FIELD: machine building; metallurgy; agriculture.
SUBSTANCE: invention relates to machine building, metallurgy and agricultural production, in particular to a method of improving reliability of cast-iron anchor ploughshares of stubble seeders using thermal treatment. Method involves melting, alloying and modifying cast iron, obtaining a cast into a sand mould, removing the casting from the mould at a given temperature, moving into a liquid bath with a given temperature, wherein the cast iron containing, wt.%: C 3.2–3.3, Si 2.0–2.2, Mn 0.5–0.6, Ni 1.5–1.6, Mo 0.9–1.1, Cr 1.1–1.3, Cu 1.2–1.4, Mg 0.04–0.05, Co 0.2–0.25, Ti 0.2–0.25, Ba 0.06–0.08, S ≤ 0.08, P ≤ 0.08, Fe is the rest, removed from the mould at temperature of 950–1,020°C and moved into a bath with water with temperature of 20°C, wherein heat treatment is carried out by four cycles of immersion and extraction of the cutting part of the anchor ploughshare, at that, at the first cycle, the cutting part is immersed in water and held for 2.3 seconds, then extracted and held in air for 3.0 seconds, on second cycle immersed in water and held for 2.2 seconds, then extracted and held in air for 4.2 seconds, in the third cycle, immersed in water and held for 1.5 seconds, then extracted and held in air for 8.7 seconds, in the fourth cycle, immersed in water and held for 1.0 seconds, then removed and held in air until completely cooled, wherein at the first cycle, the cutting part is immersed in water from the upper frontal angle of the first bulge from above to the perpendicular to the middle of the distance from the lower part of the second bulge from above to the lower occipital angle relative to the installed state, and in the second and subsequent cycles, the cutting part is immersed in water from the upper frontal angle of the first bulge from above to the lower occipital angle relative to the set state.
EFFECT: zonal distribution of metallographic structures on functional zones of anchor ploughshares of stubble seeders in accordance with type of prevailing loads.
1 cl, 2 dwg, 1 tbl, 2 ex
