JPS60210377A - Welding of workpiece - 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 Field of the Invention The present invention relates to a method for welding workpieces by deflecting an energy beam at least in the processing direction of the workpieces.

PRIOR ART In particular, when welding large wall thicknesses of workpieces made of meltable materials, the point of impact of the energy beam, preferably the electron beam, is filled with metal vapor and surrounded by a jacket of molten liquid material. A capillary is formed through which the energy beam penetrates deeply into the workpiece. Hydrostatic pressure acts on the melt jacket surrounding the vapor capillary, which is absorbed by the height and density of the liquid column above it, and thus also by the direction of the capillary relative to the direction of gravity. Depends on it. In this case,
Due to the evaporation of the abrasive material, the steam pressure acting on the surface of the gear clary side of the melt jacket causes a steam capillary to be formed through which the energy beam can deeply penetrate into the workpiece. .

PC'l' Application US 81101740 (International Publication No. W
082102652), it is known to weld workpieces with a pulsed energy beam with a thickness of about 38 mm. In this case, in order to avoid spikes and cavities and porosity that occur in the pulses, especially in the base region of the seam, the energy introduced into the workpiece is distributed over the workpiece with a dot screen.

However, in a dot screen with controlled energy penetration into the workpiece, the dot/seam cross section is melted, which in turn reduces the depth to width ratio of the weld. This leads to a wide weld seam with a small addition/depth and a poor energy utilization of the energy beam.
65-';) From the specification, an electron beam abrasive welding process is known in which a beam is introduced into a preformed inlet in order to be able to weld thick pieces of material at a given power and with a low heat load. be.

However, in such a method shrinkage occurs, which must be eliminated by progressive opening of the weld seam.

Furthermore, a high-speed welding method with an electron beam is known from DE 2 204 295 A1, in which the electron beam is moved back and forth along the welding line.

Problem to be Solved by the Invention The object of the invention was to achieve large processing depths with narrow weld cross sections when welding particularly thick-walled workpieces with an energy beam.

Means for Solving the Problems The present invention provides a method for welding workpieces by deflecting the energy beam at least in the processing direction (22) of the workpiece. Directing the energy beam 13 in each case to the two beam impact positions 16.17 of the workpiece 10 with continuous changes of direction
70 respectively to form a capillary 23 and deeply insert the workpiece 10.
The problem is solved by a method for welding workpieces, which is characterized in that the energy beam 13 penetrates into the workpiece and in this case the energy beam 13 acts on the same position 20 of the two crops 10 one after another in time.

Advantageous embodiments of the invention are described in the subclaims.

Effects of the Invention The advantages obtained with the invention are, in particular, that even in the vertical beam direction, it is possible to form narrow machining or weld cross-sections without creating weld defects such as cavities, porosity, spikes, etc., e.g. It is possible to obtain welded seams with a diameter of 250 mra 4.

Example The invention will now be described in detail with reference to the illustrated embodiments.

Steel l Q Cr, Mo 9 with a thickness of 11
A workpiece consisting of 10 parts is machined in a vacuum chamber (not shown in detail) by an electron beam 130 in a vertical machining position at a constant feed speed of 1 to 9 cm at a vacuum chamber pressure of about 10-" J bar.
run underneath. The output of the electron beam 13 generated by the schematically illustrated electron beam generator 12 is 6Q KW.

The electron beam 13 is preferably directed opposite to the feed direction 14;
That is, in the longitudinal direction of a predetermined processing direction 22, the electron beam 13 is deflected by the beam guide device 15 of the electron beam generator 12 so that it impinges on two beam impact positions 16, 17 having a mutual spacing 19. For example, the first beam collision position 1 in the processing direction 22 has the same action time of 150 ms at both beam collision positions 16 and 17.
7 a first capillary 23' and a second beam impact position 16 a second capillary I) 2 g'. In this case, the first capillary 23 ′ located in front in the processing direction 22 is affected by the electron beam 13 directed at an angle 26 to the axis 25 of the energy beam generator 12 .
And the second capillary 2y is formed by the electron beam 13 impinging perpendicularly on the surface of the workpiece. Advantageously, the control of the deflection pulses of the radiation guide arrangement 150 is carried out by means of a temporally symmetrical rectangular oscillation 18.

During the first machining step, ie at the start of vibrations on the workpiece 10, no forward or second beam impact position 16 in the feed direction 14 is present on the workpiece 10. feed direction 14
The rear or first beam impingement position 17 is located at the left-hand edge 29 of the workpiece 10 by periodically deflecting the electron beam 13 in the machining direction 22 . The electron beam 13 diverted to this first beam collision position 11 is 15[
] ms, a first capillary 23' is formed, which continuously passes under the electron beam 13 in the transport direction 14 at a transport speed of preferably 1 mm s-' to the workpiece. 10 is continuously moved and at the same time moves to the right over the workpiece surface 24 due to the deflection that progresses with continuous changes of direction due to the rectangular oscillation 18. The amplitude of the rectangular vibration 18 corresponding to the distance 19 above the workpiece surface 24 is preferably 7 mm and the workpiece feed rate is 1 mt.
n s-1, the deflected electron beam 13 hits the left edge 29 of the workpiece 10 at the beam impact position 16 after 7S.
corresponds to The electron beam 13 is 1 at this beam collision position @16
The second capillary 23 by acting for 5Q ms
'' is generated, and the capillary 23'' is also the first capillary 23
', it moves over the workpiece 10 toward the right. In this case, due to the deflection of the electron beam with a feed rate of 1 mm5-1 in the feed direction 14 and an amplitude corresponding to the distance 1tua19, in the - plane d, the workpiece area 27 becomes η=; The electron beam 13 is first melted to a depth of, for example, 20111++ m and 7S
The electron beam 13 subsequently hits the surface 24 of the workpiece 10 perpendicularly.
The second melting step is performed at a depth 1 of, for example, 250+++ m. Within this workpiece region 2γ, the electron beam 1
3 is the same position 20 of 2 ditto crops 10 temporally one after the other.
It acts on In this case, practical measurements have shown that a joint coincidence of beam impact positions 16 and 17 is unnecessary. On the other hand, in front of this workpiece area 27 there is a square vibration 1
The pack-step deflection of the electron beam 13 by 8 produces a workpiece region 21 which is initially connected to the capillary 2 formed by the deflected electron beam 13.
3' in parallel, preferably at a switching frequency of 6 Hz and at the same time a transmission speed of 1 ma s-1.
6 beam impact positions on the weld seam length of mm 17
exists.

Advantageously, the beam impact position 16,1γ is loaded with an electron beam power of 60 Kw with the same beam power during welding. When the same electron beam 13 is made to collide twice at the same position 20 with respect to beam collision positions 16 and 17 located apart from each other by a distance of 19 while the electron beam 13 advances in the processing direction 22 with a direction change. , two temporally and positionally successive steps of the workpiece 10 with perpendicular beam direction, each time diverted between the two beam impact positions 16, 17 so that the deep melt zone is almost hardened. The above process consisting of is repeated until the predetermined weld seam length is achieved.

The deflected electron beam 13 striking the colder material, which is still being melted by the electron beam 13, causes intense heating of the material at the first beam impact location 17, penetrating deep into the material. Due to the pulsed electron beam action and the intense heat induction into the still cold material around the forward first beam impact location 11, a small and uneven amount of melt is created between the capillary 23' and the solid material. Regularly shaped layer thicknesses result. This too small and non-uniformly formed melt exerts a hydrostatic pressure commensurate with its mass, which causes a steam jet to open the capillary 23' as well as an electronic beam entering the capillary 23'.
13 cannot be made to act. The electron beam 13 therefore penetrates deeper into the material than would be possible with a corresponding sustained beat weld and a larger melt volume.

The energy penetrating after a 7 s inactive period of the electron beam 13 impinging perpendicularly on the first beam impingement location 17 forms a narrow bath with sufficient volume of the melt. The distance 19 from the first beam impact location 47 to the second beam impact location 161, which depends substantially on the beam rate, beam power and workpiece thickness, is such that the melt deep in the material is just about to harden. However, if the workpiece zone 21 loaded with this already deflected electron beam 13 is impinged by the electron beam 13 perpendicular to the surface 24 of the crop 10, heat will be transferred to the seam surface. In fact, a defect-free weld seam occurs at a distance 19 of 2 to 22 mm between the first beam impact position 16 and the second beam impact position 17. This temporal and spatial control of the electron beam 13 is such that at the second loading of the workpiece with the electron beam 13, the depth 2 of the capillary 2y is 250 mm.
8 is achieved.

In this working sequence with backstep turning, due to the mutually strong preheating in the workpiece area 21, a sufficient melt volume is created during the second loading with the electron beam, so that in this case Bath formation during pauses in electron beam action is substantially undisturbed.

In the method described, a cavity- and porosity-free /-mem 30 was obtained with a weld depth 28 of 250 mra at the narrowest /-mem width 31. Due to the different direction of the deflected electron beam 13 when machining the workpiece 1o in the vertical beam direction, a favorable seam actually occurred. Moreover, the capillary 23' located at the front in the direction 22 is applied to the electron beam 13 hitting the surface 24 of the workpiece 10 at an angle 26 to the axis 25 of the electron beam generator 12, and the second capillary at the rear
In the embodiment of FIG. 1, special advantages are obtained with respect to the opal horn in the welding/membrane 30 by virtue of the fact that the capillary 23 is formed by the electron beam 13 impinging perpendicularly on the surface 24 of the workpiece 10. , two workpieces 10 of approximately the same dimensions are welded together, only one of which is shown in the drawing for clarity.The method according to the invention welds workpieces of different dimensions. In particular, it can be used with particular advantage when welding thin workpieces with a width 36 in the range from 5 to 15+ mm to thick-walled workpieces.

In FIG. 2, a thick-walled workpiece is indicated at 10. The workpiece 10 has a notch 32, into which a thin plate 33 (width 6 mra) is fitted, for example, so that its surfaces match. This plate is connected to the workpiece 10 over its entire height according to the method of the invention. A deep and narrow weld seam is obtained with operating parameters similar to the embodiment according to FIG. 1 described above.

When welding parts 10.33 made of different materials exhibiting different thermoelectromotive forces (e.g. between ferritic and austenitic steels), large thermocurrents are formed near the melt bath and the magnetic field The electron beam 13 is the workpiece 10
Before it hits the workpiece surface 24, it can have a detrimental effect, especially in the area in front of the workpiece surface 24. A corresponding beam deflection, as shown in FIG. 2, takes place in particular in a plane perpendicular to the seam direction and can thus lead to coupling defects. Since the temperature distribution around the welding bath depends on the workpiece geometry and the control of the welding process, the electron beam deflection is not constant in time. Compensation by a corresponding tilting of the beam direction before the beam penetrates the workpiece can therefore only provide a partial aid. Therefore, the magnetic shield plate 35 (FIG. 6) of the electron beam 13 is
It is advantageous to fasten the shield plate on the joint to be welded on at least one side of the joint in such a way that it has a lateral distance of, for example, 30+++ m from the magnetic contact to this workpiece 10. At the start and end points of the welding sample,
The magnetic shield plates 35 protrude above the welding sample by 30 orders.

This shielding effect is so complete that the sheet metal can be mounted close to the workpiece surface 24 without being permanently welded thereto.

Occasional spatter during welding can advantageously be avoided in the following way.

1. The rectangular deflection is temporally asymmetric, e.g. short at the leading point (long dead period, i.e. typical pulse action in cold solid metal), whereas at the rear welding point Long residence times and short dead periods (effect similar to continuous beam welding); whereas synchronous beam current modulation, the first (shorter) welding point has a higher beam current.

2. Avoidance of spatter due to pulse action in the rear welding position due to periodic oscillation of the spot: in the second long pulse first defocusing and then focusing or vice versa is carried out. This is achieved, for example, by high voltage variations based on beam current modulation. In this case, of course, the switching ratio and the beam current difference of this temporally asymmetric modulation should be matched to the motion and internal resistance of the high-voltage device or the vibration of the spot due to turning: the longitudinal vibration of the high frequency is forwarded by square turning. Overlap under the notch at the weld location. Particularly if the working time at the rear welding location is longer than at the front, various methods can be used to shape the hardening front there into an elongated bruise shape.

[Brief explanation of drawings]

The drawings show two embodiments of the method of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a workpiece showing a predetermined processing process during welding, along with an electron beam device for carrying out the method of the present invention. Figure 2 is a cross-sectional view of a workpiece showing a predetermined processing process when welding two different materials together with an electron beam device, and Figure 6 is a joint welding of two different materials. FIG. 3 is a cross-sectional view of the seam portion of FIG. 2, which has a magnetic shielding plate that compensates for the magnetic field generated during this process. DESCRIPTION OF SYMBOLS 10... Workpiece, 12... Energy beam generator, 13... Energy beam, 16.17... Beam collision position, 18... Periodic square vibration, 19... Amplitude, 20. ...beam action position, 22...processing direction, 23', 23''...first and second capillaries,
24...Workpiece surface, 25...Axis of the game generatorContinued from page 1 ■Inventor Johannes Coy @ inventor Kurt Leb0 Inventor Klausbater Mönch @ inventor Wilhelm Scheff Erles Federal Republic of Germany Germering Steinbergstrasse 22 Federal Republic of Germany Munich 80 Rosenheimer
Strasse 165 Grafrat Haubstrasse, Federal Republic of Germany

Claims (1)

[Claims] 1. A method for welding a workpiece by deflecting an energy beam at least in the processing direction of the workpiece, comprising:
The energy beam (13) is directed at the two beam collision positions (16, 17) of the workpiece (10) while continuously changing its direction in the processing direction (22), and each time the energy beam (13) is directed to the two beam collision positions (16, 17). Collision position (16, 17)
Form a capillary (23) with each of the holes and deeply insert the workpiece (
10) and at that time an energy beam (13)
) is applied to approximately the same position (20) of the second target crop (10) at different times. 2. Method 3 according to claim 1, in which the action time of the energy beam (13) is 10 to 500 ms when processing in a vertical beam direction, beam collision of the energy beam (13) Position (1
3. The method according to claim 1, wherein the deflection to 6, 17) is controlled by periodic rectangular oscillations (18). 4. The amplitude (19) of the rectangular vibration (18) is
4) is 2 to 20 tom, the method according to any one of claims 1 to 6. 5. The method according to any one of claims 1 to 4, wherein the frequency of the square vibration (18) is between 1 and 60 hertz. 6. The energy beam (13) is an electron beam.
A method according to any one of claims 1 to 5. Z The first capillary (23') located at the front in the machining direction (22) forms an angle (26) with the axis (25) of the energy beam generator (12) and connects the workpiece (10).
by the energy beam (13) impinging on the surface (24) of the second cabin! J (23″) is formed by an energy beam (13) impacting perpendicularly to the surface (24) of the workpiece (10), according to one of the claims 1 to 6. 8. The method according to any one of claims 1 to 7, wherein the energy beam (13) is caused to collide with the same beam output at both beam collision positions (16, 17). The method according to any one of claims 1 to 8, wherein both beams collide at the collision positions (16, 17) with the same focus. 10. To both the beam collision positions (16, 17) 10. The method according to claim 1, wherein the energy beams (13) have the same duration of action, preferably between 10 and 50 Qms.