SU1537367A1 - Method of determining the rate of hardening of metal in pressure casting with crystallization - Google Patents

Abstract

The invention relates to foundry, in particular to casting with crystallization under pressure. The aim of the invention is to improve the accuracy of determination and simplify the process. Molten metal is poured into the matrix, the working surface of which is thermally insulated, press pressed for a predetermined time, pressure is removed and the punch on which the solidified metal layer is formed is removed, this layer is measured and the rate of solidification is calculated. 2 Il.

Description

The invention relates to foundry, in particular to casting with crystallization under pressure.

The aim of the invention is to improve the accuracy of determination and simplify the process.

FIG. Figure 1 shows the mold at the time of pressing; in fig. 2 - mold after pressing.

A mold for carrying out the method consists of a punch 1, on the lower end of which a longitudinal groove 2 is made in the form of a dovetail tail. The melt 3 is poured into the matrix 4, the inner surface of which is lined with a heat insulating coating 5. The casting is pushed out of the matrix by the pusher 6.

The method is carried out in the following sequence.

The melt 3 is poured into the matrix 4, pressed under pressure for a predetermined time, the pressure is released and the punch 1 is withdrawn, on which a layer of solidified metal with thickness X is formed, this layer is measured and the rate of solidification is calculated from its value.

Example. Alloy grade AL2 with S / 12.5% content at 730 ° C is poured into the matrix, the working surface of which is covered with a layer of sheet asbestos 5 with a thickness of 3 mm, is kept for 4 s before contact with the pu-anson 1 and then pressed under pressure MPa for time 60 s.

During pressing at the end of the punch, due to thermal insulation of the walls and the bottom of the die, directional solidification of the sample 7 is carried out.

After pressing for a specified time, the solidified sample 7 is separated from the uncured melt 3 and removed from it. The melt 3 solidifies without pressure and removes from the matrix 4 with the help of the pusher 6.

After cooling the sample 7, it is separated from the punch 1 and the thickness of the crust A is measured. The crystallization rate g is determined from the equation

.

SP

WITH

WITH

about 1

rjne UkR - crystallization rate, mm / s; A is the sample thickness, mm; t is the pressing time, s.

The change in the thickness of the crust L depending on the pressing time t at pressure MPa is shown in the table.

5 120

2 32

6

90

The method provides an increase in the accuracy of fixation of the crystallization front and simplifies the process of determining the rate of solidification in various technological modes of casting.

Claims (1)

Invention Formula The method of determining the rate of metal plating during casting with crystallization under pressure, including pouring the metal into the matrix, applying pressure to the punch, holding it under pressure and fixing the front of the hardened metal, characterized in that, in order to improve the accuracy of determination and simplification of the process, the working surface of the matrix is insulated, and the crystallization front is fixed along the thickness of the metal layer that has hardened on the core. 1