The evaluation of ductile cast iron is common foundry practice. For the correct non-destructive evaluation (NDE) of mechanical properties (ultimate tensile strength; relative lengthening; Brinell’s hardness; elasticity modulus) by means ultrasonic testing and inverse regression analysis are used.
Author: Alexander Popov
CRACK RESISTANCE EVALUATION FOR Al+3.5% Mg ALLOYS BY MEASURMENTS OF ULTRASONIC VELOCITIES AND HARDNESS
The crack resistance in fracture mechanics is defined as critical value of stress intensity factor in the plane-strain fracture toughness. A mechanical test is used to assess it under certain conditions. This is a complicated, long and expensive procedure. In practice, it is of interest to determine the crack resistance for construction elements by means non-destructive evaluations (NDE).
Ultrasonic testing (UT) of castings is common foundary practice. For the correct calibration of UT, it is necessary to measure the velocity propagation of the ultrasound waves in the castings. It is inverse ultrasonic problem. A method for velocity measurement, according to ASTM E 494: 2015, with one-sided access to the casting, is being considered.
In this article the equations for determined of transversal and longitudinal velocities propagation – ( Vt;Vl ) V ;V , through measurement: distance between transducers (source-reflector) – 2.W X and the time of propagation – ( X ) T/t are obtained.