METHOD FOR MANUFACTURING A PISTON BLANK FROM HYPEREUTECTIC SILUMIN

摘要

FIELD: metallurgy.;SUBSTANCE: invention relates to metallurgy and can be used for production of pistons of internal combustion engines from hypereutectic silumin. Melt is refined to level of hydrogen content of not more than 0.35 cm³/100 g. Out-of-furnace modification is performed with supply of ligature bar from quickly crystallized, with cooling rate of not less than 1⋅10² K/s of aluminum-based alloy contains disperse phases of compound of aluminum with phosphorus with particle size from 50 nm to 10 mcm. Piston blank is obtained by casting melt at temperature of 750–780 °C into a mold heated to 250–280 °C, and applying pressure on liquid and crystallisable metal according to the program: pressuring by 5–7 % under pressure to 100 MPa for 3 s, pressure testing to 11–12 % under pressure from 100 MPa to 250 MPa for 5–6 s and pressing to 13–13.5 % under pressure to 400 MPa for 50–60 s. Piston blank is processed by mode: cooling after mold opening at 400–420 °C in water heated to 80–90 °C, and natural aging.;EFFECT: homogeneous fine-grained structure is provided in the blank volume, reduced thermal coefficient of linear expansion.;1 cl, 1 dwg, 1 tbl