Shear cracks at a pressed part - 1.5513
Treatment : spheroidised
Magnification : 6,5 : 1
Etching medium :
Sampling / Specification : surface - head burst
Testing result :
diagonal bursts in the area of the upseted
screw head
Treatment : spheroidised
Magnification : 200 : 1
Etching medium : 3 % alcoholic nitric acid
Sampling / Specification : transverse
Testing result :
insufficient spheroidised microstructure
local lamellar pearlite