Sand Casting

Sand casting is one of the most widely used and most practical metal casting methods. Preferred across many areas of industry for many years, it holds an important place both because it is economical and because it allows the production of parts in a wide range of sizes and geometries.

In this method, a mold is prepared to match the form of the part to be cast. Molten metal is poured into the cavity formed inside the sand mold. Once the metal has cooled and solidified, the mold is broken apart and the casting is removed. Additional processes such as cleaning, deburring, inspection and, where needed, heat treatment are then applied.

One of the main reasons sand casting is so widely used is that sand, the mold material, is easy to shape and offers a cost advantage. It provides an especially flexible solution for producing parts with complex forms and varying weights and dimensions.

What Is Sand Casting?

Sand casting is the process of pouring molten metal into a sand mold to obtain the desired part form. In this method, a pattern suited to the part being produced is prepared first. Special foundry sand is packed around the pattern to create the mold cavity. The pattern is then removed from the mold, and liquid metal is poured into the resulting cavity.

The metal cools inside the mold and turns solid. Once solidification is complete, the sand mold is broken and the part is taken out. Depending on production requirements, the resulting casting can go through additional operations such as grinding, shot blasting, machining, surface treatment or heat treatment.

Sand casting is a flexible method that can be used to produce gray iron, ductile iron, steel, stainless steel, bronze, aluminum and various alloyed metals. For this reason it is preferred across many fields, from automotive to machinery manufacturing, and from agricultural equipment to the pump industry.

How Is Sand Mold Casting Done?

Sand mold casting generally consists of a few basic stages. First, the technical drawing and pattern of the part to be produced are prepared. The pattern is designed with shrinkage allowances and machining tolerances that may occur after casting taken into account.

Next, the molding sand is prepared and packed around the pattern. A gating system that lets the metal flow through the mold and feeders that ensure the part is fed properly are formed. If the part has internal cavities or special forms, cores are used.

Liquid metal brought to the appropriate temperature is poured into the prepared mold. Once casting is complete, the metal is left to solidify. The solidified part is removed from the mold, cleaned and put through the quality-control process.

The Stages of Sand Mold Casting

Although sand casting may look simple, every step must be carried out carefully to achieve a quality result. The general production stages are as follows:

• Part design and pattern preparation are carried out.
• The sand mold is prepared.
• If needed, cores are produced and positioned.
• The gating and feeder system is formed.
• Molten metal is poured into the mold cavity.
• The metal is left to cool and solidify.
• The mold is broken apart and the part is removed.
• Cleaning, grinding and shot blasting are applied.
• Dimensional and visual quality checks are performed.
• Heat treatment or machining is applied if required.

Each of these stages directly affects casting quality. In particular, molding sand quality, metal temperature, pouring speed, gating design and the cooling process are decisive for the final performance of the part.

Advantages of Sand Mold Casting

Compared with many production methods, sand casting offers significant advantages. One of its biggest strengths is that it is suitable for producing parts in different sizes and complex geometries.

The key advantages of sand mold casting are:

• The mold material is cost-advantageous.
• It suits small, medium and large-scale part production.
• Parts with complex geometries can be produced.
• It allows working with different metals and alloys.
• It can be adapted to both prototype and serial-production needs.
• Pattern changes can be made relatively easily.
• It is an effective method for producing large and heavy parts.

Thanks to these advantages, sand casting is used as a reliable solution both in classic industrial production and in special, project-based manufacturing.

What Are the Types of Sand Casting?

Sand casting is divided into several different methods. The method chosen depends on the part's size, material type, surface expectations, production quantity and mechanical-property requirements.

The main types of sand casting are:

Green Sand Mold

Green sand molding is one of the most widely used molding methods in the casting industry. In this method, the molding sand is prepared from a mixture of sand, bentonite, water and certain additives. The mixture is packed around the pattern to form the mold.

Green sand molding is frequently preferred because it is economical, suitable for serial production and recyclable. It is especially common for gray iron and ductile iron castings.

In this method, the moisture content, strength, permeability and compaction properties of the molding sand are very important. Sand that does not have the desired properties can cause surface defects, gas problems, mold breakdowns and production losses.

Dry Sand Mold

Dry sand molds are prepared similarly to green sand molds but are dried at certain temperatures before casting. This process increases the strength of the mold and can prevent some defects that may occur during casting.

Dry sand molds can be preferred especially for applications requiring higher surface quality, better gas permeability and a more durable mold structure. However, the preparation process can be longer than green sand molding.

Resin Sand Mold

Resin sand molding is a method in which resin and hardener additives are added to dry silica sand. It is preferred for parts requiring high dimensional accuracy and a smoother surface quality.

Resin sand molds offer an advantage especially in the production of complex and precision castings. Because the mold is more durable, it holds its form better during casting. For this reason it can be used to produce bronze, stainless steel and special alloy parts.

Factors Affecting Quality in Sand Casting

For a successful sand casting operation, pouring the metal into the mold is not enough on its own. Many technical factors determine quality. Chief among them are correct mold design, suitable sand selection, controlled melting, the right pouring temperature and an effective quality-control process.

The main factors affecting quality in sand casting are:

• Grain structure and moisture content of the molding sand
• Mold strength and gas permeability
• Pouring temperature of the metal
• Gating and feeder design
• Core quality and placement
• Cooling and solidification process
• Post-casting cleaning and inspection operations

Managing these processes correctly both improves product quality and reduces production losses.

Which Parts Can Be Produced with Sand Casting?

Sand casting can be used to produce parts for many different industries. Depending on the part design, the material to be used and technical requirements, different casting solutions can be applied.

At Bordomet, we offer production solutions in sand casting for different material and industry needs. The main material groups that can be produced with sand casting are:

• Gray iron castings
• Ductile iron castings
• Steel castings
• Stainless steel castings
• Duplex stainless steel
• High-chromium cast irons
• Tin bronzes
• Aluminum bronzes

These materials are selected according to requirements for strength, wear resistance, corrosion resistance, temperature performance and mechanical properties.

Industries That Use Sand Casting

Because sand casting has a broad range of applications, it plays an important role in the production processes of many industries. It is preferred especially for durable, custom-designed parts with high technical requirements.

Industries in which sand casting is widely used include:

• Automotive industry
• Machinery manufacturing
• Defense industry
• Maritime and marine industry
• Agricultural machinery
• Pump and valve industry
• Energy sector
• Mining
• Construction equipment
• Process industry

The cast parts used in these industries can be specially designed according to operating conditions, load cases and environmental effects.

Sand Casting Solutions with Bordomet

Bordomet operates with a production approach that provides sand casting solutions for the needs of different industries. Technical requirements are taken into account across all processes, from part design and pattern preparation to casting and quality control.

In sand casting, the goal is not only to produce the part. The real aim is to obtain long-lasting, ready-to-use parts through correct material selection, suitable mold design, controlled production and a reliable quality process.

At Bordomet, we adopt a solution-oriented approach to project-based production, technical evaluation, material selection and post-casting processes according to customer requirements. That the produced parts suit their application, their dimensional accuracy and their mechanical performance are among our priority criteria.

Post-Casting Operations

After the sand casting process is complete, parts may not be directly ready for use. For this reason, post-casting operations are very important for production quality.

Operations that can be applied after casting include:

• Shot blasting
• Grinding
• Deburring
• Heat treatment
• Machining
• Painting
• Coating
• Dimensional inspection
• Visual inspection
• Non-destructive testing (NDT)

These operations are determined according to the part's application and technical specification. Machining and detailed quality-control processes are especially important for parts requiring precise dimensions.

Conclusion

Thanks to its flexibility, economical nature and wide range of material options, sand casting is one of the most widely used casting methods in industry. Many different products, from small parts to large and heavy castings, can be produced with this method.

With correct mold design, quality sand, suitable metal selection and a controlled production process, high efficiency can be achieved from sand casting. Bordomet aims to provide reliable solutions to different industries with its production capability and technical approach in sand casting.

For the cast parts you need, contact Bordomet to get detailed information about the most suitable material, production method and technical solution for your project.