Already on ArticleSlash?

Forgot your password? Sign Up

Sand Inclusion, Sand Hole - Casting Defects -

 


Visitors: 837

Sand inclusion is also called as sand hole, which is a kind of metal casting defect. It looks like small or middle holes with sand grain in the internal or on the surface of castings.

There are 3 main reasons caused the sand inclusion defect.

1. sand crush, sand drop

The partial sand blocks drop because of the mechanical force on the sand molds or sand cores. It will cause the embossing metal blocks, at the same time, the positions where the sand blocks drop to will have sunk holes after sand blasting.

2. Overbaking

If the sand molds or cores have been overbaked, then their surfaces will become more fragile because the adhesive will lose its stickiness, which will cause some sand inclusion defects.

3. Sand cut, erosion, sand wash

The sand molds or cores can not stand the flush of hot metal liquid during pouring process, so on the surfaces of fragile positions, there will be some coarse, irregular metal tumors, which normally happened at the pouring gate positions. The sand blocks and grains will cause the sand inclusions at the other positions.

Repairing sand inclusion, sand holes

1. Putty, paint filler

Putty is suitable for the unimportant surface positions. After filled by putty, the painting will be needed.

2. Metal fill glue, fill agent

Metal-filled glue contain quartz and metal components, so casting surface after filled by this glue will have a certain hardness, and it can stand further machining process and a temperature of 125 to 200 Celsius degree. Repairing with metal filled glue is very common method in iron and steel foundries in China.

3. Electrical welding

Welding is used for repairing middle or large sand inclusion. After welding, the positions with sand holes will still keep good strength and can stand the high temperature as metal.

Sand inclusion is the most common defect for sand castings, and any piece of sand casting will have this defect. However, good metal foundries can control the sand holes as small as possible. Normally, it will be acceptable for few sand holes with diameter under 2.0 mm, and with depth under 1.0 mm.

This article was from Dandong Foundry . For the whole article, please check Dandong Foundry Blog .

(409)

Article Source:


 
Rate this Article: 
 
Hand Molding Method of Sand Casting
Rated 4 / 5
based on 5 votes
ArticleSlash

Related Articles:

Casting Defects - Sand Mold, Metal Casting

by: Galen Wang (November 07, 2011) 
(Business/Industrial Mechanical)

How to prevent sand casting defect: slag hole

by: Galen Wang (August 02, 2011) 
(Business/Industrial Mechanical)

The difference between green sand casting process and resin sand casting process

by: Galen Wang (March 08, 2011) 
(Business/Industrial Mechanical)

Sand Casting vs. Investment Casting

by: Galen Wang (July 23, 2012) 
(Business/Industrial Mechanical)

Resin Sand Casting

by: Galen Wang (March 01, 2011) 
(Business/Industrial Mechanical)

Sand Casting Foundries Sand Casting Foundries

by: Galen Wang (June 25, 2012) 
(Business/Industrial Mechanical)

The Sand Casting No Bake

by: Galen Wang (October 05, 2012) 
(Business/Industrial Mechanical)

Casting Pattern and Sand Mold

by: Galen Wang (February 29, 2012) 
(Business/Industrial Mechanical)

The China Sand Casting Factory

by: Galen Wang (October 04, 2012) 
(Business/Industrial Mechanical)

Hand Molding Method of Sand Casting

by: Galen Wang (December 27, 2011) 
(Business/Industrial Mechanical)