CN101716650A

CN101716650A - Composite sand core and manufacturing method thereof

Info

Publication number: CN101716650A
Application number: CN200910155536A
Authority: CN
Inventors: 李毅
Original assignee: ZHEJIANG HONGMA FOUNDRY CO Ltd
Current assignee: ZHEJIANG HONGMA FOUNDRY CO Ltd
Priority date: 2009-12-17
Filing date: 2009-12-17
Publication date: 2010-06-02

Abstract

The invention discloses a composite sand core and a manufacturing method thereof. The body of the sand core is formed by compounding a middle core and a protective layer covering outside the middle core; and the middle core is manufactured by using limestone sand. To manufacture the sand core, two core boxes are manufactured at first, wherein the first core box is filled with the middle core manufactured by using the limestone sand; the second core box is sleeved outside the middle core and encloses an annular cavity structure with the middle core; and the 10 to 15 millimeter thick protective layer which is manufactured by using chromite sand is filled in the annular structure. Using the limestone sand instead of the traditional quartz sand to manufacture the middle core part, the cleaning is easy as the limestone sand begins to decompose at 700 DEG C and becomes powder with the intensification of pyrolysis after being heated to above 900 DEG C; the chromite sand which is high temperature resistant is coated on the outer surface of the middle core to protect the limestone sand against deformation caused by erosion and washing by molten steel; and the two core boxes are used for manufacturing the middle core and the protective layer respectively, so that the chromite sand is uniformly coated on the surface of the middle core is ensured.

Description

A kind of composite sand core and preparation method thereof

Technical field

The present invention relates to the casting mold field shaping technique, especially a kind of composite sand core and preparation method thereof.

Background technology

At present in most casting industries for the steel-casting hole elongated in the product yoke, wall thickness of especially generating electricity, the scheme that adopts usually when casting mold is with chromite sand control surface one deck, the inner quartz sand that adopts is made the loam core.Though this method has solved part scab problem, but the inner quartz sand fusing point of making the loam core is higher, generally all more than 1800 ℃, thereby still can not solve the problem that elongated hole loam core sintering can't be cleared up for the foundry goods of wall thickness, cause casting cleaning expense height, serious even cause product rejection.

Summary of the invention

Problem to be solved by this invention is exactly the not shortcoming of easy to clean of existing casting mold loam core, and a kind of composite sand core is provided, and is simple in structure, easy to make, solves effectively that foundry goods is elongated, the wall thickness hole sintering problem of easy to clean not.

For reaching above-mentioned purpose, the present invention adopts following technical scheme: a kind of composite sand core, loam core body are to be composited by intermediate core and the protective layer that is coated on the intermediate core appearance, and it is characterized in that: described intermediate core adopts limestone sand to make.Limestone sand just begins to decompose at 700 ℃, surpass 900 ℃ after the pyrolysis aggravation that limestone sand is become is Powdered, easy to clean.

Further, described protective layer adopts chromite sand to make.Chromite sand is high temperature resistant, and protection limestone sand can be out of shape by molten steel erosion, sand washing.

Further, the thickness of protective layer is 10mm ~ 15mm.

The present invention also provides the preparation method of above-mentioned composite sand core, it is characterized in that comprising the steps:

(1) makes a core box, in a core box, fill limestone sand and make intermediate core;

(2) make No. two core boxes, No. two core box diameters are nested with No. two core boxes in the intermediate core outside greater than a core box, make between No. two core boxes and the intermediate core and form the ring cavity structure.

(3) in the ring cavity structure, fill chromite sand and make protective layer.

Above-mentioned preparation method can reduce the use amount of chromite sand, reduces cost, and can guarantee that chromite sand evenly is attached to the intermediate core surface.

Advantage of the present invention: utilize limestone sand to replace original quartz sand as the intermediate core part, limestone sand just begins to decompose at 700 ℃, surpass 900 ℃ after the pyrolysis aggravation that limestone sand is become is Powdered, easy to clean; Chromite sand is high temperature resistant, is attached to intermediate core outer surface protection limestone sand and can be out of shape by molten steel erosion, sand washing; Adopt two core boxes to make intermediate core and protective layer respectively, guarantee that chromite sand evenly is attached to the intermediate core surface.

Description of drawings

The present invention is further illustrated below in conjunction with accompanying drawing:

Fig. 1 is a loam core of the present invention structural representation.

The specific embodiment

As shown in Figure 1, the invention provides a kind of composite sand core and preparation method thereof, its loam core body is to be composited by intermediate core 2 and the protective layer 1 that is coated on intermediate core 2 appearances; Intermediate core 2 adopts limestone sand to make, and protective layer 1 adopts chromite sand to make; Limestone sand replaces original quartz sand as intermediate core 2 parts; limestone sand just begins to decompose at 700 ℃; that limestone sand is become is Powdered in the pyrolysis aggravation after surpassing 900 ℃; chromite sand is high temperature resistant; be attached to intermediate core 2 outer surfaces protections limestone sand and can be out of shape, solved the problem that foundry goods elongated hole sintering is difficult for sand removal with regard to fine like this by molten steel erosion, sand washing.

When making the loam core; carry out two core boxes earlier; fill limestone sand in the core box and make intermediate core 2; No. two core boxes are nested with in intermediate core 2 outsides; make and form the ring cavity structure between No. two core boxes and the intermediate core 2; fill chromite sand and make protective layer 1 in the ring cavity structure, the thickness of protective layer 1 is 10mm ~ 15mm.This preparation method can reduce the use amount of chromite sand, reduces cost, and can guarantee that chromite sand evenly is attached to intermediate core 2 surfaces.

Claims

1. composite sand core, loam core body are to be composited by intermediate core (2) and the protective layer (1) that is coated on intermediate core (2) appearance, and it is characterized in that: described intermediate core (2) adopts limestone sand to make.

2. a kind of composite sand core according to claim 1 is characterized in that: described protective layer (1) adopts chromite sand to make.

3. a kind of composite sand core according to claim 1 and 2 is characterized in that: the thickness of protective layer (1) is 10mm ~ 15mm.

4. the preparation method of composite sand core according to claim 1 is characterized in that comprising the steps:

(1) makes a core box, in a core box, fill limestone sand and make intermediate core (2);

(2) make No. two core boxes, No. two core box diameters are nested with No. two core boxes in intermediate core (2) outside greater than a core box, make formation ring cavity structure between No. two core boxes and the intermediate core (2).

(3) in the ring cavity structure, fill chromite sand and make protective layer (1).