SU1678520A1 - Method for determining casting process parameter - Google Patents

Abstract

The invention relates to foundry. The aim of the invention is to improve the accuracy of measuring the mass of the feed phase coming from the profit to the casting. The method for determining the parameter of the casting production process includes filling the mold with melt, holding the casting to crystallization and measuring the mass of the melt transferred from profit to the casting. 1 sludge.

Description

The invention relates to foundry.

The aim of the invention is to improve the accuracy of measuring the amount of melt transferred from profit to casting.

The drawing shows a device that implements the method.

The device includes a scale 1 of the mark 12 61 VN-ZTST, a block 2 of the information output of the mark BVI-2 and a printing device 3 of the mark PU-2M. A bucket 4 with liquid metal is mounted on the scale. A thin-walled toe of the form 5, suspended on a special bracket (not shown), is immersed in it. From above, the mold is hermetically sealed with a lid 6, in which a groove 7 is made, communicating via ventilation ducts with the working cavity of the mold and through fitting 8 with a vacuum system. The vacuum system includes pump 9 of the RVN-20 brand, receiver 10 (standard gas cylinder) with vacuum gauge 11 of the OBB1-100 brand, valve 12, throttle 13 and auxiliary receiver 14 with 1 liter capacity to stabilize the pouring mode in the final stage of filling the mold. Melting and melt processing are carried out in a resistance furnace 15 with a graphite crucible capacity of 5 liters. The screen 16 protects the scales from excessive heat.

Example. The method is used to study pore formation in a cylindrical cast (58 mm in diameter and 86 mm long) from AI + 12% S1. The ratio of massive and thin-walled parts of the mold provides the direction of solidification of the casting. Melt gas saturation is carried out at 850 ° C by immersing a bell with wet asbestos for 3 minutes. The gas content of the melt varies during standing. The melt for casting the mold is taken after a predetermined holding time.

During the investigation, a vacuum (60 kPa) is created in the receiver 10. the value of which is controlled by a vacuum meter 11. and with the help of throttles 13, the rate of melt suction in the form 5 is equal to 2-3 cm / s, for which the open toe of form 5 is tightly closed with a stopper from O VI CO

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A version connected to a water manometer. To protect the scales from overheating on their plates, sheet asbestos is placed with a thickness of 8-10 mm and the metal screen 16 is attached to the bracket. After preheating to the melt temperature, the ladle 4 is mounted on an asbestos-covered tray with a handle and filled with the melt to a predetermined level.

After removing the slag and reducing the melt temperature to 730 ° C, the ladle 4 together with the pallet is placed on the scale plate 1. The mold 5 is lowered into the bracket slot, while its toe is lowered into the working ladle, the crane 12 is opened, and the mold filled with melt. 8, the moment of its completion, the electromagnetic device is activated, the sensor of which is installed in the upper part of the form, and a signal is given to start the operation of the printing device 3, which records the change in weight during the movement of the feeding phase from profit to casting. The minimum frequency of data acquisition is 1.5 s. The minimum fixed change in weight is 1 g.

After the solidification of the casting is completed, mold 5 is removed from coosh 4 and sent for disassembly, and the melt remaining in the ladle is poured into the crucible. The numbers printed on paper ribbon, although reflecting the change in weight on the weighing plate in grams, are nevertheless conditional relative to the melt entering the form and require an appropriate recalculation, due to the fact that, with a constant melt density, the balance responds only to a decrease in its level. ladle

Thus, the readings of the scales with a ladle mounted on them with the melt and the filled mold prior to the beginning of feeding the casting correspond to the value

Pi SKhi y,

where 5k is the cross-sectional area of the bucket;

hi is the depth of the melt level in the ladle after filling the mold;

in bulk melt weight. In the course of feeding the casting, the feeding phase moves from the ladle, the total weight of which

Rpit "() Ah-y,

where Zf is the area of the cross section of the part immersed in the melt along the outer contour;

Ah is the magnitude of the decrease in the level of melt in the ladle during the solidification time of the casting.

Balance readings after curing.

R2 5kP2U ,.

where h2 is the depth of the melt level in the ladle after the solidification of the casting.

The difference in the balance readings before the casting starts to harden and after the end of the feeding process is AP Pi - Prg SKhiy-SKh2y SK (h-h2) rHuchayushch that hi - ha Ah, the ratio of the amount of the feed phase moved from the ladle to the casting , Rpt to the difference in showing the scales of the AR has the form

RpA (SK - ZF) A h y

Then the number of feed fgzy, taking into account the weights, is calculated by the formula

-AR.

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In this case, the inner diameter of the bucket is 118.4, and the outer diameter of the nozzle of the form 5 is equal to 60.6 mm, then the coefficient of recalculation of the feed mass

K 0.74.

R

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ZK

A decrease in the K value is equivalent to an increase in the sensitivity of the balance by 1 / K times. Thus, for example, at K - 0.5, the number on the scale board changes by one after switching from the ladle to the form of every 0.5 g of the melt, i.e. sensitivity of scales increases by 2 times.

Claims (1)

Claim Method A method for determining a parameter for a casting process, including filling the mold, aging the casting and measuring the mass of melt transferred from profit to casting, characterized in that, in order to improve the accuracy of measuring the amount of melt transferred from profit to casting, the measurement is carried out by weighing the profit separately from the casting during its crystallization. tt