Welding is a process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filter material to form a pool of molten material (the weld pool) that cools to become a strong joint.
The aim of welding is to ensure the continuity of the assembled product. In the case of metals, the continuity is realised to a scale of atomic structure.
Apart of the ideal case when the inter-atomic forces and the diffusion ensures the slow welding of metallic pieces put entirely in contact together without any form of pollution, it is necessary to use an energy of activation to realise the rapid continuity required.
What is the protocal TIG ?
TIG welding is a procedure of Arc Welding using a non-consumable tungsten electrode to create the weld. TIG is an acronym for Tungsten Inert Gas, in which the weld area is protected from atmospheric contamination by a shielding gas (Inert Gas). The ‘arc’ is created between the refractory electrode (- sign on the generator) and the piece (+ sign on the generator) under a protective gas flow.
The electrodes used are mostly composed of tungsten (more than 99% of the mass) with metallic oxydes to increase the current capacity while improving arc stability and starting and increasing electrode life, and so, the efficiency.
In the majority of the cases, the inert gas is argon (mostly use in the European Union). This gas is neutral and helps protect against instantaneous oxydation during the fusion of the metal and also to preserve the electrode.
What is the MIG-MAG protocol ?
The MIG-MAG welding (or GMAW for the american system) is a protocol of semi-automatic welding. The fusion of metals is obtained by the energy produced by an electric arc which explodes in a protected atmosphere between an electrode wire and the pieces to be assembled.
The acronyms MIG and MAG stand respectively for Metal Inert Gas and Metal Active Gas. The difference between the two procedures is the composition of the gas. The protocol MIG uses a neutral gas which does not react with melted metal (argon or argon + helium), in contrast with MAG (a mix of argon with carbon dioxide and hydrogene in various proportions according to the metals which need to be welded together). The gas is injected continuously on the arc to isolate the fusing metals completely from the surrounding air. The protective atmosphere differs according to the type of MIG or MAG.
Quality and advantages for MIG-MAG welding
This protocol is in competition with the ‘enrobe electrode’ to increase the productivity by reducing the down time while changing electrodes. A qualified solderer with proper welding equipment will be able to realise perfect welding.
The MIG-MAG welding allows a wide flexibility of use :
– welding of different materials: steel, inoxydable steel, aluminium, titanium…
– position welding: flat, roof, side…
– augmentation of the number of applications of protocols for the welding of sheet-metal
It is possible now to weld a metal-sheet with a thickness of 0.5mm, with a speed of 5 meters per minutes with high quality ensured.
TIG-MAG-MIG welding course =>
Registration =>
POLYNÉSIE NOUVELLE-CALÉDONIE
78.01.19 74.00.81
mandrake@mail.pf mandrake@multiforse.nc
Working in a safe environment
Like with any other procedures, the employees are exposed to the following risks :
-> electric hazards
-> toxic welding fumes
-> electromagnetic radiation
-> ultraviolet radiation
-> the hazard of fire and explosion
-> burning hazards
-> hearing hazards
-> musculo-skeleton pains
-> mental breakdown
Electric Hazards
It is necessary for the staff to be qualified (UTE C 18 510) and to posses a valid B0V or B1V.
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The users must :
– not touch the live electric parts
– wear isolating gloves and a protection suit dry and without holes
– isolate the part to cut from the floor using an appropriate carpet
– not use the electric ressources in humid areas
– use welding equipment under constant tension
– never work alone
Toxic welding fumes
Welding can generate fumes composed of oxides, silicates and metallic fluorides. The welding fumes can cause irritations, can be toxic and are composed of gas produced by combustion or by the action of air (CO,NO, NO2).
The users must :
– not inhale the fumes
– always ventilate the area to evacuates the fumes and gas
– if the ventilation is not strong enough, wear an adapted respirator
– read and understand the specifications of the materials and the instruction manual of the manufacturer, especially the metal, consummable and cleaning product chapters
Electromagnetic radiation
An electromagnetic zone is created every time there is an electric charge. An electromagnetic zone is created with the movement of electric charges. Those zones can be consider as carcinogenic for a human.
The users must :
– maintain the cables together by tangling them or envelloping them
– keep the welding equipment and the cables close to themselves
Fire hazards and explosions
In France, there is an explosion a day and every two seconds an fire starts.
Often, the solderers are obliged to work close or in the proximity of :
– flammable liquids or combustibles
– compressed gas
Fire or explosions can occur from sparks or hot metal.
The users must :
– install a good ventilation system (when possible)
– make sure that any flammable material and combustible is situated far from himself
– move any flammable substances a distance of 10 meters from the welding equipment. If it is not possible, cover them with appropriate protection.
Ultraviolet burns
The MIG or TIG solderer must be completly protected (mask and gloves), as the light produced during use is so powerful that it can provoke intense burns especially on the skin and retina. The blue light is as powerful as sunllight and has similar effects on the human body (sunburns, burns, etc.).
However, the skin and the retina can regenerate themselves, pain and marks disappear quickly.
The user must :
– wear an appropriate mask
– wear the appropriate safety googles under the mask
– use protective curtains to protect against additional radiation/sparks
– inform other people around the area not to look at the sparks
Hearing Hazards
Often the solderers work in workshops where the noise is greater than 85 decibels. At 85 decibels, hearing damage can quickly become irreversible. This is considered a professional hazard; deafness.
The users must :
– wear the appropriate protection
– wear said protection ALL THE TIME (not occasionally)
Musculo-skeletal problems
Employees often use complicated positions and carry heavy weights.
The users must :
– know the proper safety equipment, and use it at all time
– learn the proper lifting technics
– take regular breaks if the worker is in a complicated position
– use lifting equipment if the weight of the object is heavier than 55kg
Mental breakdown
The difficulty of work, requirements and deadlines can contribute to stress in the workplace. More and more solderers are obliged to work extra hours or in rotations, which can have negative repercussions on their mental health.
In this case the complexity of tasks can be very stressful, added sometimes to a hostile environnment.
The users must :
– have regular breaks (5 minutes every 55 minutes).
– variate their tasks as much as possible.
