JPS58103982A - Electron-beam welding method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electron beam welding, and more particularly to an apparatus and method for electron beam welding of bulk metals with inherent magnetic fields.

For welding a large amount of metal, the conventionally well-known TIC or M
The IIG welding process has been used for a long time. These technologies had their own limitations. In particular, such approaches required the use of large amounts of heat and often resulted in large wastes of power. Additionally, such techniques often resulted in weak welds due to metal crystallization. These techniques were also very inefficient.

More recent electron beam welding techniques have been used in place of these older techniques. In electron beam welding, a normalized stream of electrons is directed at the abutting portions of the metal materials to be welded. This technique works very well when welding relatively thin pieces of metal together, or when welding relatively thick (heavy) chunks of metal that have no inherent magnetic field. However, electron beam welding has a magnetic field There are particular constraints when welding heavy metal blocks, where the electron beam tends to deviate from its intended path after being partially transmitted through the metal. Such path deviations result from the influence of magnetic fields and can further result in low-quality defective welds.Such problems can occur, for example, in large joint applications, including coal liquefaction plants. This is particularly severe when welding plates, pipes, and other heavy metal pieces in industrial applications.

The limitations that exist in currently available electron beam welding techniques are overcome by the present invention. In the present invention, large mass or heavy metal plates with inherent magnetic fields can be welded by first butting each metal piece together to define the interface to be welded. The plate is then heated from one side at its interface by means of an electron beam welding device to a temperature up to, preferably to, the transformation point of the metal. As is well known in the art,
By heating the metal to this transformation point, the magnetic field is removed. While the metal plate is still being heated to the transformation point in the area of the interface on one side, this interface is then welded from the opposite side by means of conventional electron beam welding methods. Electrons passing through the butted metal plates at the interface heat the interface beyond the transformation point, thereby performing welding. The electrons cannot be deflected by any magnetic field as they pass through and maintain their predetermined path, preferably coinciding with said interface. Since the electrons are not normally deflected in the unheated metal until the electron beam has passed through the metal a sufficient distance, the electron beam maintains its predetermined force. The electrons then reach the heated area where there is no magnetic field and are therefore not influenced to deviate from the path to which they were initially directed.

The foregoing apparatus provides an improved apparatus and method for joining very thick plates of various steels and other metals with more effective and stronger welds than heretofore possible. It is something to do. The invention is particularly suited for use in welding special alloy materials, which are now more often used in the manufacture of pressure vessels. Such special alloy materials often have residual magnetic fields that are even stronger than those normally encountered in steel and conventionally known alloy compositions.

The present invention further contemplates the provision of a more effective welding apparatus in which the metal interface can be heated quickly enough to increase the efficiency of the welding operation.

Still another advantage and object of the present invention is that large quantities of metal can be welded in an environment where the cooling rate of the metal after the welding operation is optimized to cause hardening without the risk of creating a hot water mark at the base of the full penetration zone of the nugget. An object of the present invention is to provide an improved preheating device for localized heating of an interface where two objects are butted together.

Yet another object and advantage of the present invention is the provision of a welding method in which the accidental formation of gas pockets in thick-walled joints is minimized or eliminated. Another object of the invention is that the electron beam, which is primarily used for preheating the interface, is also used for partial welding before being completely welded by an electron beam gun from the outside. The object of the present invention is to provide an apparatus in which electron beam welding can be performed partially from the heated side.

Still another object of the invention is an improved apparatus for welding processes in which the energy requirements for welding bulk metals are greatly reduced and preheating by induction or resistance devices is not required. On offer.

The foregoing objects and advantages of the present invention will be more clearly understood when the text is considered in conjunction with the drawings.

The present invention relates to a method of welding metal plates having an inherent magnetic field at .degree. C. using a plurality of electron beam firing guns of a conventionally known configuration. Thickness is approximately 15 crrL (6 inches)
In joining the above-mentioned plates, after the electrons partially pass through the plates, the inherent magnetic field irregularly deflects or warps the electrons from the abutment interface of the plates to be joined. Problems arose in the use of the welding method. The magnetic field in this type of plate causes the steel material to 768
Although it is known that it is possible to reduce the temperature by heating to the transformation point of It wasn't done.

In particular, the mass of plates hitherto used in large steel structures requires enormous amounts of heat, even if heating to remove the magnetic field is actually unnecessary. . Among other things, such approaches are too slow and consume too much energy.

In the present invention, 2 indicated schematically by the numbers 1 and 2
Show me how to weld two plates together. These plates may be of any length (in the illustrated embodiment approximately 20 crIL (8 inches) thick from side 4 to side 5).
having facing surfaces along abutting edges forming an interface 6 . These plates are shown as flat slabs of uniform thickness of approximately 8 inches, but other shapes and dimensions are also contemplated. For example, tubular steel used in tanks or pressure vessels as well as structural steel beams and supports can be welded using this technique.Although the steel or metal used may vary according to the particular application, the present invention It is particularly designed for use with chisels having residual magnetic fields with a strength of 1 to 2 Gauss or more. Electron beam welding of such metals is problematic because the inherent magnetic field tends to disturb the desired direction of the electrons after they pass through a portion of the metal. Disadvantageously, this inherent magnetic field is not constant in its swing, resulting in irregular deflection of the electrons after they partially pass through the abutting portions of the metal plates.

In the method contemplated by the invention, a pair of t-beam guns are directed against both sides of plates 1 and 20 and aligned so that electron streams can be fired in the directions of arrows 7 and 8, respectively. Accordingly, the gun for directing the electron stream 7 is arranged so as to direct the electron stream from the longitudinal edge 9 to the interface B, and the gun used to direct the electron stream 8 is from the edge 10 of the interface. It is matched to allow these electrons to pass through.

In a preferred embodiment, the guns respectively represented by block 11 for electron stream 7 and block 12 for electron stream 8 are suitably supported on a common support so that these guns are parallel to the plane of interface B. and in a direction aligned therewith, the gun is preferably arranged such that it can be moved synchronously with respect to the metal plate. stomach(
This can be achieved by providing a suitable support so that the metal plate can be moved between two mutually fixed guns.

In a preferred embodiment, the gun 8 is approximately 1.27 cm (approximately 0.2 cm) in front of the electron stream 7 directed by the guide 11.
5 inches) to direct electron flow to the interface along the INK. The distance between the paths of the two electron streams 7 and 8 is such that the metal remains substantially at the desired transformation point where it is heated by the electron stream 8 until after it has been exposed to the electron stream 7. It must be something like that.

Sufficient energy is provided to inject the electrons in the electron stream 8 into the interface 5 by at least -1, preferably a fraction, of the thickness of the metal. In a preferred embodiment, the nugget 14 defining the heating area is connected to the filter plates 1 and 2 at the interface A.
must pass through the thickness from edge 10 to edge 9 for a sufficient distance so that the electrons subsequently induced in the electron stream 7 are not deflected by the inherent magnetic field of the metal.

On the downstream side of the gun 12 is the gun 7 as described above.

Operating at a relatively high energy level, this gun directs a stream of electrons from the edge 9 into the interface 6 with sufficient energy to raise the temperature of the nugget above the transformation temperature A2 (768 DEG C.). This electron flow 7 is nugget 15 + ζ'a
The electron flow 7 is reduced in order to eliminate or substantially minimize the heating section which melts the metal and thereby welds the two plates 1 and 2 together to form the weld 17. It is not deflected or deflected as it passes from edge 9 towards edge 10 of the interface.

Suitable devices are arranged to cause the guns 11 and 12 to operate synchronously from one end of the plates 1 and 2 to the other.

Guns 11 and 12 are thus moved at opposite edges 9 and 1 of interface A at a controlled rate of speed in the direction of arrows 20 and 21.
0 and commonly supported for movement along arrow 20
indicates the route of the section heated to the transformation temperature A2 (768° C.). Arrow 21 indicates the path of the nugget defining the weld.

In the second section, temperature curves appropriately labeled with respect to heating and welding passes or directions are also shown.

FIG. 3 shows another embodiment of the invention. In this example, the metal is heated along the interface 3 at a transformation point temperature A2 (768°C
) is parallel to the direction of electrons 62 from an electronic welding gun 63 used to weld the two plates together. (placed at an angle as shown).

The beam 31 to beam 320 angular relationship minimizes deterioration of gun 3'5 performance. This relationship also minimizes the potential for pitting or gas pockets that occur when welding is performed by the electron stream 32. This angular relationship not only preheats the metal (but also appears to remove gases). This relationship results in a better quality weld and also reduces the beam pressure on the beam from gun 30. It turns out.

Controlling the angle of beam 31 so that it is not parallel to beam 62 also facilitates the removal of gas from edge 10 of interface 6.

FIG. 4 shows yet another modification of the present invention, in which an electron beam 40 from the edge 10 is used to move a nugget 42 in the direction of arrow 4 to a transformation point temperature A.
2. Preheat to the selling temperature (768℃). At this temperature, the nuggets 42 will melt and define a weld zone through the length of the nuggets, preferably to a depth of more than half the thickness of plates 1 and 2. The innermost point of the weld 44 is chosen so that the electron beam 40 does not deviate from its predetermined path. A second electron beam 46 from an electron source on the opposite side of the plate is focused within the interface with sufficient energy to form a weld. The repulsion of nugget 47 formed by electron beam 46 is sufficient to cause the weld formed by beam 40 to merge with the nugget terminating at point 48. This beam 46 moves parallel to beam 40 in the direction of arrow 49.

The common weld section that constitutes the space between points 44 and 48 is made by one pass from each side of the joint.

Several passes can be made from each side of the joint in the preferred embodiment described with respect to FIG. However, if the temperature of the steel is heated to 100° C., the penetration depth of the electron beam welding process can be increased by about 7%.

FIG. 5 illustrates the use of multiple electron guns to focus beams 50 and 51 from one side of beam 52 to the other. - The beams 50 and 52 are directed inwardly from 9 and 1° on either side of the interface 3, respectively, at an energy level sufficient to heat the interface 2 to a temperature not exceeding the transformation temperature A2 (768° C.). . This heated section allows the beam 51 to pass through the preheated interface portion without causing deflection or deflection of the beam (sufficient to completely pass through the heated interface to form a nugget 54). A relatively high energy capacity beam 51 is advanced.The movement of the beam relative to the metal plate is indicated by arrows 55 and 56 in FIG.
and 57.

FIG. 1 shows the deflection of a nugget fin by fin against the strength of the residual magnetic field, as measured in Gauss, in the case of a pair of steel plates joined using electron beam welding. In this graph, the thickness of each plate is approximately 5
．． 08.1016.15.24 and 20.32 (2
, 4, 6 and 8 inches). From this figure, it can be seen that a residual magnetic field of 5 Gauss still causes a plate thickness of about 10.16 to 1
It is clear that when 5.2.41111 (4 to 6 inches) is exceeded, there may be a lack of transmission on the back side of the joint.

For this reason, the present invention provides an improved method of forming relatively thick steel plate welds with residual magnetic fields in excess of 5 Gauss.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between the magnitude of the residual magnetic field and the amount of nugget escape when welding steel plates using the electron beam welding method of the present invention, and Fig. 2 is a graph showing a preferred embodiment of the present invention. FIG. 3 is a perspective view showing an electron beam welding method according to another embodiment of the present invention, and FIG. 4 is a diagram showing an electron beam welding method according to another embodiment of the present invention. and FIG. 5 are perspective views showing an electron beam welding method according to still another embodiment of the present invention. 1゜2...Plate, 6...Interface, 4.5...Side surface, 7, 8.31, 32.50~52...Electron beam,
9.10...edge, 11.12,30,33,40...electron beam gun, 14.15,42,47,54...nugget, 17
．． 44...Welding part. Patent Applicant: International T-, -Q Curum Aibe's engraving (no change in content) Amendment to the pitfall procedure (method) 1966 ≠ Mon. 2 Commissioner Shima 1) Spring 1 seal 1 Indication of the case Showa F〆 year rt application No. 2 p/Guge No. J, Hand Bi A = 14-A Hiro 6, Person making the amendment Relationship to the case Applicant Address A4 Ibo Internoshi 1 Yoshi 1'・/Guinea Yam・
Inc.%I-'4, Agent

Claims (1)

[Claims] 1) An electron beam welding method for welding two metal plates, at least one of which is made of a magnetic material, along a butt edge that forms an interface between the two metal plates. directing the electron beam from one edge of the inner interface of the plate until the temperature of the metal at the interface approaches the transformation point of the metal and the magnetic field inherent in the metal is removed; While the metal maintains the temperature with respect to the plate 71, the other edges of the interface also direct the electron beam until the temperature rises above the transformation point of the metal between the edges, thereby A method comprising the step of welding the two parts together along the interface. 2) In an electron beam welding method in which two metal plates, at least one of which is made of a magnetic material, are welded along their abutting edges forming an interface therebetween, the edge is also at least partially along said interface. A flow of electrons is transmitted from the far edge to the path through the interface while maintaining the magnetic temperature, thereby raising the metal at the interface to the welding temperature and bonding the plate. A method characterized in that the two are welded together. 3) A method according to claim 2, characterized in that the temperature in the path is increased by transmitting a flow of electrons from the edge to the interface. 4) A method according to claim 5, characterized in that the electron stream is simultaneously moved along the interface. 5) A method as claimed in claim 6, characterized in that the path is at an angle to the electron flow from the far edge.