The Method for Determining Fracture Toughness and Impact Strength of 40АГФТ Steel

Abstract

The article deals with the method for determining fracture toughness and impact
strength of 40АГФТ steel. For the fracture toughness test approximate method of calculating
energy characteristic (JIC) was selected. After calculating energy characteristic,
power characteristic (KIc) of fracture toughness was determined. Fracture diagram
was recorded on the C8-2 electronic oscillator during testing. Strain meters were used
to register the force. It is noteworthy that for determining structural strength of steels,
specific work of crack propagation must be calculated by impact tests and recording
the fracture process. For the testing, three 5mm x 10 mm x 55 mm V-notch 45o sharp
(r=0.25mm) standard prismatic specimens were used and arithmetic mean value was
calculated. The tests were carried out on MK-30 pendulum impact testing machine.