AN INVESTIGATION OF CERTAIN INTERGRANULAR CRACKS IN THE CORE OF A 20Cr2Ni4A STEEL BILLET

An investigation has been carried out on the so-called intergranular cracks appearing in the central part of a macroetched transverse section of a 20Cr2Ni4A steel billet. It is shown that this in fact was a kind of acid-etching phenomenon, due to low-melting inclusions at the interdendritic boundaries appearing as cracks. The above observation was further substantiated in laboratory ingots by the introduction of certain low-melting inclusions into experimental melts.