A method for solving the wavy edge of L415M steel plate in longitudinal submerged arc welded pipe

Abstract

The invention belongs to the technical field of steel rolling finishing, and relates to a method for solving the wavy shape of the edge of a straight seam submerged arc welded pipe L415M steel plate. The method comprises the following steps: S1: directly lifting the straight seam submerged arc welded pipe L415M steel plate running to the 1 / 3 to 2 / 3 position in a cooling bed to a conveying roller where a double-sided shear is located by a crane, so as to ensure that the surface temperature of the straight seam submerged arc welded pipe L415M steel plate before the crane lifting is 100°C to 200°C; S2: the conveying roller conveys the straight seam submerged arc welded pipe L415M steel plate to the double-sided shear for warm shearing to eliminate the edge stress of the straight seam submerged arc welded pipe L415M steel plate. The present invention comprehensively considers the effects of a cooling bed and a double-sided shear of a plate production line in the absence of a pre-straightening machine. Under the existing plate production line, the L415M steel plate of the straight seam submerged arc welded pipe is directly lifted from the 1 / 3 to 2 / 3 position of the cooling bed to the conveying roller where the double-sided shear is located by a crane located between the cooling bed and the double-sided shear, and the L415M steel plate of the straight seam submerged arc welded pipe is sheared with temperature, thereby eliminating the edge stress and restoring the plate shape to normal.

Description

Technical Field

[0001] The invention belongs to the technical field of steel rolling finishing and relates to a method for solving the wavy shape of the edge of an L415M steel plate of a straight seam submerged arc welded pipe. Background Art

[0002] At present, the research and development of pipeline steel at home and abroad mainly takes the design route of low carbon components, combines the composite microalloying method, and applies the TMCP steel rolling process technology. The pipeline steel produced has excellent strength, toughness and welding performance. Usually the normal production process of the plate production line is: upstream process → finishing rolling → ACC cooling (the temperature is usually greater than 400℃ after cooling) → online straightening → cooling bed cooling (cooling to room temperature) → bilateral shearing → quality inspection and packaging. Because the L415M steel plate of the straight seam submerged arc welded pipe adopts the design route of low carbon components, combined with the composite microalloying method, and applies the TMCP steel rolling process technology, the plate shape of the steel plate after finishing rolling has a certain amount of ripples, and compared with ordinary low alloy steel, the L415M straight seam submerged arc welded pipe requires a faster cooling speed and a lower red-returning temperature in ACC, which will further aggravate the plate shape ripples after ACC cooling. The lower the red-returning temperature, the more serious the ripples. Due to the low return temperature, the strength of the steel plate increases, and the cooling rate of the edge is greater than that of the middle, so that the edge temperature of the steel plate is lower than that of the middle. Even after online straightening, the edge stress cannot be completely eliminated. After the L415M steel plate of the straight seam submerged arc welded pipe is cooled on the bed, the edge stress will recover again, and the edge wave shape is easy to appear. Some steel plates with slight edge waves can be straightened in the subsequent cold straightening machine, but it takes a long time and is inefficient. However, the cold straightening machine cannot straighten the steel plates with serious edge waves.

[0003] In the prior art, a pre-straightening machine is usually set before ACC cooling to alleviate the problem of the wavy edge of the L415M steel plate of the straight seam submerged arc welded pipe. However, due to the extremely high cost of the pre-straightening machine, it is obviously not economically valuable to introduce a pre-straightening machine to solve the problem of the wavy edge of the L415M steel plate of the straight seam submerged arc welded pipe, and the existing production line needs to be modified, which is too costly. Alternatively, the steel plate with wavy edges needs to be heat treated to save it, which can easily cause the performance of the steel plate to drop below the lower limit, resulting in a change in the steel plate, resulting in cost losses and waste of energy.

[0004] Therefore, there is an urgent need for a method to solve the edge ripple of the L415M steel plate of the straight seam submerged arc welded pipe through the existing plate production line without a pre-straightening machine and without adding new equipment. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for solving the edge wavy problem of L415M steel plate of straight seam submerged arc welded pipe, aiming at solving the edge wavy problem of L415M steel plate of straight seam submerged arc welded pipe through the existing plate production line in the absence of a pre-straightening machine.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for solving the wavy shape of the edge of the L415M steel plate of a longitudinal submerged arc welded pipe comprises the following steps:

[0008] S1: Lift the L415M steel plate of the LSAW pipe running to the 1 / 3~2 / 3 position in the cooling bed directly to the conveyor roller where the double-sided shear is located by the crane to ensure that the surface temperature of the L415M steel plate of the LSAW pipe before the crane lifting is 100℃~200℃;

[0009] S2: The conveying roller conveys the L415M steel plate of the LSAW pipe to the double-sided shear for warm shearing to eliminate the edge stress of the L415M steel plate of the LSAW pipe.

[0010] Further, in step S1, the crane lifts the L415M steel plate of the longitudinal submerged arc welded pipe at a position 1 / 3 of the running direction of the cooling bed.

[0011] Further, in step S2, the double-sided shearing width is 20 mm to 30 mm.

[0012] Further, in step S2, the conveyor roller runs at full speed to reduce the temperature drop of the L415M steel plate of the longitudinal submerged arc welded pipe.

[0013] The beneficial effects of the present invention are:

[0014] The present invention provides a method for solving the edge wavy problem of the L415M steel plate of the straight seam submerged arc welded pipe. In the absence of a pre-straightening machine, the method solves the edge wavy problem of the L415M steel plate of the straight seam submerged arc welded pipe through an existing plate production line. The method comprehensively considers the effects of the cooling bed and the double-sided shear of the plate production line, directly lifts the L415M steel plate of the straight seam submerged arc welded pipe from the 1 / 3 to 2 / 3 position of the cooling bed to the conveying roller where the double-sided shear is located through a crane located between the cooling bed and the double-sided shear, and runs the conveying roller at full speed to reduce the temperature drop of the L415M steel plate of the straight seam submerged arc welded pipe, and then uses the double-sided shear to perform warm shearing on the L415M steel plate of the straight seam submerged arc welded pipe, which not only eliminates the edge stress of the L415M steel plate of the straight seam submerged arc welded pipe, and restores the steel plate with wavy edges to a normal plate shape, but also speeds up the production process to a certain extent, and has unexpected technical effects.

[0015] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. DETAILED DESCRIPTION

[0016] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0017] Example 1

[0018] A method for solving the wavy shape of the edge of the L415M steel plate of a longitudinal submerged arc welded pipe comprises the following steps:

[0019] S1: Lift the L415M steel plate of the LSAW pipe running to the 1 / 3~2 / 3 position in the cooling bed directly to the conveyor roller where the double-sided shear is located by the crane to ensure that the surface temperature of the L415M steel plate of the LSAW pipe before the crane lifting is 100℃~200℃;

[0020] S2: The conveying roller conveys the L415M steel plate of the LSAW pipe to the double-sided shear for warm shearing to eliminate the edge stress of the L415M steel plate of the LSAW pipe.

[0021] Preferably, in step S1, the crane lifts the L415M steel plate of the longitudinal submerged arc welded pipe at a position 1 / 3 of the running direction of the cooling bed.

[0022] Preferably, in step S2, the double-sided shearing widths are both 20 mm to 30 mm.

[0023] It should be noted that the key to this embodiment is to shorten the time for the L415M steel plate of the straight seam submerged arc welded pipe to reach the double-sided shear, so that when the L415M steel plate of the straight seam submerged arc welded pipe is double-sided sheared, the surface temperature is still greater than 100°C, but after partial cooling on the cooling bed, its temperature is not greater than 200°C, thereby achieving the purpose of warm shearing to eliminate edge stress, and also facilitating quality inspection and warehousing after double-sided shearing. The shearing width is set to 20mm~30mm because the double-sided shearing width in the conventional plate production process is usually also set to 20mm~30mm. The purpose of shearing in the normal production process is to shear the burrs, but it cannot achieve the effect of eliminating edge stress, so there is no waste of the L415M steel plate of the straight seam submerged arc welded pipe in this embodiment; the crane is set between the cooling bed and the double-sided shear, and is a conventional device of the existing plate production line.

[0024] Preferably, in step S2, the conveyor roller runs at full speed to reduce the temperature drop of the L415M steel plate of the longitudinal submerged arc welded pipe.

[0025] Example 2

[0026] To produce 10mm thick L415M steel plate for straight seam submerged arc welded pipe, when the steel plate runs to the 1 / 3 position of the cooling bed, the temperature of the steel plate is 200℃, the steel plate is lifted from the 1 / 3 position of the cooling bed by a crane, placed on the conveyor roller of the double-sided shear, and the conveyor roller is started to convey the steel plate to the double-sided shear. At this time, the temperature is 150℃. After shearing, the unevenness (wavy shape) of the edge of the steel plate is reduced from 14mm / m before shearing to 4mm / m after shearing.

[0027] Example 3

[0028] To produce 10mm thick L415M steel plate for straight seam submerged arc welded pipe, when the steel plate runs to the 1 / 2 position of the cooling bed, the temperature of the steel plate is 140℃. The steel plate is lifted from the 1 / 2 position of the cooling bed by a crane and placed on the conveyor roller of the double-sided shear. The conveyor roller is started to convey the steel plate to the double-sided shear. At this time, the temperature is 120℃. After shearing, the unevenness (wavy shape) of the edge of the steel plate is reduced from 16mm / m before shearing to 4.5mm / m after shearing.

[0029] Example 4

[0030] To produce 12.5mm thick L415M steel plate for straight seam submerged arc welded pipe, when the steel plate runs to the 1 / 2 position of the cooling bed, the temperature of the steel plate is 160℃. The steel plate is lifted from the 1 / 2 position of the cooling bed by a crane and placed on the conveyor roller of the double-sided shear. The conveyor roller is started to convey the steel plate to the double-sided shear. At this time, the temperature is 150℃. After shearing, the unevenness (wavy shape) of the edge of the steel plate is reduced from 11mm / m before shearing to 4mm / m after shearing.

[0031] Example 5

[0032] To produce 16mm thick L415M steel plate for straight seam submerged arc welded pipe, when the steel plate runs to the 2 / 3 position of the cooling bed, the temperature of the steel plate is 160℃. The steel plate is lifted from the 1 / 2 position of the cooling bed by a crane and placed on the conveyor roller of the double-sided shear. The conveyor roller is started to convey the steel plate to the double-sided shear. At this time, the temperature is 150℃. After shearing, the unevenness (wavy shape) of the edge of the steel plate is reduced from 9mm / m before shearing to 3.5mm / m after shearing.

[0033] The method provided by the present invention solves the edge wavy of the L415M steel plate of the straight seam submerged arc welded pipe. In the absence of a pre-straightening machine, the method solves the edge wavy of the L415M steel plate of the straight seam submerged arc welded pipe through the existing plate production line. The method comprehensively considers the effects of the cooling bed and the double-sided shear of the plate production line, and directly lifts the L415M steel plate of the straight seam submerged arc welded pipe from the 1 / 3 to 2 / 3 position of the cooling bed to the conveying roller where the double-sided shear is located by a crane located between the cooling bed and the double-sided shear, and runs the crane at full speed. The conveying roller is used to reduce the temperature drop of the L415M steel plate of the straight seam submerged arc welded pipe, and then the double-sided shear is used to perform warm shearing on the L415M steel plate of the straight seam submerged arc welded pipe to reduce the edge unevenness (wave shape) of the steel plate from 9mm / m~16mm / m to below 4mm / m, which meets the quality inspection requirements of the L415M steel plate of the straight seam submerged arc welded pipe, and there is no need to add new equipment or heat treat the L415M steel plate of the straight seam submerged arc welded pipe. Under the premise of ensuring product quality, the production cost is greatly reduced.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for solving the wavy edge of L415M steel plate of straight seam submerged arc welded pipe, characterized in that: The following steps are involved: S1: Lift the L415M steel plate of the LSAW pipe running to the 1 / 3~2 / 3 position in the cooling bed directly to the conveyor roller where the double-sided shear is located by the crane to ensure that the surface temperature of the L415M steel plate of the LSAW pipe before the crane lifting is 100℃~200℃; S2: The conveying roller conveys the L415M steel plate of the LSAW pipe to the double-sided shear for warm shearing to eliminate the edge stress of the L415M steel plate of the LSAW pipe; In step S1, the crane lifts the L415M steel plate of the longitudinal submerged arc welded pipe at a position 1 / 3 of the running direction of the cooling bed; In step S2, the double-sided shearing width is 20 mm to 30 mm; In step S2, the conveyor roller runs at full speed to reduce the temperature drop of the L415M steel plate of the longitudinal submerged arc welded pipe.