The joints of magnesium, aluminum, copper, titanium alloy or heavy steel obtained by traditional fusion welding method have defects such as pores and microcracks, and the wide heat-affected zone and large deformation, which limit the welding structure and restrict the wide application of welding parts in related fields.  Frictionstir welding (FSW), as a new solid phase welding technology, can avoid problems such as coarse grain structure of fusion welding joint and delamination between ceramic particles (such as Y2O3, al2o3) and molten matrix.  Therefore, FSW has unique advantages in welding of aluminum, magnesium low melting point materials, ultra-fine crystal steel, particle dispersion reinforced steel and titanium alloy.  However, the application of FSW in the connection of high melting point materials is limited, and one of the main reasons is the instability and functional failure of mixing head materials.  As the core component of FSW, the mixing head needs to work in a harsh environment such as high stress, high temperature and high viscosity rheology, resulting in serious deformation of the mixing head material, aggravation of wear and degradation of microstructure, and the service life of the mixing head is greatly reduced.  

Working principle diagram  

At present, FSW stirring head tools for high melting point materials mainly include tungsten based materials, cobalt based materials and polycrystalline hexagonal boron nitride materials.  Cobalt-based materials are easy to form and prepare, but have poor wear resistance. After high temperature stirring, the tool has lost its original geometric shape and turned into mushroom head shape, and the material instability is obvious.  Polycrystalline hexagonal boron nitride is difficult to process, and will react with titanium, which makes the chemical corrosion of boron nitride stirring head serious.  Tungsten based materials are ideal materials for high temperature mixing head due to their high melting point and relatively excellent mechanical properties at high temperature.  Due to the rhenium effect, the mixing head made of tungsten - rhenium alloy can meet the requirements of strength and toughness at high temperature.  

Practical application of friction stir welding  

Hunan Rheniumet  Ltd. is a high-tech enterprise specializing in the research and manufacture of rare and high melting point metal "rhenium" and "rhenium alloy" materials.  Rhenium company has many years of research experience in tungsten rhenium alloy, the production of 3 grades of mixing head materials have been applied in various fields, can also be customized according to customer needs of new alloy grades.  

1, Grade WR25, can be used for low alloy structure steel welding, such as A36, AISI1020, AISI4140, A572, HSLA80, DS980, Q235, etc.  Can also be used for welding pipeline steel, such as X80, X70;  Suitable for austenitic stainless steel, ferritic stainless steel;  Able to weld solid solution reinforced deformed superalloys, such as Inconel600, Inconel625, Inconel800, and Hastelloy alloys.  

2, brand WRH25, can weld martensitic stainless steel (SS440), hot work die steel (H-13), high strength superalloy (Inconel718).  

3, brand WL4, can weld titanium alloy, copper alloy.