Research Of Flaking And Its Fractography In A Wheel Steel
车轮钢中的白点及其断口形貌研究

Forming process of flaking in a wheel steel has been investigated. The cracking surface of the flaking was got using a special method, and compared to various fracture surfaces of samples containing flaking. The results show that a cavity with hydrogen, i.e. hydrogen blistering, formed and grew firstly, then microcracks initiated from the wall of the blistering, grew and connected each other resulting in formation of flaking. The cracking surface of flaking is a different idea with fracture surface of the sample containing flaking. The former is quasi-cleavage, similar to that of hydrogen-induced delayed cracking, but the later is dependent upon the failure method and the thickness of the sample. There is no effect of flaking in the steel on various fracture surface morphologies besides secondary cracks. Hydrogen-induced delayed failure is due to atomic hydrogen instead of flaking.