JPH0613142B2 - Gas welding equipment - Google Patents

Description

Detailed Description of the Invention a. TECHNICAL FIELD The present invention relates to a gas welding apparatus, and more particularly to a gas welding apparatus used in a gas welding (or pressure welding) method using oxygen-acetylene gas.

B. 2. Description of the Related Art In this type of gas welding method, a pair of rebars and other objects to be welded are joined to each other, and a nozzle for jetting a mixed gas of acetylene and oxygen is provided around the joined portion (welded portion). It is generally practiced to dispose and spray the mixed gas from the nozzle onto the welded part.

FIG. 15 and FIG. 16 are partial plan views of the nozzle of the gas welding apparatus used for the above welding and its surroundings.
Branch pipe 71, 72 or 81 that branches from the tip of the
In 82, a plurality of nozzles 73 are symmetrically arranged toward the center Q, and mixed gas is blown from the nozzles 73 to heat a welded part (not shown).

FIG. 17 shows a method of butt-welding a pair of reinforcing bars by using the gas welding apparatus of FIG. 15 or FIG. V-shaped notch 3 at the abutting portion of the reinforcing bars 19a, 19b
3 is formed, the flame 32 of the mixed gas from the nozzle 73 is ejected toward the abutting portion while pressing the reinforcing bars 19a and 19b against each other as shown by arrows P and P by a hydraulic device (not shown). And rebar 19a, 19
Weld b together. The notch 33 is formed by the reinforcing bars 19a, 19
It is provided so that not only the surface layer of b but also the central portion of these can be surely welded.

In the gas welding in which welding is performed while applying the pressing forces P and P as described above, welding is performed while moving the flame focal point from the abutting portion of the reinforcing bars 19a and 19b to the left and right in the axial direction of these. This moving distance 1 is, for example, about 3 to 5 mm for a reinforcing bar having a diameter of 25 mm or less.

If the heating temperature of the welded part is too high, oxidation of the welded part progresses when the flame focal point moves, and impurities such as water and acetone are generated from the acetylene gas of the fuel, and these are taken into the welded part. The welded part becomes brittle, which is very inconvenient. The reason why welding is performed while moving the flame focal point to the left and right as described above is to prevent such impurities from entering the welded portion.

After welding, as shown in FIG. 18, pressing protrusions P, P form annular projections (called bumps) 35 at the welding points. The work tends to concentrate the flame on the welded portion until the annular projection 35 is formed and move the flame focus left and right after the annular projection 35 is formed. In such work, the temperature of the welded part rises too much and the above-mentioned impurities infiltrate into the welded part and oxidize the welded part,
On the contrary, the strength of the welded part is reduced.

In addition, welding of rebar is often performed outdoors, and in addition, it is often performed in high places and in strong winds. If it is not good, the strength of the welded part is not reliable. For example, the annular protrusion 35 should be formed around the welded portion, but sometimes the annular protrusion 35 is formed deviating from the welded portion 20 shown by the broken line in FIG. Called roasting). Needless to say, the strength of the welded portion is insufficient in such welding.

C. OBJECT OF THE INVENTION The present invention has been made in view of the above circumstances,
Impurities generated from fuel gas do not enter the welded part, oxidation of the welded part does not proceed, high reproducibility even if the working environment changes, and reliable welding can be performed with high reliability. The purpose is to provide a device.

D. According to the present invention, when a pair of rod-shaped objects to be gas-welded are brought into contact with each other at these welded portions and a mixed gas of a fuel gas and an oxidizing gas is attached, The rod-shaped objects are pressed against each other in the axial direction, and the relative positions of the welded portion and the spouted portion of the mixed gas are substantially fixed, and are configured to perform gas welding, and intersect the axial direction. Along the entire circumference of the welded portion that is formed in a direction, a plurality of mixed gas ejection portions (for example, FIG. 1 to FIG.
Nozzles 13, 14, 15, 16 described later shown in FIG. 7 and a portion of a set of adjacent jet outlets 51 and 52 shown in FIGS. 10 to 12 are provided as a unit at a substantially equal angle in a radial pattern. Are present at both sides of the welded portion in the axial direction, and the pair of rod-shaped objects (for example, a reinforcing bar 19a described later,
19b) a plurality of ejection ports (for example, 29 described later) for simultaneously spraying the mixed gas (29 described below) to the respective outer peripheral surfaces facing the opposite end surfaces (for example, the surface of the later-described welded portion 20 shown in FIG. 6). For example, mixed gas jet ports 21, 22; 23, 2 described later
4; 25,26; 27,28; 51,52) is provided in each of the plurality of mixed gas jetting parts.

E. Examples Hereinafter, examples of the present invention will be described.

First, with reference to FIG. 1, the overall configuration of the gas welding apparatus according to the present embodiment will be described. This device is composed of a blow tube section 1 and a nozzle section (or a burner section) 2. An oxygen gas introduction tube 3 and an acetylene gas introduction tube 4 are provided at the tip of the blow tube section 1, and each gas from these introduction tubes is provided. Are mixed with each other in the merging pipe portion 5 via the grip portion 7 and guided from the blow pipe 6 to the nozzle portion 2. In the figure, 8 is an acetylene gas control valve (nut), 9 is an oxygen gas control valve (nut), 1
0 is a control valve (nut) for oxygen-acetylene mixed gas
Both are configured as known screw-in valves. The mixed gas blowing pipe 6 is further branched into U-shaped branch pipes 11 and 12 of the nozzle portion 2 and communicated with nozzles 13 and 14 and 15 and 16 respectively integrated with the branch pipes.

Here, it is important that the nozzle portion 2 is configured as shown in FIGS. First, the nozzles 13 to 16 are welded parts 2 of an object 19 (for example, a reinforcing bar) to be welded.
0 is arranged radially symmetrically in the radial direction,
At each tip, mixed gas jet ports 21 and 22, 23 and 24, 25 and 26 and 2 along the circumferential direction of the welded part 20 are provided.
7 and 28 are respectively formed on the upper and lower sides in the drawing. The mixed gas 29 from each of these jet ports is evenly sprayed onto the welded portion 20 at eight locations, so that heating by the gas flame can be performed uniformly. In addition, at the time of gas welding, the target object 19 is placed at the intersection Q of the central axes of the nozzles 13 to 16.
It is preferable to arrange each nozzle so that the center of the nozzle is located, and to determine each positional relationship so that a perpendicular line from the center and an extension line of the blow tube 6 intersect each other at right angles. That is, it is possible to ensure that the distribution of the mixed gas during welding is uniform. In addition to the above nozzle arrangement, a noteworthy configuration is that the above mixed gas is guided to the tip through nozzles 13 and 16 and 14 and 15 facing each other at an angle of 180 degrees, and one of the nozzles 21 Is the upper side of the welded part 20 in the drawing, and the other ejection port 22
Is the mixed gas 2 on the lower side of the welded portion 20 in the drawing.
It is arranged to blow 9. Nozzle 1
3 is an enlarged partial cross-sectional view of 3 to 16 and the nozzle 13
The enlarged front view of FIG.
Each of the above jets is shown in more detail.

Next, a method of welding using the gas welding (or pressure welding) device configured as described above will be described.

First, as shown in FIG. 5, objects to be welded to each other, for example, each welded portion 20 of a pair of reinforcing bars 19a and 19b.
Appoint. At this time, the welded portion 20 is obliquely cut in order to improve heating efficiency during welding, so that there is a constant gap 33 therein. In addition, from FIG.
FIG. 7 shows a state in which the reinforcing bars 19a and 19b are horizontal and welded to each other.

Then, as shown in FIG.
The oxygen-acetylene mixed gas 29 is set so as to surround the welded parts (or joint parts) 20 of a and 19b, and is supplied from each nozzle.
Is ejected as shown by the arrow. Welded part 2 due to gas flame
When the temperature of both sides of 0 increases, the reinforcing bars 19a and 19b are pressed against each other by a hydraulic drive (not shown) (pressing force P,
(P is applied), and welding is performed in this state to form a welded portion (annular protrusion) 35 that is uniformly raised over the entire circumference.
It occurs as shown in the figure, and both reinforcing bars can be completely welded.

As described above, the mixed gas is not directly blown to the welded portion 20, but the welded portion 20 is sandwiched between the two sides (for example,
In the case of a 25 mm diameter reinforcing bar, the mixed gas is simultaneously sprayed from the welded part to both sides of 3 to 5 mm or more), and the sprayed parts on both sides are heated by the combustion heat of acetylene gas,
By heating the welded portion by heat conduction to perform pressure welding, the welded portion 20 does not become excessively high in temperature, oxidation does not proceed, and the impurities generated from the fuel gas described above are not welded. 20 never invades. Further, since it is not necessary to move the gas welding device to the left and right and welding is performed at a fixed position, an annular projection is not formed at a position offset from the welded portion as described above regardless of the work environment, The welding position is accurate. Therefore, the strength of the welded portion is sufficiently high, and the reliability of welding is high. Further, since the flame of the mixed gas does not hit the surface of the reinforcing bar perpendicularly but obliquely at a predetermined angle, the trouble such as the deformation of the nozzle due to the reflection of the flame does not occur.

After welding, a notch was made at the welding point and fractured, and the fracture surface was observed, and no defects such as inclusions of impurities such as oxides, blowholes, pinholes, etc. were observed, and it was confirmed that the welding was reliable. confirmed. In addition, when the welded rebar was finished using a black skin mask and lathing, and then subjected to a bending test, no cracks were observed at a bending angle of 115 degrees.

8 and 9 show a modification of the nozzle structure described above.

In these examples, one ejection port 21 and the other ejection port 22
Two sets (nozzle 43) or three sets (nozzle 44) are provided, and as the diameter of the object to be welded increases, the number of ejection ports is increased to perform welding efficiently. For example, the nozzle 44 shown in FIG. 9 can weld a reinforcing bar having a diameter of about 51 mm.

FIG. 10 and FIG. 11 show an example in which the branch pipes 41, 42 are formed in a ring shape, and a large number of pairs of jet ports 51, 52 are directly provided in the branch pipes 41, 42 without providing nozzles. 10 is a plan view, and FIG. 11 is an enlarged sectional view taken along the line XI-XI in FIG.

A large number of through holes are provided in two rows in the inner peripheral side wall of the ring-shaped branch pipes 41, 42 to form the ejection ports 51, 52.
52 is directed toward the center line Q of the ring-shaped branch pipes 41, 42. Further, as shown in FIG. 11, one ejection port 51 is directed to the upper side of the welded part 20 and the other ejection port 52 is directed to the lower side of the welded part 20 as indicated by a virtual line. In order to direct the ejection ports 51, 52 in a predetermined direction in this manner, the wall thicknesses of the branch pipes 41, 42 need to be sufficient to determine these directions.

By providing a large number of jet ports 51 and 52 as described above, it is possible to easily weld an object having a larger diameter.

Further, as shown in FIG. 12, a large number of jet outlets 51, 52 are provided in one row in the branch pipes 41, 42, and the jet outlet 5 directed upward is provided.
It is also possible to alternately arrange 1 and the jet outlet 52 provided below.

FIG. 13 shows an example in which auxiliary jet outlets 23 and 24 are provided on both sides of the jet outlets 21 and 22 of the nozzle so as to match the flame focus.

By configuring the nozzle 45 in this way, the heating efficiency of the object to be welded can be increased.

FIG. 14 shows still another embodiment, which is different from the above-mentioned embodiment in that the grip portion 17 is provided in the same direction as the blow pipe 6 (that is, not bent). There is. This linear welding device may be appropriately selected and used according to the place of use.

Although the present invention has been illustrated above, the above-described example can be further modified based on the technical idea of the present invention.

For example, the number and position of the above-mentioned nozzles and mixed gas ejection ports, and the angle between a set of ejection ports can be variously changed. Further, the type of gas used is not limited to the above as long as it can be used for gas welding or pressure welding.

F. EFFECTS OF THE INVENTION As described above, the present invention provides a pair of rod-shaped objects (bar-shaped objects to be gas-welded) that are present on both sides of the welded portion in the axial direction. Since a plurality of jet ports for simultaneously spraying the mixed gas are provided on each of the outer peripheral surfaces in each of the plurality of mixed gas jet parts, the flame of the mixed gas is not blown to the welded object, and the welded object is not welded. Since the parts are not excessively heated, the oxidation of the welded part does not proceed. Moreover, the impurities generated from the fuel gas are not contained in the welding part. In addition, since welding can be performed at a predetermined position without moving the gas welding device during welding, the welded portion can be accurately welded. As a result, the welded part is sound and defect-free, and the strength is guaranteed and the reliability is high. Further, since it is not necessary to move the gas welding device during welding, reliable welding can be performed regardless of the working environment.

[Brief description of drawings]

1 to 14 show an embodiment of the present invention. FIG. 1 is a perspective view of a gas welding apparatus, and FIG. 2 is a plane (partial cross section) of a nozzle portion (burner portion).
Fig. 3, Fig. 3 is an enlarged cross-sectional view of the nozzle, Fig. 4 is an enlarged front view of the nozzle as seen from the ejection port side, and Figs. 5, 6, and 7 are front views showing respective stages of welding work, 8 and 9 are enlarged front views of the other nozzles as seen from the ejection port side, FIG. 10 is a plan view of another burner portion, and FIG. 11 is an enlarged view taken along the line XI-XI of FIG. Sectional view, FIG. 12 is an enlarged partial front view of yet another burner portion, FIG. 13 is an enlarged front view seen from the jet outlet side of yet another nozzle, and FIG. 14 is a gas welding apparatus according to still another example. It is a front view. FIGS. 15 to 18 show a conventional example. FIGS. 15 and 16 are plan views of a nozzle portion (burner portion), and FIGS. 17 and 18 show respective stages of welding work. It is a front view shown. In addition, in the code | symbol shown by drawing, 1 ... Blowing pipe part 2 ... Nozzle part (burner part) 6 ... Blowing pipe 11,12,41,42 ... Branching pipe 13,14,15,16,43 , 44, 45 ...... Nozzle 19 ...... Target 20 ...... Welded part 21, 22, 51, 52 ...... Mixed gas jet 29 ...... Mixed gas 33 ...... Gap 35 ...... Welded part (annular protrusion) P: Pressing force.

Claims (1)

[Claims] 1. A pair of rod-shaped objects to be gas-welded are brought into contact with each other at their welded portions, and a mixed gas of a fuel gas and an oxidizing gas is sprayed on the pair of rod-shaped objects. The object is axially pressed against each other and the relative position between the welded part and the jet part of the mixed gas is substantially fixed, and is configured to perform gas welding. A direction intersecting the axial direction A plurality of mixed gas jetting portions are provided radially at substantially equal angles along the entire circumference of the welded portion formed in, and are present at both side positions of the welded portion in the axial direction, respectively, and the pair of A plurality of jet outlets for simultaneously spraying the mixed gas are provided in each of the plurality of mixed gas jetting portions on the outer peripheral surfaces facing the opposite end surfaces of the rod-shaped object, respectively.