Extra-thick steel plate arcing hole perforating apparatus and perforating method

Abstract

An extra-thick steel plate arcing hole perforating apparatus, composed of a protective cover (1), an air discharge pipe (2), nuts (3), joints (4), a rubber hose (5), hose clamps (6), an air supply pip

Description

[0001] The present disclosure belongs to the technical field of metal cutting, and in particular to an arc-starting hole perforating device for an extra-thick steel plate, and a perforating method. BACKGROUND

[0002] Extra-thick steel plates are mostly used for the ring plate, upper and lower disks and other parts of hydroelectric machines. The steel plate has a maximum thickness up to 340 mm, and is made of Q345B or S500Q. Before the assembly of components, unloading should be done first. According to the requirements of drawings, some circular holes or square holes should be cut on the steel plate by flame cutting to participate in the assembly. Because the holes are located in the steel plate and sometimes even in the geometric center of the steel plate, the arc can be started at the edge of the steel plate by conventional numerical control gas cutting. However, if the holes cutting by starting the arc at the edge of the steel plate may cause great waste of raw materials, and even the scrapping of the steel plate. Therefore, it is necessary to set a cutting arc-starting point inside the steel plate. For the steel plate with the thickness below 160 mm, the steel plate can be directly perforated and then cut by the flame penetration ability of the numerical control cutting machine. For the steel plate with a larger thickness, due to the small size of a cutting nozzle on the cutting machine, it is unable to form enough heat and pressure to penetrate the steel plate, and molten steel is easy to splash during the perforation process, which will not only cause the cutting nozzle to be blocked, but also may burn the machine tool and suspend the cutting operation.

[0003] Therefore, at present, for the extra-thick steel plate with the thickness of more than 160 mm, the surface of the steel plate is often drilled by machining and then is cut according to the normal process. However, because of the large size of steel plate, the drilling by machining needs to occupy large machining equipment, with long machining cycle and high machining cost. Moreover, it is time-consuming and laborious to transfer the steel plate to the machining workshop, which is not conducive to the improvement of production efficiency. SUMMARY

[0004] In view of this, for the disadvantages in the prior art, the present disclosure provides an arc-starting hole perforating device for an extra-thick steel plate, and a perforating method, so as to solve the problems of large splash, long machining cycle, high machining cost, occupation of large machining equipment, high transfer cost, low production efficiency, etc., for the flame cutting perforation of extra-thick steel plates over 160 mm in the prior art.

[0005] The objective of the present disclosure is achieved through the following technical solution: an arc-starting hole perforating device for an extra-thick steel plate is composed of a protective cover, an air outlet pipe, nuts, connectors, a rubber hose, hose clamps, an air supply pipe, a control valve, and an oxygen cylinder. One end of each of the air outlet pipe and the air supply pipe is sleeved with the nut, one end of each connector is clamped at an inner side of the nut, and the other end of the connector passes through the nut. Each of both ends of the rubber hose is sleeved on one end of the connector passing through the nut. Each hose clamp is used to seal the connector and the rubber hose. The other end of the air outlet pipe passes through a circular hole at the top of the protective cover, and the other end of the air supply pipe is welded to the oxygen cylinder. A control valve is installed on the air supply pipe, and communication and closing of the air supply pipe and the oxygen cylinder are controlled through an open state and a closing state of the control valve. The top of the protective cover is provided with a circular hole having a diameter of (p40 mm, a lower cylinder of the protective cover is provided with a rectangular door of 200 mm *200 mm, the nut is machined with an internal thread and a first spigot. The connector is spherical at a lower side, is machined with a second spigot and a ladder-like step at an outer cylinder part, and is machined with a vent hole at a central part. The second spigot of the connector is closely attached to the first spigot of the nut.

[0006] In the arc-starting hole perforating device for an extra-thick steel plate, the air outlet pipe and the air supply pipe are machined with external threads at positions connected to the nuts. Each of the air outlet pipe and the air supply pipe has an outer diameter of 18 mm, a wall thickness of 3 mm, and a length of 2500 mm, and is made of Q235B.

[0007] In the arc-starting hole perforating device for an extra-thick steel plate, the rubber hose has an inner diameter of 8 mm, a wall thickness of 3 mm, a length of 30 m, and a rated operating pressure of 15-20 MPa.

[0008] A perforating method for an arc-starting hole perforating device for an extra-thick steel plate is further provided, the arc-starting hole perforating device for an extra-thick steel plate above is adopted, and the method includes the following steps:

[0009] Step one: positioning, marking a position of an arc-starting hole to be machined on a steel plate, placing a protective cover on the steel plate, and moving the protective cover to position a circular hole on the top of the protective cover at the arc-starting hole;

[0010] Step two: preparing, enabling an air outlet pipe to pass through the circular hole at the top of the protective cover, and enabling a lower air outlet hole of the air outlet pipe to make contact with the arc-starting hole on the surface of the steel plate, and checking whether a control valve is in a closed state;

[0011] Step three: preheating, opening an acetylene valve of a hand-held ejection-absorption cutting torch and igniting the cutting torch, opening an oxygen valve of the hand-held ejectionabsorption cutting torch and adjusting flam to neutral flame, and making the neutral flame burn stably; enabling the hand-held ejection-absorption cutting torch to pass through a rectangular door of the protective cover to align with the arc-starting hole on the surface of the steel plate for preheating, so as to achieve a temperature of spontaneous combustion of the steel plate and oxygen, and when the arc-starting hole on the surface of the steel plate starts to burn and melt, drawing out the hand-held ejection-absorption cutting torch rapidly, and closing the acetylene valve and the oxygen valve;

[0012] Step four: perforating, opening the control valve to introduce oxygen, enabling the steel plate with the arc-starting hole to continuously burn and melt with the oxygen, slowly moving the air outlet pipe downwards, wherein slag overflows to the surface of the steel plate under the action of an oxygen flow, and still remains in the protective cover; swinging the air outlet pipe rapidly along a conical surface within a range from 15° to 30°, and making a steel plate core continue to burn and melt under the action of the oxygen flow, wherein when the flame penetrates the thickness of the steel plate, the slag flows out from a lower part of the steel plate through the arc-starting hole; then, drawing out the air outlet pipe and closing the control valve to stop oxygen supply, wherein an air supply pressure of the air outlet pipe is from 8 MPa to 10 MPa; and

[0013] Step five: cleaning, cleaning the slag on the surface of the steel plate around the arcstarting hole to prepare for a formal cutting.

[0014] In the perforating method for an arc-starting hole perforating device for an extra-thick steel plate, in Step three, the acetylene valve of the hand-held ejection-absorption cutting torque has a pressure of 0.8 MPa, and the oxygen valve of the hand-held ejection-absorption cutting torque has a pressure ranging from 6 MPa to 8 MPa.

[0015] Compared with the prior art, the present disclosure has the following beneficial effects:

[0016] (1) The perforating device provided by the present disclosure is simple in structure, low in manufacturing cost, can directly machine on a raw steel plate and a steel plate assembled with components, thus avoiding the occupation of large machining equipment.

[0017] (2) The perforating device is convenient to dismount and carry and capable of achieving rapid connection. The perforating method provided by the present disclosure can significantly 3 improve the arc-starting hole machining efficiency of the extra-thick steel plate, effectively reduce the arc-starting hole machining cost, and save transfer cost, and the machining time and cost of a single hole are less than 4% of those of traditional mechanical drilling.

[0018] (3) According to the arc-starting hole perforating device for the extra-thick steel plate and the perforating method, the diameter of the air outlet pipe is large, and the oxygen supply pressure is sufficient, so that the operation is not easy to be stopped due to blockage in the arcstarting hole machining process. Through practice, the maximum thickness of the penetrable steel plate is up to 340 mm, so the problem of machining the arc-starting hole of the extra-thick steel plate is effectively solved, which is the first in the industry.

[0019] (4) By reasonably designing the protective cover structure, the problem of splashing of the molten steel when the arc-starting hole is machined by flame is solved, which can effectively ensure the safety of equipment and personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a front view of an arc-starting hole perforating device for an extra-thick steel plate;

[0021] FIG. 2 is an A-A sectional diagram of an arc-starting hole perforating device for an extrathick steel plate;

[0022] FIG. 3 is a B-B sectional diagram of an arc-starting hole perforating device for an extrathick steel plate;

[0023] FIG. 4 is an enlarged view of an I region of an arc-starting hole perforating device for an extra-thick steel plate;

[0024] FIG. 5 is a sectional diagram of an I region of an arc-starting hole perforating device for an extra-thick steel plate;

[0025] FIG. 6 is a sectional diagram of external threads at an upper part of an air outlet pipe and an air supply pipe;

[0026] FIG. 7 is a sectional diagram of a nut;

[0027] FIG. 8 is a sectional diagram of a connector;

[0028] FIG. 9 is a schematic step diagram of a perforating method for an arc-starting hole perforating device for an extra-thick steel plate;

[0029] FIG. 10 is a preheating diagram of a perforating method for an arc-starting hole perforating device for an extra-thick steel plate.

[0030] In the drawings:

[0031] 1-protective cover; 2-air outlet pipe; 3-nut; 4-connector; 5-rubber hose; 6-hose clamp; 7-air supply pipe; 8-control valve; 9-oxygen cylinder; 10-circular hole; 11-rectangular door; 12-external thread, 13-internal thread; 14-first spigot; 15-second spigot; 16-ladder-like step; 17-vent hole; 18-arc-starting hole; 19-hand-held ejection-absorption cutting torque; 20-acetylene valve; 21-oxygen valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The present disclosure is further described below with reference to accompanying drawings and specific embodiments.

[0033] As shown in FIG. 1 to FIG. 5, FIG. 7 and FIG. 8, an arc-starting hole perforating device for an extra-thick steel plate is composed of a protective cover 1, an air outlet pipe 2, nuts 3, connectors 4, a rubber hose 5, hose clamps 6, an air supply pipe 7, a control valve 8, and an oxygen cylinder 9. One end of each of the air outlet pipe 2 and the air supply pipe 7 is sleeved with the nut 3, one end of each connector 4 is clamped at an inner side of the nut 3, and the other end of the connector 4 passes through the nut 3. Each of both ends of the rubber hose 5 is sleeved on one end of the connector 4 passing through the nut 3. Each hose clamp 6 is used to seal the connector 4 and the rubber hose 5. The other end of the air outlet pipe 2 passes through a circular hole 10 at the top of the protective cover 1, and the other end of the air supply pipe 7 is welded to the oxygen cylinder 9. A control valve 8 is installed on the air supply pipe 7, and communication and closing of the air supply pipe 7 and the oxygen cylinder 9 are controlled through an open state and a closing state of the control valve 8. The top of the protective cover 1 is provided with a circular hole 10 having a diameter of q>40 mm, a lower cylinder of the protective cover 1 is provided with a rectangular door 11 of 200 mm *200 mm, and the nut 3 is machined with an internal thread 13 and a first spigot 14. The connector 14 is spherical at a lower side, is machined with a second spigot 15 and a ladder-like step 16 at an outer cylinder part, and is machined with a vent hole 17 at a central part. The second spigot 15 of the connector 4 is closely attached to the first spigot 14 of the nut 3.

[0034] As shown in FIG. 6, further, the air outlet pipe 2 and the air supply pipe 7 are machined with external threads 12 at positions connected to the nuts 3. Each of the air outlet pipe 2 and the air supply pipe 7 has an outer diameter of 18 mm, a wall thickness of 3 mm, and a length of 2500 mm, and is made of Q235B.

[0035] Further, the rubber hose 5 has an inner diameter of 8 mm, a wall thickness of 3 mm, a length of 30 m, and a rated operating pressure of 15-20 MPa.

[0036] A perforating method for an arc-starting hole perforating device for an extra-thick steel plate includes the following steps as shown in FIG. 9.

[0037] Step one. Positioning: a position of an arc-starting hole 18 to be machined is marked on a steel plate, a protective cover 1 is placed on the steel plate, and the protective cover 1 is moved to position a circular hole 10 on the top of the protective cover 1 at the arc-starting hole 18.

[0038] Step two. Preparing: an air outlet pipe 2 passes through the circular hole 10 at the top of the protective cover 1, a lower air outlet hole of the air outlet pipe 2 is in contact contact with the arc-starting hole 18 on the surface of the steel plate, and whether a control valve 8 is in a closed state is checked.

[0039] Step three. Preheating: as shown in FIG. 10, an acetylene valve 20 of a hand-held ejectionabsorption cutting torch 19 is opened to ignite the cutting torch 19, an oxygen valve 21 of the hand-held ejection-absorption cutting torch 19 is opened to adjust flame to neutral flame, making the neutral flame bum stably. The hand-held ejection-absorption cutting torch 19 passes through a rectangular door 11 of a protective cover 1 to align with the arc-starting hole 18 on the surface of the steel plate for preheating, so as to achieve a temperature of spontaneous combustion of steel plate and oxygen, and when the arc-starting hole on the surface of the steel plate starts to burn and melt, the hand-held ejection-absorption cutting torch 19 is drawn out rapidly, and the acetylene valve 20 and the oxygen valve 21 are closed.

[0040] Step four. Perforating: the control valve 8 is opened to introduce oxygen, the steel plate with the arc-starting hole 18 continue to burn and melt with the oxygen, the air outlet pipe 2 is slowly moved downwards, and slag overflows to the surface of the steel plate under the action of oxygen flow, and remains in the protective cover 1. The air outlet pipe 2 is swung rapidly along a conical surface in a range from 15° to 30°, and a steel plate core continues to burn and melt under the action of oxygen flow; when the flame penetrates the thickness of the steel plate, the slag flows out from a lower part of the steel plate through the arc-starting hole 18. At the moment, the air outlet pipe 2 is drawn out, the control valve 8 is closed to stop oxygen supply, where an air supply pressure of the air outlet pipe 2 is from 8 MPa to 10 MPa.

[0041] Step five. Cleaning: the slag on the surface of the steel plate around the arc-starting hole 18 is cleaned to prepare for a formal cutting.

[0042] Further, in Step three, the acetylene valve 20 of the hand-held ejection-absorption cutting torque 19 has a pressure of 0.8 MPa, and the oxygen valve 21 of the hand-held ejection-absorption cutting torque 19 has a pressure ranging from 6 MPa to 8 MPa.

[0043] As can be seen from this embodiment that the rapid and accurate positioning of the arcstarting hole can be achieved, and the perforation operation can be directly conducted on the steel 6 plate, thus avoiding the occupation of large machining equipment, canceling the transfer procedure of machining drilling, and greatly saving the transfer cost and time. The perforation time is extremely short, and the perforated hole is used as the arc-starting hole to facilitate the subsequent gas cutting of holes with larger sizes on the numerical control gas cutting machine tool, thus greatly improving the production efficiency.

[0044] In addition, the air outlet pipe 2 used for perforation is large in diameter and sufficient in oxygen pressure, thus the steel plate with a thickness of 340 mm can be directly penetrated, and the stop of operation caused by blockage can be avoided in the perforation process. Due to the increase of the protective cover 1, the molten steel is prevented from splashing and spreading around during the perforation operation, the safety is higher, and the safety of equipment and personnel is effectively protected.

[0045] Taking a lower disk of many components of a hydro-generator set as an example, the lower disk has a dimension of (pl 180 mm (inner diameter) x (p3800 mm (outer diameter) x 335 mm (thickness), and is made of a Q345B steel plate. There is a (pl 180 mm large hole and twenty-four (p 100 mm small holes on the lower disk, a total of 25 arc-starting holes are required to open. The raw material specification of a steel plate for suit cutting is 3820 mm (length) / 3820 mm (width) / 340 mm (thickness). If the traditional flame cutting method is adopted, starting arc from edge can only be used for gas cutting of excircle, but the central hole cannot be directly penetrated by the traditional flame cutting method, and a hole with a diameter of (p20mm is drilled by machining as an arc-starting point of gas cutting, the time for machining the above twenty-five holes is 25 hours, and the machining cost is 1,500 yuan. However, by adopting the arc-starting hole piercing device for the extra-thick steel plate and the piercing method, the total time for penetrating the twenty-five holes is only 37. 5 minutes, and the cost for perforating is only 50 yuan.

[0046] The above is only the preferred embodiment of the present disclosure, and is not used to limit the present disclosure. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. An arc-starting hole perforating device for an extra-thick steel plate, composed of a protective cover (1), an air outlet pipe (2), nuts (3), connectors (4), a rubber hose (5), hose clamps (6), an air supply pipe (7), a control valve (8), and an oxygen cylinder (9), wherein one end of each of the air outlet pipe (2) and the air supply pipe (7) is sleeved with the nut (3), one end of each connector (4) is clamped at an inner side of the nut (3), and the other end of the connector (4) passes through the nut (3); each of both ends of the rubber hose (5) is sleeved on one end of the connector (4) passing through the nut (3); and each hose clamp (6) is used to seal the connector (4) and the rubber hose (5); the other end of the air outlet pipe (2) passes through a circular hole (10) at the top of the protective cover (1), and the other end of the air supply pipe (7) is welded to the oxygen cylinder (9); a control valve (8) is installed on the air supply pipe (7), and communication and closing of the air supply pipe (7) and the oxygen cylinder (9) are controlled through an open state and a closing state of the control valve (8); the top of the protective cover (1) is provided with a circular hole (10) having a diameter of (p40 mm, a lower cylinder of the protective cover (1) is provided with a rectangular door (11) of 200 mm *200 mm, the nut (3) is machined with an internal thread (13) and a first spigot (14); the connector (14) is spherical at a lower side, is machined with a second spigot (15) and a ladder-like step (16) at an outer cylinder part, and is machined with a vent hole (17) at a central part; and the second spigot (15) of the connector (4) is closely attached to the first spigot (14) of the nut (3).

2. The arc-starting hole perforating device for an extra-thick steel plate according to claim 1, wherein the air outlet pipe (2) and the air supply pipe (7) are machined with external threads (12) at positions connected to the nuts (3), each of the air outlet pipe (2) and the air supply pipe (7) has an outer diameter of 18 mm, a wall thickness of 3 mm, and a length of 2500 mm, and is made of Q235B.

3. The arc-starting hole perforating device for an extra-thick steel plate according to claim 1, wherein the rubber hose (5) has an inner diameter of 8 mm, a wall thickness of 3 mm, a length of 30 m, and a rated operating pressure of 15-20 MPa.

4. A perforating method for an arc-starting hole perforating device for an extra-thick steel plate, wherein the arc-starting hole perforating device for an extra-thick steel plate according to claim 1 is adopted, and the method comprises the following steps:Step one: positioning, marking a position of an arc-starting hole (18) to be machined on a steel plate, placing a protective cover (1) on the steel plate, and moving the protective cover (1) to position a circular hole (10) on the top of the protective cover (1) at the arc-starting hole (18);Step two: preparing, enabling an air outlet pipe (2) to pass through the circular hole (10) at the top of the protective cover (1), and enabling a lower air outlet hole of the air outlet pipe (2) to make contact with the arc-starting hole (18) on the surface of the steel plate, and checking whether a control valve (8) is in a closed state;Step three: preheating, opening an acetylene valve (20) of a hand-held ejection-absorption cutting torch (19) and igniting the cutting torch (19), opening an oxygen valve (21) of the handheld ejection-absorption cutting torch (19) and adjusting flam to neutral flame, and making the neutral flame burn stably; enabling the hand-held ejection-absorption cutting torch (19) to pass through a rectangular door (11) of the protective cover (1) to align with the arc-starting hole (18) on the surface of the steel plate for preheating, so as to achieve a temperature of spontaneous combustion of the steel plate and oxygen, and when the arc-starting hole on the surface of the steel plate starts to burn and melt, drawing out the hand-held ejection-absorption cutting torch (19) rapidly, and closing the acetylene valve (20) and the oxygen valve (21);Step four: perforating, opening the control valve (8) to introduce oxygen, enabling the steel plate with the arc-starting hole (18) to continuously bum and melt with the oxygen, slowly moving the air outlet pipe (2) downwards, wherein slag overflows to the surface of the steel plate under the action of an oxygen flow, and still remains in the protective cover (1); swinging the air outlet pipe (2) rapidly along a conical surface within a range from 15° to 30°, and making a steel plate core continue to bum and melt under the action of the oxygen flow, wherein when the flame penetrates the thickness of the steel plate, the slag flows out from a lower part of the steel plate through the arc-starting hole (18); then, drawing out the air outlet pipe (2) and closing the control valve (8) to stop oxygen supply, wherein an air supply pressure of the air outlet pipe (2) is from 8 MPa to 10 MPa; andStep five: cleaning, cleaning the slag on the surface of the steel plate around the arc-starting hole (18) to prepare for a formal cutting.

5. The perforating method for an arc-starting hole perforating device for an extra-thick steel plate according to claim 4, wherein in Step three, the acetylene valve (20) of the hand-held ejection-absorption cutting torque (19) has a pressure of 0.8 MPa, and the oxygen valve (21) of the hand-held ejection-absorption cutting torque (19) has a pressure ranging from 6 MPa to 8 MPa.PCT / CN2023 / 126325A. CLASSIFICATION OF SUBJECT MATTERB23K 7 / 00(2006.01)i; B23K 7 / 10(2006.01)iAccording to International Patent Classification (IPC) or to both national classification and IPCB. FIELDS SEARCHEDMinimum documentation searched (classification system followed by classification symbols)IPC:B23KDocumentation searched other than minimum documentation to the extent that such documents are included in the fields searchedElectronic data base consulted during the international search (name of data base and, where practicable, search terms used) CNKI, CNTXT, ENTXT, VEN: M®, 5IM ff?L, SM, Wffi, iWI, Wf IW^, SHIf, HWS, Zplate, board, start, arc, hole, punching, protect, safety, cover, box, acetylene, ethine, ethyneDOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. PX CN 116000407 A (HARBIN ELECTRIC MACHINERY CO., LTD.) 25 April 2023 (2023-04-25) description, paragraphs 0005-0018 1-5 X CN 1046489 A (LI BENMAO) 31 October 1990 (1990-10-31) description, page 4, paragraph 4-page 6, last paragraph, and figures 1-4 1-5 A CN 106312238 A (ANHUI JINGLONG METAL MATERIAL CO., LTD.) 11 January 2017 (2017-01-11) entire document 1-5 A CN 114378402 A (GUANGXIJINCHUAN NONFERROUS METALS CO., LTD.) 22 April 2022 (2022-04-22) entire document 1-5 A CN 201799739 U (ANHUI XIRUI HEAVY INDUSTRY TECHNOLOGY CO., LTD.) 20 April 2011 (2011-04-20) entire document 1-5 A US 2018202653 Al (CLEARSIGN COMB CORP.) 19 July 2018 (2018-07-19) entire document 1-5| | Further documents are listed in the continuation of Box C.annex.* Special categories of cited documents: “T” later document published after the international filing date or priority “A” document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular relevance principle or theory underlying the invention “D” document cited by the applicant in die international application “X” document of particular relevance; the claimed invention cannot be “E" earlier application orpatent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone •SL” document which may throw doubts on priority claim(s) or which is “Y” document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified) combined with one or more other such documents, such combination “O” document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in the art means document member of the same patent family “P” document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 11 December 2023 Date of mailing of the international search report 21 December 2023 Name and mailing address of the ISA / CN China National Intellectual Property Administration (ISA / CN) China No. 6, Xitucheng Road, Jimenqiao, Haidian District, Beijing 100088 Authorized officer Telephone No.INTERNATIONAL SEARCH REPORT Information on patent family membersInternational application No.PCT / CN2023 / 126325Patent document cited in search report Publication date (day / month / year) Patent family member)s) Publication date (day / month / year) CN 116000407 A 25 April 2023 None CN 1046489 A 31 October 1990 None CN 106312238 A 11 January 2017 None CN 114378402 A 22 April 2022 None CN 201799739 U 20 April 2011 None US 2018202653 Al 19 July 2018 WO 2017048638 Al 23 March 2017 EP 3325877 Al 30 May 2018 EP 3325877 A4 20 March 2019

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