Abstract
The electron beam welding of metals is performed by the travelling of the focusing point along the junction of two pieces to be connected. Welding parameters are the electron gun power W, the value of the electron impact surface S, the welding speed s. From the beginning of our research in 1954, the preponderant part played by specific power W/s on the shape of the welded zone and the penetrating depth, became evident. A more methodical research has been undertaken in the laboratories of C.E.N. under the patronage of Professor CHAUDRON, in order to define in a better way the importance of the different welding parameters and to determine their influence on the metallurgical qualities of welded assemblies. This research induced us to define an electron gun adapted as well as possible to the performance of weldings, not only from the point of view of behaviour, especially during the passage from the atmospheric to a low pressure at 10{sup -5} Torr, necessary for the carrying out of a welding, but also from the point of view of adjustment conveniences of the different welding parameters, indispensable to the intended research work. The variations of welding parameters show that the shape of
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Stohr, J
[1]
- Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Citation Formats
Stohr, J.
Contribution to a research on electron beam welding of metals; Contribution a l'etude de la soudure des metaux par faisceau d'electrons.
France: N. p.,
1964.
Web.
Stohr, J.
Contribution to a research on electron beam welding of metals; Contribution a l'etude de la soudure des metaux par faisceau d'electrons.
France.
Stohr, J.
1964.
"Contribution to a research on electron beam welding of metals; Contribution a l'etude de la soudure des metaux par faisceau d'electrons."
France.
@misc{etde_20793547,
title = {Contribution to a research on electron beam welding of metals; Contribution a l'etude de la soudure des metaux par faisceau d'electrons}
author = {Stohr, J}
abstractNote = {The electron beam welding of metals is performed by the travelling of the focusing point along the junction of two pieces to be connected. Welding parameters are the electron gun power W, the value of the electron impact surface S, the welding speed s. From the beginning of our research in 1954, the preponderant part played by specific power W/s on the shape of the welded zone and the penetrating depth, became evident. A more methodical research has been undertaken in the laboratories of C.E.N. under the patronage of Professor CHAUDRON, in order to define in a better way the importance of the different welding parameters and to determine their influence on the metallurgical qualities of welded assemblies. This research induced us to define an electron gun adapted as well as possible to the performance of weldings, not only from the point of view of behaviour, especially during the passage from the atmospheric to a low pressure at 10{sup -5} Torr, necessary for the carrying out of a welding, but also from the point of view of adjustment conveniences of the different welding parameters, indispensable to the intended research work. The variations of welding parameters show that the shape of the molten zone turns from a circle segment to that of a very high triangle, which implies a continual change of the mode of heat transmission. Tests have been made, in order to confirm this way of looking, especially in order to achieve isotherms in dynamic operating and also the comparison of these isotherms with that recorded while using a method of argon arc welding. The thermal balance of energy supplied to the part, the necessary welding energy, and the energy loss (through conduction, radiation and evaporation) has also been established. These results proved that almost the whole of energy has been used for melting, that the different losses are negligible and that heat transmission can not occur by thermal conduction through the part during 'welding' time, when operating under such conditions that the molten zone shows a small section, which is the main characteristic of this method. These tests have also established that the hollow cut by the electron beam, is free of molten metal, which allows a flow of electrons, whose penetration into the material is negligible. This way of looking has been confirmed by macro-graphies of mixtures, where very short welding points have been performed. These macro-graphies show the existence of a central hole. Tests made under dynamic operating confirm also the existence of a hole, when during the welding process, the electron beam pressure, the molten metal is pushed against the height, then existence of a hole, when during the welding process, the electron beam is suddenly cut off. Therefore, the welding process can be explained as follows: Through electron beam pressure, the molten metal is pushed against the height, then flows down, once the electron beam has moved away, and fills the previously made hole. The existence of a welding seam corroborates this point of view: autoradiographic of straight sections of parts containing radiotracers, show well the mixing due to metal flow. As a matter of fact, the filling of the hole is made by the molten metal coming as well from the higher part, as the lateral back part of the hole (on grounds of way of moving); The penetrating depth also depends on material's characteristics. Tests made with pieces of Cu, Fe, Al show that the penetrating depth is almost proportional to specific heat and in this particular case, one gets: h(Al) / C(Al) = h (Fe) / C (Fe) = h (Cu) / C (Cu) This proportionality comes to an end, welding alloys with one or several additional elements show a high vapour pressure at the melting pint. Tests made with Aluminium and an Al-Mg alloy show indeed a considerable increase of penetrating depth for the latter, in spite of the fact, that the specific heat is practically the same. This increase of penetrating depth can be explained by the pressure, occasioned by additional elements with high vapour pressure, put on the formation of the hole. Micrographs made with welded parts of different metals show melting segregations similar to those obtained when filling a mould of great length. One may point out, that the geometrical configuration adopted by these segregations confirm the hypothesis of the metal flow, as previously contemplated. The study of these segregations, observed during examination through an interferential contrast microscope, has been attempted with a Castaing probe and by radiographical inspection of thin plates: no heterogeneity whatever has been observed. Mechanical tests operated on welded parts, did not show any appreciable difference existing between failure, elongation, yield point and impact values of a welded piece and those of a piece of the basic metal. This method applied on stainless steel shows not only excellent results, but also that the number of calories provided per length unit increases slightly with the welded thickness, whereas one could have expected a linear expression. Results obtained during this work, allow us to sift a certain number of data inherent to the electron beam welding, and to reflect on the definition of welding parameters versus aim to be reached. (author) [French] La soudure des metaux par faisceau d'electrons s'effectue par deplacement du point de focalisation du faisceau sur la ligne de jonction des deux pieces a assembler. Les parametres de soudure sont la puissance du canon W, la valeur de la surface d'impact des electrons S, la vitesse de soudure s. Des le debut de notre etude en 1954, est apparu le role essentiel joue par la puissance specifique W/s, sur la forme de la zone soudee et la profondeur de penetration. Une etude plus systematique a ete entreprise aux laboratoires du C.E.N. Saclay sous le patronage de Monsieur le Professeur CHAUDRON pour mieux definir l'Importance des divers parametres de soudure et voir l'influence exercee par eux sur les qualites metallurgiques des ensembles soudes. Cette etude a amene a definir un canon a electrons aussi adapte que possible a la realisation de soudures, tant au point de vue comportement, notamment lors des passages de la pression atmospherique a la pression reduite de 10{sup -5} Torr necessaire pour la realisation de la soudure, qu'au point de vue de la facilite du reglage des divers parametres de soudure necessaire pour l'etude envisagee. La variation des parametres de soudure montre que la forme de la zone fondue, passe du segment de cercle a celle d'un triangle a grand elancement. Ce qui implique un changement continu du mode de transmission de chaleur. Des essais ont ete realises pour confirmer cette maniere de voir, notamment l'obtention, des isothermes en regime dynamique et la comparaison de ces isothermes avec celles relevees en utilisant le procede de soudure par argon arc. Le bilan thermique de l'energie fournie a la piece, de l'energie necessaire a la fusion et de l'energie perdue (conduction, rayonnment, vaporisation) a ete etabli. Ces resultats mettent en evidence que la quasi totalite de l'energie est utilisee pour la fusion, que les diverses pertes sont negligeables et que la transmission de la chaleur ne peut s'etablir par conduction dans la piece pendant le temps 'soudure' lorsqu'on opere dans des conditions de regime telles que la zone fondue presente une section faible, caracteristique essentielle du procede. Ces essais confirment egalement que la cavite creusee par le faisceau d'electrons est libre de metal fondu, ce qui permet le passage des electrons dont la penetration dans la matiere est negligeable. Cette maniere de voir est confirmee par des macrographies sur pieces fixes sur lesquelles ont ete executes des points de soudure tres courts: ces macrographies montrent l'existence d'un canal central. Les essais effectues en regime dynamique confirment egalement l'existence de ce canal, lorsque en cours de soudure on interrompt brutalement le faisceau d'electrons. Le processus de soudure peut donc s'expliquer de la facon suivante: Le metal fondu est repousse vers le haut par la pression des electrons, coule vers le bas lorsque le faisceau se deplace et remplit la cavite precedemment creee. L'existence d'un cordon de soudure confirme ce point de vue; les radioimages obtenues a partir de sections droites de pieces comportants des traceurs radioactifs, montrent bien le brassage resultant de l'ecoulement du metal. En fait, le templissage de la cavite s'opere par le metal fondu provenant a la fois de la partie superieure de la piece et de la partie laterale arriere de la cavite (en considerant le sens du mouvement). La profondeur de penetration depend egalement des caracteristiques des materiaux; les essais effectues sur des pieces en Cu, Fe, Al montrent que cette profondeur de penetration est pratiquement proportionnelle a la chaleur specifique, on obtient dans le cas precite: h(Al) / C(Al) = h (Fe) / C (Fe) h (Cu) / C (Cu) cette proportionnalite cesse d'etre vraie lorsque l'on soude des alliages dont un ou plusieurs elements d'addition presentent une notable tension de vapeur a la temperature de fusion. En effet, les essais effectues sur l'aluminium et sur l'alliage Al-Mg montrent un accroisment notable de la profondeur de penetration pour ce dernier, bien que les chaleurs specifiques soient pratiquement identiques. Cet accroissement de la profondeur de penetration peut s'expliquer par l'aide qu'apporte a la formation de la cavite, la pression creee par l'element d'addition a tension de vapeur elevee. Les micrographies effectuees sur des pieces soudees de metaux divers, montrent des segregations de fonderie semblables a celles que l' obtient lorsqu'on remplit un moule a grand elancement. On peut signaler au passage que la configuration geometrique prise par ces segregations confirme l'hypothese de l'ecoulement du metal tel qu'il a ete envisage precedemment. L'etude de ces segregations, mises en evidence par examen microscopique a contraste interferentiel, a ete entreprise a la sonde de Castaing et par radiographie de plaques minces: aucune heterogeneite n'a pu etre mise en evidence. Les essais mecaniques effectues sur pieces soudees, ont montre qu'aucune difference appreciable n'existait pour les valeurs de rupture, d'allongement, de limite elastique et de resilience entre une piece soudee et une piece du metal de base. L'application du procede a l'acier inoxydable montre l'excellence des resultats obtenus et montre que le nombre de calories fourni par longueur unitaire de soudure croit legerement avec l'epaisseur soudee, alors que l'on pouvait s'attendre a une expression lineaire. (auteur)}
place = {France}
year = {1964}
month = {Mar}
}
title = {Contribution to a research on electron beam welding of metals; Contribution a l'etude de la soudure des metaux par faisceau d'electrons}
author = {Stohr, J}
abstractNote = {The electron beam welding of metals is performed by the travelling of the focusing point along the junction of two pieces to be connected. Welding parameters are the electron gun power W, the value of the electron impact surface S, the welding speed s. From the beginning of our research in 1954, the preponderant part played by specific power W/s on the shape of the welded zone and the penetrating depth, became evident. A more methodical research has been undertaken in the laboratories of C.E.N. under the patronage of Professor CHAUDRON, in order to define in a better way the importance of the different welding parameters and to determine their influence on the metallurgical qualities of welded assemblies. This research induced us to define an electron gun adapted as well as possible to the performance of weldings, not only from the point of view of behaviour, especially during the passage from the atmospheric to a low pressure at 10{sup -5} Torr, necessary for the carrying out of a welding, but also from the point of view of adjustment conveniences of the different welding parameters, indispensable to the intended research work. The variations of welding parameters show that the shape of the molten zone turns from a circle segment to that of a very high triangle, which implies a continual change of the mode of heat transmission. Tests have been made, in order to confirm this way of looking, especially in order to achieve isotherms in dynamic operating and also the comparison of these isotherms with that recorded while using a method of argon arc welding. The thermal balance of energy supplied to the part, the necessary welding energy, and the energy loss (through conduction, radiation and evaporation) has also been established. These results proved that almost the whole of energy has been used for melting, that the different losses are negligible and that heat transmission can not occur by thermal conduction through the part during 'welding' time, when operating under such conditions that the molten zone shows a small section, which is the main characteristic of this method. These tests have also established that the hollow cut by the electron beam, is free of molten metal, which allows a flow of electrons, whose penetration into the material is negligible. This way of looking has been confirmed by macro-graphies of mixtures, where very short welding points have been performed. These macro-graphies show the existence of a central hole. Tests made under dynamic operating confirm also the existence of a hole, when during the welding process, the electron beam pressure, the molten metal is pushed against the height, then existence of a hole, when during the welding process, the electron beam is suddenly cut off. Therefore, the welding process can be explained as follows: Through electron beam pressure, the molten metal is pushed against the height, then flows down, once the electron beam has moved away, and fills the previously made hole. The existence of a welding seam corroborates this point of view: autoradiographic of straight sections of parts containing radiotracers, show well the mixing due to metal flow. As a matter of fact, the filling of the hole is made by the molten metal coming as well from the higher part, as the lateral back part of the hole (on grounds of way of moving); The penetrating depth also depends on material's characteristics. Tests made with pieces of Cu, Fe, Al show that the penetrating depth is almost proportional to specific heat and in this particular case, one gets: h(Al) / C(Al) = h (Fe) / C (Fe) = h (Cu) / C (Cu) This proportionality comes to an end, welding alloys with one or several additional elements show a high vapour pressure at the melting pint. Tests made with Aluminium and an Al-Mg alloy show indeed a considerable increase of penetrating depth for the latter, in spite of the fact, that the specific heat is practically the same. This increase of penetrating depth can be explained by the pressure, occasioned by additional elements with high vapour pressure, put on the formation of the hole. Micrographs made with welded parts of different metals show melting segregations similar to those obtained when filling a mould of great length. One may point out, that the geometrical configuration adopted by these segregations confirm the hypothesis of the metal flow, as previously contemplated. The study of these segregations, observed during examination through an interferential contrast microscope, has been attempted with a Castaing probe and by radiographical inspection of thin plates: no heterogeneity whatever has been observed. Mechanical tests operated on welded parts, did not show any appreciable difference existing between failure, elongation, yield point and impact values of a welded piece and those of a piece of the basic metal. This method applied on stainless steel shows not only excellent results, but also that the number of calories provided per length unit increases slightly with the welded thickness, whereas one could have expected a linear expression. Results obtained during this work, allow us to sift a certain number of data inherent to the electron beam welding, and to reflect on the definition of welding parameters versus aim to be reached. (author) [French] La soudure des metaux par faisceau d'electrons s'effectue par deplacement du point de focalisation du faisceau sur la ligne de jonction des deux pieces a assembler. Les parametres de soudure sont la puissance du canon W, la valeur de la surface d'impact des electrons S, la vitesse de soudure s. Des le debut de notre etude en 1954, est apparu le role essentiel joue par la puissance specifique W/s, sur la forme de la zone soudee et la profondeur de penetration. Une etude plus systematique a ete entreprise aux laboratoires du C.E.N. Saclay sous le patronage de Monsieur le Professeur CHAUDRON pour mieux definir l'Importance des divers parametres de soudure et voir l'influence exercee par eux sur les qualites metallurgiques des ensembles soudes. Cette etude a amene a definir un canon a electrons aussi adapte que possible a la realisation de soudures, tant au point de vue comportement, notamment lors des passages de la pression atmospherique a la pression reduite de 10{sup -5} Torr necessaire pour la realisation de la soudure, qu'au point de vue de la facilite du reglage des divers parametres de soudure necessaire pour l'etude envisagee. La variation des parametres de soudure montre que la forme de la zone fondue, passe du segment de cercle a celle d'un triangle a grand elancement. Ce qui implique un changement continu du mode de transmission de chaleur. Des essais ont ete realises pour confirmer cette maniere de voir, notamment l'obtention, des isothermes en regime dynamique et la comparaison de ces isothermes avec celles relevees en utilisant le procede de soudure par argon arc. Le bilan thermique de l'energie fournie a la piece, de l'energie necessaire a la fusion et de l'energie perdue (conduction, rayonnment, vaporisation) a ete etabli. Ces resultats mettent en evidence que la quasi totalite de l'energie est utilisee pour la fusion, que les diverses pertes sont negligeables et que la transmission de la chaleur ne peut s'etablir par conduction dans la piece pendant le temps 'soudure' lorsqu'on opere dans des conditions de regime telles que la zone fondue presente une section faible, caracteristique essentielle du procede. Ces essais confirment egalement que la cavite creusee par le faisceau d'electrons est libre de metal fondu, ce qui permet le passage des electrons dont la penetration dans la matiere est negligeable. Cette maniere de voir est confirmee par des macrographies sur pieces fixes sur lesquelles ont ete executes des points de soudure tres courts: ces macrographies montrent l'existence d'un canal central. Les essais effectues en regime dynamique confirment egalement l'existence de ce canal, lorsque en cours de soudure on interrompt brutalement le faisceau d'electrons. Le processus de soudure peut donc s'expliquer de la facon suivante: Le metal fondu est repousse vers le haut par la pression des electrons, coule vers le bas lorsque le faisceau se deplace et remplit la cavite precedemment creee. L'existence d'un cordon de soudure confirme ce point de vue; les radioimages obtenues a partir de sections droites de pieces comportants des traceurs radioactifs, montrent bien le brassage resultant de l'ecoulement du metal. En fait, le templissage de la cavite s'opere par le metal fondu provenant a la fois de la partie superieure de la piece et de la partie laterale arriere de la cavite (en considerant le sens du mouvement). La profondeur de penetration depend egalement des caracteristiques des materiaux; les essais effectues sur des pieces en Cu, Fe, Al montrent que cette profondeur de penetration est pratiquement proportionnelle a la chaleur specifique, on obtient dans le cas precite: h(Al) / C(Al) = h (Fe) / C (Fe) h (Cu) / C (Cu) cette proportionnalite cesse d'etre vraie lorsque l'on soude des alliages dont un ou plusieurs elements d'addition presentent une notable tension de vapeur a la temperature de fusion. En effet, les essais effectues sur l'aluminium et sur l'alliage Al-Mg montrent un accroisment notable de la profondeur de penetration pour ce dernier, bien que les chaleurs specifiques soient pratiquement identiques. Cet accroissement de la profondeur de penetration peut s'expliquer par l'aide qu'apporte a la formation de la cavite, la pression creee par l'element d'addition a tension de vapeur elevee. Les micrographies effectuees sur des pieces soudees de metaux divers, montrent des segregations de fonderie semblables a celles que l' obtient lorsqu'on remplit un moule a grand elancement. On peut signaler au passage que la configuration geometrique prise par ces segregations confirme l'hypothese de l'ecoulement du metal tel qu'il a ete envisage precedemment. L'etude de ces segregations, mises en evidence par examen microscopique a contraste interferentiel, a ete entreprise a la sonde de Castaing et par radiographie de plaques minces: aucune heterogeneite n'a pu etre mise en evidence. Les essais mecaniques effectues sur pieces soudees, ont montre qu'aucune difference appreciable n'existait pour les valeurs de rupture, d'allongement, de limite elastique et de resilience entre une piece soudee et une piece du metal de base. L'application du procede a l'acier inoxydable montre l'excellence des resultats obtenus et montre que le nombre de calories fourni par longueur unitaire de soudure croit legerement avec l'epaisseur soudee, alors que l'on pouvait s'attendre a une expression lineaire. (auteur)}
place = {France}
year = {1964}
month = {Mar}
}