In the application of various titanium alloy products, titanium alloy forgings are mostly used in air turbine compressor disks and medical artificial bones, which require high strength, high toughness and high reliability. Therefore, the titanium forgings not only require high dimensional accuracy, but also require the material to have excellent characteristics and high stability, the following mainly introduces the six problems existing in titanium alloy flaw detection.
Titanium alloy ring
1. Segregation defects
In addition to β segregation, β spot, titanium rich segregation and strip α segregation, the most dangerous is the gap type α stable segregation (type I α segregation), which is often accompanied by small holes, cracks, containing oxygen, nitrogen and other gases, brittle. There is also an aluminum-rich α-stabilized segregation (type II α-segregation), which is also a dangerous defect due to its accompanying cracks and brittleness.
2. Inclusions
Most of them are metal inclusions with high melting point and high density. By the titanium alloy composition of high melting point, high-density elements are not fully melted to form in the matrix (such as molybdenum inclusion), there are also mixed in smelting raw materials (especially recycled materials) carbide tool chips or inappropriate electrode welding process (titanium alloy smelting generally uses vacuum consumable electrode remelting method), such as tungsten arc welding, leaving high-density inclusions, such as tungsten inclusions, tungsten inclusions. In addition, there are titanium inclusions.
The existence of inclusions can easily lead to the occurrence and expansion of cracks, so it is not allowed to exist defects (for example, the Soviet Union's 1977 data stipulates that high-density inclusions with a diameter of 0.3 to 0.5mm must be recorded during X-ray inspection of titanium alloys).