A control method for preventing camber deformation in thermal cutting of narrow metal sheets

Abstract

The present invention relates to a control method for preventing sickle bending deformation during thermal cutting of narrow strip metal plates, which belongs to a steel plate cutting method. The mother plate to be cut is squared on a cutting operation table, and the head cut-in line, tail cut-in line, and long side cutting lines on both sides are determined on the mother plate according to the narrow strip specifications. The middle area surrounded by the head cut-in line, tail cut-in line, and two long side cutting lines is the blanking area, and the splitting lines for cutting each narrow strip are determined in the blanking area; when cutting, the edge materials on both sides of the width direction are completely cut off along the long side cutting line, and then cut along the splitting line. When cutting, the head and tail of the current narrow strip are both connected to the mother plate and are not cut off; when all the splitting lines are cut, all the narrow strips are still connected together, the material is placed horizontally and each narrow strip is supported below, and after cooling to room temperature, the head and tail of the mother plate are cut along the head cut-in line and the tail cut-in line to separate the narrow strips. The problem of compression plastic deformation along the cutting direction during hot cutting of narrow strips is solved.

Description

Technical Field

[0001] The invention relates to a steel plate cutting control method. Background Art

[0002] Thermal cutting of steel plates refers to the process of melting the area to be cut by local high temperature to achieve the purpose of material separation. Common steel plate cutting methods include flame cutting, plasma cutting, and laser cutting. Since the steel plate is locally exposed to high temperature during cutting, the cut seam expands locally due to heat, but cannot be deformed freely due to the constraints of the surrounding cold metal. Compressive stress will be generated in the heat-affected zone, forming compressive plastic deformation along the cutting direction, especially in the case of narrow strip cutting specifications, which will cause irreparable lateral bending deformation (sickle bending), and ultimately lose its use value and fail to meet user needs. Summary of the invention

[0003] The purpose of the present application is to solve the technical problem that when the existing steel plate is hot-cut into a number of narrow strips, the narrow strips are deformed into sickle shape due to the compressive stress generated by cutting.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problem is: a control method for preventing sickle bending deformation in thermal cutting of narrow strip metal plates, square the mother plate to be cut on the cutting operation table, determine the head sizing line at the head position of the mother plate according to the narrow strip specifications, determine the tail sizing line at the tail position, determine the long side cutting lines on both sides in the width direction of the mother plate, the middle area surrounded by the head sizing line, the tail sizing line and the two long side cutting lines is the blanking area, and determine the splitting lines for cutting each narrow strip in the blanking area; when cutting, first completely cut off the edge materials on both sides in the width direction along the long side cutting lines, and then cut along the splitting lines, when cutting, the head and tail of the current narrow strip are entangled with the mother plate and are not cut off; after all the splitting lines are cut, all the narrow strips are still entangled together, the material is placed horizontally and it is ensured that each narrow strip has support underneath, and after cooling to room temperature, the head and tail of the mother plate are cut along the head sizing line and the tail sizing line respectively to separate the narrow strips.

[0005] Preferably, the distance between the head cut-to-length line and the head edge of the board is ≥5 cm; the distance between the tail cut-to-length line and the tail edge of the board is ≥15 cm.

[0006] Preferably, when cutting along the splitting line, the cutting starts before the head sizing line and ends after the tail sizing line, and the distance between the cutting start point and the head edge of the board is ≥5 cm; the distance between the cutting end point and the tail edge of the board is ≥10 cm.

[0007] Preferably, a stress release hole is arranged along the dividing line. The stress release hole is arranged on the board head side of the dividing line, and the cutting starts from the stress release hole. The stress release hole is a circular hole with a hole diameter of ≥2cm, or an elliptical hole with a diameter of ≥2cm*5cm.

[0008] Preferably, the parent material is stably and reliably laid flat on the cutting work surface during cutting, and sufficient support is provided under each narrow strip to be cut.

[0009] Preferably, along the length direction, the length between the head cut line and the tail cut line is the length of the narrow strip; along the width direction, the length between the two long side cutting lines is an integer multiple of the width of the narrow strip.

[0010] Compared with the prior art, the advantages of the present invention are: (1) When the steel plate is hot cut, the head and tail are connected without being cut off. The reverse traction at the connection is used to counteract the compressive stress in the heat-affected zone of the cut, so that the material cannot shrink inward and produce compressive plastic deformation. Adding stress release holes accelerates the release of thermal stress during the cooling process of the material and prevents the end from cracking during the cooling process. After the material is fully cooled, the head and tail parts are cut off, and the final material achieves the ordered size and meets the plate shape requirements.

[0011] (2) Before cutting, sufficient length margin must be left at the head and tail to ensure that the subsequent narrow strips can be pulled together and provide tensile stress.

[0012] (3) Before cutting, ensure that there is sufficient support under each narrow strip corresponding to the parent material laid on the cutting operation table to avoid collapse and deformation of the narrow strip after cutting.

[0013] (4) Before splitting, use tools to set stress relief holes on each splitting line at one end of the parent material. This is used to accelerate stress release during formal cutting and cooling and prevent end cracking. When hot cutting, start cutting from the stress release hole and retract the knife a certain distance away from the tail. Do not cut it off. In this way, each narrow strip is split. Due to the principle of thermal expansion and contraction of metal materials, the material is locally exposed to high temperature during cutting, and the cut seam is locally heated and expanded, but it cannot deform freely due to the constraints of the surrounding cold metal. Compressive stress is generated in the heat-affected zone, and compressive plastic deformation is formed along the cutting direction. At this time, the reverse traction force at the connection between the two ends counteracts the compressive stress in the heat-affected zone of the cut seam, so that the material cannot shrink inward and produce compressive plastic deformation. (5) The material must be fully cooled to room temperature before the head and tail connection can be cut off to completely separate each narrow strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the principle diagram of narrow strip thermal cutting compression plastic deformation (sickle bending); Figure 2 This is a schematic diagram of the head and tail cut-to-length lines; Figure 3 It is a schematic diagram of the long side cutting line; Figure 4 It is a schematic diagram of the splitting line; Figure 5 Schematic diagram of the structure of the stress relief hole. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with examples. The examples are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0016] In order to prevent the compressive plastic deformation formed along the cutting direction during hot cutting of narrow strips, the head and tail ends of the mother rod (the left and right ends in the figure) are connected without being cut off, and the reverse traction force of the connected parts is used to counteract the compressive stress in the heat affected zone of the dividing line, so that the material cannot shrink inward and produce compressive plastic deformation; additional stress release holes are added to accelerate the release of thermal stress during the cooling process of the material, preventing cracking at the ends during the cooling process and residual stress rebound.

[0017] This embodiment provides a control method for preventing camber deformation during thermal cutting of a narrow metal sheet, including: Step 1: Use a crane to lay the mother board to be flame-cut flat on the cutting operation table, and ensure that there is sufficient support under each narrow strip to be cut to avoid collapse and deformation of the narrow strip after cutting.

[0018] Step 2: Use the ink fountain to draw the head and tail length lines. The head length line should be ≥5cm away from the board head, and the tail length line should be ≥15cm away from the board tail. Figure 2 .

[0019] Step 3: Use the ink fountain to draw the long side cutting line (total width fixed line). The parallel distance between the two long side cutting lines is: (narrow strip width + margin) * quantity. Figure 3 .

[0020] Step 4: Use the ink fountain to draw the narrow strip dividing line. The width of a single narrow strip is the nominal width + allowance. Figure 4 .

[0021] Step 5. Use a handheld cutting torch to make "stress relief holes" on each split line of the board head. The hole diameter is ≈ 2cm*5cm ellipse. The hole is located on each split line and between the head cut line and the edge of the board head. Figure 5 .

[0022] Step 6: Use a flame cutting machine to cut off the two burrs in the length direction. Cut the two burrs from the beginning to the end and separate them from the motherboard.

[0023] Step 7: Split the body, starting from the stress release hole, cutting along the splitting line to the tail of the board, and ending the cut when the tail cut line is >10cm. The head and tail must be connected and cannot be cut off.

[0024] Step 8. Cut each narrow strip one by one according to the method in step 7. The head and tail of each narrow strip cannot be cut off.

[0025] Step 9: The motherboard is hoisted to a flat surface and the material needs to be fully cooled naturally to room temperature (20±10℃).

[0026] Step 10: Lift the motherboard to the cutting operation table again, and cut the material to the required length according to the head and tail cut lines. There are sufficient supports under each narrow strip to prevent the narrow strip from collapsing after cutting.

[0027] Step 11. The inspector measures the narrow strip sickle according to the standard method. The measurement method and evaluation are based on the corresponding technical protocol or standard.

[0028] The validation data of this method are shown in Table 1.

[0029] Table 1 Statistics of hot-cut narrow strip camber measurement data Material Brand Specification Inspection basis Sickle value Quality judgment Q4119078020 S355J2 65*1033*24942 EN10025 4mm qualified Q4119078010 S355J2 65*1033*24942 EN10025 8mm qualified Q4117113010 S355J2 65*1033*24942 EN10025 4m qualified Q4117113020 S355J2 65*1033*24942 EN10025 6m qualified Q4103292020 S355JR / IS2062 E350BR 45*520*10544 GB / T709 3m qualified Q4103292040 S355JR / IS2062 E350BR 45*520*10544 GB / T709 4m qualified Q4103292060 S355JR / IS2062 E350BR 45*520*10544 GB / T709 4m qualified Q4103292070 S355JR / IS2062 E350BR 45*520*10544 GB / T709 3m qualified Q4103292100 S355JR / IS2062 E350BR 45*520*10544 GB / T709 4m qualified Q4103292120 S355JR / IS2062 E350BR 45*520*10544 GB / T709 4m qualified In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A control method for preventing camber deformation during thermal cutting of narrow metal plates, characterized in that: Place the mother board to be cut squarely on the cutting operation table, determine the head cut-off line at the head position of the mother board according to the narrow strip specifications, determine the tail cut-off line at the tail position, determine the long side cutting lines on both sides in the width direction of the mother board, and the middle area surrounded by the head cut-off line, the tail cut-off line and the two long side cutting lines is the blanking area, and determine the splitting lines for cutting each narrow strip in the blanking area; when cutting, first completely cut off the edge materials on both sides of the width direction along the long side cutting lines, and then cut along the splitting lines. When cutting, the head and tail of the current narrow strip are connected to the mother board and are not cut off; after all the splitting lines are cut, all the narrow strips are still connected together, place the material horizontally and ensure that each narrow strip is supported underneath, and after cooling to room temperature, cut the head and tail of the mother board along the head cut-off line and the tail cut-off line respectively to separate the narrow strips.

2. The method according to claim 1, characterized in that: The distance between the head cut-to-length line and the head edge of the board is ≥5cm; the distance between the tail cut-to-length line and the tail edge of the board is ≥15cm.

3. The method according to claim 1, characterized in that: When cutting along the splitting line, the cutting starts before the head cut line and ends after the tail cut line, and the distance between the cutting start point and the head edge of the board is ≥5cm; the distance between the cutting end point and the tail edge of the board is ≥10cm.

4. The method according to claim 1, characterized in that: Stress relief holes are set along the sectioning line.

5. The method according to claim 4, characterized in that: The stress release hole is arranged on one side of the plate head of the dividing line, and the cutting starts from the stress release hole.

6. The method according to claim 4, characterized in that: The stress release hole is a circular hole with a hole diameter of ≥2cm, or an elliptical hole with a diameter of ≥2cm*5cm.

7. The method according to claim 1, characterized in that: During cutting, the base material is laid flat and stable on the cutting work surface, and sufficient support is provided under each narrow strip to be cut.

8. The method according to claim 1, characterized in that: Along the length direction, the length between the head cut line and the tail cut line is the length of the narrow strip; along the width direction, the length between the two long side cutting lines is an integer multiple of the width of the narrow strip.

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