The surrounding conditions during welding include: base material, plate thickness, groove shape, joint form, restraint state, ambient temperature and humidity, cleanliness, and the type and diameter of welding wire (or electrode), welding current, voltage, welding speed, welding sequence, deposition method, gun (or strip) method, etc. determined according to the above factors.

1, the use of electrode: in the narrow or poor ventilation conditions of the occasion, should choose acid electrode or low dust electrode. For structures with large welding workload, high-efficiency electrodes, such as iron powder electrodes, high-efficiency gravity electrodes, etc., or special electrodes such as vertical downward electrodes of bottom electrodes, should be used when conditions permit, so as to improve welding productivity.

Wire is used as filler metal or together as a conductive wire welding material, including carbon steel welding wire, low alloy steel welding wire, alloy structure steel welding wire, stainless steel welding wire and non-ferrous metal welding wire. The surface of the welding wire is not coated with anti-oxidation flux, which is used as filler metal in gas welding and tungsten gas maintenance arc welding; it is both filler metal and conductive electrode in submerged arc welding, electroslag welding and other metal gas maintenance arc welding. Now online Chinese welding wire trading is also very fast.

Two or more than two kinds of materials (the same or different), through heating or pressure or both, to achieve the combination of atoms and form a permanent connection between the process called welding.

Intergranular corrosion is a type of localized corrosion that spreads inward along the boundaries between metal grains. Is due to the difference between the grain surface and internal chemical composition and grain boundary impurities or the existence of internal stress, will destroy the combination between grains, greatly reduce the mechanical strength of the metal, mechanical properties deterioration, can not withstand the knock, is a very dangerous corrosion.