High-strength steel conical tube axis line press forming method

Abstract

The application discloses a high-strength steel taper pipe axis profiling method and belongs to the technical field of water turbine production and processing. The method is characterized in that the theoretical calculation of the geometric parameters of the taper pipe is used to accurately determine the clamping angle of the mold, the opening size of two ends, and the relative positioning size of the sector-shaped spread material of the mold and the taper pipe, and the calculation results are used to guide the mold debugging and workpiece positioning, and the sector-shaped spread material is punched and formed along the axis by cooperating with the upper cylindrical punch mold, the radian is checked in real time during the punching process by combining the taper sample, and finally the profiling, jointing and welding are completed. The application breaks away from the dependence on manual experience in the traditional process, effectively eliminates the manual positioning deviation and error accumulation, improves the forming precision of the taper and the generatrix curvature of the high-strength steel taper pipe, guarantees the size consistency of the products in the same batch, and is suitable for the processing and forming of the high-strength steel taper pipe of the high-water-head impulse turbine unit.

Description

Technical Field

[0001] This invention relates to the field of water turbine manufacturing and processing technology, specifically to a method for forming the shaft of a high-strength steel tapered tube. Background Technology

[0002] The core flow-through components of high-head impulse turbine units include a large number of tapered tube parts made of medium-thick plate high-strength steel. These parts have high requirements for taper accuracy, generatrix straightness, and the mechanical properties of the base material. Currently, the mainstream forming process for these tapered tubes in the industry is the axial stamping forming method. This process is derived from the bending forming process. By cooperating with a cylindrical upper die and two rectangular lower dies (dies) arranged at an angle, the fan-shaped unfolded material undergoes progressive plastic bending, ultimately forming a tapered curved surface.

[0003] The specific process of the existing axial stamping forming process is as follows: First, the fan-shaped plate is cut according to the unfolded size of the tapered tube, and several parallel forming lines are drawn on the surface of the blank. The operator adjusts the placement angle and opening size of the lower die based on experience, places the blank on the die, manually aligns the forming lines with the axis of the upper die, and then performs axial stamping. After stamping several forming lines, the forming arc is compared with the inner template of the tapered tube by hand, and the stamping depth and pressure are adjusted according to the deviation, and the stamping is supplemented until the forming meets the standard. Finally, the workpiece is flame-shaped, the seam is assembled and the longitudinal seam is welded to complete the tapered tube processing.

[0004] The existing technology has the following shortcomings: the placement angle and opening size of the mold have no theoretical calculation basis and rely entirely on the on-site experience of the operator; after multi-line stamping, the error continues to accumulate, the positioning error accumulates, and the forming accuracy is insufficient. Summary of the Invention

[0005] To simultaneously address the technical problems of existing shaft stamping processes that rely on manual experience and lack sufficient forming accuracy, this invention provides a method for forming high-strength steel tapered tube shafts, comprising the following steps:

[0006] Step 1: Basic Parameter Acquisition: Record the core geometric parameters of the tapered tube to be processed, including: inner radius R of the large end of the tapered tube, inner radius r of the small end of the tapered tube, slant length L of the tapered tube, height h of the tapered tube, and wall thickness t of the tapered tube.

[0007] Step 2, Geometric Dimension Calculation: Based on the solid geometry of the tapered tube, calculate the tapered tube development parameters and the matching positioning dimensions of the lower die and the fan-shaped development material of the tapered tube in sequence:

[0008] Step 3, Mold Adjustment and Positioning: Based on the calculated distances A1 and A2 between the fan-shaped unfolded material and the two ends of the mold, the distance B1 between the small ends of the two molds, the distance B2 between the large ends of the two molds, and the included angle θ of the mold; adjust the mold length center to coincide with the lower die length center, and ensure that the overall posture of the upper and lower dies is precisely matched with the fan-shaped unfolded material;

[0009] Step 4, Axis stamping and inspection: Place the fan-shaped unfolded material of the tapered tube with the forming line marked on the mold, fix the relative position of the fan-shaped unfolded material and the mold according to the dimensions A1 and A2, align the axis of the upper die with the forming line, and perform the axis stamping.

[0010] Step 5, Assembly and Welding: After all the forming lines are stamped, the seams are joined and welded to obtain the finished high-strength steel tapered tube.

[0011] Preferably, in step 2, the calculation formulas for each parameter are as follows:

[0012] included angle of the tapered tube's generatrix:

[0013]

[0014] Inner radius of the sector when the tapered tube is unfolded:

[0015]

[0016] Tapered tube unfolded sector median diameter:

[0017]

[0018] Distance between the small ends of the two mold pieces:

[0019]

[0020] Length of the mold:

[0021]

[0022] Development angle of tapered tube HAF billet:

[0023]

[0024] The included angle of the mold:

[0025]

[0026] Distance between the fan-shaped unfolded material and the end of the mold:

[0027]

[0028] Distance between the large ends of the two mold pieces:

[0029] .

[0030] Preferably, in step 3, the included angle between the two molds and the distance between the openings at both ends are adjusted according to the calculated θ, B1, and B2, so that the center of the mold length is aligned with the center of the lower mold length, and the center axis of the lower mold width, the mold axis and the upper mold axis are coplanar, thus completing the mold positioning.

[0031] Preferably, in step 4, the forming curvature is checked using an inner template every 3 to 5 forming lines during the stamping process.

[0032] Preferably, in step 4, the first forming line is tested with small pressure twice, and the stamping pressure is finely adjusted according to the springback obtained from the test. Subsequent forming lines are formed using a small deformation progressive stamping method.

[0033] Preferably, in step 4, when using a conical inner template to compare the forming curvature, the acceptable standard is that a 0.5mm feeler gauge cannot be inserted into the gap between the template and the inner wall of the workpiece.

[0034] Preferably, in step 5, before the joint assembly, the bevel and pressure head allowance are prepared, and the roundness of the tapered tube is finely adjusted by adjusting the joint gap. After controlling the joint gap to be no more than 0.5mm, the longitudinal joint is welded by symmetrical welding.

[0035] The present invention has the following beneficial effects:

[0036] 1. This invention uses the three-dimensional geometry calculation of tapered tubes as its core basis to quantitatively determine the mold angle, opening size, and relative position of the workpiece and the mold. It eliminates the reliance on operator experience in traditional processes and avoids problems such as workpiece translational displacement and poor mold matching from the source. It completely solves the problem of error accumulation defects after multi-line stamping and the forming accuracy of tapered tube taper and generatrix curvature.

[0037] 2. This invention adopts a process of precise positioning combined with small-amplitude progressive stamping, which matches the material characteristics of high-strength steel with low plasticity, effectively reducing the risk of stamping cracks and excessively deep indentations; at the same time, precise shape control ensures the one-time forming qualification rate, thus guaranteeing the structural performance and service life of the high-strength steel tapered tube.

[0038] 3. Mold debugging and workpiece positioning have clear numerical basis, which greatly reduces the workload of repeated manual comparison, trial and error and pressure replenishment, improves processing efficiency, and at the same time reduces the skill level requirements of operators; theoretical calculation parameters are uniformly used to guide production, the dimensional deviation of workpieces in the same batch is small, the parts are interchangeable, and the requirements for mass production of high-strength steel cone tubes for high-head impact turbine units are met. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of the compression mold and tapered tube forming of the present invention;

[0040] Figure 2 This is a schematic diagram illustrating the basic parameters of the tapered tube of the present invention;

[0041] Figure 3 This is a schematic diagram showing the dimensions of the mold placement and the positioning dimensions of the sector-shaped steel plate of the present invention;

[0042] Figure 4 This is a diagram showing the actual parameters of an embodiment of the present invention. Detailed Implementation

[0043] The following detailed description illustrates the specific implementation methods:

[0044] The reference numerals in the accompanying drawings include: upper mold 1, laser level 2, lower mold 3, conical tube 4, and mold 5.

[0045] Example 1

[0046] like Figure 1-4 As shown, a method for forming the axis of a high-strength steel tapered tube includes the following steps:

[0047] The calculation process and processing steps are as follows:

[0048] Step 1: Collect basic geometric parameters

[0049] Tapered tube 4 body parameters:

[0050] inner radius of the small end of the tapered tube 4

[0051] Inner radius of the large end of tapered tube 4

[0052] Wall thickness of tapered tube 4

[0053] Height of tapered tube 4

[0054] tapered tube slant length or unfolded width ;

[0055] Step 2: Calculate the core dimensions of the shaft.

[0056] included angle of the tapered tube's generatrix:

[0057] =

[0058] The inner radius of the fan-shaped section of the tapered tube 4 is:

[0059] =

[0060] Tapered tube 4 unfolded sector median diameter:

[0061] =

[0062] Distance between the small ends of the two mold pieces:

[0063] =4×40=160

[0064] Length of mold 5:

[0065] =

[0066] Development angle of tapered tube HAF billet:

[0067] = =62°

[0068] The included angle of mold 5:

[0069] = =11.9°

[0070] Distance between the fan-shaped unfolded material and the end of mold 5:

[0071] =408.4mm

[0072] Distance between the five ends of the two mold pieces:

[0073] =658.4mm.

[0074] Step 3: Mold Adjustment and Positioning

[0075] A hydraulic press is used, and the upper die 1 is selected with a diameter of... Cylindrical indenter; based on the mold angle Fix and adjust the lower die opening. , Adjust the center of the mold length to be consistent with the center of the lower die 2 length; adjust the center axis of the lower die width to be the same as the mold axis, the upper die axis, and the laser infrared treatment plane; precisely adjust the position of the fan-shaped unfolded material of the cone tube 4 on the mold 5 A1=A2=408.4mm; set the initial stamping pressure of the press and check the downward stroke;

[0076] Step 4: Axis stamping and inspection

[0077] (1) Cut the fan-shaped high-strength steel plate 610CF according to the unfolded size of the tapered tube 4, remove the edge burrs, and draw the forming lines of equal distance and even distribution on the surface of the blank.

[0078] (2) Place the fan-shaped unfolded material stably in the support area of ​​mold 5, align the forming line of the fan-shaped unfolded material with the laser infrared, start the equipment to press, test the first forming line twice to sense the springback, and adopt the method of multiple presses with small deformation.

[0079] (3); After stamping 4 forming lines, pause the operation and compare the forming curvature with the inner template. If the 0.5mm feeler gauge fails the check, the theoretical value of the previous stamping curvature in this embodiment is ≤0.5mm from the actual value, and no parameter adjustment is required; complete the stamping of all forming lines in sequence.

[0080] Step 5: Assembly and Welding

[0081] (1) Match the bevel and pressure head allowance, and assemble the joint;

[0082] (2) Adjust the roundness by fine-tuning the gap between the joints to control the gap between the joints to ≤0.5mm. After fixing the gap, weld the longitudinal joints symmetrically. After grinding and flaw detection, complete the fabrication of the medium-thick plate high-strength steel tapered tube 4.

[0083] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method of high-strength steel conical tube axis profile forming, characterized by, Includes the following steps: Step 1: Collect basic parameters of the tapered tube: Record the core geometric parameters of the tapered tube to be processed, including: inner radius R of the large end of the tapered tube, inner radius r of the small end of the tapered tube, slant length L of the tapered tube, height h of the tapered tube, and wall thickness t of the tapered tube. Step 2, Geometric Dimension Calculation: Based on the solid geometry of the tapered tube, calculate the tapered tube development parameters and the matching positioning dimensions of the lower die and the fan-shaped development material of the tapered tube in sequence: Step 3, Mold Adjustment and Positioning: Based on the calculated distances A1 and A2 between the fan-shaped unfolded material and the two ends of the mold, the distance B1 between the small ends of the two molds, the distance B2 between the large ends of the two molds, and the included angle θ of the mold; adjust the mold length center to coincide with the lower die length center, and ensure that the overall posture of the upper and lower dies is precisely matched with the fan-shaped unfolded material of the tapered tube. Step 4, Axis stamping and inspection: Place the tapered fan-shaped unfolded material with the forming line marked on the mold, fix the relative position of the fan-shaped unfolded material and the mold according to the dimensions A1 and A2, align the axis of the upper die with the forming line, and perform axis stamping. Step 5, Assembly and Welding: After all the forming lines are stamped, the seams are joined and welded to obtain the finished high-strength steel tapered tube.

2. The high strength steel cup-in-cone axial coining method of claim 1, wherein: In step 2, the parameter calculation formula is as follows: the included angle between the generatrix of the cone and the generatrix of the pipe: The inner radius of the developed sector of the cone pipe: The pitch diameter of the developed sector of the cone pipe: The distance between the small end of the two tire molds: The length of the tire mold: The angle of the developed sector of the cone pipe: The included angle of the tire mold: The distance between the developed sector and the end of the tire mold: The distance between the large end of the two tire molds: .

3. The high strength steel cup-in-cone axial coining method of claim 2, wherein: In step 3, adjust the included angle of the two molds and the distance between the openings at both ends according to the calculated θ, B1, and B2, so that the center of the mold length is aligned with the center of the lower mold length, and the center axis of the lower mold width, the mold axis and the upper mold axis are coplanar, thus completing the mold positioning.

4. The high strength steel cupped tube axis line coining method of any of claims 1-3, wherein: In step 4, during the stamping process, the forming curvature is checked using an inner template every 3 to 5 stamping lines.

5. The high strength steel conical tube axis profile method according to claim 4, characterized in that: In step 4, the first forming line is tested with small pressure twice. The stamping pressure is finely adjusted according to the springback obtained from the test. Subsequent forming lines are formed by small deformation progressive stamping.

6. The high strength steel cupped tube axis line coining method of claim 5, wherein: In step 4, when using a conical inner template to compare the forming curvature, the acceptable standard is that a 0.5mm feeler gauge cannot be inserted into the gap between the template and the inner wall of the workpiece.

7. The high strength steel conical tube axis profile method according to claim 6, characterized in that: In step 5, before assembling the joint, the bevel and pressure head allowance are prepared. The roundness of the tapered tube is finely adjusted by adjusting the joint gap. After controlling the joint gap to be no more than 0.5mm, the longitudinal joint is welded using a symmetrical welding method.

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