DD256335A1

DD256335A1 - METHOD FOR ELECTRON BEAM MELTING OF SHORT STAINS

Info

Publication number: DD256335A1
Application number: DD29862486A
Authority: DD
Inventors: Eberhard Lugenheim; Karl-Heinz Werner
Original assignee: Sket Veb Ingenieurbetrieb Fuer
Priority date: 1986-12-29
Filing date: 1986-12-29
Publication date: 1988-05-04

Abstract

Die Erfindung betrifft ein Verfahren zum Elektronenstrahlschmelzen von kurzen Staeben, insbesondere zylindrischen Staeben beliebigen, jedoch gleichen Durchmessers und beliebiger, jedoch gleicher Laenge und mit beliebig geformten, jedoch deckungsgleich zusammengehoerenden Endflaechen in den Kristallisator eines Elektronenstrahlofens. Die Stabstoesse erhalten im Bereich der Stabauflage nur kleine Heftschweissungen, waehrend die vollflaechige Verschweissung ueber den gesamten Stabquerschnitt erst erfolgt, wenn der betreffende Stabstoss aus dem Bereich der Stabauflage herausgeschoben worden ist und frei ueber dem Kristallisator haengt. Das Verfahren laeuft nach zeitlich und oertlich programmierten Zyklen der Strahlablenkung ab. FigurThe invention relates to a method for electron beam melting of short rods, in particular cylindrical rods of any but the same diameter and any, but the same length and arbitrarily shaped, but congruent zusammengehoerenden Endflaechen in the crystallizer of an electron beam furnace. The Stabstoesse received in the rod support only small tack welds, while the vollflaechige welding over the entire rod cross-section only occurs when the relevant Stabstoss has been pushed out of the range of rod support and hanging freely on the crystallizer. The method runs after time and locally programmed cycles of the beam deflection. figure

Description

Erfindungsgemäß wird diese Aufgabe gelöst, indem die Stabstöße im Bereich über der Stabauflage nur kleine Heftschweißungen erhalten, so daß die nötwendigen Dreh- und Vorschubbewegungen der Abschmelzstäbe nicht behindert werden. Die vollflächige Verschweißung der Stabstöße über dem Ganzen erfolgt erst, wenn die gehefteten Stöße aus dem Bereich der Stabauflage herausgeschoben worden sind und die Abschmelzstäbe frei über dem Kristallisator hängen. Das Verfahren ist dadurch gekennzeichnet, daß durch zeitlich und örtlich programmierte zyklische Strahlablenkungen geheftet, geschweißt und abgeschmolzen wird, ohne daß ein Orten der Stabtrennstellen notwendig ist.According to the invention, this object is achieved by the rod joints in the area above the rod support receive only small tack welds, so that the necessary rotation and feed movements of Abschmelzstäbe not be hindered. The full-surface welding of the bar joints over the whole takes place only when the stapled joints have been pushed out of the area of the rod support and the Abschmelzstäbe hang freely over the crystallizer. The method is characterized in that stapled by temporally and locally programmed cyclic beam deflections, welded and melted, without locating the bar separation points is necessary.

Bei Verwendung einer einzigen Kanone wechseln Programmschritte zum Heften, Schweißen, Erhitzen und Abschmelzen einander ab. Das Verfahren läßt sich auch mit zwei getrennt arbeitenden Kanonen zum Heften und Schweißen und zum Erhitzen und Abschmelzen durchführen.When using a single gun program steps for stapling, welding, heating and melting alternate each other. The process can also be carried out with two separate guns for stapling and welding and for heating and melting.

embodiment

Das Verfahren soll nachstehend an Hand eines Ausführungsbeispiels näher erläutert werden. Die dazugehörige Zeichnung zeigt ein Schema der Anordnung.The method will be explained in more detail below with reference to an embodiment. The accompanying drawing shows a schematic of the arrangement.

Auf einer Stabauflage 1 werden Stabstücke 2,3,4... 6 usw. zugeführt und durch die Elektronenkanone 7 über dem Schmelzbad 8 im Kristallisator 9 abgeschmolzen. Bewegt sich der Stoß zwischen den Stäben 4 und 5 in den Ablenkbereich des Elektronenstrahls, wird für eine Zeit I₁ der Brennfleck angehalten und das I.Heften durchgeführt. Die 1.Heftstelle hat den Strahlablenkwinkel a-\ und die Brennfleckverweilzeit tv Infolge der Ortsveränderung der 1. Heftstelle durch die Vorschub- und Rotationsbewegung der Stäbe 4 und 5 erhält die n. Heftstelle der Stäbe 4 und 5 den Strahlablenkwinkel <x„ und die Brennfleckverweilzeit t,. Die 1. Schweißstelle der bereits gehefteten Stäbe 2 und 3 hat den Strahlablenkwinkel ^₁ und die Brennfleckverweilzeitt₂. Die k.Schweißstelle hat den Strahlablenkwinkel ß_kund die Brennfleckverweilzeitt₂.On a rod support 1 rod pieces 2,3,4 ... 6, etc. supplied and sealed off by the electron gun 7 on the molten bath 8 in the crystallizer 9. If the impact between the rods 4 and 5 moves into the deflection region of the electron beam, the focal spot is stopped for a time I ₁ and the I.Heften performed. The 1st stitching point has the beam deflection angle a- and the focal spot dwell time tv. As a result of the movement of the 1st stitching point by the advancing and rotating movement of the rods 4 and 5, the nth stitching point of the rods 4 and 5 receives the beam deflection angle <x " and the focal spot dwell time t ,. The 1st weld of the already stitched rods 2 and 3 has the beam deflection angle _{1 1} and the focal spot dwell time ₂ . The k.Schweißstelle has the beam deflection angle ß _k and the Brennfleckverweilzeitt _2nd

Die Zeittakte ti und t₂ werden zyklisch zwischen die Zeittakte t3 zum Erhitzen des Schmelzbades 8 und t₄ zum Abschmelzen des Stabes 2 eingeordnet.The clocks ti and t ₂ are cyclically arranged between the clocks t3 for heating the molten bath 8 and t ₄ for melting the rod 2.

Claims

1. A method for electron beam melting of short rods of cylindrical cross-section of any, but the same diameter and any, but the same length and arbitrarily shaped, but congruent belonging together end surfaces, characterized in that by temporally and locally programmed cyclic beam deflection between the on a rod support (1) successively pushed rod pieces (2) to (6) in program steps "1" from "αϊ" to "a _n " a rod thrust heated by electron beam and stapled and in further program steps "2" from "fr" to "ß _k " outside the rod support (1) the already stapled joint is fully welded.

2. The method according to claim 1, characterized in that when using a gun, the program steps "1", "2", then a program step "3" for melting the respective rod piece (2) to (6) and a program step "4" Heating the molten bath (8) in the crystallizer (9) on the basis of a cyclic program sequence "3", "4", "3", "4" ,, .. with inserts of the program steps "1" and "2" according to the impact sequence respectively.

3. The method according to claim 1 and 2, characterized in that the program steps "1" to "4" are divided among these guns when using two guns.

For this 1 page drawing

Field of application of the invention

The invention relates to a method for electron beam melting of short bars, which must be connected to each other to ensure a continuous melting operation before entering the melting area.

Characteristic of the known technical solutions

It is known to remelt cylindrical short bars with smooth, parallel end surfaces in the electron beam furnace continuously. The rods are pushed on a rod support successively over the molten bath and, starting at the front side, melted by the electron beam. The electron beam is programmed in time so that it alternately melts in one cycle and pulls a weld bead in the following cycle on top of the rods. This bead is continuous to avoid the search of the butt joint. However, as the abutting surface between the bars melts, the bars can only be joined together by the melt flowing and solidifying in the gap such that there is a risk of the refractory material falling into the molten bath in the crystallizer. It is also known, by rotating the rods in their longitudinal axis to weld them together at the abutting surface over the entire circumference. In the case of unequal bars, the butt joint between the bars must be sought by the smelter and the electron beam directed at them.

With electron guns, as they are used for melting, the diameter of the electron beam can not be set arbitrarily small. If the rod diameter is small, about twice the size of the diameter of the electron beam, welding involves the risk that weld material drips from the butt joint onto the rod support. They drip on the rod support hinder the rod feed, and in the rotational movement occur by circumferentially adhering protruding droplets eccentric displacements of the bars against each other, so that the rotational movement of the rods and the secure connection of the same can be prevented.

Object of the invention

The object of the invention is to provide a method for electron beam melting of short bars, which avoids the deficiencies of the prior art. The process must ensure a continuous melting process and avoid broke smelting.

Explanation of the essence of the invention

The object of the invention is to present a method for electron beam melting of short rods, with the short cylindrical rods of any, but the same diameter and any, but the same length and with arbitrarily shaped, but congruent belonging together end surfaces can be so welded together in the melting unit, that a dropping of unmelted remnants into the crystallizer during the melting process is avoided. At the same time, it must be ensured that the rod support is not contaminated by welding side effects, such as welding spatter or drops. The same applies to the bars to be joined, in which, in particular still occurring welding distortion is to be avoided in order not to hinder necessary rotational and feed movements on the rod support.