Type and characteristics of flux cored wire

According to the structure of the aluminum welding wire, the flux-cored wire can be divided into a seamed welding wire and a seamless welding wire. Seamless wire can be copper plated, with good performance and low cost, which has become the direction of future development.

According to whether there is protective gas, the flux-cored wire can be divided into gas-shielded welding wire and self-protecting welding wire; the composition of the flux-cored wire core powder is similar to that of the electrode strip, and contains a stabilizer, a deoxidizer, a slag-forming agent and an alloying agent, According to the presence or absence of slag-forming agent in the inner layer filler powder of the flux-cored wire, it can be divided into "medicine powder type" welding wire and "metal powder type" welding wire; according to the alkalinity of slag, it can be divided into titanium type, titanium calcium type and calcium type welding wire. .

The welding process performance of the metal powder type flux-cored wire is similar to that of the solid wire, and its deposition efficiency and crack resistance are superior to those of the "powder type" wire. Most of the powder core is metal powder (iron powder, deoxidizer, etc.). Special arc-increasing agent is also added to ensure less slag formation, high efficiency, small splash, stable arc, and low diffusion hydrogen content of the weld, and the crack resistance is improved.

The weld bead of the titanium type slag-based flux-cored wire is beautifully formed, the whole-position welding process has good process performance, the arc is stable, and the splash is small, but the toughness and crack resistance of the weld metal are poor. In contrast, the calcium-type slag-based flux-cored wire has excellent weld toughness and crack resistance, but the weld bead forming and welding process performance is slightly inferior. The titanium calcium type slag system is between the two.

The cross-sectional shape of the flux-cored wire has a great influence on the welding process performance and metallurgical properties. According to the cross-sectional shape of the flux-cored wire, it can be divided into two types: a simple O-shape and a complex cross-section. The folded shape can be divided into a plum shape, a T shape, an E shape, and an intermediate filler shape.

The more complex and symmetrical the cross-sectional shape of the flux-cored wire, the more stable the arc, and the more complete the metallurgical reaction and protection of the core. However, as the diameter of the wire decreases, the difference is gradually reduced. When the wire diameter is less than 2 mm, the effect of the shape is not obvious.

Flux cored wire has good welding process performance, good weld quality and strong adaptability to steel. It can be used for welding various types of steel structures including low carbon steel, low alloy high strength steel, low temperature steel, heat resistant steel, stainless steel and resistant. Grinding and so on. The shielding gas used is CO2 and Ar+CO2. The former is used for common structures and the latter is for important structures. Flux cored wire is suitable for automatic or semi-automatic welding, DC or AC arc.

Most of the welding wires of low-carbon steel and high-strength steel flux-cored wire are titanium type slag system, which has good welding process and high welding productivity, and is mainly used for shipbuilding, bridge, building and vehicle manufacturing. There are many types of flux-cored wire for low carbon steel and high-strength steel. From the perspective of weld strength level, the flux-cored wire with tensile strength of 490MPa and 590Mpa has been widely used; from the performance point of view, some focus on process performance, and some Focus on weld mechanical properties and crack resistance, some for all-position welding including downright welding, and some for fillet welds.