A magnesium alloy plate and a temperature control hot rolling method thereof

Abstract

The application discloses a temperature control hot rolling preparation method of a magnesium alloy plate, which is characterized by the following steps: after the homogenization heat treatment step and the hot extrusion step, temperature control hot rolling is further carried out, and the temperature control hot rolling is specifically divided into three stages, the first stage is rolling at a temperature of 360-385 DEG C with a rolling deformation of 50-60%, the second stage is rolling at a temperature of 340-360 DEG C with a rolling deformation of 30-40% after the first deformation, and the third stage is rolling at a temperature of 320-350 DEG C with a rolling deformation of 20% after the second deformation. In the application, the mechanical properties and the chemical stability of the alloy are effectively adjusted, the comprehensive mechanical properties of the magnesium alloy plate are effectively adjusted by increasing the hot rolling treatment step, the corrosion rate uniformity of the alloy in a high-temperature environment is improved, the corrosion stability and controllability of the alloy in different high-temperature environments are improved, and the corrosion rate is regulated to 30-40 mg.cm ‑2 ·h ‑1 .

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature control hot rolling preparation of alloy plates, in particular to a magnesium alloy plate and a temperature control hot rolling preparation method thereof. BACKGROUND

[0002] Fossil fuels such as oil, natural gas and coal are the main sources of energy supply in the world today, and their exploitation technology is constantly improving. In the exploitation of low-permeability shale resources, traditional exploitation methods have problems such as high operation risk, low efficiency and high cost. Dissolvable magnesium alloys are widely used in the exploitation of such resources due to their excellent corrosion rate and performance.

[0003] The volume fracturing technology is a new technology developed in recent years at home and abroad for the development of unconventional oil and gas reservoirs. This technology can shorten the seepage distance of fluid, improve the reservoir flow capacity, and effectively achieve yield improvement and transformation of ultra-low permeability oil and gas reservoirs. Dissolvable magnesium alloys can be used to make fracturing balls. In the technology of horizontal well staged fracturing, the fracturing balls made of dissolvable magnesium alloys are key components. During fracturing operations, the fracturing balls are used to block specific channels to achieve staged fracturing. After the operation is completed, the dissolvable magnesium alloy fracturing balls can dissolve in the electrolyte liquid underground, avoiding the situation that the traditional fracturing balls may be stuck in the channel, and without the need for subsequent complex operations such as downhole milling, the operation efficiency is improved and the cost is reduced. Dissolvable magnesium alloys can also be used to make bridge plugs to form effective blockage and separation underground to achieve the purpose of staged fracturing. After the fracturing task is completed, the bridge plugs dissolve and do not hinder subsequent operations. In addition, dissolvable magnesium alloys can also be used to manufacture other downhole fracturing tools such as dissolvable ball valves, which also take advantage of their dissolubility to gradually dissolve in the downhole environment after the corresponding fracturing operation is completed, reducing the impact on the downhole environment and providing convenience for subsequent exploitation operations.

[0004] Generally, in some conventional oil and gas well fracturing operations, the downhole temperature is usually tens of degrees Celsius to about 100℃, and dissolvable magnesium alloys can better adapt to such temperature environment and play a role. However, with the development of deep oil and gas resources, the downhole temperature of some ultra-high temperature oil and gas wells may exceed 150℃ or even higher, which is a challenge to the high-temperature resistance of dissolvable magnesium alloys, and the alloy composition and preparation process need to be improved to improve its stability at high temperatures. And dissolvable magnesium alloys need to have sufficient strength and toughness to ensure that they do not deform, break or other situations under high pressure, and ensure the smooth progress of fracturing operations. And a specific dissolution rate at a certain temperature determines the time that the dissolvable material can withstand pressure, which directly affects the fracturing production time and the time when the pipeline returns to smoothness. SUMMARY

[0005] The present application aims to provide a high-temperature-resistant soluble magnesium alloy with adjustable and narrow corrosion rate at high temperature.

[0006] The present application aims to provide a preparation method of the soluble magnesium alloy plate.

[0007] The present application aims to achieve the above technical solutions.

[0008] The present application aims to achieve the above technical solutions.

[0009] In addition to alloy design, Ca, Mn and Si are added in the Mg-Zn-Ni alloy, and hot rolling is further carried out between the homogenization heat treatment step and the hot extrusion step, which effectively adjusts the comprehensive mechanical properties of the magnesium alloy and improves the plasticity of the material.

[0010] Further, the hot extrusion step is followed by post-treatment, specifically, the magnesium alloy material obtained by extrusion is kept at 380-420 DEG C for 6-8 hours, and then air-cooled to room temperature.

[0011] In the present application, post-treatment is carried out after hot extrusion, which effectively reduces the corrosion rate of the magnesium alloy at high temperature and controls it within a stable target range.

[0012] Further, in the magnesium alloy plate, Zn is 0.5-3.5%, Ni is 0.8-2%, Ca is 0.01-0.05%, Mn is 0.35-0.55%, Si is 0.1-0.3%, and the rest is Mg.

[0013] Further preferably, in the alloy, each component is Zn 2.0%, Ni 1.0%, Ca 0.03%, Mn 0.4%, Si 0.2%, and the rest is Mg.

[0014] Further, the smelting is according to the component design, the magnesium ingot, zinc ingot, magnesium nickel intermediate alloy, magnesium calcium intermediate alloy, anhydrous manganese chloride, magnesium silicon intermediate alloy raw materials weighed according to the component design are dried and preheated in a preheating furnace at 120-200 DEG C, then the magnesium ingot is first fed into the crucible of the magnesium alloy smelting furnace, heated and melted, the magnesium liquid is fully melted and heated to 700-720 DEG C, the zinc ingot, magnesium nickel intermediate alloy, magnesium calcium intermediate alloy, anhydrous manganese chloride, magnesium silicon intermediate alloy are sequentially added, heat preservation is carried out for 30-50 min to melt, and the alloy melt composition is uniform through argon blowing stirring, then heated to 720-750 DEG C, a refining agent is added, and argon blowing stirring is carried out for 20-30 min. After refining, the slag liquid is separated to obtain pure magnesium alloy melt at 720-750 DEG C for 20-40 min.

[0015] Further, the casting is that the alloy melt is cast into a copper mold, and a semi-continuous casting mode is adopted to prepare the blank, the casting blank speed is 300 mm / min, and the cooling water flow speed is 2 m 3 / h.

[0016] Further, the homogenization heat treatment is that the blank obtained by casting is covered with aluminum silicate insulation cotton, and homogenization heat treatment is carried out at 390 DEG C for 3 h, and then water quenching is carried out to obtain the homogenized blank.

[0017] Further, the hot extrusion is that the hot-rolled blank is cut and peeled, and then extrusion is carried out at 310-340 DEG C, the extrusion ratio is 22-28, and the extrusion speed is 12-16 mm / s.

[0018] Most specifically, a temperature-controlled hot rolling preparation method of a magnesium alloy plate is characterized in that the following steps are adopted:

[0019] (1) smelting: the magnesium ingot, zinc ingot, magnesium nickel intermediate alloy, magnesium calcium intermediate alloy, anhydrous manganese chloride, magnesium silicon intermediate alloy raw materials weighed according to the component design are dried and preheated in a preheating furnace at 120-200 DEG C, then the magnesium ingot is first fed into the crucible of the magnesium alloy smelting furnace, heated and melted, the magnesium liquid is fully melted and heated to 700-720 DEG C, the zinc ingot, magnesium nickel intermediate alloy, magnesium calcium intermediate alloy, anhydrous manganese chloride, magnesium silicon intermediate alloy are sequentially added, heat preservation is carried out for 30-50 min to melt, and the alloy melt composition is uniform through argon blowing stirring, then heated to 720-750 DEG C, a refining agent is added, and argon blowing stirring is carried out for 20-30 min. After refining, the slag liquid is separated to obtain pure magnesium alloy melt at 720-750 DEG C for 20-40 min.

[0020] (2) Casting: the alloy melt is cast into a copper mold, and a semi-continuous casting method is used for billet preparation, the casting billet speed is 300 mm / min, and the cooling water flow speed is 2 m 3 / h;

[0021] (3) Homogenization heat treatment: the billet obtained by casting is covered with aluminum silicate insulation cotton, and is subjected to homogenization heat treatment at 390°C for 3 h, and then is water quenched to obtain a homogenized billet;

[0022] (4) Hot rolling: the homogenized billet is subjected to hot rolling in three stages, the first stage temperature is 360~385°C, the rolling deformation is 50~60%, the second stage rolling temperature is 340~360°C, the rolling deformation is 30~40% after the first deformation, and the third stage, the rolling temperature is 320~350°C, and the rolling deformation is 20% after the second deformation;

[0023] (5) Hot extrusion: the hot-rolled billet is cut and peeled, and then is extruded at 280~310°C, the extrusion ratio is 22~28, and the extrusion speed is 12~16 mm / s;

[0024] (6) Post-extrusion treatment: the hot-extruded magnesium alloy is kept at 380~420°C for 6~8 h, and then is air cooled to room temperature.

[0025] A high-temperature controllable narrow corrosion rate soluble magnesium alloy, characterized in that: the magnesium alloy is composed of Mg, Zn, Ni as main elements, and Ca, Mn and Si as trace elements.

[0026] Further, in the alloy, each component is Zn 0.5~3.5%, Ni 0.8~2%, Ca 0.01~0.05%, Mn 0.35~0.55%, Si 0.1~0.3%, and the rest is Mg.

[0027] Further preferably, in the alloy, each component is Zn 2.0%, Ni 1.0%, Ca 0.03%, Mn 0.4%, Si 0.2%, and the rest is Mg.

[0028] The main use of the soluble magnesium alloy of the present application is a soluble bridge plug in volume fracturing in oil exploitation. The solubility of the soluble bridge plug is strictly required in use, and the strength needs to be maintained at a certain strength in a deeper stratum and at a higher temperature of 80 DEG C or above, even 200 DEG C, so as to fracture the stratum by pressure holding to improve the exploitation efficiency. The soluble magnesium alloy needs to maintain a certain stability in such a high temperature, high pressure and complex working condition environment of chemical condition, on the one hand, to maintain the performance of the tool during fracturing operation, and on the other hand, to be dissolved in the electrolyte solution at a designed speed after the operation is completed. If the corrosion rate is too fast, the pressure holding time is not enough, and the fracturing exploitation cannot be realized, and if the corrosion rate is too slow, the production efficiency is affected.

[0029] In the present application, Zn and Ni are alloyed with Mg, and trace amounts of Ca, Mn and Si are added. The addition of Ca alone is to prevent the alloy from being oxidized during smelting, and has little effect on the mechanical properties and corrosion rate of the alloy. The addition of Si and Mn can adjust the mechanical properties of the alloy, and Mn can also reduce the corrosion rate of the alloy at high temperature. During the combined addition, the grain refinement effect of Ca provides more nucleation sites for the strengthening phase of Mn and Si, so that the strengthening phase is more uniformly distributed, and the three cooperate with each other to improve the high temperature strength of the alloy from multiple aspects. Mn promotes the enrichment of Si and Ca on the surface, enhances the content and stability of SiO2 and calcium-containing compounds in the surface film, and improves the density, integrity and chemical stability of the surface film. The three work together to optimize the microstructure of the alloy, reduce impurities and defects, and reduce the possibility of forming corrosion microcells, thereby effectively controlling the corrosion rate of the magnesium alloy at high temperature.

[0030] The high-temperature-resistant soluble magnesium alloy with controllable narrow corrosion rate is prepared by the steps of smelting, casting, homogenization heat treatment, hot rolling, hot extrusion and post-treatment after the hot extrusion step. After the hot extrusion step, post-treatment is further carried out, specifically, the magnesium alloy material obtained by extrusion is kept at 380-420 DEG C for 6-8h, and then air-cooled to room temperature.

[0031] Further, the hot rolling is specifically divided into three stages, the first stage temperature is 360-385 DEG C, the rolling deformation is 50-60%, the second stage rolling temperature is 340-360 DEG C, the rolling deformation is 30-40% after the first deformation, and the third stage, the rolling temperature is 320-350 DEG C, and the rolling deformation is 20% after the second deformation.

[0032] The present application has the following technical effects:

[0033] In this invention, Ca, Mn, and Si are added to the Mg-Zn-Ni alloy, which effectively adjusts the alloy's mechanical properties and chemical stability. Combined with post-extrusion processing, this results in ideal tensile strength and elongation at high temperatures, while the corrosion rate is controlled within 30-40 mg·cm⁻¹. -2 ·h -1 Secondly, by adding a hot rolling step, the comprehensive mechanical properties of the magnesium alloy sheet were effectively adjusted, and the corrosion rate uniformity of the alloy in high-temperature environments was improved, thus enhancing the corrosion stability and controllability of the alloy under different high-temperature environments. Attached Figure Description

[0034] Figure 1 Scanning electron microscope image of Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si prepared in this invention.

[0035] Figure 2 Energy dispersive spectroscopy (EDS) of Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si prepared in this invention.

[0036] Figure 3 The stress-strain curves of Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si prepared by this invention.

[0037] Figure 4 The stress-strain curves of Mg-3.5Zn-0.8Ni-0.01Ca-0.35Mn-0.3Si prepared by this invention. Detailed Implementation

[0038] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0039] Under conditions of high temperature, high pressure, and the presence of electrolytes (such as sodium chloride, calcium chloride, and possibly some acidic or alkaline substances), the soluble bridge plug needs to maintain high strength for a certain period (the first 3 days) to facilitate fracturing, and then completely dissolve for a certain period (the 4th to 5th day). To achieve this effect, the soluble magnesium alloy needs to have a suitable corrosion rate. Through continuous testing, the corrosion rate of the soluble magnesium alloy at high temperature needs to be controlled at 30-40 mg·cm⁻¹. -2 ·h -1, both to ensure sufficient pressure holding time, to achieve fracturing exploitation, and also will not be affected by the slow corrosion rate of production efficiency. Under the premise of ensuring the stable corrosion rate of magnesium alloy at high temperature, the magnesium alloy also needs to have excellent mechanical properties at high temperature, which can resist the plastic stability performance under high temperature and high pressure.

[0040] Example 1

[0041] A high-temperature controllable narrow corrosion rate soluble magnesium alloy, in which each component is 2.0% of Zn, 1.0% of Ni, 0.03% of Ca, 0.4% of Mn, 0.2% of Si, and the rest is Mg.

[0042] According to the above alloy design, the soluble magnesium alloy plate is prepared based on temperature control hot rolling, and the specific steps are as follows:

[0043] (1) Melting: The magnesium ingot, zinc ingot, magnesium-nickel intermediate alloy, magnesium-calcium intermediate alloy, anhydrous manganese chloride, and magnesium-silicon intermediate alloy raw materials weighed according to the component design are dried and preheated in a 150℃ preheating furnace. Then, the magnesium ingot is first put into the crucible of the magnesium alloy melting furnace, heated and melted, and when the magnesium liquid is completely melted and heated to 710℃, the zinc ingot, magnesium-nickel intermediate alloy, magnesium-calcium intermediate alloy, anhydrous manganese chloride, and magnesium-silicon intermediate alloy are added in turn. After 40 min of heat preservation, the alloy melt is uniformly melted by argon blowing stirring, and then heated to 720~750℃, and the refining agent is added and stirred by argon blowing for 25 min. After refining, the slag is separated at 740℃ for 30 min to obtain pure magnesium alloy melt;

[0044] (2) Casting: The alloy melt is cast into a copper mold, and the semi-continuous casting method is used to prepare the billet at a casting speed of 300mm / min and a cooling water flow rate of 2m 3 / h;

[0045] (3) Homogenization heat treatment: The billet obtained by casting is covered with aluminum silicate insulation cotton and subjected to homogenization heat treatment at 390℃ for 3h, and then water quenched to obtain a homogenized billet;

[0046] (4) Hot rolling: The homogenized billet is hot rolled in three stages, the first stage rolling temperature is 370℃, the rolling deformation is 55%, the second stage rolling temperature is 350℃, the rolling deformation is 35% of the first deformation, and the third stage rolling temperature is 340℃, the rolling deformation is 20% of the second deformation;

[0047] (5) Hot extrusion: the hot-rolled blank is cut and peeled, and then extruded at 300 ℃, with an extrusion ratio of 25 and an extrusion speed of 15 mm / s, to obtain a hot-extruded magnesium alloy; the magnesium alloy after hot extrusion is subjected to a tensile test, and the tensile strength of the alloy at room temperature is 294 Mpa, and the elongation is 11.2%; the sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 9.5 mg·cm -2 ·h -1 , and the corrosion rate at 93 ℃ is 90.7 mg·cm -2 ·h -1 .

[0048] (6) Post-extrusion treatment: the hot-extruded magnesium alloy is kept at 400 ℃ for 8 h, and then air-cooled to room temperature to obtain a magnesium alloy plate, which is recorded as Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si.

[0049] The tensile strength of the magnesium alloy plate Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si obtained by post-extrusion treatment at room temperature is 292 Mpa, and the elongation is 11.8%; the sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 3.5 mg·cm -2 ·h -1 , and the corrosion rate at 93 ℃ is 36.4 mg·cm -2 ·h -1 . That is, the post-extrusion treatment step effectively reduces the corrosion rate of the alloy at high temperature under the premise of ensuring excellent mechanical properties, so that the alloy can completely dissolve within the target time.

[0050] According to the preparation process of Example 1, the composition of each component in the magnesium alloy is adjusted, and the specific composition is as follows:

[0051] Comparative Example 1

[0052] According to the preparation process of Example 1, the composition of the alloy is adjusted to Zn 2.0%, Ni 1.0%, and the rest is Mg. The prepared alloy material is recorded as Mg-2Zn-Ni.

[0053] The Mg-2Zn-Ni magnesium alloy plate without post-treatment after hot extrusion is subjected to a tensile test, and the tensile strength of the alloy at room temperature is 247 Mpa, and the elongation is 10.8%; the sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 26.5 mg·cm -2 ·h -1 , and the corrosion rate at 93 ℃ is 107.7 mg·cm -2 ·h -1; the tensile strength of the extruded and post-processed Mg-2Zn-Ni magnesium alloy plate at room temperature was 241 Mpa, the elongation was 10.1%, and the corrosion rate was 18.6 mg·cm -2 ·h -1 ; the corrosion rate at 93℃ was 84.8 mg·cm -2 ·h -1 .

[0054] Without the addition of trace amounts of Ca, Mn and Si, the mechanical properties of the magnesium alloy after extrusion and without post-processing were low, the corrosion rate of the extruded and post-processed magnesium alloy Mg-2Zn-Ni at room temperature and high temperature decreased significantly, and the mechanical properties also decreased to a certain extent.

[0055] Comparative Example 2

[0056] According to the preparation process of Example 1, the composition of the alloy was adjusted to Zn 2.0%, Ni 1.0%, Ca 0.03%, and the rest was Mg. The prepared alloy plate is recorded as Mg-2Zn-Ni-0.03Ca.

[0057] In the Mg-2Zn-Ni-0.03Ca alloy plate, trace amounts of Ca were added to prevent oxidation of Mg and other alloy elements during smelting. The Mg-2Zn-Ni-0.03Ca magnesium alloy after hot extrusion without post-processing was subjected to tensile test, and the tensile strength of the alloy at room temperature was 246 Mpa, the elongation was 10.5%, and the sample was placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature was measured to be 26.6 mg·cm -2 ·h -1 ; the corrosion rate at 93℃ was 106.2 mg·cm -2 ·h -1 ; the tensile strength of the extruded and post-processed Mg-2Zn-Ni-0.03Ca magnesium alloy plate at room temperature was 243 Mpa, the elongation was 10.2%, and the corrosion rate was 18.3 mg·cm -2 ·h -1 ; the corrosion rate at 93℃ was 83.5 mg·cm -2 ·h -1 . That is, the addition of Ca has little effect on the mechanical properties and corrosion properties of the alloy.

[0058] Meanwhile, we prepared Mg-2Zn-Ni-0.4Mn and Mg-2Zn-Ni-0.2Si by adding 0.4% Mn and 0.2% Si respectively on the basis of Mg-2Zn-Ni. The tensile strength of the extruded Mg-2Zn-Ni-0.4Mn without post-treatment is 265 MPa, the elongation is 11.1%, and the corrosion rate of the alloy at room temperature is 23.2 mg·cm -2 ·h -1 , the corrosion rate at 93°C is 99.4 mg·cm -2 ·h -1 ; the tensile strength of the extruded Mg-2Zn-Ni-0.4Mn sheet at room temperature is 264 MPa, the elongation is 11.2%, and the corrosion rate is 4.7 mg·cm -2 ·h -1 , the corrosion rate at 93°C is 14.1 mg·cm -2 ·h -1 .

[0059] The tensile strength of the extruded Mg-2Zn-Ni-0.2Si without post-treatment is 269 MPa, the elongation is 11.7%, and the corrosion rate of the alloy at room temperature is 17.2 mg·cm -2 ·h -1 , the corrosion rate at 93°C is 109.1 mg·cm -2 ·h -1 ; the tensile strength of the extruded Mg-2Zn-Ni-0.2Si sheet at room temperature is 266 MPa, the elongation is 11.5%, and the corrosion rate is 14.3 mg·cm -2 ·h -1 , the corrosion rate at 93°C is 88.6 mg·cm -2 ·h -1 .

[0060] Comparative Example 3

[0061] According to the preparation process of Example 1, the composition of the alloy is adjusted to Zn 2.0%, Ni 1.0%, Ca 0.03%, Mn 0.4%, and the rest is Mg. The prepared alloy sheet is denoted as Mg-2Zn-Ni-0.03Ca-0.4Mn.

[0062] The tensile strength of the extruded Mg-2Zn-Ni-0.03Ca-0.4Mn without post-treatment is 281 MPa, the elongation is 11.9%, and the corrosion rate of the alloy at room temperature is 17.2 mg·cm-2 • h -1 The corrosion rate at 93°C was 79.1 mg-cm -2 • h -1 The tensile strength of the extruded and post-processed magnesium alloy sheet Mg-2Zn-Ni-0.03Ca-0.4Mn was 275 MPa, the elongation was 11.5%, and the corrosion rate was 10.3 mg-cm -2 • h -1 The corrosion rate at 93°C was 21.8 mg-cm -2 • h -1 Compared with Mg-2Zn-Ni-0.4Mn, the addition of Ca increased the corrosion rate of the extruded and post-processed alloy at high temperature.

[0063] Comparative Example 4

[0064] According to the preparation process of Example 1, the composition of the alloy was adjusted to Zn 2.0%, Ni 1.0%, Ca 0.03%, Si 0.2%, and the rest was Mg. The prepared alloy sheet was recorded as Mg-2Zn-Ni-0.03Ca-0.2Si.

[0065] The tensile strength of the Mg-2Zn-Ni-0.03Ca-0.2Si that was not post-processed after hot extrusion was 288 MPa, the elongation was 11.1%, and the corrosion rate of the alloy at room temperature was 25.2 mg-cm -2 • h -1 The corrosion rate at 93°C was 102.3 mg-cm -2 • h -1 The tensile strength of the extruded and post-processed magnesium alloy sheet Mg-2Zn-Ni-0.03Ca-0.2Si was 286 MPa, the elongation was 11.5%, and the corrosion rate was 17.9 mg-cm -2 • h -1 The corrosion rate at 93°C was 81.6 mg-cm -2 • h -1 Although the mechanical properties of the final alloy were excellent, and the corrosion rate at room temperature was similar to that of Example 1, the corrosion rate of the magnesium alloy at high temperature was rapid, which was significantly higher than the expected 30-40 mg-cm -2 • h -1 The problem of rapid dissolution, reduced yield, and increased mining cost would occur.

[0066] Comparative Example 5

[0067] The alloy composition was adjusted to be Zn 2.0%, Ni 1.0%, Si 0.2%, Mn 0.4%, and the rest Mg according to the preparation process of Example 1. The prepared alloy plate was recorded as Mg-2Zn-Ni-0.2Si-0.4Mn.

[0068] The tensile strength of the extruded Mg-2Zn-Ni-0.2Si-0.4Mn without post-treatment was 308 Mpa, and the elongation was 12.4%. The sample was placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature was measured to be 11.2 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ was 90.8 mg·cm -2 ·h -1 . The tensile strength of the extruded Mg-2Zn-Ni-0.2Si-0.4Mn without post-treatment was 308 Mpa, and the elongation was 12.4%. The sample was placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature was measured to be 11.2 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ was 90.8 mg·cm -2 ·h -1 .

[0069] Comparative Example 6

[0070] Compared with Example 1, no hot rolling was carried out between the homogenization heat treatment and hot extrusion, and the overall process flow was melting-casting-homogenization heat treatment-hot extrusion-extrusion post-treatment. The specific process of each step was the same as that of Example 1. The magnesium alloy after hot extrusion was subjected to a tensile test, and the tensile strength of the alloy at room temperature was 285 Mpa, and the elongation was 10.4%. The sample was placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature was measured to be 11.6 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ was 104.8 mg·cm -2 ·h -1 ;

[0071] The tensile strength of the extruded Mg-2Zn-Ni-0.2Si-0.4Mn without post-treatment was 308 Mpa, and the elongation was 12.4%. The sample was placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature was measured to be 11.2 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ was 104.8 mg·cm -2 ·h -1 .

[0072] The alloy prepared by Mg-2Zn-Ni without Ca, Mn and Si addition, and without hot rolling between homogenization heat treatment and hot extrusion is taken as a blank group for comparison. The change of corrosion rate of the Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si prepared in the blank group, example 1 and comparative example 6 with temperature change is shown in table 1.

[0073] Table 1:

[0074]

[0075] It can be seen that the corrosion rate of the alloy Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si prepared in example 1 increases with the increase of temperature at high temperature, but the increase rate range is narrow, and the corrosion rate of the alloy does not change greatly in different temperature environments, and the corrosion stability is excellent, so that the alloy is suitable for application in different temperature environments. The corrosion rate of the alloy sheet Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si prepared in comparative example 6 changes obviously with the increase of temperature at high temperature, and the rate change range is large, and the controllability decreases.

[0076] Example 2

[0077] A soluble magnesium alloy with controllable narrow corrosion rate at high temperature, in which the components are Zn 2.0%, Ni 1.0%, Ca 0.03%, Mn 0.4%, Si 0.2% and the rest is Mg.

[0078] According to the above alloy design, the soluble magnesium alloy sheet is prepared based on temperature control hot rolling, and the specific steps are as follows:

[0079] (1) Melting: the magnesium ingot, zinc ingot, magnesium-nickel intermediate alloy, magnesium-calcium intermediate alloy, anhydrous manganese chloride and magnesium-silicon intermediate alloy raw materials weighed according to the component design are dried and preheated in a 120℃ preheating furnace, then the magnesium ingot is first put into the crucible of the magnesium alloy melting furnace, heated and melted, and when the magnesium liquid is completely melted and the temperature is raised to 700℃, the zinc ingot, magnesium-nickel intermediate alloy, magnesium-calcium intermediate alloy, anhydrous manganese chloride and magnesium-silicon intermediate alloy are added in turn, and the alloy melt is uniformly melted by argon blowing and stirring for 30 min, and then heated to 750℃, and the refining agent is added, and the argon blowing and stirring is carried out for 20 min. After refining, the pure magnesium alloy melt is obtained by separating the slag liquid at 750℃ for 20 min;

[0080] (2) Casting: the alloy melt is cast into a copper mold, and the semi-continuous casting mode is adopted for billet preparation, the casting billet speed is 300mm / min, the cooling water flow speed is 2m 3 / h;

[0081] (3) homogenization heat treatment: the casting obtained blank is covered with aluminum silicate insulation cotton, and homogenization heat treatment is carried out at 390℃ for 3h, and then water quenching is carried out to obtain a homogenization blank;

[0082] (4) hot rolling: the casting blank is hot rolled in three stages, the first stage rolling temperature is 385℃, the rolling deformation is 50%, the second stage rolling temperature is 360℃, the rolling deformation is 40% after the first deformation, and the third stage, the rolling temperature is 350℃, and the rolling deformation is 20% after the second deformation;

[0083] (5) hot extrusion: the hot rolled blank is cut and peeled, and then extruded at 310℃, the extrusion ratio is 28, and the extrusion speed is 12mm / s, to obtain a hot extruded magnesium alloy;

[0084] (6) post-extrusion treatment: the hot extruded magnesium alloy is kept at 380℃ for 7h, and then air cooled to room temperature.

[0085] The tensile strength of the magnesium alloy Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si obtained by post-extrusion treatment is 290 Mpa at room temperature, and the elongation is 11.6%. The sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 3.8 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ is 36.1mg·cm -2 ·h -1 .

[0086] Example 3

[0087] A high-temperature controllable narrow corrosion rate soluble magnesium alloy, in which each component is 2.0% of Zn, 1.0% of Ni, 0.03% of Ca, 0.4% of Mn, 0.2% of Si, and the rest is Mg.

[0088] According to the above alloy design, a soluble magnesium alloy plate is prepared based on temperature-controlled hot rolling, and the specific steps are as follows:

[0089] (1) Melting: The magnesium ingot, zinc ingot, magnesium-nickel intermediate alloy, magnesium-calcium intermediate alloy, anhydrous manganese chloride, and magnesium-silicon intermediate alloy raw materials weighed according to the component design are dried and preheated in a preheating furnace at 200°C. Then, the magnesium ingot is first put into the crucible of a magnesium alloy melting furnace, heated and melted, and when the magnesium liquid is completely melted and the temperature is raised to the range of 720°C, the zinc ingot, magnesium-nickel intermediate alloy, magnesium-calcium intermediate alloy, anhydrous manganese chloride, and magnesium-silicon intermediate alloy are sequentially added, and the mixture is heated and melted for 50 min, and the composition of the alloy melt is made uniform by argon blowing and stirring. Then, the temperature is raised to 720°C, a refining agent is added, and the mixture is stirred by argon blowing for 30 min. After refining, the mixture is kept at 720°C for 40 min, and the slag is separated from the liquid to obtain a pure magnesium alloy melt;

[0090] (2) Casting: The alloy melt is cast into a copper mold, and a semi-continuous casting method is used to prepare the billet at a casting speed of 300 mm / min and a cooling water flow rate of 2 m 3 / h;

[0091] (3) Homogenization heat treatment: The billet obtained by casting is covered with aluminum silicate insulation cotton and subjected to homogenization heat treatment at 390°C for 3 h, and then water quenched to obtain a homogenized billet;

[0092] (4) Hot rolling: The cast billet is hot rolled in three stages, with the first stage rolling temperature being 385°C, the rolling deformation being 60%, the second stage rolling temperature being 340°C, the rolling deformation being 30% of the first deformation, and the third stage rolling temperature being 320°C, the rolling deformation being 20% of the second deformation;

[0093] (5) Hot extrusion: The hot-rolled billet is cut and peeled, and then extruded at 280°C, with an extrusion ratio of 22 and an extrusion speed of 16 mm / s, to obtain a hot-extruded magnesium alloy;

[0094] (6) Post-extrusion treatment: The hot-extruded magnesium alloy is kept at 420°C for 6 h, and then air-cooled to room temperature.

[0095] The tensile strength of the alloy Mg-2Zn-Ni-0.03Ca-0.4Mn-0.2Si obtained after post-extrusion treatment at room temperature is 289 MPa, and the elongation is 11.7%. When the sample is placed in a 3wt.% KCl solution, the corrosion rate of the alloy at room temperature is measured to be 4.7 mg·cm -2 ·h -1 , and the corrosion rate at 93°C is 38.6 mg·cm -2 ·h -1 .

[0096] Example 4

[0097] A soluble magnesium alloy with controllable narrow corrosion rate at high temperature, wherein each component is Zn 3.5%, Ni 0.8%, Ca 0.01%, Mn 0.35%, Si 0.3%, and the rest is Mg in percentage by mass. The preparation process is the same as that of Example 3, and the prepared alloy is recorded as Mg-3.5Zn-0.8Ni-0.01Ca-0.35Mn-0.3Si.

[0098] The magnesium alloy without post-treatment after hot extrusion is subjected to a tensile test, and the tensile strength of the alloy at room temperature is 315 Mpa, and the elongation is 12.0%. The sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 7.5 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ is 83.5 mg·cm -2 ·h -1 ; the tensile strength of the alloy Mg-3.5Zn-0.8Ni-0.01Ca-0.35Mn-0.3Si after extrusion is 310 Mpa, and the elongation is 11.8%. The sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 3.9 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ is 32.7 mg·cm -2 ·h -1 .

[0099] Example 5

[0100] A soluble magnesium alloy with controllable narrow corrosion rate at high temperature, wherein each component is Zn 0.5%, Ni 2.0%, Ca 0.05%, Mn 0.55%, Si 0.1%, and the rest is Mg in percentage by mass. The preparation process is the same as that of Example 3, and the prepared alloy is recorded as Mg-0.5Zn-2Ni-0.05Ca-0.55Mn-0.1Si.

[0101] The Mg-0.5Zn-2Ni-0.05Ca-0.55Mn-0.1Si without post-treatment after hot extrusion is subjected to a tensile test, and the tensile strength of the alloy at room temperature is 278 Mpa, and the elongation is 12.3%. The sample is placed in a 3wt.% KCl solution, and the corrosion rate of the alloy at room temperature is measured to be 9.1 mg·cm -2 ·h -1 , and the corrosion rate at 93℃ is 104.2 mg·cm -2 ·h -1; the tensile strength of the extruded and post-processed alloy Mg-0.5Zn-2Ni-0.05Ca-0.55Mn-0.1Si at room temperature is 274 Mpa, the elongation is 11.9%, the corrosion rate of the alloy at room temperature is 5.1 mg·cm -2 ·h -1 in the solution of 3wt.% KCl is measured. -2 ·h -1 .

Claims

1. A method for preparing magnesium alloy sheet by temperature-controlled hot rolling, comprising the steps of alloy melting, casting, homogenization heat treatment, and hot extrusion in sequence, characterized in that: Hot rolling was performed between the homogenization heat treatment step and the hot extrusion step, specifically in three stages. The first stage rolling temperature was 360~385℃, and the rolling deformation was 50~60%. The second stage rolling temperature was 340~360℃, and the rolling deformation was 30~40% of the first deformation. The third stage rolling temperature was 320~350℃, and the rolling deformation was 20% of the second deformation. After the hot extrusion step, post-treatment was performed, specifically, the extruded magnesium alloy material was held at 380~420℃ for 6~8 hours, and then air-cooled to room temperature.

2. The method for preparing magnesium alloy sheet by temperature-controlled hot rolling as described in claim 1, characterized in that: In the alloy, the components by mass percentage are Zn 0.5~3.5%, Ni 0.8~2%, Ca 0.01~0.05%, Mn 0.35~0.55%, Si 0.1~0.3%, and the remainder is Mg.

3. A method for preparing magnesium alloy sheet by temperature-controlled hot rolling as described in claim 1 or 2, characterized in that: The smelting process is designed according to the composition. Magnesium ingots, zinc ingots, magnesium-nickel master alloy, magnesium-calcium master alloy, anhydrous manganese chloride, and magnesium-silicon master alloy raw materials are weighed and dried and preheated in a preheating furnace at 120~200℃. Then, the magnesium ingots are first added to the crucible of the magnesium alloy smelting furnace and heated to melt. After the magnesium liquid is completely melted and the temperature is raised to 700~720℃, zinc ingots, magnesium-nickel master alloy, magnesium-calcium master alloy, anhydrous manganese chloride, and magnesium-silicon master alloy are added in sequence. The mixture is kept at this temperature for 30~50 minutes to melt, and the alloy melt is stirred by blowing argon gas to make the composition of the alloy melt uniform. Then, it is heated to 720~750℃, a refining agent is added, and the mixture is stirred by blowing argon gas for 20~30 minutes. After refining, the mixture is kept at 720~750℃ for 20~40 minutes, and the slag and liquid are separated to obtain a pure magnesium alloy melt.

4. The method for preparing magnesium alloy sheet by temperature-controlled hot rolling as described in claim 3, characterized in that: The casting process involves pouring the molten alloy into a copper mold, using a semi-continuous casting method to prepare the billet. The billet casting speed is 300 mm / min, and the cooling water flow rate is 2 m / s. 3 / h.

5. The method for preparing magnesium alloy sheet by temperature-controlled hot rolling as described in claim 4, characterized in that: The homogenization heat treatment involves covering the cast billet with aluminum silicate insulation cotton, subjecting it to homogenization heat treatment at 390°C for 3 hours, and then water quenching to obtain a homogenized billet.

6. The method for preparing magnesium alloy sheet by temperature-controlled hot rolling as described in claim 5, characterized in that: The hot extrusion involves cutting and peeling a uniformly heated billet, followed by extrusion at 310~340℃, with an extrusion ratio of 22~28 and an extrusion speed of 12~16 mm / s.

Images