SU1694317A1 - Sampling mould to determine the alloys volume shrinkage - Google Patents

Abstract

The invention relates to a foundry, in particular, to devices for determining curb shrinkage of a metal. The purpose of the invention is to reduce the time to determine volumetric shrinkage and reduce labor intensity. The mold form consists of two half-molds with a horizontal connector, in the upper mold half there is a measuring protrusion cavity having a cylinder, a cone or a truncated cone geometry, while the area of the base of the measurement protrusion refers to the rest of its area as 1: (2-10 ), and its volume is associated with the volume of the sample cavity as 1: (8-16), while the upper mold half has a cavity for heating the measuring protrusion with a liquid metal, the reduced size of which is 1.2-1.5 greater than the size of the cavity of the mold test and connect a metal receiver cavity in which a vertical gating channel is made, the feeder being located in the lower half-form along the horizontal surface of the mold connector, and its reduced size and the reduced size of the horizontal channel of the specimen is 40-60 times smaller than the reduced size of the sample-shaped cavity, while the vertical part the vypor is made of variable cross section, and the transition from the lower smaller section of the vertical part of the vypor to the larger one is performed at the height of the measuring protrusion, and the ratio of their cross section It is equal to 1: (2–3), while the thickness of the walls of the protrusion of the measuring protrusion is 3-5 times smaller than the given size of the cavity for heating the measuring protrusion, while the shape of the measuring protrusion is provided in the upper part with a cylindrical venting projection located along the axis of symmetry sample sizes with a diameter of 0.2–0.4 of the diameter of the measuring protrusion, and the total height of the measuring and gas exhausting protrusions is 1.1 –1.2 of the height of the upper half-form, and the upper half-form has a threshold separating Many cavity from the heating cavity with a height of 0.8-0.9 height of the shape of the measuring ledge. 1 il. SP C o S with

Description

The invention relates to a foundry, in particular, to devices for determining the volumetric shrinkage of a metal.

The purpose of the invention is to reduce the time to determine volumetric shrinkage and reduce labor intensity.

The drawing shows a sample mold for determining volumetric shrinkage. The casting mold consists of the bottom half-form 1, the top half-form 2, in which a cylindrical measuring ledge 3 is made together with a gas outlet

the protrusion 4, the upper proforma has an additional cavity consisting of the cavity 5 for heating the measuring protrusion 3 with liquid metal and the metal-receiving cavity 6, which is separated from the cavity 5 by the separating threshold 7. The metal-receiving cavity 5 passes into the funnel 8 and one hundred to 9. Under the floor In the lower mold half 1, a sump 10 and a feeder 11 are located. A horizontal slot channel 12 extends from the sample cavity, passing into the retainer 13 of a variable cross section, made vertically in the upper mold half 2.

Sample casting to determine volumetric shrinkage is obtained as follows.

The metal is poured into the cavity to heat the measuring protrusion 3, it rises to the threshold level 7 and enters the vertical sprue channel 12 and through the feeder 11 into the cavity of the half-mold 1 of the sample.

The metal level during casting should not exceed the level of the upper part of the form of the protrusion 3. When the form is filled, i.e. the metal is fit in a large section of the bobbin 13, it is necessary to fill the cavity for heating 5 to the top. Gases when filling the mold with metal are removed through the retainer 13, and when filling the measuring protrusion through the gas outlet porous protrusion 4 and the end surface of the form of the measuring protrusion. When cooling the metal in the form, the horizontal channels of the sprue and vypor first harden, since their reduced size is 40-60 times smaller than the sample size. As a result, the gating system does not feed the sample.

Then the sample solidifies towards the measuring ledge. This is provided by the geometry of the sample cavity. Due to the greater heat content of the metal in the cavity for heating 5, sufficient thermal conductivity and a small wall thickness of the measuring protrusion, the metal in it is in a liquid state until the sample is completely solidified, providing shrinkage compensation. Its level decreases in proportion to the volume shrinkage of the cast alloy.

After complete solidification of the metal, the casting is removed from the mold, the sprues are slammed off, the heating part of the sample is separated. The sample is cooled and the height of the measuring ledge obtained in the casting is measured. According to the formula

p- 10 ° -K

l (B - 16)

moreover, for a cylindrical protrusion K h-hx;

for conical protrusion

K (h-hx) 3. K h3

for a protrusion with a frustoconical geometry

U (. - .. cU) 1)

TO

Mr,

g, I V L-cTSN (g, - C-cCeb1g)

Where

Ј - volume shrinkage,%;

h is the height of the measuring ledge before the sample is solidified, mm;

hx is the height of the measuring ledge after the sample is solidified, mm;

ri is the radius of the protrusion base, mm;

and - the angle of inclination of the generatrix of the cone to the horizontal.

This dependence can be represented in the form of a graph, which allows to determine the volume shrinkage by the results of the measurement of the protrusion, or according to the specially calibrated ruler according to the dependence of the height of the protrusion -% of the volume shrinkage, or according to the previously prepared

the table.

The vaporized protrusion 4, located in the upper part of the measuring protrusion 3, performs the function not only of the gas outlet when filling the measuring

the protrusion by the molten metal, but also the function of equalizing the pressure in the mold during solidification of the metal with the atmospheric one, which provides favorable conditions for feeding the sample casting.

Bottom half-form where

The sample cavity is made from the existing production mold material. The upper half-form, where the measuring protrusion cavity and its heating cavity are located, is made on a dry sand mixture. The given sample casting size should be equal to the average reduced casting size produced. Using this form to obtain a sample, with the help of which volumetric shrinkage is determined, makes it possible to reduce the scrap produced by shrinkable defects, to increase the rapidity of volumetric shrinkage determination and to reduce

the complexity of the determination.

Claims (1)

The invention The casting mold for determining the volumetric shrinkage of alloys, containing two half-molds, a cavity of a variable cross-section sample, a metal receiving cavity, stand-up, and a feeder, which is designed with a horizontal connector to shorten the time for determining volumetric shrinkage and reduce labor intensity. and boosted and provided with measuring and located at the top coaxially with gas outlet lugs placed in the upper half-form and having a total height equal to 1.1-1.2 the height of the upper half-form, and the gas the diverting protrusion has a diameter equal to 0.2-0.4 of the diameter of the measuring protrusion, and the measuring protrusion has a cavity in the form of a cylinder, a cone or a truncated cone in communication with the sample cavity, the base area of the measuring protrusion being related to the rest of the area 1: (2-10), and its volume refers to the volume of the sample cavity as 1: (8-16), while in the upper mold half there is a cavity for heating the measuring ledge, shown the size of which is 1.2-1.5 larger than the size of the sample cavity and is separated from the metal reception chamber by a threshold, the height of which is 0.8-0.9 the protrusion, and the thickness of the walls of the measuring protrusion is 3-5 times smaller than the given size of the cavity for heating the measuring protrusion, while the feeder is located in the lower half-form along the connector, at the same time, the strut has a horizontally located part and a vertical part made of variable cross section with transition from the lower smaller section to the upper larger section located at the level of the measuring ledge, with a ratio of sections equal to 1: (2-3), and the reduced size of the feeder and the reduced size horizontal channel of a vypor by 40-60 times less than the size of the sample cavity. /five