Materials Science. Non-Equilibrium Phase Transformations.
Vol. 5 (2019), Issue 3, pg(s) 74-77

The mode of hardening heat treatment for deformable piston hypereutectic silumins

  • 1 Siberian State Industrial University, Russia

Abstract

A series of piston hypereutectic silumin based on Al – (15÷20) % Si, alloyed with copper, magnesium, nickel, chromium is investigated. The mechanical characteristics of ingots from experimental alloys were determined: temporary tensile strength, hardness, relative elongation depending on the composition of the alloys, and temperature coefficient of linear expansion (TCLE). It is shown that the tensile strength of forged blanks is 1.5-2.4 times higher than ingots of hypereutectic silumins. The resulting structure of forgings ensures their high plasticity (relative elongation δ = 5.7÷7.5%; relative narrowing Ψ = 10.3÷14.2%). The optimal mode of heat treatment of deformed silumin is determined: quenching from step heating and aging, which allows increasing the strength of forgings up to 370-470 MPa. Moreover, the plasticity indicators remain at a high level, and the average thermal expansion coefficient of the alloys is (18.0 ÷ 19.2) · 10-6 K-1 in the range of 50 ÷ 200 ° C.

Keywords

References

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