FIELD: technological processes.
SUBSTANCE: invention relates to foundry and can be used in production of castings from aluminum and other alloys. Sealing cap is made in the form of hollow housing with flat end part and associated with it side conical part, maximum outer diameter of which corresponds to maximum diameter of hole of the vent. Cap is made from highly elastic thermoplastic elastomer selected from a group comprising a block copolymer of styrene-butadiene-styrene elastomer (SBS), a block copolymer of styrene-ethylene-polypropylene-styrene rubber (SEBS), compositions based on a block copolymer of styrene-butadiene-styrene elastomer (SBS) containing 50 wt % block copolymer of styrene-ethylene-polypropylene-styrene rubber (SEBS), ethylene vinyl acetate rubber (EVA) and thermoplastic rubber (TPR). Maximum outer diameter of side conical part of cap is 46–52 mm, outer diameter of collar of end part is 1.13–2.0 of maximum outer diameter of side conical part of cap, wall thickness of the side conical part is 1.0–2.5 mm, cap height makes 40–90 mm and thickness of butt end part is 0.5–5.0 mm. Taper side conical part taper corresponds to vent hole taper and makes from 1 to 5°, wherein the highly elastic thermoplastic elastomer of the sealing cap has Shore hardness of 60–75 units, tensile strength of 3.0–10.0 MPa, elongation at break of 350–650 %, density of 0.9–1.5 g/cm3, melt flow index (190 °C/5.0 kg) 2.0–70.0 g/10 min.
EFFECT: invention provides considerable reduction of labor intensity and time of preparatory operations when making sand casting mold using sealing cap, improved quality of produced casts, as well as improved manufacturability both in production of sealing cap and during its practical use.
1 cl, 5 ex, 1 dwg
