Processing technology of special-shaped square tube

Abstract

The invention discloses a machining process for a special-shaped square tube. The machining process comprises the following steps that firstly, a heat rolled plate with the corresponding size is selected according to the process requirement to be unrolled and leveled; secondly, the flattened rolled plate is pulled to pass through a round corner forming die, and a round corner structure protruding upwards is rolled on the rolled plate; thirdly, the rolled plate with the fillet structure is pulled into the square pipe forming die under the traction effect to form a square pipe blank; fourthly, the square tube blank is pulled and welded and formed through a high-frequency induction coil, then a weld joint is quenched through a quenching pool, welding slag and burrs on the weld joint are removed after quenching, and then the weld joint is inspected; and fifthly, the welded and formed steel pipe is cut according to the technological requirements, and the cut steel pipe is conveyed into a warehouse to be stored for use. In this way, the overall structural stability of the machined special-shaped square pipe can be improved, and therefore the finished square pipe can meet the machining requirement of non-standard accessories in an elevator.

Description

Technical Field

[0001] The invention relates to the field of elevator parts processing, in particular to a processing technology for special-shaped square tubes. Background Art

[0002] With the development of the times and the intensification of competition, the elevator industry has gradually begun to develop special products for various special working conditions. For these special products, manufacturers need to develop a variety of corresponding non-standard components. The special-shaped square tube with concave rounded corners on the four corners is one of the raw materials for non-standard components. The traditional processing method of special-shaped square tubes is generally to process the steel strip into round tubes or square tube blanks before the welding step, and then after welding, the tube blanks are processed through a special sizing die for secondary processing. However, when the special-shaped square tube with concave rounded corners on the four corners is processed according to this process, the four-side structure of the square tube is often destroyed because the four corners are subjected to force at the same time, resulting in the square tube shape being difficult to meet the processing requirements of the corresponding parts in the elevator. Therefore, the process needs to be further adjusted to enhance the product yield. Summary of the invention

[0003] The main technical problem solved by the present invention is to provide a processing technology for special-shaped square tubes, which can improve the yield rate of products.

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a processing technology for a special-shaped square tube, wherein the four top corners of the special-shaped square tube are provided with a concave rounded corner structure. The processing technology of the special-shaped square tube includes the following steps:

[0005] The first step is unwinding and leveling. According to the process requirements, hot rolled coils of corresponding sizes are selected for unwinding and leveling.

[0006] The second step is to preform the rounded corners. The rolled plate after pulling and leveling passes through the rounded corner forming die, and a rounded corner structure convex upward is rolled out on the rolled plate.

[0007] The third step is tube blank forming. The rolled plate with rounded corners is pulled into the square tube forming die under traction, so that the two sides of the rolled plate are symmetrically rolled up vertically and then relatively closed to form a square tube blank, and the rounded corners are just located at the four corners of the square tube blank in a concave state;

[0008] The fourth step is high-frequency welding. The square tube blank is pulled through the high-frequency induction coil for welding and forming. The welded steel pipe is pulled through the quenching pool arranged behind the high-frequency induction coil to quench the weld. The length of the quenching pool is 5 to 8 meters. A grinder and a weld online inspection device are arranged at the exit of the quenching pool to remove the welding slag and burrs on the weld and then inspect the weld.

[0009] The fifth step is cutting and storage. The welded steel pipes are cut according to the process requirements and then sent to the warehouse for storage.

[0010] In a preferred embodiment of the present invention, before cutting the steel pipe, the quenched steel pipe needs to be pulled into a vertex trimming mold to trim the four corners of the steel pipe and regularize the rounded corner structures on the four vertex corners.

[0011] In a preferred embodiment of the present invention, when the two sides are closed in the third step, the closing position is in the middle of the corresponding surfaces of the square tube, and there is a gap of 1 to 3 MM at the closing position.

[0012] In a preferred embodiment of the present invention, the pulling speed of the special-shaped square tube during the processing is 10-30 m / min.

[0013] In a preferred embodiment of the present invention, the induced current of the high-frequency induction coil is 180A-240A.

[0014] In a preferred embodiment of the present invention, the weld online inspection device is an eddy current flaw detector or an ultrasonic flaw detector.

[0015] The beneficial effect of the present invention is that the present invention optimizes the existing special-shaped square tube processing technology. By adjusting the position of the square tube deformation processing, the concave rounded corner structure is pre-processed according to the process requirements before the square tube is formed, and then the square tube body is formed. In this way, the pre-processed rounded corner structure will not interfere with the forming of the square tube body during the whole process. Therefore, the four-side structure of the square tube after forming is stable and will not be deformed due to the extrusion of the rear section, which significantly improves the overall yield rate and can meet the processing requirements of non-standard accessories in elevators. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of the special-shaped steel pipe in a preferred embodiment of the present invention; DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0018] See also Figure 1 , the embodiments of the present invention include:

[0019] Example 1

[0020] A processing technology for a special-shaped square tube, wherein the wall thickness of the special-shaped square tube is 1 mm, the overall cross-sectional profile is a square with a width of 33 mm, four vertex corners are provided with concave rounded corner structures, and the side length between adjacent vertex corners is 23 mm. The processing technology of the special-shaped square tube includes the following contents:

[0021] The first step is unwinding and leveling. According to the process requirements, hot rolled coils of corresponding sizes are selected for unwinding and leveling.

[0022] The second step is to preform the rounded corners. The rolled plate after pulling and leveling passes through the rounded corner forming die, and a rounded corner structure convex upward is rolled out on the rolled plate.

[0023] The third step is tube blank forming. The rolled plate with rounded corners is pulled into the square tube forming die under traction, so that the two sides of the rolled plate are symmetrically rolled up vertically and then relatively closed to form a square tube blank, and the rounded corners are just located at the four corners of the square tube blank in a concave state. There is a gap of 1 to 3 mm at the middle closing position of the top of the tube blank to prevent defects caused by excessive stress at the weld position due to thermal expansion and contraction during welding;

[0024] The fourth step is high-frequency welding. The square tube blank is pulled through a high-frequency induction coil for welding. The induction current of the high-frequency induction coil is between 180A and 240A, and is usually 200±10A in actual application. The welded steel pipe is pulled through a quenching pool arranged behind the high-frequency induction coil to quench the weld. The designed length of the quenching pool is 8 meters. A grinder and a weld online detection device are arranged at the outlet of the quenching pool. The weld online detection device can be an eddy current flaw detector or an ultrasonic flaw detector. After the grinder removes the welding slag and burrs on the weld, the online weld detection device performs online inspection on the weld quality. After the inspection is successful, the quenched steel pipe is pulled into the vertex trimming mold to trim the four corners of the steel pipe and regularize the rounded corner structure shape on the four vertex corners.

[0025] The fifth step is cutting and storage. The welded steel pipes are cut according to the process requirements and then sent to the warehouse for storage.

[0026] The pulling speed of the special-shaped square tube during processing is 10-30 m / min. According to the thickness and cross-sectional specifications of the special-shaped square tube, the larger the thickness and side length, the smaller the pulling speed, and vice versa. In this embodiment, the pulling speed is 15 m / min.

[0027] In this way, the concave rounded corner structure has been pre-processed before the special-shaped square tube is finalized. In the subsequent deformation process, the position of the concave structure does not interfere with the square tube forming mold, so it does not affect the overall forming. No secondary forming is required after welding. It only needs to be trimmed on the original basis to make the rounded corner structure regular. The special-shaped square tube formed in this way has a stable structure on all four sides and a significantly improved yield rate, which can meet the processing requirements of non-standard accessories in elevators.

[0028] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A processing technology for a special-shaped square tube, wherein the four top corners of the special-shaped square tube are provided with a concave rounded structure, characterized in that: The processing technology of the special-shaped square tube includes the following steps: The first step is unwinding and leveling. According to the process requirements, hot rolled coils of corresponding sizes are selected for unwinding and leveling. The second step is to preform the rounded corners. The rolled plate after pulling and leveling passes through the rounded corner forming die, and a rounded corner structure convex upward is rolled out on the rolled plate. The third step is tube blank forming. The rolled plate with rounded corners is pulled into the square tube forming die under traction, so that the two sides of the rolled plate are symmetrically rolled up vertically and then relatively closed to form a square tube blank, and the rounded corners are just located at the four corners of the square tube blank in a concave state; The fourth step is high-frequency welding. The square tube blank is pulled through the high-frequency induction coil for welding and forming. The welded steel pipe is pulled through the quenching pool arranged behind the high-frequency induction coil to quench the weld. The length of the quenching pool is 5 to 8 meters. A grinder and a weld online inspection device are arranged at the exit of the quenching pool to remove the welding slag and burrs on the weld and then inspect the weld. The fifth step is cutting and storage. The welded steel pipes are cut according to the process requirements and then sent to the warehouse for storage.

2. The processing technology of the special-shaped square tube according to claim 1 is characterized in that: Before the steel pipe is cut, the quenched steel pipe needs to be pulled into a vertex trimming mold to trim the four corners of the steel pipe and regularize the rounded corner structure shapes on the four vertex corners.

3. The processing technology of the special-shaped square tube according to claim 1 is characterized in that: When the two sides are closed in the third step, the closing position is in the middle of the corresponding surface of the square tube, and there is a gap of 1 to 3MM at the closing position.

4. The processing technology of special-shaped square tube according to claim 1 is characterized in that: The pulling speed of the special-shaped square tube during the processing is 10-30 m / min.

5. The processing technology of special-shaped square tube according to claim 1 is characterized in that: The induction current of the high-frequency induction coil is 180A-240A.

6. The processing technology of special-shaped square tube according to claim 1 is characterized in that: The weld online inspection device is an eddy current flaw detector or an ultrasonic flaw detector.

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