Determination of hardness in welded rail surface via Barkhausen noise

At present, the railway mainly uses eutectoid pearlite rails. The hyper-eutectoid steel improves the strength and hardness of the rail compared to the eutectoid pearlite steel, and is now laid on heavy-duty railway lines. Aiming at the failure of welded rail, welding surface was tested by the magnetic Barkhausen noise (MBN) method. Combined with the surface hardness test and metallographic analysis, hardness changed and structural transformation caused by flash welding was analyzed from the microscopic point of view. The relationship between hardness and MBN signal was quantitatively analyzed, results showed that there was a good correlation between two parameters.