrusions with a height of 2 to 2000 μm on the surfaces to be composited.

[0031] Among them, mechanical grinding is, for example, offline mechanical grinding or online mechanical grinding; the Mohs hardness of the multi-sized hard particles on the surface of the grinding tool is, for example, ≥7, which can ensure that the grinding tool has sufficient cutting ability for high-strength and high-hardness metals, improve grinding efficiency, avoid oxidation and formation of built-up edge structure on the surface of the composite due to long-term grinding of the blank, and significantly extend the service life of the grinding tool and reduce costs; the multi-sized hard particles on the surface of the grinding tool are, for example, at least one of diamond, corundum, corundum or tungsten steel; the diameter of the multi-sized hard particles on the surface of the grinding tool is, for example, 2 to 2000 μm, the diameter of the multi-sized hard particles on the surface is, for example, 2 or more sizes, the difference between at least 2 diameters of the multi-sized hard particles on the surface is, for example, ≥5 μm, the proportion of hard particles of any one diameter is at least, for example, 1% of the multi-sized hard particles on the surface, and the multi-sized hard particles on the surface are, for example, periodically distributed on the surface of the grinding tool.

[0032] In addition, the ridge-like protrusions preferably occupy 20% to 90% of the area of ​​the surface to be composited, and the angle between the extension direction of at least 50% of the ridge-like protrusions and the width direction of the metal billet is less than 15°, which is convenient for promoting the cooperative deformation ability between the ridge-like protrusions and the metal billet layers during rolling composite, and further improving the efficiency of rolling deformation at the interface.

[0033] Step 103: stacking the metal blanks to form metal layered blanks.

[0034] The stacking and assembling of blanks is, for example, off-line stacking and assembling of blanks or on-line stacking and assembling of blanks.

[0035] Step 104: cold-rolling and compounding the metal layered blank below the recrystallization temperature of the metal to obtain a metal layered composite blank, wherein the number of cold-rolling and compounding passes is, for example, 1 to 10 times, and the reduction rate of the cold-rolling and compounding passes is, for example, ≥30%, which can ensure sufficient deformation of the ridge-like protrusions at the interface and achieve an interface composite rate of 100% between the metal blanks.

[0036] Step 105: performing diffusion heat treatment on the metal layered composite blank in an air atmosphere, wherein the heating temperature of the diffusion heat treatment is higher than the lowest recrystallization temperature of the metal.

[0037] Among them, the diffusion heat treatment is, for example, offline diffusion heat treatment or online diffusion heat treatment, the heating method of the diffusion heat treatment is, for example, at least one of resistance heating, flame heating, induction heating, pulse heating, radiation heating or laser heating, and the atmosphere of the diffusion heat treatment is, for example, at least one of vacuum, reducing atmosphere or protective atmosphere.

[0038] Step 106: The metal layered composite blank is taken out of the furnace and air-cooled or cooled in the furnace to obtain a metal layered composite material with high interface bonding quality.

[0039] The number of layers of the metal layered composite material is, for example, 2 to 10 layers, and the metal is, for example, at least one of titanium, titanium alloy, carbon steel or alloy steel.

[0040] The technical solution of the present invention also provides a metal layered composite material with high interface bonding quality, and the metal layered composite material with high interface bonding quality is prepared by the method described in any one of the above aspects.

[0041] Embodiment 1:

[0042] Pure titanium slabs and 304 stainless steel slabs with a thickness of 3 mm were used as raw materials to prepare pure titanium / 304 stainless steel composite plates:

[0043] Firstly, the pure titanium slab and the 304 stainless steel slab are softened and annealed respectively to obtain the soft pure titanium slab and the 304 stainless steel slab;

[0044] Then, the surfaces of the pure titanium slab and the 304 stainless steel slab to be composited are mechanically polished by a rigid grinding tool with a Mohs hardness of 10 and multi-sized diamond hard particles brazed on the surface. The diameters of the multi-sized diamond hard particles are 10, 50 μm and 100 μm, respectively, accounting for 40%, 40% and 20%, respectively. The multi-sized diamond hard particles are periodically distributed on the surface of the grinding tool. After grinding, the surfaces of the pure titanium slab and the 304 stainless steel slab to be composited are clean fresh metals without oxidation and built-up edge formation, and there are periodically distributed ridge-like protrusions with a height of 10 to 100 μm, which account for about 80% of the area of ​​the surface to be composited, and the angle between the extension direction of 60% of the ridge-like protrusions and the width direction of the blank is less than 15°.

[0045] Then the polished pure titanium slab and the 304 stainless steel slab are stacked and assembled, and then sent to a rolling mill for one pass of cold rolling at a temperature of 200° C., with a pass reduction rate of 50%, to obtain a pure titanium / 304 stainless steel layered composite billet;

[0046] Finally, the pure titanium / 304 stainless steel layered composite billet was sent into a resistance furnace at a temperature of 650°C for diffusion heat treatment in an air atmosphere for 30 minutes, and then air-cooled to obtain a pure titanium / 304 stainless steel composite plate with an interface bonding strength of 303 MPa and an interface recombination rate of 100%.

[0047] Embodiment 2:

[0048] Pure titanium slabs and Q235 carbon steel slabs with thicknesses of 2 mm and 4 mm respectively were used as raw materials to prepare pure titanium / Q235 carbon steel composite plates:

[0049] Firstly, the pure titanium slab and the Q235 carbon steel slab are softened and annealed respectively to obtain the soft pure titanium slab and the Q235 carbon steel slab;

[0050] Then, the surfaces of the pure titanium slab and the Q235 carbon steel slab to be composited are mechanically polished by a rigid grinding tool made of multi-sized corundum hard particles with a Mohs hardness of 8. The diameters of the multi-sized corundum hard particles are 5, 100, 400, 600 μm and 1000 μm, respectively. The proportion of corundum hard particles of different diameters is 20%, and they are periodically distributed on the surface of the grinding tool. The surfaces of the pure titanium slab and the Q235 carbon steel slab to be composited after grinding are clean fresh metals without oxidation and built-up edge formation, and there are periodically distributed ridge-like protrusions with a height of 5 to 1000 μm, which account for about 65% of the area of ​​the surface to be composited, and the angle between the extension direction of 70% of the ridge-like protrusions and the width direction of the blank is less than 15°.

[0051] Then the polished pure titanium slab and Q235 carbon steel slab are stacked and assembled into a rolling mill for two passes of room temperature cold rolling, with a pass reduction rate of 45%, to obtain a pure titanium / Q235 carbon steel layered composite billet;

[0052] Finally, the pure titanium / Q235 carbon steel layered composite billet was sent into a resistance furnace at a temperature of 800°C for diffusion heat treatment for 15 minutes under the protection of inert gas, and then air-cooled to obtain a pure titanium / Q235 carbon steel composite plate with an interface bonding strength of 252MPa and an interface recombination rate of 100%.

[0053] Embodiment 3:

[0054] Pure titanium slabs and Q345 carbon steel slabs with thicknesses of 1 mm and 4 mm respectively were used as raw materials to prepare pure titanium / Q345 carbon steel composite plates:

[0055] Firstly, the pure titanium slab and the Q345 carbon steel slab are softened and annealed respectively to obtain the soft pure titanium slab and the Q345 carbon steel slab;

[0056] Then, the surfaces of the pure titanium slab and the Q345 carbon steel slab to be composited are mechanically polished using a rigid abrasive tool made of multi-sized corundum hard particles with a Mohs hardness of 9. The diameters of the multi-sized corundum hard particles are 5, 20 μm and 40 μm, respectively, accounting for 20%, 40% and 40%, respectively. The corundum hard particles of each size are periodically distributed on the surface of the abrasive tool. The surfaces of the pure titanium slab and the Q345 carbon steel slab to be composited after grinding are clean fresh metals without oxidation and built-up edge formation, and there are periodically distributed ridge-like protrusions with a height of 5 to 40 μm, which account for about 70% of the area of ​​the surface to be composited, and the angle between the extension direction of 55% of the ridge-like protrusions and the width direction of the blank is less than 15°.

[0057] Then, the polished pure titanium slab and the Q345 carbon steel slab are stacked and assembled, and then sent to a rolling mill for one pass of room temperature cold rolling and compounding, with a pass reduction rate of 55%, to obtain a pure titanium / Q345 carbon steel layered composite billet;

[0058] Finally, the pure titanium / Q345 carbon steel layered composite billet was sent into a resistance furnace at a temperature of 550°C for diffusion heat treatment in an air atmosphere for 100 minutes, and then cooled with the furnace to obtain a pure titanium / Q345 carbon steel composite plate with an interface bonding strength of 261MPa and an interface recombination rate of 100%.

[0059] Embodiment 4:

[0060] Q235 carbon steel slabs and 430 stainless steel slabs with thickness of 4 mm and 2 mm respectively were used as raw materials to prepare Q235 carbon steel / 430 stainless steel composite plates:

[0061] Firstly, Q235 carbon steel slab and 430 stainless steel slab are softened and annealed respectively to obtain soft Q235 carbon steel slab and 430 stainless steel slab;

[0062] Then, the surfaces of the Q235 carbon steel slab and the 430 stainless steel slab to be composited were mechanically polished by a rigid grinding tool with a Mohs hardness of 10 and inlaid with multi-sized diamond hard particles on the surface. The diameters of the multi-sized diamond hard particles were 10, 50, 200 μm and 500 μm, and the proportion of diamond hard particles of each size was 25%, and they were periodically distributed on the surface of the grinding tool. The surfaces of the Q235 carbon steel slab and the 430 stainless steel slab to be composited after grinding were clean fresh metals without oxidation and built-up edge formation, and there were periodically distributed ridge-like protrusions with a height of 10 to 500 μm, which accounted for about 85% of the area of ​​the surface to be composited, and the angle between the extension direction of 55% of the ridge-like protrusions and the width direction of the blank was less than 15°.

[0063] Then, the polished Q235 carbon steel slab and the 430 stainless steel slab are stacked and assembled, and then sent to a rolling mill for one pass of room temperature cold rolling and compounding, with a pass reduction rate of 50%, to obtain a Q235 carbon steel / 430 stainless steel layered composite billet;

[0064] Finally, the Q235 carbon steel / 430 stainless steel layered composite billet was sent into a resistance furnace at a temperature of 1100°C for diffusion heat treatment for 30 minutes under the protection of inert gas, and then cooled with the furnace to obtain a Q235 carbon steel / 430 stainless steel composite plate with an interface bonding strength of 406MPa and an interface recombination rate of 100%.

[0065] Comparative Example 1:

[0066] Pure titanium slabs and 304 stainless steel slabs with a thickness of 3 mm were used as raw materials to prepare pure titanium / 304 stainless steel composite plates:

[0067] Firstly, the pure titanium slab and the 304 stainless steel slab are softened and annealed respectively to obtain the soft pure titanium slab and the 304 stainless steel slab;

[0068] Then, the surfaces of the pure titanium slab and the 304 stainless steel slab to be composited were mechanically polished by a non-rigid abrasive tool with a Mohs hardness of 6 and silicon-based particles of uniform size on the surface. The diameter of the silicon-based particles was 3 μm. During the polishing, the abrasive tool would undergo 10% to 15% elastic deformation. After polishing, the surfaces of the pure titanium slab and the 304 stainless steel slab to be composited were significantly oxidized and a large amount of built-up edge tissue was formed. The morphology of the surfaces to be composited was 5% grooves and 95% elliptical pits.

[0069] Then the polished pure titanium slab and 304 stainless steel slab were stacked and fed into the rolling mill for one pass of cold rolling at 200°C, with a pass reduction of 50%. The pure titanium slab and 304 stainless steel slab were not pre-compounded after rolling. Due to the low hardness of silicon-based particles and the non-rigidity of the abrasive tool, the cleaning efficiency was low during the polishing process, and the surface to be composited was significantly oxidized and a large amount of built-up edge tissue was formed. In addition, the wear rate of the abrasive tool was high, which significantly increased the cost of mechanical polishing. At the same time, a large amount of silicon-based particle fragments and dust were generated, which affected the operation of related equipment and harmed human health.

[0070] Comparative Example 2:

[0071] Pure titanium slabs and 304 stainless steel slabs with a thickness of 3 mm were used as raw materials to prepare pure titanium / 304 stainless steel composite plates:

[0072] Firstly, the pure titanium slab and the 304 stainless steel slab are softened and annealed respectively to obtain the soft pure titanium slab and the 304 stainless steel slab;

[0073] Then, the surfaces of the pure titanium slab and the 304 stainless steel slab to be composited are mechanically polished by a rigid grinding tool with a Mohs hardness of 8 and a uniform-sized corundum hard particle on the surface, wherein the diameter of the corundum hard particle is 100 μm. After polishing, no built-up edge structure is formed on the surfaces of the pure titanium slab and the 304 stainless steel slab to be composited, and only a trace amount of oxidation occurs. There are periodically distributed ridge-like protrusions with a height of 60 to 70 μm on the surfaces to be composited, and the ridge-like protrusions occupy about 80% of the area of ​​the surface to be composited, and the angle between the extension direction of 90% of the ridge-like protrusions and the width direction of the blank is greater than 15°.

[0074] Then, the polished pure titanium slab and the 304 stainless steel slab are stacked and assembled, and then sent to a rolling mill for one pass of cold rolling at a temperature of 200° C., with a pass reduction rate of 50%, to obtain a pure titanium / 304 stainless steel layered composite billet;

[0075] Finally, the pure titanium / 304 stainless steel layered composite billet was sent into a resistance furnace at a temperature of 650°C for diffusion heat treatment in an air atmosphere for 30 minutes, and then air-cooled to obtain a pure titanium / 304 stainless steel composite plate with an interface bonding strength of 260 MPa and an interface recombination rate of 95%. When a rigid abrasive tool with a Mohs hardness of 8 on the surface hard particles is used for grinding, the unit grinding force will not be weakened due to elastic deformation of the abrasive tool during grinding, and the grinding efficiency of the abrasive tool is improved. At the same time, a ridge-like protrusion with a height of 60 to 70 μm is constructed on the surface to be composited, which improves the efficiency of rolling deformation at the interface. Therefore, a titanium / 304 stainless steel composite plate with an interface bonding strength of 260 MPa and an interface composite rate of 95% is obtained. However, since the surface of the abrasive tool is hard particles of uniform size, the cutting ability and unit grinding force of the abrasive tool are still not high enough, and the grinding efficiency is still low, so that trace oxidation occurs on the surface to be composited, and the angle between the extension direction of most of the ridge-like protrusions after grinding and the width direction of the blank is greater than 15°. Therefore, the interface bonding quality of the manufactured titanium / 304 stainless steel composite plate is slightly lower than that of Example 1.

[0076] Comparative Example 3:

[0077] Pure titanium slabs and Q235 carbon steel slabs with thicknesses of 2 mm and 4 mm respectively were used as raw materials to prepare pure titanium / Q235 carbon steel composite plates:

[0078] Firstly, the pure titanium slab and the Q235 carbon steel slab are softened and annealed respectively to obtain the soft pure titanium slab and the Q235 carbon steel slab;

[0079] Then, the surfaces of the pure titanium slab and the Q235 carbon steel slab to be composited were mechanically polished by a rigid grinding tool with a Mohs hardness of 8 made of uniform-sized corundum hard particles. The diameter of the uniform-sized corundum hard particles was 1 μm. After polishing, no built-up edge structure was formed on the surfaces of the pure titanium slab and the Q235 carbon steel slab to be composited, but a small amount of oxidation occurred. The surfaces to be composited were relatively smooth planes without ridge-like protrusions.

[0080] Then, the polished pure titanium slab and the Q235 carbon steel slab are stacked and assembled, and then sent to the rolling mill for one pass of room temperature cold rolling and compounding. When the pass reduction rate is ≤60%, pre-compounding cannot be achieved, so the pass reduction rate is set to 65% to obtain a pure titanium / Q235 carbon steel layered composite billet;

[0081] Finally, the pure titanium / Q235 carbon steel layered composite blank was sent into a resistance furnace at a temperature of 800°C for diffusion heat treatment under inert gas protection for 15 minutes, and then air-cooled to obtain a pure titanium / Q235 carbon steel composite plate with an interface bonding strength of 170MPa and an interface recombination rate of 83%. Due to the use of a rigid abrasive tool with a Mohs hardness of 8 on the surface hard particles, the unit grinding force will not be weakened due to elastic deformation of the abrasive tool during grinding, and the grinding cleaning efficiency is improved. However, the size of the hard particles is small and uniform, and the grinding efficiency is still low, resulting in a small amount of oxidation on the surface to be composited and a relatively smooth plane. The critical deformation of cold rolling composite is large, and the interface bonding strength and interface recombination rate of the prepared pure titanium / Q235 carbon steel composite plate are low.

[0082] The above are only specific embodiments of the present invention, but the protection of the present invention is not limited thereto. Any equivalent changes or substitutions of the features of the present technical solution that can be thought of by a person skilled in the art are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for forming a difficult-to-combine metal layered composite material with high interface bonding quality, characterized in that: The method comprises the following steps: Step 1: Softening and annealing are performed on the metal blanks to be composited respectively to obtain the metal blanks in a soft state; Step 2: using a rigid grinding tool with hard particles of multiple sizes on the surface and a Mohs hardness of ≥7 to mechanically grind the surfaces of the metal blanks to be composited, and constructing periodically distributed ridge-like protrusions with a height of 2 to 2000 μm on the surfaces to be composited; Step 3: stacking the metal blanks to form metal layered blanks; Step 4: cold-rolling and compounding the metal layered blank below the recrystallization temperature of the metal to obtain a metal layered composite blank, wherein the number of passes of the cold-rolling and compounding is 1 to 10, and the reduction rate of each pass of the cold-rolling and compounding is ≥30%; Step 5: subjecting the metal layered composite blank to a diffusion heat treatment in an air atmosphere, wherein the heating temperature of the diffusion heat treatment is higher than the lowest recrystallization temperature of the metal; Step 6: The metal layered composite blank is taken out of the furnace and air-cooled or cooled along with the furnace to obtain a metal layered composite material with high interface bonding quality.

2. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The metal blank is in the shape of at least one of a wire, a rod, a tube, a plate, a strip, a foil or a profile, and is in the form of a single piece, a single block or a coil.

3. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The mechanical grinding is off-line mechanical grinding or on-line mechanical grinding.

4. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The multi-sized hard particles on the surface of the grinding tool are at least one of diamond, corundum, corundum or tungsten steel.

5. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The diameter of the multi-sized hard particles on the surface of the grinding tool is 2 to 2000 μm, the diameter of the multi-sized hard particles on the surface is 2 or more sizes, the difference between at least 2 diameters of the multi-sized hard particles on the surface is ≥5 μm, the proportion of the hard particles of any one diameter is at least 1% of the multi-sized hard particles on the surface, and the multi-sized hard particles on the surface are periodically distributed on the surface of the grinding tool.

6. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The ridge-shaped protrusions occupy 20% to 90% of the area of ​​the surface to be composited, and the angle between the extension direction of at least 50% of the ridge-shaped protrusions and the width direction of the metal blank is less than 15°.

7. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The stacking and assembling of blanks is off-line stacking and assembling or on-line stacking and assembling.

8. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The diffusion heat treatment is an offline diffusion heat treatment or an online diffusion heat treatment, the heating method of the diffusion heat treatment is at least one of resistance heating, flame heating, induction heating, pulse heating, radiation heating or laser heating, and the atmosphere of the diffusion heat treatment is at least one of vacuum, reducing atmosphere or protective atmosphere.

9. The method for forming a difficult-to-combine metal layered composite material with high interface bonding quality as claimed in claim 1, characterized in that: The number of layers of the metal layered composite material is 2 to 10; the metal is at least one of titanium, titanium alloy, carbon steel or alloy steel.

10. A difficult-to-combine metal layered composite material with high interface bonding quality, characterized in that: The difficult-to-combine metal layered composite material with high interface bonding quality is prepared by the forming method according to any one of claims 1 to 9.

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