JPH044973A - Powder gas cutting method and device for high alloy stainless steel - Google Patents

Abstract

PURPOSE:To perform gas cutting with satisfactory workability by simultaneously injecting mixed powder of iron powder with aluminum powder toward the cutting air flow from nozzles for adding powder provided before and behind in the cutting direction of a gas cutting torch. CONSTITUTION:The powder is supplied toward the cutting air flow 6 from the gas cutting torch 1 to cut the thick high alloy stainless steel. The nozzles 2A and 2B for adding the powder are then provided respectively before and behined in the cutting direction of the gas cutting torch 1. The mixed powder 5 produced by mixing the iron powder 3 with the aluminum powder 4 is injected simultaneously toward the cutting air flow 6 from the nozzles 2A and 2B for adding the powder before and behined. The mixed powder 6 is stored in a powder feeder 7 and supplied to the nozzles 2A and 2B for adding the powder from this feeder. Consequently, the thick high alloy stainless steel can be cut by increasing the cutting speed.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention is applied to gas cutting of steel materials that are thick, such as slabs and ingons, and require high reaction heat, such as high-alloy stainless steel needles. The present invention relates to a powder gas cutting method and an apparatus thereof.

<Prior art> In ordinary gas (oxygen) cutting, high-purity cutting oxygen is blown onto the cutting area heated by preheating flammable gas and preheating oxygen to oxidize and burn Fe in the mesh, and the oxygen This is done by blowing away molten iron oxide using the mechanical energy of a jet stream, but the mesh contains large amounts of alloying elements (Cr, Ni).
, Mo, etc.), impurities, etc.
The high melting point oxide formed by the combustion of these components is Fe.
This impedes the combustion of molten iron oxide and impairs the fluidity of molten iron oxide, making it difficult or impossible to proceed with cutting.

Therefore, as a method for cutting such difficult-to-cut metals, fine iron powder is supplied to the cutting oxygen stream and combusted, the heat generated melts the cutting material and the fluid iron oxide is supplied for cutting. A powder gas cutting method is generally used in which the cutting is progressed by cutting. Conventionally, the following powder gas cutting method has been proposed.

(i) "Stainless Steel Mesh Handbook" As shown in Figure 6, 150 to 300 meshes of fine iron powder is supplied into the cutting oxygen stream from the supply pipe P provided outside the cutting torch 1, or Method of supplying cutting oxygen in l.

Further, in order to increase the calorific value, iron powder mixed with about 25 to 40% of Aj2 powder may be used.

(ii) Japanese Unexamined Patent Publication No. 59-199170 Two wood powder adding nozzles are provided on the forward side of the cutting torch in the cutting direction, and the powder is jetted from these two nozzles so that extremely thick products can be cut. Also, if one nozzle, etc. breaks down, the other nozzle can be used.

In addition, the above-mentioned "Stainless steel mesh handbook" states that if the thickness of the plate becomes large or if the powder cannot be supplied satisfactorily, insert it into the cutting groove from the opposite side of the cutting direction, as shown in Figure 7. It is shown that the powder is supplied to the central part from the supplied supply pipe P'.

<Problems to be Solved by the Invention> In the case of the powder supply method (i) described above, the amount of powder supplied is insufficient, so it cannot be applied to thick high-alloy stainless steel mesh, and it is difficult to avoid a decrease in cutting speed. do not have.

In the case of 00, the amount of powder supplied can be increased by using two nozzles, but since the powder is only supplied from the forward side in the cutting direction, the powder is not supplied from the center to the bottom in the thickness direction. This is not sufficient, the cutting speed is reduced due to delayed cutting, and a sufficient cutting result cannot be obtained for thick high alloy stainless steel.

In the case of GiD, the supply of powder from the supply pipe installed outside is unstable and has poor workability, making it unsuitable for processing in large quantities such as continuous casting slabs.

This invention was made to solve the above-mentioned problems, and its purpose is to increase the cutting speed and gas cutting even when cutting thick high-alloy stainless steel, and to achieve an excellent cutting surface. It is an object of the present invention to provide a powder gas cutting method and an apparatus therefor, which can obtain the following properties, stably supply powder, and have good workability.

<Means for Solving the Problems> The powder gas cutting method according to the present invention is a method for gas cutting a thick high-alloy stainless steel by supplying powder toward a cutting airflow from a gas cutting torch. , as shown in FIGS. 1 and 2, powder adding nozzles 2A and 2B are provided at the front and rear of the gas cutting torch 1 in the cutting direction, respectively,
A mixed powder 5 in which iron powder 3 and aluminum powder 4 are mixed is simultaneously injected toward a cutting air stream 6 from front and rear powder addition nozzles 2A and 2B.

The powder gas cutting device according to the present invention is a device for gas cutting a thick high-alloy stainless steel by supplying powder toward a cutting airflow from a gas cutting torch, in which the cutting direction of the gas cutting torch 1 is Powder addition nozzles 2A are installed before and after the .

Equipped with 2B, mixed powder 5 is a mixture of iron powder 3 and aluminum powder 4.
is stored in a powder feeder 7, and the mixed powder 5 can be supplied from the powder feeder 7 to the powder addition nozzles 2A, 2B.

The powder addition nozzles 2A and 2B may be arranged one each at the front and rear, or may be arranged in plurality on one side or on both sides.

The present invention is applicable to high alloy stainless steel with a Ni addition amount of 225% as shown in Table 1.

Table 1 Main high-alloy stainless steels to which the present invention is applied (Function) Figures 3 and 4 are examples of application to slab S. In the conventional powder gas cutting method shown in Figure 3, the slab thickness Cutting occurs later than in the center, which causes a decrease in cutting speed.

In the present invention shown in FIG. 4, since the slab can be cut perpendicularly to the thickness direction, the cutting speed can be improved and the cut surface can be made beautiful. As shown in Fig. 5, the 0 part from the slab surface to the center of the plate thickness is gas-cut with powder sprayed from nozzle 2A, and the 0 part from the center of the plate thickness to the lower part is cut by the powder sprayed from nozzle 2B. This is because by using powder, heat generation in the lower part is promoted and the cutting delay is eliminated.

In addition, - By using a mixed powder of iron powder and aluminum powder used for boat fishing, it is possible to improve the cutting speed and the quality of the cut surface compared to cutting with only iron powder, and the quality is also better than the basic one. Workability is greatly improved.

Table 2 AI! , and the physical properties of Fe As shown in Table 2, Af has a high calorific value even at low temperatures (it is advantageous for powder cutting, and it is relatively easy to obtain in terms of cost.

Table 3 shows the optimum cutting speed when mixed powder is used in the conventional powder gas cutting method (single nozzle method).

Table 3 Saki type, powder mixing ratio, and optimal cutting speed (comparison) Supply steel slab thickness: 200II111 Simultaneous injection of powder by powder addition nozzles before and after the cutting torch as described above, and mixed powder of iron powder and aluminum powder By gas cutting, it is possible to improve the cutting speed and obtain a good cut surface even when using extremely thick high-alloy stainless steel with a Ni addition amount of 25% or more.

<Example> The present invention will be described below based on an illustrative example. As shown in Figure 1, the cutting torch l has a
Oxygen 9 for preheating and flammable gas 10 such as C gas can be supplied, and a powder addition nozzle 2A whose tip faces the cutting airflow 6 is provided before and after the cutting direction at the tip of the cutting torch 1. , 2B one by one.

A powder feeder 7 is connected to the powder addition nozzles 2A and 2B via a powder feeder pipe 8, and a mixed powder 5 in which iron powder 3 and aluminum powder 4 are mixed is stored in the powder feeder 7. At the same time, a carrier gas 11 such as air or nitrogen is supplied via a dryer 12,
The mixed powder 5 is fed under pressure to the powder addition nozzles 2A and 2B, and can be injected from the nozzles 2A and 2B.

Table 5 shows the results of powder gas cutting performed using the sample steels and cutting conditions shown in Table 4.

According to the present invention, it is possible to gas-cut an Inconel plate approximately twice as thick as the single-nozzle method using mixed powder at twice the cutting speed. Moreover, the cut surface is also extremely good.

<Effects of the Invention> As mentioned above, the present invention simultaneously injects powder into the cutting air stream from the powder addition nozzles arranged before and after the cutting direction of a gas cutting torch, and adds a mixed powder of iron powder and aluminum powder to the powder. By using this method, even thick high-alloy stainless steel can be gas-cut by increasing the cutting speed, and an excellent cut surface can be obtained. In addition, powder can be stably supplied and gas cutting can be performed with good workability.

[Brief explanation of the drawing]

1 and 2 are an overall schematic diagram and a partially enlarged view showing a cutting device according to the present invention, FIG. 3 is a schematic diagram showing a cutting situation according to a conventional cutting method, and FIG. 4 is a cutting situation according to the present invention. 5 is an explanatory diagram showing the function of the nozzle in the present invention. FIG. 6 is a sectional view showing a conventional general powder gas cutting torch. FIG. 7 is a diagram showing a conventional cutting device for extremely thick materials. FIG.

Claims (2)

[Claims] (1) In a method of gas cutting large-thick high-alloy stainless steel by supplying powder to the cutting airflow from a gas cutting torch, powder adding nozzles are installed at the front and rear of the cutting direction of the gas cutting torch. A powder gas cutting method for high-alloy stainless steel, characterized in that a mixed powder of iron powder and aluminum powder is simultaneously injected toward the cutting air stream from the front and rear powder addition nozzles. (2) In a device for gas cutting large-thick high-alloy stainless steel by supplying powder to the cutting airflow from a gas cutting torch, there are powder adding nozzles at the front and rear of the cutting direction of the gas cutting torch. A high alloy characterized in that a mixed powder of iron powder and aluminum powder is stored in a powder feeder, and the mixed powder can be supplied from the powder feeder to the front and rear powder addition nozzles. Stainless steel powder gas cutting equipment.