Pre-welding preparation and post-welding treatment of aluminum alloy

Aluminum and aluminum alloy is an important metal material, because of its special logistics, in many industrial, civil and other fields are widely used. In the process of processing aluminum and aluminum alloy, welding is an important link, how to get a better and more reliable welding quality, in addition to good welding technology and equipment, scientific welding before and after treatment is also very important.

Weld preparation

1. Cleaning before welding: When welding aluminum and aluminum alloy, the oxide film and oil on the welding joint and the welding wire surface of the workpiece should be strictly removed before welding;

   1) Chemical cleaning Chemical cleaning efficiency is high, stable quality, suitable for cleaning welding wire and small size, batch production of the workpiece.Available dip and scrub method two kinds.

   2) mechanical cleaning: mechanical cleaning is often used when the workpiece size is large, the production cycle is long, and the multi-layer welding or chemical cleaning is stained.

2. Backing plate: aluminum alloy at high temperature strength is very low, liquid aluminum flow performance is good, welding seam metal is easy to produce the phenomenon of collapse.In order to ensure penetration and not collapse, welding is often used to support the molten pool and nearby metal.The backing plate can be graphite plate, stainless steel plate, carbon steel plate, copper plate or copper bar, etc.Open a circular groove on the surface of the backing plate to ensure that the reverse side of the weld is formed.It can also be single-sided welding and double-sided forming without backing plate, but it requires skilled welding operation or advanced technological measures such as strict automatic feedback control of arc welding energy.
   

3. Preheating before welding: thin, small aluminum parts generally do not preheat, thickness of 10mm ~ 15mm can be preheating before welding, according to different types of aluminum alloy preheating temperature can be 100℃ ~ 200℃, available oxygen acetylene flame, electric furnace or torch heating.Preheating can reduce the deformation and porosity of welding parts.

postweld treatment

1. The residual flux and welding slag left in the weld and nearby after welding will destroy the passivation film on the aluminum surface, and sometimes corrode the aluminum parts, so they should be cleaned up.Simple shape, general requirements of the workpiece can be used hot water scour or steam brush and other simple methods to clean.

2. Heat treatment after welding is generally not required for aluminum containers.