The health and safety of our employees, of our customers as well as of our suppliers, are of the highest priority for us. At the same time, we need to ensure business continuity in the best possible way, with the inevitable restrictions. For this reason, since it is not possible to deal with the matter via telecommunications or other appropriate remote tools, we appeal that the visits to our facilities to be restricted to what is absolutely necessary, avoiding close contacts with our employees. In the event of an identified risk, the employees of Electrex – João R. Matos, S.A., are instructed to prevent any external employee from entering the premises of Electrex – João R. Matos, S.A.
TIG pulsed arc welding is a variation of the TIG process, which switches between two levels: a peak current and a base current. Although this variant existed for several years, nowadays with electronic power control technologies we can achieve pulses per second (pulse frequency) much higher than those of a machine with conventional technology. For this, we need an inverter welding machine with pulsed Tig as such of the Electrex’s TP range (163, 203, 223, 253, 323, 403, 503 DC ou AC/DC).
PULSED TIG ADVANTAGES
This process allows the incensement of the quality of the welds, it reduces the costs of the process, obtaining narrower or wider arcs, it controls the temperature of the welding bath, it allows welding with more or less penetration or even reproduce the dimes effect more easily.
Besides these, allows:
less heat input to the work piece, preventing the deformation of the work piece.
an arc more concentrated, allowing more penetration.
possibility of welding plates of different thicknesses
More control of the welding bath.
PULSED TIG ADJUSTING PARAMETERS
Take the example of ELECTREX TP 323, for regulating the pulsed parameters and its consequences in the welding process. After selecting process of TIG welding and pulsed mode, we have 4 specific parameters that can regulate pulsed TIG: Main Current (Amperes), the base current (Ampere), pulse frequency (Hz) and peak current ratio time / Base current time (%). The main current or peak current is the current with higher intensity, while the base current is the current at a lower intensity. The welding current value is the average of the two currents levels. The pulsed rate is represented by the number of cycles per second between 0.5 and 200 cycles per second. At a higher pulse rate corresponds to a more concentrated arc, producing narrower seams and decreasing the thermally affected zone. The cadence of the dimes effect will also be proportional to the pulse frequency and a smooth seam with a very high pulse rate can also be obtained. Finally, the pulse time or length can be adjusted at both current levels and the effects of pulse length identical to pulse rate can be adjusted. The shorter the main current time, the lower the heat induction, there will be greater penetration and narrower seams will be obtained.
Problems at the end of the weld, when using tig with lift? We present video about ARCOFF function, which when the welding voltage value set by the operator is reached, the arc extinguishes automatically to improve the end of the weld. This function is available in all DC models of MMA/TIG serie3.
TIG Dynamics, present in all serie 3 TP DC machines. It allows that, when there is a variation of the distance between the TIG welding torch and the workpiece, there is a compensation in terms of power of the machine to maintain the same thermal delivery.
“I had no problem integrating in a masculine environment, in fact in uniform we are all the same”
We took the Women’s Day to interview a female welder. Isabel Ferreira is a female professional welder in a metal workshop in Viana do Castelo, Portugal, who claims to have the privilege of doing what she likes.
Electrex: What motivated to take the Welding Technician course? Isabel Ferreira: My father was a welder, and hence my interest since I was very little in this area.
Electrex: A question we cannot escape: Was it difficult for you as a woman to enter a mostly male world? Isabel Ferreira: While I did the course no. But, for me, my biggest obstacle was when I looked for an internship and companies closed doors for not being prepared to receive women, I speak at the level of conditions, there are no women’s balnearies. When I got an internship, I can say that I was very well received and I had no problem integrating in a masculine environment, in fact in uniform we are all the same.
Electrex: What’s the reaction of people when they ask you about the profession and you answer that you’re a welder? Isabel Ferreira: Most people are amazed, others ask me if I’m not afraid breaking my nails (laughs). Others, as they know my father was a welder, say that he must be proud to have followed his footsteps. It is normal for people to have these reactions, in Portugal the mentalities are still very closed.
Electrex: What advice would you give to young women who want to be welders? Isabel Ferreira: I think that if women really want to follow this area, they must take a change, regardless of what other people might think or say. The best thing that happened to me was getting to work in this area feel fulfilled. Many people get up in the morning and it seems that they will be annoyed to work, I am glad because I joined the useful to the pleasant.
TIG welding feeder that allows the addition of wire over the bath with tig welding intermittently or continuously. Reduce costs with addition material thanks to the lack of material waste, productivity gain and quality due to a consistent and fast material addition, faithfully reproducing the movement of the welder’s hand. Suitable for manual, automatic or orbital TIG welding applications on thin or thick metalsheets, pipes and refill. Suitable for steel, stainless steel aluminium alloys, titanium, from 0.8 to 1.2 mm, in 5kg,15 kg spool or large wire packs.
“Technological areas, where the demand for qualified technicians is superior to supply, also offer women prospects of interesting and well-paid professional careers.”
On Women’s Day, we interview Luísa Coutinho. Through her professional career we realize that it is possible for a woman to achieve success in the world of welding, if not let’s see: Luísa Coutinho is Executive Director of the European Federation for Welding, Joining and Cutting (EWF), consultant of ISQ (the Portuguese welding institute) in addition to being a PhD in Welding and a professor and researcher in the Mechanical Engineering Department of IST (Instituto Superior Técnico).
Electrex: With so many fields of study in mechanical engineering, what motivated you to follow the field of welding and to do a PhD in this area? Luísa Coutinho: A good teacher! At Instituto Superior Técnico I had Engineer Dias Alves, from Sorefame, as professor of mechanical technology. He was a great teacher who linked theory to practice and aroused interest in welding technology. Later, ISQ put me in touch with Prof. Apps at Cranfield University, where I went on to do my PhD with a scholarship from the Gulbenkian Foundation.
Electrex: A question we cannot escape: Was it difficult for you as a woman to enter a mostly male world? Luísa Coutinho: It is well known that in Portugal women find it more difficult to have their skills recognized and promoted in their professional careers than men. My case was no different. With work, dedication and persistence the recognition finally arrived, first internationally and only later in Portugal.
Electrex: In April of last year, you said that Europe is at risk of implosion. Do you still have this concern? What paths should Europe follow? Luísa Coutinho: Europe continues to experience difficult times, with a mosaic of electoral results in several countries that create situations of political, social and economic instability. Economic growth has, however, brought many positive aspects. I continue to believe in a united and strong Europe.
Electrex: What advice would you give to young women who want to pursue the field of welding either as an area of academic study or as a welder per se? Luísa Coutinho: Welding and, more generally, manufacturing technologies are not appealing areas for women. I am now in Brazil and today I visited Senai Technological Center, a reference in professional qualification in Brazil. One of the aspects mentioned in the meeting with the Management was the need to make inform of the professional options of welding to secondary school students. We have addressed several initiatives in this direction implemented by European welding institutes. Technological areas, where the demand for skilled technicians is superior to supply, also offer women prospects of interesting and well-paid professional careers.
The old TIG machines with conventional technology used the sinusoidal waveform in TIG welding in alternating current (AC). Nowadays, the new inverter TIG AC/DC machines allow the selection of various waveforms in TIG welding in alternating current (AC). This selection, without changing other parameters of welding, allows to change the characteristics of the arc, the seam, and the cleaning / penetration effect.
Cordões de soldadura em alumínio. Onda quadrada, onda sinusoidal e onda triangular (da esquerda para a direita).
Penetration in aluminum (rear side of the plate). Square wave, sine wave and triangular wave (from left to right).
Square wave:
Welding of light alloys with more penetration into thick plates. It forms a more “strong” arc, then more rough and noisy, where there is more heat transfer. It forms a broader and thicker seam.
Sine wave:
É usada na maioria das aplicações. O arco é mais suave e menos ruidoso, do que a onda quadrada.
Triangular wave:
Welding of thin plates with little transference energy and thus, less penetration. It reduces the distortion of the parts and allows a fast solidification of the welding bath. It is especially recommended for thin-thickness aluminum.
There are many ways to inspect a weld, but one of the simplest, practical to do, is the visual inspection. This is surely a non-destructive testing, which lets you monitor what is happening on the surface with the naked eye or through a magnifying glass. There are other techniques such as radiographic testing or ultrasound testing, which should be part of the quality proceedings. The weld bead, its shape and form, is a major defect indicator in a weld, but not the only: the heat-affected zone, the presence of projections, cracks or distortions in the workpiece, among others are also indicators of welding quality. The most common defects in a weld joint may be due to the following causes:
Falta de penetração – corrente ou velocidade de soldadura muito baixas – abertura excessiva da junta – chanfro inadequado – grande espessura da peça de trabalho – distância excessiva entre o eléctrodo e a peça de trabalho – posição ou movimento do eléctrodo inadequados – diâmetro do eléctrodo inadequado
Mordedura: – corrente ou velocidade de soldadura demasiado elevadas
Preparação incorrecta da junta: – chanfro inadequado – desalinhamento das peças a soldar
Fissuras: – Crateras no final da soldadura – tipo de eléctrodo inadequado – eléctrodo húmido – grande espessura da peça de trabalho – chanfro incorrecto
Excesso de respingos: – corrente de soldadura muito elevada – grande distância entre eléctrodo e a peça de trabalho – peça suja- eléctrodo húmido
Inclusão de escória: – escória não removida durante passes ou na troca de eléctrodo – posição ou ângulo de eléctrodos inadequados – diâmetro do eléctrodo muito elevado ou chanfro muito estreito
Porosidade: – Peça suja, enferrujada ou húmida – corrente de soldadura incorrecta – velocidade de soldadura elevada – distância excessiva entre o eléctrodo e a peça de trabalho – eléctrodo húmido
Distorção de contracção e angular: – corrente ou velocidade de soldadura demasiado elevadas
MecaPulse system for low heat continuous welding with less workpiece distortion and excellent gap bridging of thin plates. Great reduce of wire and energy consumption. Present in MIG/MAG DIGIT II, SYNERGIC II and LTRONIC SYNERGIC machines.
