Q: Recently, it was found that the ultrasonic horn made of TC4 was produced by rolling, and no defects were found in the inspection. In a short time of use, micro-cracks will be found on the surface, affecting the use effect. I would like to ask you what is the main cause of insect friends, how should be analyzed. There are different organizations of titanium alloys will have an impact on the spread of ultrasonic waves in which, I hope you will be free to advise. Thank you?
A: It should be rolling orientation or there is an adiabatic shear band near the surface, and generally the alloy falls off along the grain boundary or phase boundary under ultrasonic action. Do not know the alloy grade and rolling process and specifications of your horn, the specific reasons can not be determined. This is due to the rolling before the blank forging, the number of block pulling is not enough, that is, the deformation is not enough, resulting in the grain is not completely refined, and the rolling process will increase the anisotropy of material properties, you only said the final product temperature and specifications, the front process is the key to affect the performance, Such as the composition, forging pier drawing process, the amount of deformation per fire, and the final heat treatment temperature and time. This material is generally made according to the national military standard will not be a problem.