Copper & alloys (alloys take pure copper as the base and be added to one or more other elements, commonly divided into brass, bronze, and white copper) have characteristics of good electrical and thermal conductivity, corrosion resistance, high strength, excellent plasticity, welding, and hot and cold pressure processing, are rare superior materials in the industrial field, and rare welding materials in the field of welding technology.

However, because of the particularities of copper & alloys, copper & alloy welding faces some difficulties and challenges.

Difficulties of Copper & Alloys Welding:

1. Affected by high thermal conductivity: the thermal conductivity of copper is 7~11 times higher than carbon steel. When adopting the same welding parameters as welding the same thickness carbon steel, the copper material will be hard to metal, the filler metal and base material can not be well fused.

2. Large hot cracking tendency of weld joints: copper is easy to oxidize and generate cuprous oxide when it is in the liquid state.

After crystallization, eutectic with a lower melting point is generated, thus reducing the plasticity and generating cracks.

3. Porosity defect is much more severe than carbon steel: the weld beam cools too fast during welding, which is not conducive to the effusion of hydrogen in the base material, easy to form hydrogen porosity;

4. Welding joint performance changes: grain coarsening, plasticity decline, corrosion resistance decline and etc.

Faced with these difficulties, people could only realize connection through brazing, ERW, and other technological methods in the past. However, with the development of technology, welding methods such as shielded metal arc welding, AC TIG welding, pulse MIG welding, and composite laser welding can make the welding of copper & alloys more convenient. Megmeet Artsen series multifunctional models adopt the pulsed MIG welding process and constantly upgrade the process software, thus realizing the efficient welding of copper & alloy on coal mine hydraulic support bottom cylinder.

Customer Case--Melted Copper Overlaying of Coal Mine Hydraulic Support Bottom Cylinder

Hydraulic support is a critical mechanical equipment in coal exploitation and is of great significance to coal mine safety. The hydraulic support bottom cylinder, as the main source of hydraulic power in the coal mine, plays a vital role in successful coal mine operations. However, affected by various external factors, the bottom cylinder surface will inevitably be worn or corroded, and once not well treated, there will occur problems such as oil leakage, lack of power, and the increasing difficulty of coal mining.

Therefore, special attention is paid to wear resistance and corrosion resistance when producing the hydraulic support bottom cylinder. The solution of aluminum bronze overlaying on the inner wall of the bottom cylinder satisfies the usability of hydraulic support bottom steel. However, aluminum bronze overlaying generally has the following problems:

1. Serious porosity tendency.

2. Incomplete fusion of inter-channel or inter-layer due to high thermal conductivity of copper. 

3. Obvious hot brittleness and welded joints are prone to thermal cracking.

4. High dilution rate of weld bead leads to lower performance of surfacing metal.

According to the welding characteristics of aluminum bronzes, Megmeet-welding has developed special copper alloy welding processes, and its unique arc control makes aluminum bronze welding simpler, meeting customers’ process requirements and bringing huge economic benefits to them.

Welding Parameter Setting & Welding Details

• Current: 220A

• Voltage: 24.5V   

• Material: Aluminium Bronze

• Wire diameter: 1.2mm

• Shielding gas: Argon

Welding Video of Coal Mine Hydraulic Support Bottom Cylinder:

Megmeet Artsen series welding power sources solved the difficulties of copper & alloy welding so that copper&alloy MIG welding can be easier and more efficient. In the future, Megmeet will further upgrade the process software to help customers surpass their competitors in welding production and ensure customers can focus on the core business other than welding, and make themselves stand out.