Welding Basics

I. Welding Overview
Welding is a process in which two or more materials (of the same or different species) are bonded interatomically by heat or pressure (or both) to form a permanent connection. This type of connection is widely used to connect metallic materials and is an integral part of modern industry.
Second, the basis of the arc
Arc is supplied by the welding power supply, between the two poles to produce a strong and persistent gas discharge phenomenon. According to the type of current, arc state and electrode materials, the arc can be divided into AC arc, DC arc, pulsed arc, free arc, compression arc (such as plasma arc), melting electrode arc and non-melting electrode arc.
Third, the welding terminology explained
Base metal: the metal to be welded is called the base material.
Molten drop: the apex of the wire is heated and melted, and the transition to the molten pool of liquid metal droplets.
Molten pool: the weldment formed on the weldment with a certain geometry of the liquid metal part.
Weld seam: the bonding part formed in the weldment after welding.
Weld metal: The part of the metal formed by the solidification of the molten base metal and filler metal (wire, electrode, etc.).
Shield gas: welding used to protect the molten metal droplets and the molten pool from the outside world of harmful gases (hydrogen, oxygen, nitrogen) invasive gas.

Fourth, welding technology and process
Welding technology covers a variety of welding methods, welding materials, welding process and welding equipment and its basic theory. Welding technology is a complete set of procedures and its technical regulations, including welding methods, welding preparation, welding materials, welding equipment, welding sequence, welding operations, welding process parameters and post-welding treatment.
V. Welding method introduction
CO2 welding: use the purity of > 99.98% of CO2 as a protective gas fusion electrode gas shielded welding, with high efficiency, energy saving, welding deformation and other advantages.
MAG welding: using mixed gas (such as 80% Ar + 20% CO2) as a shielding gas of the melting electrode gas shielded welding, suitable for stainless steel, carbon steel and other materials welding.
MIG welding: the use of high-purity argon or mixed gases as a shielding gas fusion electrode gas shielded welding, mainly used for welding aluminum and aluminum alloys, copper and copper alloys and other non-ferrous metals.
TIG (tungsten argon arc welding) welding: the use of pure tungsten or activated tungsten as a non-melting electrode of the inert gas shielded arc welding, suitable for stainless steel, carbon steel and other materials welding.
SMAW (Stick Arc Welding) Welding: Arc welding method using manually manipulated electrodes, widely used in the welding of various metal materials.

Six, welding advantage analysis
CO2 welding compared to electrode arc welding has a higher efficiency, better quality of welded joints and lower overall costs. This is mainly due to the CO2 welding melting speed and melting coefficient is high, small bevel cross-section, the amount of molten metal is small, low power consumption and low equipment costs and other advantages.
Seven, pulse welding technology
Pulse welding technology is a method of welding using pulsed current, divided into low-frequency pulse and medium-frequency pulse. Low-frequency pulse is mainly used for stainless steel, steel and titanium and other non-ferrous metals TIG welding; medium-frequency pulse has an arc compression effect, arc concentration, good stiffness, suitable for thin stainless steel, steel and titanium and other non-ferrous metals, TIG welding and stainless steel and aluminum and aluminum alloys MIG welding.
Through the above introduction, we can have a more comprehensive understanding of welding technology and its application areas. In practical applications, the selection of appropriate welding methods and processes to ensure welding quality and cost reduction is of great significance.