There are many welding methods for aluminum alloy, and various methods have different applications.
In addition to the traditional fusion welding, resistance welding, gas welding methods, other welding methods (
Such as plasma arc welding, electron beam welding, vacuum diffusion welding, etc)Aluminum alloys can also be easily welded together.
The characteristics and application scope of common welding methods for aluminum alloy are shown in Table 1.
It should be selected according to the brand number of aluminum and aluminum alloy, weldment thickness, product structure and weldability requirements. (1)Gas welding oxygen-
Acetylene gas welding flame has low thermal power and scattered heat, so the weldment has large deformation and low productivity.
When welding thick aluminum weldments by gas welding, preheating is required. The weld metal after welding is not only coarse in grain and loose in structure, but also prone to defects such as alumina inclusions, pores and cracks. This method is only used for thickness ranges of 0.
5 ~ Welding of 10 ㎜ unimportant aluminum structural parts and castings. (2)
Tungsten argon arc welding is a method of welding under argon protection, with relatively concentrated heat, stable arc combustion, dense weld metal, and high strength and plasticity of welded joints, the more widely it is used in industry.
TIG welding for aluminum alloy is a relatively perfect welding method, but TIG welding equipment is relatively complex and should not be operated in outdoor open air. (3)
The arc power of automatic and semi-automatic argon arc welding is large, the heat is concentrated, the Heat influence area is small, and the production efficiency is 2 ~ higher than that of manual argon arc welding ~ 3 times.
Pure aluminum and aluminum alloy plates with a thickness of less than 50 ㎜ can be welded.
For example, the aluminum plate with a welding thickness of 30 ㎜ does not need to be preheated, and only the positive and negative two layers can be welded to obtain a weld with smooth surface and excellent quality.
Semi-Automatic argon arc welding is suitable for locating welds, intermittent short welds and weldments with irregular structural shapes. Semi-automatic argon arc welding torch can be used for welding conveniently and flexibly, but the diameter of welding wire for semi-automatic welding is relatively thin, the porosity of the weld is more sensitive. (4)Pulsed argon arc welding 1)
This method can obviously improve the stability of small current welding process by tungsten pulse argon arc welding, and is convenient to control arc power and weld formation by adjusting various process parameters.
The weldment has small deformation and small heat affected zone, and is especially suitable for thin plate, all-position welding and other occasions as well as forging aluminum, hard aluminum, ultra-hard aluminum and the like with strong thermal sensitivity.
It can be used to weld aluminum alloy sheets with a thickness of less than 4 ㎜.
For products with high quality requirements, DC shock wave spot welding and seam welding can be used.
More complicated equipment is required for welding, with large welding current and high productivity, which is especially suitable for mass production of parts and components. (6)
Friction stir welding friction stir welding is a solid state connection technology that can be used for welding various alloy plates.
Compared with the traditional fusion welding method, friction stir welding has no splash, no smoke, no need to add welding wire and shielding gas, and no air holes and cracks in the joint.
Compared with ordinary friction, it is not limited by Shaft parts and can weld straight welds.
This welding method has a series of other advantages, such as good mechanical properties of joints, energy saving, no pollution, low preparation requirements before welding, etc.
Due to the low melting point of aluminum and aluminum alloy, it is more suitable for friction stir welding. 2)
The average welding current that can be used for pulsed argon arc welding is small, the parameter adjustment range is large, the deformation and heat affected zone of the weldment are small, the productivity is high, the gas hole resistance and crack resistance are good, and the thickness is 2 ~ All-position welding of 10 ㎜ aluminum alloy sheet. (5)Resistance spot welding, seam welding