Preparation method of inlet guide vane for large-sized air separation compressor

Abstract

The application provides a preparation method of an inlet guide vane for a large air separation compressor, and aims at solving the technical problems of low material utilization, long manufacturing period and high manufacturing cost of the prior art. The preparation method comprises the following steps: 1) according to the structure and size requirements of the inlet guide vane, blanking is performed to obtain a vane, a sealing platform and a handle of the inlet guide vane; 2) welding grooves are respectively machined on the vane and the handle; 3) based on the welding grooves, the vane, the sealing platform and the handle are sequentially welded to obtain an inlet guide vane blank; 4) the inlet guide vane blank is placed in a resistance furnace for heat treatment to obtain an inlet guide vane semi-product; 5) the inlet guide vane semi-product is subjected to welding seam detection; and 6) the inlet guide vane semi-product is machined to remove the machining allowance, and then polished and cleaned to obtain an inlet guide vane product for a large air separation compressor. The material utilization of the method is greatly improved, and the manufacturing cost is obviously reduced.

Description

Technical Field

[0001] This invention relates to a method for preparing an inlet guide vane, and more particularly to a method for preparing an inlet guide vane for a large air separation compressor. Background Technology

[0002] Large air separation compressors are core and critical equipment widely used in industries such as petrochemicals, coal deep processing, fertilizers, and metallurgy. The inlet guide vanes are located at the front end of the air separation compressor flow channel. Through the inlet guide vane adjustment mechanism, pre-swirl is generated before the airflow enters the impeller to improve the gas flow conditions, thereby improving the working efficiency of the compressor impeller.

[0003] Because the imported guide vanes are generally large in size and are mostly custom-made parts, they are manufactured in small batches. The existing method is to forge the imported guide vanes into an integral structure by free forging, leaving a large allowance, and then machine them to the required size. The imported guide vanes processed by this method have good overall performance, but the disadvantages are low material utilization (only 15% to 25%) and long manufacturing cycle (generally about 75 days), resulting in high overall manufacturing costs. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing inlet guide vanes for large air separation compressors, which solves the technical problems of low material utilization, long manufacturing cycle and high manufacturing cost of existing methods.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for preparing an inlet guide vane for a large air separation compressor, characterized by the following steps:

[0007] Step 1】According to the structural and dimensional requirements of the inlet guide vane, the inlet guide vane is divided into three parts: blade, sealing platform and blade shank. The blanks of the blade, sealing platform and blade shank of the inlet guide vane are cut into blanks respectively, and each blank has a machining allowance of 3 to 5 mm on one side.

[0008] Step 2】Machining corresponding welding bevels at the end of the blade near the sealing platform and at the end of the blade stalk near the sealing platform respectively;

[0009] Step 3】Based on the welding bevel described in Step 2】, the blade, sealing platform and blade shank are welded in sequence to obtain the inlet guide vane blank;

[0010] Step 4】Place the imported guide vane blank into an electric resistance furnace for heat treatment to obtain the imported guide vane semi-finished product;

[0011] Step 5】Perform weld flaw detection on the imported guide vane semi-finished product. If it passes, proceed to Step 6】; if it fails, return to Step 3】for repair welding based on the weld flaw detection results.

[0012] Step 6】The imported guide vane semi-finished product is machined to remove the machining allowance, and then polished and cleaned to obtain the finished imported guide vane for large air separation compressors.

[0013] Furthermore, in step 3, the coaxiality of the blade, sealing platform, and blade shank is first ensured by spot welding, and then the blade, sealing platform, and blade shank are welded and fixed in sequence.

[0014] Furthermore, in step 3, the welding is performed using CMT arc welding technology.

[0015] Furthermore, in step 3], the welding is performed using a combination of laser and arc welding, wherein the laser guides the welding process first, and the arc performs the welding process later. The number of welding passes is 10 to 30, the welding speed of each pass is 5 to 15 mm / s, the laser power is 1.0 kW to 1.4 kW, the arc wire feed speed is 4.0 to 6.0 m / min, the welding current is 125 to 180 A, and the welding voltage is 15 to 25 V.

[0016] Furthermore, in step 1], the blades of the inlet guide vane are made of plate material; the sealing platform and the blade holder are made of round steel bar material.

[0017] Further, in step 2], the welding bevel on the blade is located at the center of the end of the blade near the sealing platform. The welding bevel is a sloping structure with the opening facing both sides in the thickness direction of the blade. The angle α between the sloping surface and the upper surface of the sealing platform is 15-30°. The radius R of the front end of the welding bevel is 6-10 mm. The thickness of the blunt edge of the front end of the welding bevel is 2-16 mm. The vertical distance between the end face of the welding bevel near the upper surface of the sealing platform and the middle of the tip of the blade is 230-580 mm.

[0018] The welding bevel on the blade is located at the end of the blade near the lower surface of the sealing platform. The welding bevel has a conical structure with a taper of α+90°. The center of the small cone end of the conical structure is a blunt edge with a diameter of 2-16 mm.

[0019] Furthermore, in step 4], the heat treatment temperature is 550-800℃, and the time is 1-3h.

[0020] Further, step 5 specifically involves performing weld flaw detection on the heat-treated inlet guide vane blank. Weld flaw detection includes penetrant testing on the weld surface and ultrasonic testing on the weld interior. Based on the weld flaw detection results, it is determined whether the welding process of the inlet guide vane blank is qualified. If qualified, step 6 is executed; if not qualified, the process returns to step 3 for repair welding based on the weld flaw detection results.

[0021] Furthermore, step 6 also includes flaw detection on the polished inlet guide vane. Flaw detection includes magnetic particle testing on the surface of the vane and ultrasonic testing on the interior of the vane. If it fails, the vane is either locally polished or scrapped based on the results of the flaw detection. If it passes, the subsequent steps are carried out to obtain the finished inlet guide vane for large air separation compressors.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. This invention provides a method for manufacturing an inlet guide vane for a large air separation compressor. The method involves dividing the inlet guide vane into three parts: blades, a sealing platform, and a shank. These three parts are then welded together sequentially. Following heat treatment, weld flaw detection, and machining, the finished inlet guide vane is obtained. Compared with existing technologies, this method significantly improves material utilization and substantially reduces manufacturing costs.

[0024] 2. The present invention provides a method for preparing an inlet guide vane for a large air separation compressor. In the welding process of each component, spot welding is first used to ensure the coaxiality of the blade, sealing platform and blade holder, and then welding is used to fix them. This not only improves the coaxiality of the finished inlet guide vane, but also improves the quality of the finished product.

[0025] 3. The method for preparing the inlet guide vane for a large air separation compressor provided by the present invention allows for the selection of CMT arc welding process during welding, control of welding current and voltage, reduction of welding spatter and welding deformation, and improvement of the overall quality of the inlet guide vane.

[0026] 4. The method for preparing the imported guide vane for a large air separation compressor provided by the present invention can also select a combination of laser welding and electric arc welding during welding. Selecting this process can increase the welding penetration. By utilizing the dual heat sources of laser and electric arc, it combines the advantages of high efficiency and low heat input of laser welding with the strong metallurgical control capability of electric arc welding. Moreover, the heat input is smaller than that of electric arc welding.

[0027] 5. The present invention provides a method for preparing an inlet guide vane for a large air separation compressor, which allows for more diverse selection of materials for the blades, sealing platform and blade holder.

[0028] 6. The present invention provides a method for preparing an inlet guide vane for a large air separation compressor, which eliminates the stress of the inlet guide vane through heat treatment, thereby preventing weld cracking during subsequent processing.

[0029] 7. The present invention provides a method for preparing an inlet guide vane for a large air separation compressor. After welding, the quality of the weld is determined by weld flaw detection, thereby improving the quality of the finished inlet guide vane.

[0030] 8. The present invention provides a method for preparing imported guide vanes for large air separation compressors. After machining, the vanes are subjected to flaw detection. Since flaw detection is a non-destructive testing method, this method can effectively detect the impact of the machining process on the vanes, thereby further improving the quality of the finished product.

[0031] 9. The method for preparing the imported guide vane for a large air separation compressor provided by this invention can reduce the production cycle by 20% and the cost by 15% compared with the prior art, and is more conducive to industrial application. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the inlet guide vane components before welding in an embodiment of the present invention;

[0033] Figure 2 for Figure 1 The left view;

[0034] Figure 3 This is a perspective view of the inlet guide vane components before welding in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the welding bevel structure in an embodiment of the present invention;

[0036] Figure 5 for Figure 4 Sectional view along line AA;

[0037] Figure 6 for Figure 4 A magnified view of a section of the middle blade;

[0038] Figure 7 for Figure 5 A magnified view of a section of the middle blade;

[0039] Figure 8 for Figure 4 A magnified view of a portion of the petiole;

[0040] Figure 9 for Figure 8 Top view;

[0041] Figure 10 This is a schematic diagram of the structure of the imported guide vane in an embodiment of the present invention;

[0042] Figure 11 for Figure 10 Sectional view along the BB direction;

[0043] Figure 12 This is a perspective view of the imported guide vane product in an embodiment of the present invention.

[0044] The attached figures are labeled as follows:

[0045] 1-Leaf blade, 2-Pedicel, 3-Sealing stage. Detailed Implementation

[0046] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] This invention provides a method for preparing inlet guide vanes for large air separation compressors, specifically including the following steps:

[0048] Step 1】According to the structural and dimensional requirements of the imported guide vane, blanks of the blade, sealing platform and blade stalk of the imported guide vane are cut separately, with a machining allowance of 3 to 5 mm on each side.

[0049] like Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, the inlet guide vane is divided into three parts: blade 1, sealing platform 3, and blade holder 2. Each part is cut into its respective materials according to the precision machining dimensions plus allowance. Blade 1 is made of free forging or sheet metal, while sealing platform 3 and blade holder 2 are made of round steel bar. The material is SGM002 (an optimized version of X12Cr13). Each material is heat-treated to meet the performance requirements of the drawings before being returned to the factory for welding, which shortens the processing cycle.

[0050] Before the first welding, a welding procedure qualification test must be conducted according to the requirements of NB / T47014, and PQR and WPS documents must be issued. Subsequent products will be manufactured according to these documents. The mechanical properties of the blades are determined based on the results of this procedure qualification test, including indicators such as yield strength, tensile strength, reduction of area, elongation of area, impact energy, and hardness.

[0051] Step 2】Welding bevels are machined at the end of blade 1 near the sealing platform 3 and the end of blade shank 2 near the sealing platform 3, respectively.

[0052] Different welding methods and welding bevel forms are generally determined based on the thickness of blade 1 and petiole 2. The welding bevel must be obtained by mechanical means, and local grinding and repair are allowed. If the size is not specified, it must be calculated according to the actual size of the blade.

[0053] like Figures 4 to 7As shown, in this embodiment, the welding bevel on blade 1 is located at the center of the end of blade 1 near the sealing platform 3. The welding bevel has an opening facing both sides in the thickness direction of blade 1, and the angle α between this bevel and the upper surface of the sealing platform 3 is 15-30°. The end where the two bevels are close together is an arc surface with a radius R (i.e., the front radius R of the welding bevel) of 6-10 mm. The end where the two arc surfaces are close together is a blunt edge (i.e., the blunt edge at the front of the welding bevel), with a thickness d1 = d = 2-16 mm. The vertical distance H from the middle of the tip of blade 1 to the end face of the welding bevel near the upper surface of the sealing platform 3 is 230-580 mm. The welding bevel has an opening facing inwards in the width direction of blade 1, and the angle between this bevel and the central axis of blade 1 is 135° to facilitate the entry of welding equipment and welding.

[0054] like Figure 8 and Figure 9 As shown, the welding bevel on the blade stalk 2 is located at the end of the blade stalk 3 near the lower surface of the sealing platform 3. Since the blade stalk 2 is a cylindrical structure, its welding bevel is a conical structure, with the small conical end facing the sealing platform 3. The taper of this conical structure is α+90°. At the same time, the center of the small conical end of the conical structure is a blunt edge with a diameter of d2, and d2=d1=d=2~16mm. The circumference of the blunt edge and the conical surface is an arc structure with a radius of R. The parameters of the welding bevel on the blade stalk are consistent with the relevant parameters of the welding bevel on the blade 1, thereby improving the coaxiality of the blade, sealing platform 3 and blade stalk 2 during the welding process, and thus improving the welding efficiency.

[0055] Step 3】Based on the welding bevel processed in Step 2】, the blade 1, sealing platform 3 and blade shank 2 are welded in sequence to obtain the inlet guide vane blank.

[0056] Specifically, the coaxiality of blade 1, sealing platform 3 and blade shank 2 is first ensured by spot welding (using appropriate tooling for spot welding). Then, blade 1 and sealing platform 3 are welded and fixed by alternating welding on both sides. This method can reduce deformation. Finally, blade shank 2 and sealing platform 3 are welded and fixed by ring welding.

[0057] Welding can be carried out using CMT arc welding process, with ER316L, ER310, and ERNiCrMo-3 welding wires being preferred. Welding current and voltage should be controlled to reduce welding spatter and welding deformation, thereby improving the overall quality of the workpiece.

[0058] Alternatively, welding can be performed using a combination of laser and arc welding. This method increases weld penetration and utilizes both laser and arc as heat sources, combining the advantages of high efficiency and low heat input of laser welding with the strong metallurgical control capabilities of arc welding. Its heat input is even lower than that of arc welding. The number of welding passes is typically 10–30, with a welding speed of 5–15 mm / s per pass. The laser power is 1.0 kW–1.4 kW, the wire feed speed is 4.0–6.0 m / min, the welding current is 125–180 A, and the welding voltage is 15–25 V. During welding, the root of the weld is fully penetrated and welded completely. Welding is performed alternately on both sides while controlling the heat input. The combined laser and arc welding method generally uses a laser-guided mode with the laser preceding the arc. High-purity argon is used as the shielding gas. Laser beam scanning is added during welding to stir the molten pool, further improving the joint microstructure and properties, resulting in a more spread weld, grain refinement, and elimination of porosity. The scanning path is a straight line with a scanning radius of 1 mm and a scanning frequency of 50 Hz.

[0059] Step 4: Place the imported guide vane blank into an electric resistance furnace for heat treatment to obtain the imported guide vane semi-finished product.

[0060] After welding, the imported guide vane semi-finished product is generally sent into an electric resistance furnace for heat treatment to relieve stress. In this embodiment, the heat treatment temperature is 550-800℃ and the time is 1-3 hours; the preferred option is to heat treat at 700℃ for 2 hours, which can relieve stress on the imported guide vane semi-finished product, prevent cracking in subsequent processes, and thus improve the quality of the finished product.

[0061] Step 5: Perform weld flaw detection on the imported guide vane semi-finished product. If it passes the test, proceed to Step 6; if it fails the test, return to Step 3 for repair welding based on the weld flaw detection results.

[0062] After the weld is completed, the weld appearance is required to be smooth and free of defects such as cracks, undercut, and slag inclusions. Therefore, this embodiment adopts a weld flaw detection method of penetrant testing + ultrasonic testing. Penetrant testing is performed on the weld surface with a quality level not lower than NB / T47013 Class I, and ultrasonic testing is performed on the weld interior with a quality level not lower than NB / T47013 Class I. After the weld flaw detection results are qualified, the machine processing process is transferred.

[0063] If the weld inspection results show that the weld is unqualified, repair welding shall be carried out according to the specific results. If the surface layer of the weld is defective, the welding material of this layer shall be removed and re-welded according to the welding process. If the bottom layer or the middle layer of the weld is defective, the welding material outside the layer where the defect is located shall be removed and the remaining layers, including the defective layer, shall be re-welded according to the welding process (i.e., all removed parts shall be re-welded).

[0064] Step 6】The imported guide vane semi-finished product is machined to remove machining allowance, and then polished and cleaned to obtain the finished imported guide vane for large air separation compressors. The finished imported guide vane is as follows: Figure 10 , Figure 11 , Figure 12 As shown.

[0065] Machining includes roughing, finishing, polishing, flaw detection and cleaning, which can be performed in sequence. This process can be carried out in accordance with the conventional process.

[0066] Rough machining includes drilling, rough turning, and rough milling, mainly using CNC milling machines and drilling machines. Most of the excess material, such as the blade stalk, sealing platform, and blade profile, is removed according to the drawing requirements, leaving a 2mm allowance on each side. Finish machining includes finish turning and finish milling, mainly using CNC milling machines to remove all excess material and achieve the dimensional requirements of the drawing. Polishing is performed on a CNC polishing machine, ensuring that the blade profile, chord length, thickness, and other dimensions meet the drawing requirements. Flaw detection involves inspecting the machined product for defects. Generally, magnetic particle testing is performed on the blade surface, and ultrasonic testing is performed on the blade interior. If the flaw detection is successful, the product proceeds to cleaning and subsequent processes; if the flaw detection fails, local grinding or scrapping is selected based on the results.

[0067] Products that pass the flaw detection are cleaned, mainly to remove oil stains, dust particles, etc. from the product surface, and then packaged and stored, thus completing the complete preparation process.

[0068] The method for preparing the imported guide vane provided by the present invention involves dividing the imported guide vane into different parts and fixing them by welding, thereby increasing the overall utilization rate of materials by 30%, reducing manufacturing costs by 15%, and shortening the production cycle by 20%.

[0069] Although embodiments of the present invention have been shown and described above, those skilled in the art should consider any variations and modifications of the above embodiments that fall within the scope of the present invention's spirit and essence to be within the protection scope of the present invention.

Claims

1. A method for preparing an inlet guide vane for a large air separation compressor, characterized in that, Includes the following steps: Step 1】According to the structural and dimensional requirements of the inlet guide vane, the inlet guide vane is divided into three parts: blade, sealing platform and blade shank. The blanks of the blade, sealing platform and blade shank of the inlet guide vane are cut into blanks respectively, and a machining allowance of 3~5mm on each side is left. Step 2】Welding bevels are machined at the ends of the blade and the stalk near the sealing platform, respectively. The welding bevel on the blade is located at the center of the end of the blade near the sealing platform. The welding bevel is a sloping structure with the opening facing both sides in the thickness direction of the blade. The angle α between the sloping surface and the upper surface of the sealing platform is 15~30°. The welding bevel on the stalk is located at the end of the stalk near the lower surface of the sealing platform. The welding bevel is a conical structure with a taper of α+90°. The center of the small cone end of the conical structure is a blunt edge. Step 3】Based on the welding bevel described in Step 2】, first ensure the coaxiality of the blade, sealing platform, and blade shank by spot welding, and then weld and fix the blade, sealing platform, and blade shank in sequence to obtain the inlet guide vane blank; the welding is carried out using CMT arc welding process, or by a combination of laser and arc welding; in the combination of laser and arc welding, the laser guides first, and the arc welds later; Step 4】Place the imported guide vane blank in a resistance furnace at a temperature of 550-800℃ for heat treatment for 1-3 hours to obtain the imported guide vane semi-finished product. Step 5】Perform weld flaw detection on the imported guide vane semi-finished product. If it passes, proceed to Step 6】; if it fails, return to Step 3】for repair welding based on the weld flaw detection results. Step 6】The imported guide vane semi-finished product is machined to remove the machining allowance, and then polished, inspected and cleaned to obtain the imported guide vane finished product for large air separation compressors.

2. The method for preparing the inlet guide vane for a large air separation compressor according to claim 1, characterized in that: In step 3, the laser and arc welding method combines 10 to 30 welding passes, with a welding speed of 5 to 15 mm / s per pass, a laser power of 1 kW to 4 kW, an arc wire feed speed of 4.0 to 6.0 m / min, a welding current of 125 to 180 A, and a welding voltage of 15 to 25 V.

3. The method for preparing the inlet guide vane for a large air separation compressor according to claim 2, characterized in that: In step 1, the blades of the inlet guide vane are made of plate material; the sealing platform and the blade holder are made of round steel bar material.

4. The method for preparing the inlet guide vane for a large air separation compressor according to claim 3, characterized in that: In step 2], the radius R of the front end of the welding bevel on the blade is 6~10 mm; the thickness of the blunt edge of the front end of the welding bevel is 2~16 mm; the vertical distance between the end face of the welding bevel near the upper surface of the sealing platform and the middle of the tip of the blade is 230~580 mm. In the welding bevel on the blade stalk, the diameter of the blunt edge of the small cone end of the conical structure is 2~16 mm.

5. The method for preparing the inlet guide vane for a large air separation compressor according to claim 4, characterized in that: Step 5: Specifically, the heat-treated inlet guide vane blank is subjected to weld flaw detection. Weld flaw detection includes penetrant testing on the weld surface and ultrasonic testing on the weld interior. Based on the weld flaw detection results, it is determined whether the welding process of the inlet guide vane blank is qualified. If qualified, proceed to step 6; if not qualified, return to step 3 for repair welding based on the weld flaw detection results.

6. The method for preparing the inlet guide vane for a large air separation compressor according to claim 5, characterized in that: In step 6, the flaw detection includes magnetic particle testing on the surface of the blade and ultrasonic testing on the interior of the blade. If the blade fails to meet the requirements, the blade will be locally polished or scrapped based on the flaw detection results. If it passes the test, proceed to the next steps to obtain the finished imported guide vanes for large air separation compressors.

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