Factors Affecting Titanium Tubes

1. Segregation type defects
In addition to beta segregation, beta spots, titanium-rich segregation and stripe a segregation, what is very dangerous is the stable segregation of interstitial type a (type a segregation), which is usually accompanied by small holes, cracks containing oxygen, nitrogen and other Gases are more brittle. There is also aluminum-rich stable segregation (type I a segregation), which also forms dangerous defects because it is accompanied by cracks and brittleness.
2. Inclusions
Most of them are high melting point and high density metal inclusions. Titanium alloys have a high melting point. High-density elements are not completely melted into the substrate (such as molybdenum mixing), and are also mixed in smelting raw materials (especially recycled materials), fragments of cemented carbide tools or inappropriate electrode welding processes (titanium smelting - vacuum self-consumption) Extreme remelting method), such as tungsten arc welding, leaving high-density mixing, such as tungsten mixing, except titanium mixing, etc.
The presence of inclusions can easily lead to the occurrence and expansion of cracks in titanium rods and titanium tubes, so defects cannot exist.
3. Residual shrinkage
4. Holes
All holes exist alone, or there may be multiple holes in close proximity, which will accelerate the expansion rate of low-cycle fatigue cracks and lead to early fatigue damage.
5. Cracks
Mainly refers to forging cracks. Titanium alloy has high viscosity, poor fluidity and poor heat transfer. Therefore, in the case of forging deformation, due to large surface friction, obvious uneven internal deformation, and large internal and external temperature differences, it is easy for cutting bands (strain lines) to occur on the titanium rod in the titanium tube, which may lead to cracking in severe cases. --Generally along the direction of large deformation stress.
6. Overheating
Titanium alloy has poor thermal conductivity. In the case of hot processing, in addition to improper heating of the titanium rod, under forging conditions, the titanium tube or raw material is also easily overheated due to the thermal effect during deformation, resulting in changes in the microstructure and the generation of overheated Widmanstatten structure.