Evaporative pattern casting method

Patent metadata

Field	Value
Publication number	US-10099274-B2
Application number	US-201515520009-A
Country	US
Kind code	B2
Filing date	Oct 21, 2015
Priority date	Nov 19, 2014
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

In the following expression, it is assumed that a thickness of a coating agent applied to a foam pattern [ 2 ] is t (mm), a diameter of a hole part [ 3 ] is D (mm), and a normal-temperature transverse strength of the dried coating agent is σc (MPa). At the time of producing a casting provided with a hole having a diameter of 18 mm or smaller and a length of 1 (mm), a coating agent that satisfies the following expression is used when a solidification end time te (sec) at which solidification of a melt ends on a periphery of the hole part [ 3 ] is within a time t 0 (sec) at which thermal decomposition of the coating agent ends.

σ c≥{t 0/( t 0− te )}×(1.5×10 −4 ×1 2 /t 2 +160/ D 2 )

First claim

The invention claimed is:

1. An evaporative pattern casting method for producing a casting provided with a hole having a diameter of 18 mm or smaller and a length of 1 (mm) by burying into casting sand a mold, which is formed by application of a coating agent to a surface of a foam pattern, and then pouring a metal melt into the mold to cause the foam pattern to disappear and be replaced with the melt, wherein
assuming that a thickness of the coating agent applied to the foam pattern is t (mm), a diameter of a hole part in the foam pattern, which is a portion to be formed with the hole, is D (mm), and a normal-temperature transverse strength of the dried coating agent is σc (MPa), the coating agent that satisfies the following expression is used when a solidification end time te (sec) at which solidification of the melt ends on a periphery of the hole part is within a time t 0 (sec) at which thermal decomposition of the coating agent ends.
σ c≥{t 0/( t 0− te )}×(1.5×10 −4 ×1 2 /t 2 +160/ D 2 )

2. The evaporative pattern casting method according to claim 1 , wherein the time t 0 at which the thermal decomposition of the coating agent ends is 1600 seconds.

3. The evaporative pattern casting method according to claim 1 , wherein
a shape of the mold is a rectangular parallelepiped, and
the following expression is satisfied when a short side of a cross section in the mold, which is orthogonal to an axial direction of the hole part, is assumed to be T.
te=− 1.03×10 −3 T 2 +16.5 T

4. The evaporative pattern casting method according to claim 2 , wherein
a shape of the mold is a rectangular parallelepiped, and
the following expression is satisfied when a short side of a cross section in the mold, which is orthogonal to an axial direction of the hole part, is assumed to be T.
te=− 1.03×10 −3 T 2 +16.5 T.

Assignees

• Kobe Steel Ltd

Inventors

• Tsutsumi Kazuyuki

Classifications

• B22C9/046

  Use of patterns which are eliminated by the liquid metal in the mould · CPC title

• B22C9/04

  Use of lost patterns · CPC title

• B22C7/02 Primary

  Lost patterns · CPC title

• B22C3/00

  Selection of compositions for coating the surfaces of moulds, cores, or patterns · CPC title

• B22C7/023 Primary

  Patterns made from expanded plastic materials · CPC title