Metal Casting Zone Info Blog

Posts Tagged ‘sand’

Introduction to Steel Casting Process in India

Steel casting is the complicated process of casting all kinds of different steel. The complete procedure of steel casting involves melting the steel, creating molds and cores and finally cleaning the castings and heating them. Mostly the need to use steel castings results when cast irons do not provide sufficient strength or shock resistance. Through steel casting, one can obtain small yet complex machine shapes there removing the need for wielding, assembling and other finishing work.

Steel castings are used in different kinds of industries such as transportation, general industry, construction, energy and marine. Ideally these kind of casting are constructed from low temperature steel, low and high alloy steel and heat resistant steel. Since they happen to be more powerful and stronger than cast iron or malleable iron therefore they are extensively utilized in the manufacture of complex parts where it is required to resist shocks or heavy load.

The making of steel casting goes through a number of processes, among which the first one is about creating core. Cores are usually made from a combination of sand with a chemical binder system. A series of complex cores can be convened from a variety of smaller cores. Once the core has been made, the next step in process includes melting of the steel in the furnace that ideally uses three electrodes where each provides 6,500 amps of electricity. Once the metal is melted as per the specifications, it is then undergoes a process of being poured into the right kind of molds. The mold is cooled and then broken up and the sand from the mold is then used for molding. Steel casting molds are ideally created by combining sand with a chemical binder system. The process is molding is known as Nobake or Airset System. Finally the steel castings are given a finishing touch at the cleaning room, where they are fine tuned to suit with the specifications of the customer.

Related Malleable Cast Iron Articles

This will be a multi part video on foundry pattern making. A wooden pattern is used to make an impression in the sand mold. A silica sand core is inserted to produce the cylinder bore in the casting. A wooden pattern of the cylinder is turned on the Clausing lathe.

www.foundry101.com
Lost & Foundry pouring bronze medallions for the centenial trail in Spokane, Wa.

Phosphorus copper shot added to increase fluidity.

Learn more at www.foundry101.com

Sand casting is easy and fun, we have been teaching metal casting & sand casting to kids and adults for almost 10 years now. Check us out!

The problems with iron foundries in China

The iron foundries are also known as iron casting workshops, which manufacture iron and steel castings. Many overseas buyers and purchasers always try to find the suitable iron foundries in China, so they can buy good iron castings from them. However, they do not know there are many problems with those foundries.

As my years experiences in Dandong Ruiding Foundry, I sort the iron foundries in China to four types. The first type: Large foundries. These foundries own over three automatic molding lines, and can produce over 10000 tons iron castings per year. The second type: Middle foundries. These foundries own one or two automatic molding lines, and other casting processes, such as resin sand, manual green sand etc. The annual production is from 3000 tons to 10000 tons. The third type: Small foundries. These foundries do not have automatic molding lines, but have some molding machines or just manual green sand casting process. The fourth type: specific foundries. These foundries just produce one or two specific products.

What are the problems with these foundries?

As for the large foundries, since they have many auto molding lines, so their production efficiency is very high, and the casting quality is very good. The problems are they can not make large castings, or heavy castings because of the size limitation of the sand boxes. In addition, they can not make some castings with special dimensional or structures requirements. Moreover, they are not willing to accept small orders. Therefore, most of these foundries will only produce the automobile parts.

As for the middle foundries, since they have automatic molding lines, and have other casting processes. They can meet many different demand. The problems are their technical abilities are limited, and their production costs are high. Why? These foundries were developed from traditional casting workshops, so they just start to use automatic molding line, therefore, their old engineers can not reach the new technical level. In one word, their old engineers did not know how to use the automatic molding lines. They are staying in the studying stage. At the same time, these foundries have to feed many engineers and administrative staff since they have many different workshops, and each workshop has different production processes. So, they production costs are higher than small foundries. According to the opinion of Mr. Galen Wang from Dandong Foundry, these foundries will develop into large foundries or small foundries in the future. The middle foundries are not a long-time stable stage.

As for the small foundries, since they just have manual casting process, so they can do it very well. They can control their production and administrative costs very low, and their prices are very competitive. The problems with small foundries are their production efficiency is limited. Since all castings are made by hand. They have no ability to complete large orders. Moreover, their quality is not stable. Therefore, they can just accept small orders, and produce the iron castings with low requirements.

As for the specific foundries, they only produce one or two types of castings. Such as some foundries only produce ductile iron pipes. Some just produce various pipe fittings. Some just produce very large castings, and some just produce stove parts. These foundries own the related equipments and rich experiences for their products, so they can make them very well. Their problems are they can not make other types of castings. Their engineers and workers are not willing to make other products because of higher defective rate and lower output.

All in all, I believe these problems are not the exclusive in China. All foundries in the world will face the same problems. I wrote this article to advise the buyers and purchasers how to choose the suitable foundries in China. There are many good foundries in China, who are maximizing their strengths, and trying to avoiding their problems.

This article was originally written by Mr. Galen Wang from Dandong Ruiding Founding Co. Ltd.

Castings without pattern – A new way to produce iron sand castings

Nopatech™ is a new technology developed by Saguenay Foundry. Its purpose is to make very short production runs of gray & ductile iron castings faster and more cost effective by eliminating the need to produce a pattern.

In regular production, patterns are made de create an imprint in a sand mould. Metals are then poured in the “negative” of the part. After cooling, you get a part to the correct dimensions and shape. This technology has been done for hundreds of years to obtain complex shapes that could not otherwise be machine directly in a cost-effective manner.

The problem with patterns is that they are expensive. If you redo the castings dozens or hundreds of even better thousands of time, it can easily be amortized. But in certain situations, one or two castings might be all you need. For instance, prototypes of an unproven design are subject to change after a trial of one or two castings. With a pattern, some change can be made, but not always, so you are always taking a risk.

In this case, a casting that cost 2000$ can require a 5000$ wood pattern do be produced effectively. If you do only one, your casting has cost you 7000$ . Nopatech™ on the other hand might cost you only an extra 1500$ – 2000$ to cast a part without pattern . This is a very substantial gain. The lead time might also go down by half.

To obtain this low cost and fast lead-time, Nopatech™ benefits from the advance in robotic technologies to machine blank sand moulds directly to the final shapes. Cores can also be done, so there is no limit to the complexity of the final shape. Basically, what can be done with wood patterns can be done with Nopatech™.

Also, the quality matches exactly what you get from a casting made with a regular pattern. You reach an average “as cast” RMS figure of 500 and the accuracy of the mould is within 1/16” of an inch, a precision that compares favourably to pattern-made parts. The size limitations is also the same as any other part done at our foundry, with a 115” x 115” maximum flask and a 16,000 lbs gross weight pouring capacity.

The process of producing a sand casting

What is a sand casting? How dose it comes out? The following passages would give you some answers.

Have you seen a large metal made of iron, bronze, brass of aluminum with some featured patterns in the middle? Have you noticed a cavity of wood or metal? If you say yes, I think you have already got the idea of casting. The sand is a cast part produced by forming a mold from a sand mixture and pouring molten liquid metal into the cavity in the mold. After the process of cooling, the melted metal has been solidified. At the last, a sand casting would be gotten just separated from the mold. Generally speaking, it is produced as follows.

The basic step is to place a pattern in sand to create a mold. It should be mentioned that the mould has two parts divided by the parting line. The cope is the upper half and the drag is the lower half. And as you know, there are 2 main types of sand. One is called the “green sand”, and the other is the “air set”. The previous one is a mixture of silica sand, and the latter one is dry sand with other material through curing adhesive.

Then, remove the pattern and pour the melted metal to the mold. You can use the vibration and mechanical method to remove the pattern. And the cope is separated from drag. Within the mechanical methods, the sand mixture is assembled to for a mold cavity. According to the different types of sand, the change happened during this process is different. Whatever, a riser is needed to hold excess molten material to avoid the holes in the main casting.

Next, allow the metal to cool. At this moment, the liquids are solidified. It is time for you to break away the mold and remove the casting. It is true that the mold is destroyed in the removal process. However, the pattern itself can be reused to produce new sand molds. And if you want a more elaborate casting, surfaces should be polished.

The producing process appears to be simple. But it is definitely not. It is certain that each one hopes to produce a casting with high accuracy. It is a work which needs enough practice. During the process of casting, it is advisable to reuse some of the components of the sand mixture lost in the thermal casting process. Whatever, the material determines a lot. Generally speaking, sand castings made from coarse green sand impart a rough texture on the surface of the casting which makes them easy to identify. However, air-set molds can produce castings with much smoother surfaces.

Find More Sand Casting Articles

A Brief Introduction of Molding Sand

When people speak of sand casting, the first thing that comes to their mind is the sand on the beach. They do not think that sand casting is one of the most popular methods which are used to produce metal parts. In order to help people get a general idea about it, the article will introduce some information about the sand casting.

Generally speaking, the sand used in foundry industry includes two kinds, namely molding sand and core sand. The molding sand is composed of 85% natural sand, 9% clay and 6% water. Sometimes, in order to improve its property, coal powder, vegetable oil and wood flour will be added into the mold sand.

Although the sand is the main material for sand casting, it is quite different from the common sand on the beach. Anyone who has built sand castles on the beach knows how fragile sand castles are. So it is impossible to use the beach sand to hold molten metal. One question that comes to the mind is what properties can help the molding sand hold molten metal. Generally speaking, the molding sand has the following features. What comes first is permeability. The ability of allowing the steam to pass through the walls of mold material is called permeability. After the high-temperature molten metal is poured into the mold, there are a lot of gases in the mold. If the gas can not be removed successfully, the casting will produce some defeats. In addition, the permeability is also influenced by the clay content, water content and graininess. The next feature is refractoriness. This is the ability of withstanding high temperatures of sand. From this point, people also can deduce that sand used for casting steel must be more refractory than one for brass or aluminum because of the greater pouring temperature. Also, a sand used to cast large heavy castings must be more refractory than one used for light thin castings of the same metal. The third feature is strength. The ability of resisting the external force is called strength. If the strength of mold sand is not high enough, the castings easily collapse. However, the strength can not be too high. Or else, the sand castings will produce some defeats due to the decrease of permeability. The fourth feature is plasticity. It refers to the ability of maintaining the shape under the effect of external force. Because the molding sand has the good plasticity, the molding operation is very convenient and the shape of mold is quite accurate.

Find More Sand Casting Foundry Articles

Model of Aluminum Casting

Aluminum casting with cast steel inserts,made of aluminum alloy,then machining in CNC and heat treatment,suitable for machinery parts,OEM order is accepted.

* Description:
Precision casting we use water glass, composite moniker and silicasol these three available crafts producing variety of castings, including carbon steel, alloy steel, stainless steel, etc. founding craft based on the principle of resin sand, producing all kinds of castings ADI, grey iron, cupper aluminium castings. die-casting crafts mainly produce all kinds of Aluminum casting metal alloy die-castings.

* Mainly Supply:
spring parts, mining machinery parts, accessories of electro mechanic, gearbox housing parts, flange parts, vehicle parts, industrial components, motorcycles spare parts, sewing machine parts, marine parts, piling parts, locking parts, electric tomato mill accessories, electric meat mincer accessories, kebab machine parts, construction parts, hardware parts, transport parts, sheet parts, machining spindle parts, rubber parts and more…

.Die sand and mold casting process
.Can offer three types of molds die castings, sand castings and permanent mold casting (gravity or chill casting)
.Software for drawing: pro/E, auto CAD, UG, CAD, PDF and solid works 2008 flow analysis
.Further machining work: turning, cutting, milling, grinding, drilling, reaming and threading
.Surface grinding machine: polishing shot blasting, chromate plating, power coated and anodizing
.OEM and ODM parts range: auto parts, electronic parts, furniture parts, home appliance and other industrial uses
.Processes: CAD service, metal processing, surface plating, QC testing and packing
Product Description

Learn more about products detailed description, pricing and service, Please visit stainless steel pipe fittings

wocao

Find More Steel Sand Casting Articles

Precision non-ferrous casting

Precision casting differs from sand casting and shell moulding in that the moulds they employ consist of only one part, while the pattern itself is expendable each time a casting is made. Precision casting processes offer much more freedom to the designer, and produce castings of a superior surface finish and a high degree of dimensional accuracy. Among other purposes, they are used for the casting of metals and alloys that are difficult to machine, since the castings usually require very little or no finishing treatment. These castings are used in precision engineering, clockmaking, and other fields of industrial production

Sand casting can be used for all common metals, and ther are many different sand-casting processes and special processes derived from this method. These are known by various names such as open sand moulding, pit moulding, box moulding and template moulding etc. The most commonly used method for making small castings is box moulding. With this method the pattern is embedded in the sand or other mould material, within a moulding box which is usually made up of an upper and lower part, the sand being compacted by ramming, vibration or pressure. The box is then opened and the pattern is removed, the cores inserted, the box closed again and the casting is carried out.

For casting very large, heavy or intricate parts the pit moulding process is employed. The pit method is where the mould is built up in a casting pit. To give the sand greater strength when used as a mould material for large castings, cement can be added. For symmetrically shaped castings the mould is sometimes formed by means of a template, a metal plate cut to the required profile for producing a certain shape when it is moved along a guide track or rotated on a pivot.

In dry sand moulding the mould is baked ; in green sand moulding and the mould is used with sand in the damp or “green” condition. The metal is poured from above into an open mould. The more usual kind of moulds are the closed moulds which are filled through a special system of channels known as gate runners, and are usually so contrived that the metal enters at a low point and rises in the mould. Once the metal has solidified and cooled, the casting is removed from the mould and the runners and risers are detached from the casting. The casting is then cleaned up by abrasive tumbling, blasting, cutting or grinding.

When casting with expendable moulds, the individual pattern parts are first made by hand or by mechanical means and then assembled. The moulding materials are those used for constructing the actual moulds in which the metal will be cast, are usually mineral substances such as cement, fireclay, plaster etc., in conjunction with bonding agents such as water glass, synthetic resins, oil, sulphite solution etc., which give the moulds the necessary strength and dimensional accuracy. The bond action is either achieved by drying or by chemical consolidation.

Precision non-ferrrous die casting, is the casting of metals such as zinc, aluminium and brass.