The Structure Formation Peculiarities of Bimetal 'Steel - Bronze' with Powder Working Layer during Hot Deformation

摘要

The main problem is in providing good quality of layer joining to obtain bimetal. The conclusion of possibility to obtain bimetal by the hot deformation in the presence of liquid phase on the boundary of layer division is confirmed on the base of well-known method of explosive pressing. The structure peculiarities of bimetal of two types are examined in the paper: on compact steel base with applied knurlings and on the base of powder iron. Bimetal was obtained by the hot forging of irregularly heated preform. Four structure areas are separated in bimetal: adhesion interaction of steel and bronze layers (Ⅰ); bronze fusion (Ⅱ); solid-liquid state of bronze (Ⅲ); mainly solid bronze state (Ⅳ). Satisfactory quality of bimetal layer joining is explained by the active mass transfer in the area I. Besides, on the boundary division the lead and 5-phase inclusions that could lose strength are absent.