1 Chemical Composition
Casting material grade QT450-10, raw material ratio: Q12 pig iron 50%, recycled material 35%, grade I scrap 15%, chemical composition is shown in Table 1.
2 Production Parameters
(1) Discharging temperature: 1 520 ~ 1 540 ℃, adjusting temperature of molten iron: 1 480 ~ 1 500 ℃.
(2) The vibration time of sand adding in the upper box: > 120 s, the vibration time of sand adding in the lower box: > 120 s, and the hardness of sand mold ≥ 90.
(3) High pressure control – 0.050 ~ – 0.065 MPa, low pressure control – 0.024 ~ – 0.042 MPa.
(4) The sand core was painted twice, the thickness of the coating was 1 mm, and the drying time of the curing barn after painting was more than 12 h.
(5) Pouring temperature: 1 430 ℃ ± 15 ℃, pouring time: 30 ~ 45 s.
(6) High pressure to low pressure time: > 15 min, low pressure holding time: > 30 min, unpacking time after pouring: 5 ~ 6 h.
3 Raw and Auxiliary Materials and Molds
(1) Film: EVA film with thickness of 0.15 mm.
(2) Coating: alcohol based quick drying coating for V-process casting.
(3) Dry sand: 80 ~ 120 mesh quartz sand.
(4) Mold: the core part of the mold is made of high-quality Korean pine wood, the air extraction box is made of multi plywood, and all of them are made of CNC machining; After repairing the surface putty, spray V method mold special paint.
(5) Filter: with 100 × The 100 mm foam ceramic filter has a porosity of 10 PPI and a filtration flow of 70%.
(6) Fesi75a115-b inoculant, particle size 3 ~ 20 mm, fesimg8re5 spheroidizer, particle size 10 ~ 25 mm.