What are the reasons that can cause various adverse situations with titanium alloy screws?

Poor performance of titanium alloy screws can affect their effectiveness, and it is important to promptly address any issues discovered. What specific reasons can lead to various adverse conditions of titanium alloy screws? Now let the titanium alloy screw manufacturer analyze and introduce it to you.

1、 The intrinsic factors of the material itself

1. Excessive content of impurity elements (such as O, N, H)

Oxygen and nitrogen: will significantly improve the strength and hardness of titanium alloys, but will sharply reduce plasticity and toughness, making screws brittle and prone to brittle fracture during installation or stress.

Hydrogen: can cause "hydrogen embrittlement", even if the hydrogen content is very low, it may cause delayed fracture of screws under stress, which is extremely harmful.

2. Metallurgical defects

Uneven organization, such as alpha case (where an undesirable alpha phase layer appears in beta phase alloys) or coarse grain size, can seriously affect the fatigue strength and consistency of mechanical properties of screws.

Inclusions: Non metallic inclusions in raw materials can become stress concentration points and the source of fatigue cracks.

2、 Manufacturing and processing technology issues

The reason for the occurrence of non-circular heads in titanium alloy screws is usually due to insufficient filling or improper selection of the die during the punching process of the screw mold.

There may be three reasons for the occurrence of burrs or rough edges on the surface of two screws. One is that the pores are too large during the punching process. The second is that the punching rod is too short, which can also cause rough edges on the surface of the screw. The third is due to poor punching.

The head of the 3 titanium alloy screw is twisted, which is mainly caused by improper machine adjustment, or it may be due to poor installation of the screw mold.

If there are cracks or fissures on the head of the 4 screws, it is usually due to quality problems with the material itself. Therefore, before starting the screw wire, the quality department must inspect it and apply a solution.

3、 Environmental factors for use

1. Stress corrosion cracking

Under the combined action of specific corrosive media (such as chloride, methanol, etc.) and tensile stress, titanium alloys may undergo stress corrosion cracking. This is a potential risk for titanium screws used in chemical and marine environments.

2. High temperature creep

Although titanium alloys have good heat resistance, if they work at high temperatures exceeding their design temperature (such as TC4 exceeding 400 ° C) for a long time, even under stress below the yield strength, continuous plastic deformation (creep) will occur, leading to relaxation of pre tension and loose connections.

3. Fatigue

Under long-term vibration or alternating load environments, any small surface defect can become a fatigue source, causing screws to fatigue fracture under loads far below their static strength