SU1537353A1 - Method of preparing sands in production of thin-walled castings in sand-clay moulds - Google Patents

Abstract

The invention relates to foundry, in particular, to a technology for producing castings from manganese steels. The purpose of the invention is to increase the stability of the properties of the mixture and the quality of castings. Refreshing of the reverse sandy-clay mixture is carried out by a filler heat-treated at 400 ... 900 ° C with a period equal to N _I = [2,2 + 0.02 (T _I -1420) M _I ], where N _I is the number of revolutions

T _I - the initial temperature of the metal during casting, ° C

M _I - the mass of the casting, kg

and in the amount equal to A _I = 0.666 (90-N _I , where N _I is the amount (mass) of refreshment, kg. The implementation of the invention additionally saves raw materials and batch materials.

Description

The invention relates to foundry, in particular, to a method for the closed production of castings, mainly castings of manganese steels, for example, attachments for scraper conveyors, in sandy-clay forms.

The purpose of the invention is to increase the stability of the properties of the mixture and the quality of castings.

This goal is achieved by the fact that in the method involving the preparation of sand-clay mixture by mixing a rotary filler with a binder and additives, refreshing the circulating mixture with a heat-treated at 400 ... 900 ° C filler containing chamomated bentonite, refreshing it with a heat-treated filler carried out periodically with a period equal to

l, {2.2 + 0.02 (7, -1420) t, |, where n, is the number of revolutions of the mixture;

T, is the initial temperature of the metal during casting, &C;

t is the mass of the casting, kg, and in an amount equal to

#, 0.666 (90-l,), where / V.- is the amount (mass) of refreshment, kg.

Example 1. Carrying out the method in the manufacture of castings weighing 5 kg. A molding mixture of the composition,% by mass, is prepared in mixing runners of model 15104: revolving mixture 93 burned; quartz sand 5; Glinachbentonitov 1; sulfite yeast brew 1; water to a moisture content of 3.5 (strength of compression of 0.065 ... 0.75 MPa), from this mixture, using an impact molding on a 4-position installation of the OLP 446 model in flasks of 650X X550 mm, molds are made for castings of the SP202 pan fittings on an LPO19 eight-piece tooling, the relative height of the models or its parts to the distance between the models or its parts over 3: 1, the forms are poured with the initial pouring temperature of steel

sd

came to

with

110G13L 1460 ° С and knocked out after the steel hardened, ready castings are removed from the embossed mixture, and the mixture is sent to the mixing runners. This cycle is repeated n, times, p 2.2 + 0.02 (1460-1420) X5 15.

After 15 revolutions of the mixture, jV, fljjf yemoB of the burned mixture are removed in one order from the whole mass of the mixture involved in circulation, while A, U, 666 (99-15) 49.95 (take 50%).

The remote burned mixture is replaced with a burned mixture with a burned mixture at 400 ... 900 ° C, and then, over the next 5 revolutions of the mixture, the castings are made only from the mixture in circulation. At the same time, the thermal treatment of the burned mixture at 400 ... 900 ° C is carried out in a thermal furnace.

Example 2. The method is carried out in the manufacture of castings weighing 10 kg. A moldable mixture of composition,% by weight, is prepared in mixing runners of model 15104; burned revolving mixture 91.8; quartz sand; bentonite clay 1,2; hummed tall pitch 2; water to a moisture content of 4 (compressive strength 0.06 ... ... 0.07 MPa). From this mixture, using the 4-position installation of the OLP 446 model in 650x550 mm flasks, by means of impact molding, castings of the SP301 rack attachments are made using the LPO39 four-piece tooling, which relates the height of the models or its parts to the distance between the models or its parts above 2: 1, the molds are poured with the initial temperature of casting steel | 110G13L 1430 ° C and are knocked out after the steel has cured, ready castings are removed from the embossed mixture, and the mixture is sent to mixing runners. This cycle is repeated. N, times, where, 2 + 0.02 (1430- -1420) X.

After the revolutions, the gmesi are in one-time order removing N / percent of the burned

mixture of the total mass involved in the turnover, at the same time, 666 (90-24) 43.95 (take 44%).

44% of the burned mixture is replaced by the burned mixture that is heat treated at 400 ... 900 ° C, and then, over the next 24 revolutions of the mixture, the castings are made only from the mixture that is in circulation.

The proposed method allows reducing the scrap of manganese steel castings by 1.3-1.5 times, saving metal and quartz sand up to 5 ... 10%, increasing the turnaround time for operation.

equipment.

Claims (1)

Invention Formula The method of mixing in the manufacture of thin-walled castings in sand-clay forms, including the preparation of sand-clay mixture by mixing the circulating filler with a binder and additives and refreshing the mixture heated with 400 ... 5,900 ° C with a filler containing chamotised bentonite, characterized in that, in order to increase the stability of the properties of the mixture and the quality of the castings, refreshing with heat-treated filler is carried out periodically with a period equal to p, 2.2 + 0.02 (T-1420) t ,, where n, is the number of revolutions of the mixture; T, is the initial temperature of the metal 35 when casting, ° C; t, is the mass of the casting, kg; and in an amount equal to , 666 (90 p.), Where N, is the amount (mass) of refreshment, kg.