HEAT TREATMENT METHOD OF CAST-IRON FRICTION WEDGES OF FREIGHT-CAR TRUCK, HARDENING DEVICE FOR ITS IMPLEMENTATION, AND FRICTION WEDGE FROM CAST-IRON Russian patent published in 2013 - IPC C21D1/56 C21D1/62 B61F5/12 C21D5/00 

FIELD: metallurgy.

SUBSTANCE: cast-iron friction wedge is volume-heated up to 900-920°C, then, surface hardening of vertical and inclined walls is performed by means of the hardening device with water flow during 50-70 seconds at the speed of 0.5-2.0 m/s so that hardness on vertical wall surface of 45-50 HRC and on inclined wall surface of 30-35 HRC is provided. The hardening device is made in the form of ducts installed on the base with supply of cooling liquid, one of which is located vertically, and the other one is located at an angle relative to the base. Ratio of water amount is 3:1 to vertical and inclined surfaces respectively. Heat treatment involving water flow as hardening medium with its directed supply to working surfaces of the wedge and optimisation of geometrical dimensions provides the wedge life equal to more than 500,0 thousand kilometres of run-on operation.

EFFECT: improving strength properties of friction wedges and environmental conditions.

3 cl, 2 tbl, 6 dwg, 1 ex