JP2024069994A - Steel cutting device and method - Google Patents

Abstract

[Problem] Steel material in a hot working process is gas cut using hydrogen gas as fuel gas. [Solution] A steel cutting device 1 has a fuel gas supply source including a hydrogen gas supply source, an oxygen gas supply source, and a blowpipe 2 that supplies fuel gas supplied from the fuel gas supply source and oxygen gas supplied from the oxygen gas supply source to a nozzle 2a provided at the tip, forms a flame 102 with the fuel gas and oxygen gas ejected from the nozzle 2a into the atmosphere to preheat a steel material 101 in a hot working process, blows oxygen gas from the nozzle 2a toward the surface of the preheated steel material 101 so that the steel material 101 melts and penetrates due to heat generated by an oxidation reaction, and a drive device that moves the blowpipe 2 that blows oxygen gas from the nozzle 2a across the surface of the steel material 101 so that a melted portion is formed across the steel material 101 so as to penetrate the steel material 101 and cut the steel material 101. [Selected Figure] Figure 1

Description

Application for application of Article 30, Paragraph 2 of the Patent Act has been filed (1) On November 10, 2021, Mitsubishi Steel Corporation published the steel cutting device and method invented by Takayuki Toyoshima and Hikaru Matsudaira on the Mitsubishi Steel Corporation news release website, which is available at the following address: https://www.mitsubishisteel.co.jp/ https://www.mitsubishisteel.co.jp/news/2021.html https://www.mitsubishisteel.co.jp/news/pdf/20211110_2. pdf (2) On November 10, 2021, the Japan Business Federation (Keidanren) published the steel cutting device and method invented by Toyoshima Takayuki and Matsudaira Hikaru on the Innovation Cases website of the Challenge Zero website, which is available at the following addresses: Japanese version: https://www.challenge-zero.jp/jp/ https://www.challenge-zero.jp/jp/casestudy/ https://www.challenge-zero.jp/jp/casestudy/808 English version: https://www.challenge-zero.jp/en/ https://www.challenge-zero.jp/en/ jp/en/casestudy/ https://www.challenge-zero.jp/en/casestudy/810 (3) On November 11, 2021, Sangyo Shimbun Co., Ltd. published an article on the second page of the Nikkan Sangyo Shimbun regarding the steel cutting device and method invented by Toyoshima Takayuki and Matsudaira Hikaru. (4) On December 20, 2021, Sangyo Shimbun Co., Ltd. published an article on the WEB Nikkan Sangyo Shimbun website at the following address regarding the steel cutting device and method invented by Toyoshima Takayuki and Matsudaira Hikaru. https://www.japanmetal.com/ https://www.japanmetal.com/news-to20211220113515.html

(5) On May 19, 2022, Mitsubishi Steel Corporation disclosed the steel cutting device and method invented by Takayuki Toyoshima and Hikaru Matsudaira on the Mitsubishi Steel Corporation shareholder and investor information website at the following address: https://www.mitsubishisteel.co.jp/ https://www.mitsubishisteel.co.jp/ir/ https://www.mitsubishisteel.co.jp/ir/presentation/pdf/20220520. pdf (6) On May 26, 2022, Sangyo Shimbun Co., Ltd. published the steel cutting device and method invented by Toyoshima Takayuki and Matsudaira Hikaru on the website of the WEB Nikkan Sangyo Shimbun, which is available at the following address: https://www.japanmetal.com/ https://www.japanmetal.com/news-to20220526118102.html (7) On June 22, 2022, Mitsubishi Steel Corporation published the steel cutting device and method invented by Toyoshima Takayuki and Matsudaira Hikaru on the Mitsubishi Steel Corporation News Release website, which is available at the following address: https://www.mitsubishisteel.co.jp/ https://www. mitsubishisteel.co.jp/news/2022.html https://www.mitsubishisteel.co.jp/news/pdf/20220622.pdf (8) On September 13, 2022, Mitsubishi Steel Corporation published an article on the front page of the Nikkan Sangyo Shimbun about a steel cutting device and method invented by Takayuki Toyoshima and Hikaru Matsudaira.

This invention relates to a steel cutting device and method for cutting steel by gas cutting, and more specifically to a steel cutting device and method for cutting steel in a hot working process.

Conventionally, steel cutting devices that cut steel materials by gas cutting have been widely used. A gas cutting steel cutting device preheats the position where cutting of the steel material starts by blowing a flame formed from fuel gas and oxygen gas onto the steel material, and then blows oxygen gas onto the preheated position, melting the steel material with the heat generated by the oxidation reaction, thereby cutting the steel material.

Hydrocarbon gases such as LP gas are used as fuel gas for such steel cutting equipment, but Patent Documents 1 and 2 disclose technology for mixing hydrogen gas with hydrocarbon gas to create fuel gas. Patent Document 1 is for gas cutting workpieces such as steel, and Patent Document 2 provides a portable gas cutting machine for cutting steel pieces, and in both Patent Documents 1 and 2, the gas cutting is used cold.

In recent years, efforts to reduce _CO2 emissions in the manufacturing industry have been underway to realize a carbon-neutral, decarbonized society. From this perspective, research is being conducted into technologies to replace the fuel gas used in the manufacturing industry, which is a hydrocarbon gas that emits _CO2 when burned, with hydrogen gas, which does not emit _CO2 .

JP 2018-34191 A JP 2018-167299 A

In the steel industry, research is being conducted into technology to replace the fuel gas used in hot processing processes such as continuous casting with hydrogen gas instead of hydrocarbon gas. However, no technology has been provided to replace the fuel gas used in gas cutting of steel in hot processing processes with hydrogen gas.

This invention has been proposed in light of the above-mentioned circumstances, and aims to provide a steel cutting device and method that uses hydrogen gas as the fuel gas to gas-cut steel during hot processing.

In order to solve the above problems, the steel cutting device of the present invention cuts steel, includes a hydrogen gas supply source, a fuel gas supply source that supplies hydrogen gas supplied from the hydrogen gas supply source as fuel gas, an oxygen gas supply source that supplies oxygen gas, a blowpipe that supplies the fuel gas supplied from the fuel gas supply source and the oxygen gas supplied from the oxygen gas supply source to a nozzle provided at the tip, preheats the steel in the hot working process with a flame formed by the fuel gas and oxygen gas ejected from the nozzle, blows oxygen gas from the nozzle toward the surface of the preheated steel so that the steel melts and penetrates due to heat generated by an oxidation reaction, and a drive device that moves the blowpipe that blows oxygen gas from the nozzle across the surface of the steel so that the molten portion is formed across the steel to penetrate the steel and cut the steel.

The fuel gas supply source may further include a hydrocarbon gas supply source that supplies a hydrocarbon gas, and may supply a fuel gas obtained by mixing hydrogen gas supplied from the hydrogen gas supply source with hydrocarbon gas supplied from the hydrocarbon gas supply source. The hydrocarbon gas supply source may supply LP gas. The fuel gas supply source may mix the hydrogen gas with the hydrocarbon gas so that the hydrogen gas is contained in the fuel gas at a mass ratio of 10% or more.

The blowpipe tip may face the surface of the steel material with a gap ranging from 90mm to 180mm. It may be possible to cut steel material having a thickness of 130mm to 600mm in the direction in which the oxygen gas extends from the blowpipe tip.

It may be included in a series of devices that make up the continuous casting process. In the continuous casting process, the cast piece may be cut and processed into a slab or bloom. In the continuous casting process, the slab or bloom may be cut.

The steel cutting method according to this application cuts steel and includes the steps of providing steel undergoing a hot processing process, supplying hydrogen gas from a hydrogen gas supply source as fuel gas, ejecting the fuel gas and oxygen gas from a nozzle at the tip of the blowpipe into the atmosphere to form a flame, positioning the blowpipe facing the surface of the steel so that the flame extending from the nozzle of the blowpipe preheats the steel, blowing oxygen gas from the nozzle of the blowpipe toward the surface of the preheated steel so that the steel melts and penetrates due to heat generated by an oxidation reaction, and moving the blowpipe, which blows oxygen gas from the nozzle, across the surface of the steel so that a molten portion is formed across the steel to penetrate the steel and cut the steel.

The step of supplying the fuel gas may include mixing hydrogen gas with a hydrocarbon gas to provide the fuel gas. The hydrocarbon gas may be LP gas. The fuel gas may contain 10% or more hydrogen gas by mass.

The blowpipe tip may be positioned to face the surface of the steel material with a gap ranging from 90mm to 180mm. It may be possible to cut steel material having a thickness of 130mm to 600mm in the direction in which the oxygen gas extends from the blowpipe tip.

According to this invention, the steel material in the hot working process can be preheated using hydrogen gas as the fuel gas to perform gas cutting, thereby reducing the amount of _CO2 emissions generated by gas cutting of the steel material.

FIG. 1 is a diagram showing a schematic configuration of a steel material cutting device. FIG. 2 is a cross-sectional view of the nozzle of a blowpipe of a steel cutting device. 1 is a flowchart showing a series of steps of a steel material cutting method. FIG. 2 is a side view showing a mode of use of the steel cutting device. FIG. 2 is a side view showing a continuous casting process including a steel material cutting device. Photographs illustrating gas cutting of steel. 1 is a photograph showing a steel material cut in Example 1. 1 is a photograph showing a steel material cut in Example 2. 1 is a photograph showing a steel material cut in a comparative example.

The following describes in detail an embodiment of a steel cutting device and method with reference to the drawings. Figure 1 is a diagram showing the general configuration of a steel cutting device 1. The steel cutting device 1 of this embodiment is installed and used in a hot processing process such as a continuous casting process.

The steel cutting device 1 has a blowpipe 2 that ejects fuel gas and oxygen gas from the nozzle 2a at the tip into the atmosphere to form a flame 102, a fuel gas supply source (not shown) that supplies fuel gas to the blowpipe 2, and an oxygen gas supply source that supplies oxygen gas to the blowpipe 2. The fuel gas supply sources include a hydrogen gas supply source and an LP gas supply source (not shown). The respective gas supply sources may be tanks or cylinders that store gas, or may be supplied via a pipeline. The hydrogen gas and oxygen gas supply sources may also be hydrogen gas and oxygen gas manufacturing facilities.

Hydrogen gas is sent from the hydrogen gas supply source through the hydrogen gas flow path 5 to the blowpipe 2, and the pressure and flow rate of the hydrogen gas are set by the hydrogen gas valve 5a. LP gas is sent from the LP gas supply source through the LP gas flow path 6 to the blowpipe 2, and the pressure and flow rate of the LP gas are set by the LP gas valve 6a. LP gas is a liquefied petroleum whose main components are propane and butane. Oxygen gas is sent from the oxygen gas supply source through the oxygen gas flow path 4 to the blowpipe 2, and the pressure and flow rate of the oxygen gas are set by the oxygen gas valve 4a.

The hydrogen gas flow path 5 and the LP gas flow path 6 leading to the blowpipe 2 merge to form the fuel gas flow path 3, where the hydrogen gas and the LP gas are mixed to become fuel gas and supplied to the blowpipe 2. The fuel gas may consist of only hydrogen gas. In this case, the LP gas valve 6a of the LP gas flow path 6 is closed. When the fuel gas is obtained by mixing hydrogen gas and LP gas, the concentration of hydrogen gas may be 10% or more, 20% or more, or 50% or more.

Figure 2 is a cross-sectional view of the nozzle 2a of the blowpipe 2. This cross-sectional view shows the nozzle 2a cut on a plane including an axis along which the flame 102 extends from the nozzle 2a of the blowpipe 2. The nozzle 2a is provided at the tip of the blowpipe 2, and fuel gas and oxygen gas are supplied from the blowpipe 2. The tip of the nozzle 2a protrudes from the blowpipe 2, and has a first nozzle 2c formed in the center of the surface facing the steel material 101 at the tip for spraying oxygen gas for cutting the steel material 101, and a second nozzle 2d formed around the first nozzle 2c for spraying a mixture of fuel gas and oxygen gas to form the flame 102 for preheating.

In the nozzle 2a, oxygen is sent from the first oxygen gas shunt 4b branched from the oxygen gas flow path 4 to the flow path forming the first ejection hole 2c. The pressure and flow path of the oxygen sent to the first oxygen gas shunt 4b are set by the first oxygen gas shunt valve 4d provided in the first oxygen gas shunt 4b. In addition, fuel gas is sent from the fuel gas flow path 3 to the flow path forming the second ejection hole 2d, and oxygen gas is sent from the second oxygen gas shunt 4c branched from the oxygen gas flow path 4. The pressure and flow path of the oxygen sent to the second oxygen gas shunt 4c are set by the second oxygen gas shunt valve 4e provided in the second oxygen gas shunt 4c. As described later, the oxygen sent to the first oxygen gas shunt 4b is used to cut the steel material 101, and the oxygen sent to the second oxygen gas shunt 4c is used to preheat the steel material 101, so they may be referred to as cutting oxygen gas and preheating oxygen gas, respectively, below.

Referring again to FIG. 1, the steel cutting device 1 has a blowpipe 2 positioned opposite the surface of the steel material 101 so that the flame 102 extending from the nozzle 2a of the blowpipe 2 preheats the steel material 101 at the position where cutting of the steel material 101 is to begin, and a drive device (not shown) that moves the blowpipe 2 in a direction across the steel material 101 so that the steel material 101 is penetrated by heat generated by an oxidation reaction caused by oxygen gas blown from the nozzle 2a of the blowpipe 2 toward the preheated steel material 101, forming a molten portion across the steel material 101 to cut the steel material 101. Furthermore, the steel cutting device has rolls (not shown) that receive the steel material 101 sent from an upstream process in the hot processing process, support it during gas cutting, and send the gas-cut steel material 101 to a downstream process.

Figure 3 is a flow chart showing a series of steps in the steel cutting method. In the first step S1, steel 101 is provided to the steel cutting device 1 from an upstream hot processing process. The steel 101 is transported from upstream by rolls, and the steel 101 received by the steel cutting device 1 is supported at a predetermined position by the rolls provided in the steel cutting device 1.

In step S2, a mixture of fuel gas and oxygen gas is ejected from the nozzle 2a of the blowpipe 2 to form a flame 102. The mixture of fuel gas and oxygen gas ejected from the second nozzle 2d of the blowpipe 2 forms a flame 102 extending from the nozzle 2a in the axial direction of the blowpipe 2.

In step S3, the blowpipe 2 is positioned by a drive device so that the flame 102 extending from the nozzle 2a of the blowpipe 2 preheats the position on the steel material 101 where cutting will begin. The steel material 101 has a temperature of several hundred degrees because it is in a hot working process, but the position on the steel material 101 where cutting will be performed is further heated by the flame 102 to a temperature of about one thousand degrees so that cutting becomes possible.

In step S4, oxygen gas is sprayed from the nozzle 2a of the blowpipe 2 toward the surface of the steel material 101 at the position where cutting of the preheated steel material 101 begins, and the steel material 101 melts as it is penetrated by heat generated by an oxidation reaction. Oxygen gas is sprayed from the first nozzle 2c of the blowpipe 2's nozzle 2a toward the surface of the steel material 101. Since the steel material 101 has reached a predetermined temperature by the preheating in step S3, when oxygen gas is sprayed from the nozzle 2a of the blowpipe 2 toward the steel material 101, the steel material 101 undergoes a vigorous oxidation reaction, generates heat, and melts. According to the oxygen gas sprayed from the nozzle 2a of the blowpipe 2, the position where the steel material 101 melts advances gradually in the depth direction from the surface while removing the steel material 101 by the reaction, and continues until it reaches the back surface of the steel material 101 and the steel material 101 is penetrated by the molten part.

In step S5, the molten portion formed by the oxygen gas in step S4 is formed to penetrate the steel material 101 and cut the steel material 101. For this purpose, the blowpipe 2 is moved across the steel material 101 by the driving device. As in step S4, oxygen gas is blown onto the surface of the steel material 101 from the first nozzle 2c of the nozzle 2a of the blowpipe 2, the steel material 101 melts due to heat generated by an oxidation reaction with the oxygen gas, and the molten portion that penetrates the steel material 101 expands in the lateral direction while removing the steel material 101. The steel material 101 is cut by forming such a molten portion across the steel material 101. After cutting the steel material 101, it is sent to the downstream process by rolls.

Figure 4 is a side view illustrating the manner of use of the steel cutting device 1. In the figure, the steel 101 is supported by the rolls 20 of the steel cutting device 1. The steel 101 that can be cut by the steel cutting device 1 may be in the range of 70 mm to 500 mm, 100 mm to 550 mm, or 130 mm to 600 mm in the thickness T direction or depth direction of the steel 101 where the oxygen gas extends from the blowpipe 2. In this embodiment, by using hydrogen gas as the fuel gas, it is possible to cut steel 101 of such a thickness T.

The size D of the gap formed between the surface of the steel material 101 and the blowpipe 2 may be in the range of 80 mm to 190 mm, 90 mm to 180 mm, or 100 mm to 170 mm. The size D of the gap refers to the distance between the nozzle 2a protruding from the tip of the blowpipe 2 and the surface of the steel material 101. In this embodiment, by ensuring such a size D of the gap, overheating of the blowpipe 2 and the nozzle 2a is prevented.

Figure 5 is a side view showing a continuous casting process 10 including a steel cutting device 1. Figure 5 shows an example of using the steel cutting device 1 to cut steel 101 in a hot working process. The steel cutting device 1 is installed as one of a series of devices that make up the continuous casting process 10.

In the continuous casting process 10, molten steel poured into a ladle 11 is formed into a predetermined cross section through a tundish 12 and a mold 13, and is supported by support rolls 14 while being cooled and lowered, and the internal quality is improved by reduction with light reduction rolls 15, and the resulting product is a cast piece 103. This cast piece 103 is cut by a primary cutter 16 and processed into a slab or bloom 104 of a predetermined size, transported downstream by rolls 20, weighed by a weighing machine 17, deburred by a deburring device 18, and further cut by a secondary cutter 19.

The steel cutting device 1 can be used for the primary cutter 16 and the secondary cutter 19. When the steel cutting device 1 is used for the primary cutter 16, a cast piece 103 is fed to the steel cutting device 1 from the upstream light reduction roll 15. The steel cutting device 1 cuts the cast piece 103 and processes it into a slab or bloom 104 of a predetermined size. When the steel cutting device 1 is used for the secondary cutter 19, the steel cutting device 1 is fed with a slab or bloom 104 that has been deburred by the upstream deburring device 18. The steel cutting device 1 further cuts the slab or bloom 104. For example, the cutting may be a cropping process in which the end of the slab or bloom is cut so that the slab or bloom 104 has a predetermined size, or a cut for sample collection.

As described above, according to the steel cutting device 1 and method of the present embodiment, hydrogen gas can be used for gas cutting of the steel 101 in the hot working process. Therefore, the amount of hydrocarbon gas used for gas cutting can be reduced, and _CO2 emissions can be reduced.

In addition, when hydrogen gas is used as the fuel gas, the flame 102 formed by combustion reaches a higher combustion temperature than when only hydrocarbons are used as the fuel gas. Therefore, by using hydrogen gas as the fuel gas, the cut surface of the steel material 101 is clean, and a smooth cut surface with fewer notches can be obtained. In addition, the time required to preheat the steel material 101 is shortened, improving the efficiency of the process of gas cutting the steel material 101.

In this embodiment, LP gas is used as the fuel gas, but the fuel gas is not limited to LP gas, and other types of hydrocarbon gases such as natural gas may be used. Also, if only hydrogen gas is used as the fuel gas, it is not necessary to provide an LP gas supply source as the fuel gas supply source.

In this embodiment, a flame is formed by ejecting a mixture of fuel gas and oxygen gas from the second nozzle 2d of the nozzle 2a shown in FIG. 2, but the fuel gas and oxygen gas may be ejected from separate nozzles and mixed outside the nozzle 2a to form a flame. In this case, the preheating oxygen gas and cutting oxygen gas may be ejected from the same nozzle of the nozzle 2a.

In this embodiment, the continuous casting process 10 is shown as an example of a hot processing process in which the steel cutting device 1 is used, but the hot processing processes in which the steel cutting device 1 can be used are not limited to this. For example, the steel cutting device 1 can also be used in a hot rolling process in which steel is preheated in a preheating furnace and processed.

Below, examples in which the steel cutting device 1 and method of this embodiment are applied will be described. In Example 1, hydrogen gas was used as the fuel gas for the steel cutting device 1. The conditions and results of Example 1 are shown in Tables 1 and 2. Note that Tables 1 and 2 also include Example 2 and a comparative example, which will be described later.

In Example 1, assuming steel material 101 in a hot working process, a cast piece of ordinary steel (S55C) was prepared as shown in Table 1. Table 1 shows the temperatures measured at the center and end of the cast piece. Using the steel cutting device 1 of this embodiment, cutting oxygen gas, preheating oxygen gas, and hydrogen gas as fuel gas were supplied under the conditions shown in Table 1 to process the steel material 101. As described above, the cutting oxygen gas is ejected from the first ejection hole 2c of the nozzle 2a and used to cut the steel material 101, and the preheating oxygen gas is mixed with the hydrogen gas as fuel gas and ejected from the second ejection hole 2d of the nozzle 2a to form a flame 102 and used to preheat the steel material 101.

Figure 6 is a photograph illustrating gas cutting of steel material 101. Figure 6(a) is a photograph showing the cutting of steel material 101 in Example 1. The blowpipe 2 is located in the center of the photograph, and it can be seen that the edge of the steel material 101 where cutting begins on the surface of the steel material 101 is shining due to preheating, but the flame 102 extending from the blowpipe 2 to the steel material 101 is not clearly observed. Figure 6(b) is a photograph showing the cutting of steel material 101 when a mixture of hydrogen gas and LP gas is used as the fuel gas for comparison. Because the fuel gas contains LP gas, the flame 102 extending from the blowpipe 2 can be clearly observed.

When only hydrogen gas is used as the fuel gas, the flame 102 cannot be clearly observed, so a hydrocarbon gas such as LP gas may be added to the fuel gas so that the flame 102 can be clearly observed. The amount of hydrocarbon gas added may be in the range of 3 mass% to 20 mass%, 5 mass% to 15 mass%, or 7 mass% to 13 mass%. By being able to clearly observe the flame 102, it is possible to confirm the cutting position of the steel material 101, etc.

Figure 7 is a photograph showing the steel material 101 processed in Example 1. Figures 7(a) to 7(c) are photographs taken from different angles of the steel material 101, where processing was stopped when the steel material 101 was cut to 470 mm because the supply of hydrogen gas from the hydrogen gas source ran out. Figure 7(d) is a photograph of the steel material 101 being processed, taken with a thermograph. It can be observed that the position of the steel material 101 that is preheated by the flame 102 has reached 1250°C.

In the processing of Example 1 as shown in Figure 7, the results shown in Table 2 were obtained. As shown in Table 2, it became clear that cutting and cutting into the steel material 101 was possible at a specified speed even when only hydrogen gas was used as the fuel gas. However, the cutting process was stopped because the supply from the hydrogen gas source ran out.

Inscribing refers to a process in which oxygen gas reacts with the steel material 101 to melt and remove the steel material 101 while proceeding in the thickness direction or depth direction of the steel material 101, and cutting refers to a process in which the melted portion penetrates the steel material 101 from the front side to the back side by oxygen gas and melts and removes the steel material 101 while proceeding in the transverse direction or width direction of the steel material 101. Separation refers to a cutting process in which the flame 102 completely crosses the steel material 101 from one edge to the other edge, and the steel material 101 is separated into two by the cross section formed by the melting.

In Example 2, hydrogen gas was used as the fuel gas for the steel cutting device 1. The conditions and results of Example 2 are shown in Tables 1 and 2. In Example 2, assuming steel 101 in a hot working process, a slab of steel type (S55C) was prepared as shown in Table 1. Table 1 shows the temperatures measured at the center and ends of the slab. Using the steel cutting device 1 of this embodiment, cutting oxygen gas, preheating oxygen gas, and hydrogen gas as fuel gas were supplied under the conditions shown in Table 1 to process steel 101.

Figure 8 is a photograph showing the steel material 101 processed in Example 2. Figures 8(a) to 8(c) are photographs of the cut steel material 101 taken from different angles. In the processing of Example 2 as shown in Figure 8, the results shown in Table 2 were obtained. As shown in Table 2, it was revealed that cutting, cutting and cutting into the steel material 101 are possible at a specified speed even when only hydrogen gas is used as the fuel gas.

Comparative Example
In the comparative example, a cold steel material 101 is cut using the steel cutting device 1 of the present embodiment. The steel material 101 was processed under the same conditions as in Examples 1 and 2, for example, using only hydrogen gas as the fuel gas, except for using a steel type (SMn438) for the steel material 101.

In the processing of the comparative example, the results shown in Table 2 were obtained. As shown in Table 2, it became clear that even if only hydrogen gas was used as the fuel gas, it was possible to perform the processing of cutting and cutting cold steel material 101 at a specified speed. However, the cutting process was stopped because the supply from the hydrogen gas source ran out.

This invention can be used in the production of hot-rolled steel.

REFERENCE SIGNS LIST 1 Steel cutting device 2 Blowpipe 2a Burner 3 Fuel gas passage 4 Oxygen gas passage 5 Hydrogen gas passage 6 LP gas passage 10 Continuous casting process 16 Primary cutter 19 Secondary cutter 101 Steel 102 Flame 103 Cast piece 104 Slab, bloom

Claims (15)

A steel cutting device for cutting steel materials,
a fuel gas supply source including a hydrogen gas supply source and supplying the hydrogen gas supplied from the hydrogen gas supply source as a fuel gas;
an oxygen gas supply source for supplying oxygen gas;
a blowpipe which supplies fuel gas supplied from the fuel gas supply source and oxygen gas supplied from the oxygen gas supply source to a nozzle provided at a tip, preheats steel in a hot working process with a flame formed by the fuel gas and oxygen gas ejected from the nozzle, and blows oxygen gas from the nozzle toward a surface of the preheated steel so that the steel melts and penetrates due to heat generated by an oxidation reaction;
and a drive device that moves the blowpipe, which blows oxygen gas from the nozzle, across the surface of the steel material so that a molten portion is formed across the steel material so as to penetrate the steel material and cut the steel material. The steel cutting device according to claim 1, wherein the fuel gas supply source further includes a hydrocarbon gas supply source that supplies a hydrocarbon gas, and supplies a fuel gas in which the hydrogen gas supplied from the hydrogen gas supply source is mixed with the hydrocarbon gas supplied from the hydrocarbon gas supply source. The steel cutting device according to claim 2, wherein the hydrocarbon gas supply source supplies LP gas. The steel cutting device according to claim 2, wherein the fuel gas supply source mixes hydrogen gas with hydrocarbon gas so that the fuel gas contains hydrogen gas at a mass ratio of 10% or more. A steel cutting device according to any one of claims 1 to 4, wherein the nozzle of the blowpipe faces the surface of the steel material with a gap ranging from 90 mm to 180 mm. A steel cutting device according to any one of claims 1 to 4, capable of cutting steel having a thickness of 130 mm to 600 mm in the direction in which oxygen gas extends from the nozzle of the blowpipe. A steel cutting device according to any one of claims 1 to 4, which is included in a series of devices that constitute a continuous casting process. A steel cutting device according to any one of claims 1 to 4, which cuts a cast piece during a continuous casting process and processes it into a slab or bloom. A steel cutting device according to any one of claims 1 to 4, which cuts slabs or blooms during a continuous casting process. A steel cutting method for cutting a steel material, comprising the steps of:
Providing a steel product undergoing a hot working process;
supplying hydrogen gas supplied from a hydrogen gas supply source as a fuel gas;
a step of ejecting the supplied fuel gas and oxygen gas into the atmosphere from a nozzle provided at the tip of the blowpipe to form a flame;
placing the blowpipe facing a surface of the steel material so that a flame extending from a nozzle of the blowpipe preheats the steel material;
a step of blowing oxygen gas from the nozzle of the blowpipe toward the surface of the preheated steel material so that the steel material melts and penetrates due to heat generated by an oxidation reaction;
and moving a blowpipe that blows oxygen gas from the nozzle across the surface of the steel material so that a molten portion is formed across the steel material so that the steel material is penetrated by the oxygen gas directed from the blowpipe toward the steel material, thereby cutting the steel material. The steel cutting method according to claim 10, wherein the fuel gas supplying step comprises mixing hydrogen gas with a hydrocarbon gas to provide the fuel gas. The steel cutting method according to claim 11, wherein the hydrocarbon gas is LP gas. The steel cutting method according to claim 11, wherein the fuel gas contains at least 10% hydrogen gas by mass. A steel cutting method according to any one of claims 10 to 12, in which the nozzle of the blowpipe is installed so as to face the surface of the steel material with a gap ranging from 90 mm to 180 mm therebetween. A steel cutting method according to any one of claims 10 to 12, which enables cutting of steel having a thickness of 130 mm to 600 mm in the direction in which oxygen gas extends from the nozzle of the blowpipe.

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