Effect of different forming processes on ultrasonic defect signals of Ni-based powder metallurgy superalloy
SUN Zhi-kun1,2，Lü Ri-hong3，JIA Jian1,2，HAN Shou-bo1,2，ZHANG Yi-wen1,2，XIE Ling1,2
（1. High Temperature Materials Research Institute， CISRI， Beijing 100081， China 2. Beijing Key Laboratory of Advanced High Temperature Materials， Beijing 100081， China 3. Guizhou Li Yang Aero Engine Co.， Ltd.， Guiyang 550014， China）
Abstract：Contact ultrasonic testing of FGH4096 alloy rings formed by hot isostatic pressing and forging or direct hot isostatic pressing was carried out respectively. The results indicate that there are obvious defect signals when inspecting along the cylindrical surface of the ring prepared by hot isostatic pressing and forging method， and the highest signals appear at the center of the axial thickness； the height of the defect signals gradually reduces down when close to the terminal face； the defect signals still exist near the surface； there are defect signals along all of the outer circumference， and the characteristics of the signals are the same， which is similar to cracks； the location of the signals is almost invariant along the radial direction. While there is no similar defect signal when inspecting FGH4096 ring blank prepared by direct hot isostatic pressing. The experimental results show that the defect signals found along all of the outer circumference of the forging ring is a pseudo defect. It is due to the small attenuation coefficient and the high pulse repetition frequency.
2018, Vol. 28 
