Process for preparing a titanium electrode plate substrate for hydrogen production by electrolysis of water using a PEM

Abstract

The application provides a titanium electrode plate substrate preparation process for PEM electrolytic water hydrogen production, a large integral cutter head milling machine is used to process the surface of the plate blank, so that the size of the plate blank is more regular, the cross section thickness is uniform, the difficulty of product rolling plate shape control is reduced, vacuum pressing is used to remove the titanium plate stress, and stress warping deformation of the titanium plate after chemical etching is avoided, the PEM electrolytic water hydrogen production titanium electrode plate substrate prepared by the process method realizes titanium substrate same plate difference control, surface roughness control and structure homogenization control by adopting rolling parameter control, lubrication control and heat treatment parameter control, the plate shape is flat, the surface quality is excellent, the same plate difference is small, the structure is uniform, and the titanium plate is not deformed after etching, the double face unevenness is less than or equal to 1mm, the double face roughness is less than or equal to 0.4um, the same plate difference is less than or equal to 0.02mm, and the grain size is greater than or equal to 8.0.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal processing, and more specifically, to a process for preparing titanium electrode substrate for PEM electrolysis of water to produce hydrogen. Background Technology

[0002] In recent years, the hydrogen energy industry has risen rapidly. With the advancement of technology, the excellent properties of titanium metal have been continuously explored. Titanium materials with higher dimensional accuracy, superior performance and structure have broad application prospects in emerging fields such as PEM water electrolysis for hydrogen production. Proton exchange membrane water electrolyzer (PEM) hydrogen production decomposes water molecules into hydrogen and oxygen through an electrochemical process under the action of direct current, which are then released at the cathode and anode respectively. It has high hydrogen production efficiency and is suitable for the fluctuations in renewable energy power generation such as wind power and photovoltaic power generation. It is currently the mainstream and promising water electrolysis hydrogen production technology.

[0003] The main components of a PEM water electrolyzer, from the inside out, are the proton exchange membrane, anode and cathode catalyst layers, anode and cathode gas diffusion layers, and electrode plates. Among these, the electrode plates are the main site for material transport and electrochemical reactions in the entire water electrolyzer, and their characteristics and structure directly affect the performance and lifespan of the PEM water electrolyzer. PEM water electrolyzer electrode plates are usually made of titanium substrate, and the manufacturing process is "titanium material → processing (machining / stamping / etching) + coating". The metal electrode plates play a role in connecting adjacent cells in the stack, separating oxygen and hydrogen, and transferring heat and mass. PEM water electrolyzer metal electrode plates made of titanium have the advantages of being lightweight, corrosion-resistant, and having a long lifespan, enabling megawatt-level high-power PEM water electrolysis hydrogen production equipment and integrated applications. It is an ideal solution for metal electrode plate materials in future PEM water electrolysis hydrogen production equipment.

[0004] The thickness range of the titanium electrode substrate for PEM water electrolysis hydrogen production is 2.0mm-3.0mm. It has extremely high requirements for flatness and thickness. The flatness of the entire plate on both sides must be less than 1.0mm, and the thickness difference within the same plate must be less than 0.02mm. Controlling the plate shape and thickness difference within the same plate is extremely difficult. On the other hand, the titanium plate surface must be smooth and beautiful, with a double-sided roughness ≤0.4um. Since the titanium electrode substrate for PEM water electrolysis hydrogen production needs to undergo chemical etching in the subsequent process, high requirements are placed on the uniformity of the titanium electrode substrate structure. It is required that the structure be uniform and the grain size be ≥8.0 grade. At the same time, the titanium electrode substrate must not warp or deform after etching.

[0005] Currently, the standard size of 2.0mm-3.0mm titanium plates on the market is generally 3mm-5mm. The roughness of both sides of the titanium plates is 0.8um-3.0um. After chemical etching, stress warping deformation is likely to occur, and the uniformity of the structure is poor, which cannot meet the requirements for titanium electrode plates used in PEM water electrolysis for hydrogen production. Summary of the Invention

[0006] In view of this, the present invention aims to propose a process for preparing titanium electrode plate substrate for PEM water electrolysis hydrogen production to solve the problems in the prior art where titanium plates are prone to stress warping deformation after chemical etching and have poor microstructure uniformity, which cannot meet the requirements for use of titanium electrode plates for PEM water electrolysis hydrogen production.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A process for preparing titanium electrode plate substrate for PEM water electrolysis to produce hydrogen includes the following steps:

[0009] Step 1: Use an electron beam cold hearth furnace (EB furnace) to cast flat ingots in one go. The width of the flat ingot is ≥1000mm. Use a large integral cutter head milling machine to machine the upper and lower surfaces of the slab as a whole. The diameter of the cutter head is greater than the width of the slab. The single-sided milling thickness is ≥3mm. The thickness difference of the cross section of the slab after machining is ≤3mm.

[0010] Step 2: Heat the slab to 800℃~900℃, and roll the slab into a titanium strip coil with a thickness of 4.0mm-6.0mm using a furnace coil mill. Then, perform continuous annealing, pickling, and grinding to remove the surface oxide scale.

[0011] Step 3: Roll the 4.0mm-6.0mm thick titanium strip coil to 2.0mm-3.0mm thickness using a 20-roll mill, with pure rolling oil as the lubricant;

[0012] Step 4: Use degreasing and cleaning equipment to remove rolling oil and titanium powder from the surface of the titanium strip coil;

[0013] Step 5: Heat treat the titanium strip roll in a vacuum bell-type annealing furnace at a temperature of 600℃~700℃ for a holding time of ≥6 hours.

[0014] Step 6: Use a leveling machine to level the titanium strip coil;

[0015] Step 7: Use room temperature leveling and slitting equipment to level and slit the titanium strip roll to obtain titanium plates of fixed length;

[0016] Step 8: Vacuum pressing and straightening heat treatment is performed on the fixed-length titanium plate using a vacuum plate furnace;

[0017] Step 9: Sample and inspect the finished rolls.

[0018] The titanium electrode substrate preparation process for PEM electrolysis of water to produce hydrogen described in this application achieves control over the same-plate difference, surface roughness, and microstructure uniformity of the titanium substrate by controlling rolling parameters, lubrication, and heat treatment parameters. The resulting substrate has a straight plate shape, excellent surface quality, small same-plate difference, uniform microstructure, no deformation after etching, double-sided unevenness ≤1mm, double-sided roughness ≤0.4um, same-plate difference ≤0.02mm, and grain size ≥8.0 grade.

[0019] Furthermore, in step 2, the slab is rolled again after the rolls are replaced in the furnace rolling mill, and the rolling sequence is 1 to 3.

[0020] By adjusting the rolling sequence of hot-rolled coils, it is possible to avoid rolling titanium strip coils at the end of the rolling cycle, which can significantly reduce the risk of edge waviness, rib waviness, and center waviness in the finished product and reduce the difficulty of controlling the shape of the finished product.

[0021] Furthermore, in step 3, the deformation amount during rolling is 45.0% to 55.0%, the deformation amount for the first pass is 15% to 20%, and the deformation amount for the remaining passes is 10% to 15%.

[0022] This setup can adapt to the rolling requirements of titanium strip coils of different thicknesses, better control the initial deformation of the titanium strip coils, facilitate the formation of a uniform microstructure, reduce stress concentration and surface defects, and improve the stability and uniformity of the titanium electrode plates.

[0023] Furthermore, in step 6, a 380mm diameter, 1450mm four-roll cold rolling leveler is used to level the titanium strip coil. The pressure of the leveler is 150-300 tons, and the reduction is 0.005mm-0.010mm.

[0024] The four-roll cold rolling leveling machine has high leveling capability and stability, which can effectively eliminate surface defects and unevenness of titanium strip coils, improve the flatness and quality of products, and meet the leveling requirements of titanium strip coils with different thicknesses and hardnesses.

[0025] Furthermore, in step 8, the vacuum degree is 0.1 Pa to 0.5 Pa, the plate thickness is 50 mm to 150 mm, the heat preservation temperature is 400℃ to 500℃, the heat preservation time is 10 to 15 hours, and the product is removed from the furnace after cooling to 150℃.

[0026] By controlling the vacuum level, gases and impurities can be effectively removed, oxidation reactions can be reduced, and product quality can be improved. By selecting an appropriate plate thickness, uniform pressure straightening of the titanium plate can be achieved, improving the plate shape, flatness, and dimensional accuracy of the product. By controlling the holding temperature and time, the titanium plate can achieve the appropriate heat treatment effect, improving grain size and microstructure uniformity, and enhancing the mechanical properties and corrosion resistance of the product. Cooling the titanium plate to 150°C in the furnace before removing it can avoid stress and deformation caused by rapid cooling, ensuring the dimensional stability and surface quality of the titanium plate.

[0027] Furthermore, in step 2, a flap wheel is used to grind along the hot rolling direction to remove surface defects.

[0028] This setup can effectively remove defects on the surface of titanium plates, such as oxide scale, oxide layer, and scratches, thereby improving the surface quality of the titanium plates.

[0029] Furthermore, in step 1, the thickness of the slab is 190mm to 210mm.

[0030] This setup can meet the production needs of titanium plates of different thicknesses, improving production flexibility and adaptability.

[0031] Furthermore, in step 7, the width of the fixed-length titanium plate is ≥1000mm and the thickness is 2mm~3mm.

[0032] This setup reduces the cutting and splicing processes of the boards, improves production efficiency, reduces dimensional deviations in the boards, and makes the final product's dimensions and quality more stable.

[0033] Furthermore, in step 9, the inspection standards are: plate size ≤ 1.0 mm, surface roughness ≤ 0.4 μm, difference between plates ≤ 0.02 mm, grain size ≥ 8.0 grade, and no deformation after etching.

[0034] This setup ensures product quality stability and meets the performance requirements of titanium electrode substrates for PEM water electrolysis hydrogen production.

[0035] Compared with existing technologies, the preparation process of titanium electrode substrate for PEM electrolysis of water to produce hydrogen described in this invention has the following advantages:

[0036] 1) It achieves control over the same-plate difference, surface roughness and microstructure uniformity of titanium substrate, resulting in a flat plate shape, excellent surface quality, small same-plate difference, uniform microstructure, no deformation after etching, double-sided unevenness ≤1mm, double-sided roughness ≤0.4um, same-plate difference ≤0.02mm, and grain size ≥8.0 grade.

[0037] 2) The slab dimensions are more regular and the cross-sectional thickness is more uniform, which reduces the difficulty of controlling the shape of the finished rolled plate;

[0038] 3) Fewer production steps and higher yield rate significantly reduce billet production costs. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0040] A process for preparing titanium electrode plate substrate for PEM water electrolysis to produce hydrogen includes the following steps:

[0041] Step 1: Use an electron beam cold hearth furnace (EB furnace) to cast flat ingots in one go. The width of the flat ingot is ≥1000mm. Use a large integral cutter head milling machine to machine the upper and lower surfaces of the slab as a whole. The diameter of the cutter head is greater than the width of the slab. The single-sided milling thickness is ≥3mm. The thickness difference of the cross section of the slab after machining is ≤3mm.

[0042] Step 2: Heat the slab to 800℃~900℃, and roll the slab into a titanium strip coil with a thickness of 4.0mm-6.0mm using a furnace coil mill. Then, perform continuous annealing, pickling, and grinding to remove the surface oxide scale.

[0043] Step 3: Roll the 4.0mm-6.0mm thick titanium strip coil to 2.0mm-3.0mm thickness using a 20-roll mill, with pure rolling oil as the lubricant;

[0044] Step 4: Use degreasing and cleaning equipment to remove rolling oil and titanium powder from the surface of the titanium strip coil;

[0045] Step 5: Heat treat the titanium strip roll in a vacuum bell-type annealing furnace at a temperature of 600℃~700℃ for a holding time of ≥6 hours.

[0046] Step 6: Use a leveling machine to level the titanium strip coil;

[0047] Step 7: Use room temperature leveling and slitting equipment to level and slit the titanium strip roll to obtain titanium plates of fixed length;

[0048] Step 8: Vacuum pressing and straightening heat treatment is performed on the fixed-length titanium plate using a vacuum plate furnace;

[0049] Step 9: Sample and inspect the finished rolls.

[0050] The titanium electrode plate substrate preparation process for PEM water electrolysis hydrogen production described in this application uses an EB furnace to melt EB ingots as billets in a single process during the billet melting stage. This reduces the number of production steps, increases the yield, and significantly reduces billet preparation costs. A large integral milling machine is used to process the billet surface, resulting in more regular billet dimensions and uniform cross-sectional thickness. This significantly reduces the risk of edge waviness, rib waviness, and center waviness in thin strip finished products caused by uneven billet thickness, and reduces the difficulty of controlling the finished product's rolling shape. Vacuum pressure straightening is used to remove stress from the titanium plate, avoiding stress warping deformation after chemical etching. The titanium electrode plate substrate prepared by this process achieves control over the same-plate difference, surface roughness, and microstructure homogenization of the titanium substrate through rolling parameter control, lubrication control, and heat treatment parameter control. The resulting plate has a straight shape, excellent surface quality, small same-plate difference, uniform microstructure, and no deformation after etching. The double-sided unevenness is ≤1mm, the double-sided roughness is ≤0.4um, the same-plate difference is ≤0.02mm, and the grain size is ≥8.0 grade.

[0051] As a preferred example of the present invention, in step 2, the slab is rolled after the rolls are replaced in the furnace rolling mill, and the rolling sequence is 1 to 3.

[0052] Specifically, by adjusting the rolling sequence of hot-rolled coils, it is possible to avoid rolling titanium strip coils at the end of the rolling cycle, which can significantly reduce the risk of edge waviness, rib waviness, and center waviness in the finished product and reduce the difficulty of controlling the shape of the finished product.

[0053] As a preferred example of the present invention, in step 3, the deformation amount of the rolling pass is 45.0% to 55.0%, the deformation amount of the first pass is 15% to 20%, and the deformation amount of the remaining passes is 10% to 15%.

[0054] Specifically, this setup can adapt to the rolling requirements of titanium strip coils of different thicknesses, better control the initial deformation of the titanium strip coils, facilitate the formation of a uniform microstructure, reduce stress concentration and surface defects, and improve the stability and uniformity of the titanium electrode plates.

[0055] As a preferred example of the present invention, in step 6, a 380mm diameter, 1450mm four-roll cold rolling leveling machine is used to level the titanium strip coil. The pressure of the leveling machine is 150 to 300 tons, and the reduction is 0.005mm to 0.010mm.

[0056] Specifically, the four-roll cold rolling leveling machine has high leveling capability and stability, which can effectively eliminate surface defects and unevenness of titanium strip coils, improve the flatness and quality of products, and meet the leveling requirements of titanium strip coils with different thicknesses and hardnesses.

[0057] As a preferred example of the present invention, in step 8, the vacuum degree is 0.1 Pa to 0.5 Pa, the thickness of the pressure plate is 50 mm to 150 mm, the heat preservation temperature is 400°C to 500°C, the heat preservation time is 10 to 15 hours, and the plate is cooled to 150°C in the furnace before being removed from the furnace.

[0058] Specifically, by controlling the vacuum level, gases and impurities can be effectively removed, oxidation reactions can be reduced, and product quality can be improved. By selecting an appropriate plate thickness, uniform pressure straightening of the titanium plate can be achieved, improving the plate shape, flatness, and dimensional accuracy of the product. By controlling the holding temperature and time, the titanium plate can achieve the appropriate heat treatment effect, improving grain size and microstructure uniformity, and enhancing the mechanical properties and corrosion resistance of the product. Cooling the titanium plate to 150°C in the furnace before removing it can avoid stress and deformation caused by rapid cooling, ensuring the dimensional stability and surface quality of the titanium plate.

[0059] As a preferred example of the present invention, in step 2, a flap wheel is used to grind along the hot rolling direction to remove surface defects.

[0060] Specifically, this setting can effectively remove defects on the surface of titanium plates, such as oxide scale, oxide layer, scratches, etc., and improve the surface quality of titanium plates.

[0061] As a preferred example of the present invention, in step 1, the thickness of the slab is 190mm to 210mm.

[0062] Specifically, this setup can meet the production needs of titanium plates of different thicknesses, improving production flexibility and adaptability.

[0063] As a preferred example of the present invention, in step 7, the width of the fixed-length titanium plate is ≥1000mm and the thickness is 2mm~3mm.

[0064] Specifically, this setup can reduce the cutting and splicing processes of the boards, improve production efficiency, reduce dimensional deviations of the boards, and make the dimensions and quality of the final product more stable.

[0065] As a preferred example of the present invention, in step 9, the inspection criteria are: plate size ≤ 1.0 mm, surface roughness ≤ 0.4 μm, plate difference ≤ 0.02 mm, grain size ≥ 8.0 grade, and no deformation after etching.

[0066] Specifically, this setup ensures product quality stability and meets the performance requirements of titanium electrode substrates for PEM water electrolysis hydrogen production.

[0067] Example 1

[0068] Electron beam cold hearth furnace (EB furnace) casting method was used to prepare EB slabs with a width of 1280 mm and a thickness of 205 mm. A large integral milling machine with a cutter head larger than the slab width was used to machine the upper and lower surfaces of the slab. The single-sided milling thickness was 5 mm, resulting in a 1 mm thickness difference across the slab cross-section. The slab was heated to 880℃, and after changing the rolls on a hot-rolling mill, it was rolled to a thickness of 4.0 mm. After hot rolling, continuous annealing and pickling were performed, followed by grinding along the hot-rolling direction using a flap wheel to remove surface defects and oxide scale. A 20-roll mill was used to roll the 4.0 mm thick titanium strip coil to a thickness of 2.0 mm, with a rolling deformation of 50%, a first pass deformation of 15%, and subsequent passes deformation of 10%–15%. Pure rolling oil was used as the lubricant. A degreasing and cleaning system was used to remove rolling oil and titanium powder from the surface of the titanium strip coil. A pure rolling oil was used as the lubricant. The titanium strip was heat-treated in an empty-hood annealing furnace at 600℃ for 6 hours. It was then leveled using a 380mm diameter, 1450mm four-roll cold rolling mill at a pressure of 150 tons and a reduction of 0.005mm to obtain a 2.0mm thick titanium strip coil. The titanium strip coil was then leveled and slit to length using room temperature leveling and slitting equipment to obtain fixed-length titanium plates with a width of 1000mm and a thickness of 2mm. Finally, a vacuum plate furnace was used to finish the slits. The titanium plate undergoes vacuum pressing and straightening heat treatment with a vacuum degree of 0.2 Pa, a plate thickness of 50 mm, a holding temperature of 400 °C, and a holding time of 15 hours. After cooling to 150 °C in the furnace, it is removed from the furnace to obtain a titanium electrode substrate with excellent plate shape and a thickness of 2 mm. Finally, the finished rolls are sampled and inspected. The inspection standards are: plate shape ≤ 1.0 mm, surface roughness ≤ 0.4 μm, plate difference ≤ 0.02 mm, grain size ≥ 8.0 grade, and no deformation after etching.

[0069] Example 2

[0070] Electron beam cold hearth furnace (EB furnace) casting method was used to prepare EB slabs with a width of 1260 mm and a thickness of 190 mm. A large integral milling machine with a cutter head larger than the slab width was used to machine the upper and lower surfaces of the slab. The single-sided milling thickness was 10 mm, resulting in a 2 mm thickness difference across the slab cross-section. The slab was heated to 850℃, and after changing the rolls on a hot rolling mill, it was rolled to a thickness of 5.0 mm. After hot rolling, continuous annealing and pickling were performed, followed by grinding along the hot rolling direction using a flap wheel to remove surface defects and oxide scale. A 20-roll mill was used to roll the 5.0 mm thick titanium strip coil to a thickness of 2.5 mm, with a rolling deformation of 50%, a first pass deformation of 20%, and subsequent passes deformation of 10%–15%. Pure rolling oil was used as the lubricant. A degreasing and cleaning system was used to remove rolling oil and titanium powder from the surface of the titanium strip coil. A vacuum hood was used for further cleaning. The titanium strip was heat-treated in a conventional annealing furnace at 600℃ for 6 hours. It was then leveled using a 380mm diameter, 1450mm four-roll cold rolling mill at a pressure of 300 tons and a reduction of 0.010mm to obtain a 2.5mm thick titanium strip coil. The titanium strip coil was then leveled and slit to length using room temperature leveling and slitting equipment to obtain fixed-length titanium plates with a width of 1000mm and a thickness of 2.5mm. Finally, the fixed-length titanium plates were processed in a vacuum plate furnace. The plate undergoes vacuum pressing and straightening heat treatment with a vacuum degree of 0.5 Pa, a plate thickness of 100 mm, a holding temperature of 450 °C, and a holding time of 12 hours. After cooling to 150 °C in the furnace, it is removed from the furnace to obtain a titanium electrode substrate with excellent plate shape and a thickness of 2.5 mm. Finally, the finished rolls are sampled and inspected. The inspection standards are: plate shape ≤ 1.0 mm, surface roughness ≤ 0.4 μm, difference between plates ≤ 0.02 mm, grain size ≥ 8.0 grade, and no deformation after etching.

[0071] Example 3

[0072] Electron beam cold hearth furnace (EB furnace) casting method was used to prepare EB slabs with a width of 1270 mm and a thickness of 210 mm. A large integral milling machine with a cutter head larger than the slab width was used to machine the upper and lower surfaces of the slab. The single-sided milling thickness was 8 mm, resulting in a 3 mm thickness difference across the slab cross-section. The slab was heated to 900℃, and after changing the rolls on a hot-rolling mill, it was rolled in a 3-rolling sequence to a thickness of 6.0 mm. After hot rolling, continuous annealing and pickling were performed, followed by grinding along the hot-rolling direction using a flap wheel to remove surface defects and oxide scale. A 20-roll mill was used to roll the 6.0 mm thick titanium strip coil to a thickness of 3 mm, with a rolling deformation of 50%, a first pass deformation of 18%, and subsequent passes deformation of 10%–15%. Pure rolling oil was used as the lubricant. A degreasing and cleaning system was used to remove rolling oil and titanium powder from the surface of the titanium strip coil. Vacuum cleaning was employed. The titanium strip is heat-treated in a bell-type annealing furnace at 700℃ for 10 hours. It is then leveled using a 380mm diameter, 1450mm four-roll cold rolling mill at a pressure of 250 tons and a reduction of 0.075mm to obtain a 3mm thick titanium strip coil. The titanium strip coil is then leveled and slit to length using room temperature leveling and slitting equipment to obtain fixed-length titanium plates with a width of 1000mm and a thickness of 3mm. Finally, the fixed-length titanium plates are processed in a vacuum plate furnace. The plate undergoes vacuum pressing and straightening heat treatment with a vacuum degree of 0.1 Pa, a plate thickness of 150 mm, a holding temperature of 500 °C, and a holding time of 10 hours. After cooling to 150 °C in the furnace, it is removed from the furnace, resulting in a titanium electrode substrate with excellent plate shape and a thickness of 3 mm. Finally, the finished rolls are sampled and inspected. The inspection standards are: plate shape ≤ 1.0 mm, surface roughness ≤ 0.4 μm, difference between plates ≤ 0.02 mm, grain size ≥ 8.0 grade, and no deformation after etching.

[0073] Comparative Example 1: Unlike Example 1, a hot rolling mill was used to roll the slab to a thickness of 3.5 mm, and a four-roll mill was used to roll the 3.5 mm thick titanium strip to a thickness of 2.0 mm. The deformation during the rolling process was 42.8%, and the lubricating medium was emulsion.

[0074] Comparative Example 2: Unlike Example 2, the rolling sequence was 7, and no leveling, room temperature straightening, or vacuum pressure straightening was performed after heat treatment.

[0075] Comparative Example 3: Unlike Example 3, a furnace rolling mill was used to roll the slab to a thickness of 4.0 mm, and a 20-roll mill was used to roll the 4.0 mm thick titanium strip to a thickness of 3.0 mm. The deformation during the rolling process was 25%, the deformation in the first pass was 10%, and the deformation in the remaining passes was 15% to 20%. The heat treatment temperature was 580°C, the holding time was 5.5 hours, and the vacuum degree during the vacuum pressure straightening heat treatment was 100 Pa.

[0076] Table 1 shows a comparison of the properties of titanium electrode substrates for PEM electrolysis of water to produce hydrogen produced in Examples 1-3 and Comparative Examples 1-3.

[0077] Table 1. Performance Comparison of Titanium Substrates for PEM Electrolysis in Hydrogen Production in Examples and Comparative Examples

[0078]

[0079]

[0080] In summary, compared with Example 1, Comparative Example 1 does not meet the requirements of this application due to the rolling deformation amount, rolling method and lubricating medium. As a result, the surface roughness, plate difference and grain size of the titanium electrode substrate for PEM water electrolysis to produce hydrogen do not meet the requirements of this application. This is because the rolling parameters and lubricating medium directly affect the surface roughness and plate difference of the titanium electrode substrate. On the other hand, the rolling parameters also affect the grain size of the finished titanium substrate.

[0081] Compared with Example 2, Comparative Example 2 failed to meet the requirements of this application because the hot rolling roll sequence did not meet the requirements of this application, and the finished titanium electrode substrate was not leveled, opened, and vacuum pressed after heat treatment.

[0082] Compared with Example 3, Comparative Example 3 did not meet the requirements of this application because the rolling parameters and heat treatment parameters did not meet the requirements of this application, and the vacuum degree during vacuum pressure straightening heat treatment did not meet the requirements of this application. As a result, the surface roughness, plate difference and grain size of the finished titanium electrode substrate did not meet the requirements of this application. At the same time, the abnormal furnace atmosphere caused by the excessive vacuum degree during vacuum pressure straightening heat treatment led to severe oxidation of the titanium substrate surface.

[0083] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A process for preparing titanium electrode plate substrate for PEM water electrolysis to produce hydrogen, characterized in that, Including the following steps: Step 1: Use the electron beam cold hearth furnace casting method to melt flat ingots in one go. The width of the flat ingot is ≥1000mm. Use a large integral cutter head milling machine to machine the upper and lower surfaces of the slab as a whole. The diameter of the cutter head is larger than the width of the slab. The single-sided milling thickness is ≥3mm. The thickness difference of the cross section of the slab after machining is ≤3mm. Step 2: Heat the slab to 800℃~900℃, and roll the slab into a titanium strip coil with a thickness of 4.0mm-6.0mm using a furnace coil mill. Then, perform continuous annealing, pickling, and grinding to remove the surface oxide scale. Step 3: Roll the 4.0mm-6.0mm thick titanium strip coil to 2.0mm-3.0mm thickness using a 20-roll mill, with pure rolling oil as the lubricant; Step 4: Use degreasing and cleaning equipment to remove rolling oil and titanium powder from the surface of the titanium strip coil; Step 5: Heat treat the titanium strip roll in a vacuum bell-type annealing furnace at a temperature of 600℃~700℃ for a holding time of ≥6 hours. Step 6: Use a leveling machine to level the titanium strip coil; Step 7: Use room temperature leveling and slitting equipment to level and slit the titanium strip roll to obtain titanium plates of fixed length; Step 8: Vacuum pressing and straightening heat treatment is performed on the fixed-length titanium plate using a vacuum plate furnace; Step 9: Sampling and inspection of the finished coils; In Step 3, the deformation during rolling is 45.0% to 55.0%, the deformation of the first pass is 15% to 20%, and the deformation of the remaining passes is 10% to 15%; In Step 8, the vacuum degree is 0.1 Pa to 0.5 Pa, the platen thickness is 50 mm to 150 mm, the holding temperature is 400℃ to 500℃, the holding time is 10 to 15 hours, and the coils are cooled to 150℃ in the furnace before being removed from the furnace.

2. The preparation process of titanium electrode plate substrate for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, In step 2, the slab is rolled again after the rolls are replaced in the furnace rolling mill, and the rolling roll sequence is 1 to 3.

3. The preparation process of titanium electrode plate substrate for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, In step 6, a four-roll cold rolling leveling machine is used to level the titanium strip coil. The pressure of the leveling machine is 150 to 300 tons, and the reduction is 0.005 mm to 0.010 mm.

4. The preparation process of titanium electrode plate substrate for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, In step 2, a flap wheel is used to grind along the hot rolling direction to remove surface defects.

5. The method for preparing titanium electrode plate substrate for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, In step 1, the thickness of the slab is 190mm to 210mm.

6. The method for preparing titanium electrode plate substrate for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, In step 7, the width of the fixed-length titanium plate is ≥1000mm and the thickness is 2mm~3mm.

7. The method for preparing titanium electrode plate substrate for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, In step 9, the inspection standards are: double-sided unevenness ≤1mm / m, surface roughness ≤0.4um, difference between the same board ≤0.02mm, grain size ≥8.0 grade, and no deformation after etching.

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