Metal Casting Zone Info Blog

Posts Tagged ‘process’

Bangladesh Village Metal Casting

Preparing the scrap metal, the furnace and crucibles for casting and explaining a bit about the mould making process. The firing process and casting takes several hours and unfortunately we couldn’t stay. Rice husk is mixed with the clay to make it more refactory. Old crucibles are used to cap the new ones. A combination of brass, copper and zinc is used to make a ‘bell metal’. Both mould and crucible are placed in the furnace, when the metal is molten, both are removed from the furnace, a hole is pierced in the side of the crucible and the metal is poured.
Thanks to Riaz and Britto.

Dhamrai Metal Casting

Breaking the layers of clay away from a lost wax casting in brass at Dhamrai metal casting.

Cast Iron Casting- Creating complex shapes

Our daily activities comprises of using many small and big things having vital role in many activities. Big containers, candles, bottles, hammers, work pieces, sculptures etc are few of the many materials which have found their applications in our day to day activities. All these materials are designed to offer convenience and ease while working. Many statues and sculptures are shaped using created models.

Molds are created to produce items of similar shape and this process is termed as casting. A manufacturing process in which molten material is poured into the hollow cavity and after cooling it take shape of the mold. Casting is basically solidified part which is taken from mold to complete the entire process. This process is used to design shapes which are complex and difficult to design. This practice is followed due to its cost effective nature and ability to simplify the complex shapes.

Plastic, aluminum, glass or iron, any material can be melted to form shapes. Amongst many types, grey casting offers caster huge flexibility and freedom to make numerous shapes. Cast iron is used for this type of casting and it is derived from pig iron and also termed as grey iron. Grey cast iron is called because of the grey fractured surface and presence of the graphitic flakes deflects.

]]>

Cast iron casting produces metal parts having low physical requirements, like oil pan, protective cover etc, frame, floor, hammer, handle base. Frame, knife, wheels, valves, pipes, motor blocks etc are the products which are produced using this casting. Gear box, brake wheel, coupling plate, medium pressure valve, cylinder liner, flywheels, and cylinder blocks are prepared using grey casting and have also found extensive applications in industries.

Cast iron casting makes use of material with good vibration damping, good wear resistance and good machine ability. However, it has low tensile strength and elongation, but ductile casting process makes use of ductile iron and malleable iron having great strength, amazing ductile properties and is also tough and offer resistance to heat. Ductile casting’s characteristics make them win over ductile steel casting, as it has high and complex production cost. Pressure pipes and fittings, automotive applications, road and construction applications, general engineering applications are various areas where casted ductile iron and malleable iron are used.

Several advantages of grey casting have opened its door in various fields, but at the same time it has to be linked with many drawbacks. This casting process cannot be used for variety of working conditions, which can be provided by ductile steel casting and iron steel casting. Besides, not so good mechanical properties deprive cast iron from being welded and workable. There are many advantages and disadvantages which tells you to decide; what to choose and where?

This is a cast iron pipe that attached the upstairs bathroom. It will be removed and new PVC piping will be run elsewhere so this area can remain open.
Video Rating: 2 / 5

About the patterns of Sand Casting

<!– p { margin-bottom: 0.21cm; } –>

Sand casting involves various processes that include patterns, sprues and runners, casting allowance and design selection. Out of these processes, patterns find immense importance as it is the deciding factor of the final appearance of the finished product. While casting, molten metal is poured into a mold cavity fabricated from sand ( synthetic and natural). Herein, the cavity is developed by using a pattern, a replica of the real part, made from wood or metal. It is an aggregate kept in box called flask. Further, a sand shaped body, core is inserted inside the mold that develops the internal features of the part like internal passages or holes. Desired shapes can be formed by placing the cores into cavity. Core also decides the volume or location in a casting where metal will not pour into. The write-up below will surely help you to get the clear picture of the patterns:

What is pattern?

A pattern is an exact replica of the object that is required to be casted, and is utilized to form cavity in which molten material will pured in during the casting process. There are basically three types of patterns namely;

Master Pattern: It is the primary design that are used for actual production.

]]>

Production Pattern: From which the original castings are produced.

Permanent Pattern: It is the master pattern that is utilized as final or permanent pattern to reproduce production pattern.

Patterns of Sand Casting

In sand casting, patterns used are made out of metal, wood, plastic, and so forth. These patterns meet the specific standard of construction, that also assure durability and dimensional accuracy. Sometimes, according to the demand, an original item can also be adapted to used as a pattern.

Making of Patterns

Making of patterns is known as pattern-making or styled pattern-making. This work is also related to tool and die making or mold making incorporating the refinement of woodworking. Pattern makers learn this skill through apprenticeships and trade schools over many years of practice. Pattern-making also requires the supervision and guidance of engineers. The processes involved in the pattern making include certain allowances such as:

Contraction Allowances

Pattern requires appropriate allowance for shrinkage wherein there exact value depends on the alloy being casted and the precise sand casting method followed. The linear shrinkage can be up to 2.5% though enlarged sizes can also be witnessed sometimes.

Draft Allowances

There is scope for draft allowance, which means that while pulling out the casting from the sand, edges can be tapered up to 1 and 3 degrees.

Sprues, Gates, Risers, Cores, and Chills

Placement of Sprues, gates, risers, cores, and chills are also decided by the foundry designers in respect to the pattern.

Demand

Patterns are widely required for sand casting of metals including production of ductile iron, gray iron, and steel casting. The precise process and pattern equipment is decided by the order punctualities as well as casting design.

Sand casting is the widely used process that can develop minimum as one and maximum as a million copies. Herein, patterns will remain the vital part of its process.

More Ductile Iron Castings Articles

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 Best Method of Welding: Cast Iron

In a foundry, welding cast iron has many uses like repairing casting defects. Salvage worn or broken casting are there. They are also used in welded assembly in there fabrications. Welding cast iron is a very tricky procedure and should be handling with care. Let us see how it is useful to welders.

Using of welding cast iron is a big process to understand. First step of welding cast iron is cleaning of the cast iron to be welded. And it takes place with the help of a degreaser. If there any accessories part then it has to be removed. When welding a small crack then the beginning and the ending point of the crack has to be determined while welding it. A stop hole should also be done of one eight inch by drilling at each end of the crack, sand paper can be used for grinding and a magnifying glass is also needed to see the hole done. The length of the crack has to be grounded by a V shape, taking care of not going through all the way through the cast iron.

The whole cast iron material is pre heated and to be welded through 500 degree c is very important. This process protects from any damage that may be cause due to heat which comes out through welding process by the welder. Right equipments should be used like the defined welding road must be used and welding should be done on both the ends with short tacks and on low heat. The direction has also to be taken care only one direction is followed when welding is done each time. The weld changes according to the size of the crack, as in if the crack is too long then, short welds to be made. The time gap between the weld should be short cool down should be allowed so that the heat is kept to its lowest.

The ambient temperature has to be cooled down and it is a very important procedure in welding. it should be then place on a hot oven. The temperature should be maintained constantly from fifty to sixty degree per hour so that the air temperature is reached. A dry sand or a fire proof blanket can be used to wrap the material if the hot oven is not available. Getting the right size of the rod for welding cast iron is very peculiar. And to know this rightly the manufacturer has to be consulted.

Same method has to be followed when ever there are two pieces to be cast iron or a crack to be welded. The material gets cool really soon in open air, so to avoid that it is very important for a welder to make sure that the materials are pre- heated and cool down slowly.

Where does welding cast iron is used should be known welding cast iron is used in various places like housing, brake drums, counter weights, pipe fittings, making enclosures, machine forms and bases, clutch plates. concluding that the welders should always use the right and apt welding equipments so that welding is done with proper format and also follow all the rules and regulation of welding cast iron to get the right weld which will not crack and stay last long.

Precision Ferrous Castings and its Benefits

Casting is the industrial manufacturing process in which liquid material is purred in to mold for making desired shapes. Through casting process you can develop giant industrial parts, auto component parts, ornaments, aerospace parts with ferrous and non ferrous metal. Generally there are two types of metal like Ferrous and non ferrous metal are widely used for castings products manufacturing. Ferrous metals contains irons and they are magnetic and gives some resistance to corrosion therefore they are widely used for making big industrial parts. Find here some ferrous metal which are widely used by investment casting foundries in India

Mild Steel: It contains 0.15 to0.30% carbon and having high tensile strength, ductility and used for girders, plates, nuts and bolts.
High Speed Steel: – It includes Medium carbon, tungsten, chromium and vanadium and its remains hard in high temperature and widely used as cutting tools for lathes machine in metal industry
Stainless Steel: – It contains 18% chromium and 8% nickel therefore corrosion never place in this type of metals. And it’s widely used in kitchen draining boards, pipes, cutlery and aircraft. Many castings foundries in India used stainless steel for steel castings manufacturing
High Tensile Steel: – It contains low carbon steel, nickel and chromium and used for making auto parts components such as gears, shafts, engine parts etc.
High Carbon Steel: – It contains 0.70% to 1.40% carbon and used for making chisels, hammers, drills, files, lathe tools, taps and dies.
Medium Carbon Steels: It contains 0.30% to 0.70% carbon. It is stronger and harder then mild steels, and also it is less ductile, tough and malleable. Investment castings manufacturers in India used for making metal ropes, wire, garden tools, springs
Cast Iron: – It is hard and contain small amount of scrape steel with iron and widely used for making auto parts castings, machined castings, machine tool parts, brake drums, machine handle and gear wheels, and plumbing fitments etc.

Also I would like to solve confusion, generally people thing ferrous casting is one type of process like investment casting, die casting its right but ferrous casting means casting process used ferrous metal for investment castings, steel casting manufacturing.

Related Malleable Cast Iron Articles

Foundry: Metal Casting

Metal casting is what the name suggests. Basically metal casting is the process of melting down metal into a liquid state. The liquid metal is then poured into a cast; this cast allows the metal to cool creating the desired result of the intended mould or specific item they wish to make out of metal. The finished product is then sent off to be polished up and ready to be distributed.

Metal casting is used for more “tailor-made” areas of manufacturing metal products which would generally cost a whole lot more if they had to be machined welded. A great aspect of Metal casting is that it also allows the ability to re-create the same product with great ease and they products are identical of one another.

The most important and integral part of metal casting is the mould. The mould is essentially what the product is going to be. These moulds are manufactured in a foundry. Manufacturers take their dimensions, sketches and ideas for the mould to the foundry where the moulds are produced. These moulds then get sent off to the casters. Casters put the completed mould into a back up frame that contains cooling apparatus. The melting down of the metal happens in a very particular place in the foundry. When the mould is done and is ready to be cast, casters move the liquefied metal over large machines and equipment above the mould, this equipment helps the liquefied metal flow down into the cast. This equipment also monitors the rate at which the liquid metal flows into the cast. The cooling equipment then cools the metal down allowing the metal to harden and become a solid state. The castings are now removed and the product is now ready to be cleaned.

Metal casting isn’t the easiest process on the planet and problems can occur during the casting process. Pollution is a major problem worldwide, but in terms of metal casting, this can also have an effect on the metal. If the metal, in its liquid state is exposed to forms of pollution this will cause imperfections within the metal itself, thus when the metal is solidified it can cause weak spots and thus when the cast is removed from the mould, the cast can break. Not only can the casting become affected but the mould too. Gas bubbles can also form after the cooling process which will also cause the metal to become brittle and could possibly even show signs of bubbles on the metal itself. If there is malfunction or something goes wrong in the cooling process the cast could harden before all the metal fills the mould which will lead to deformations within the cast.

Some metal casting processes can be easily carried out by hobbyists and enthusiasts within their own chambers of work and don’t necessarily need to take place within a foundry.

Find More Metal Casting Articles

Cast Iron Finish With Cast Iron Guttering

When you hear the expression that something has a cast iron finish it means that it is solid and reliable. Cast iron gutters are exactly that and no other guttering looks as solid and permanent as ones made with this metal.

Another well-known expression is that if it isn’t broken don’t fix it. Cast iron gutters again, are an example of something which works well and has no need to be changed for any other material.

Cast iron guttering has been installed around the roofs of houses for hundreds of years. Some of the great stately homes of England have literally miles of this type of guttering around the roof tops. Last year the whole gutter system at Blenheim Palace in Oxfordshire was repainted and it took three men most of the summer to achieve this.

Aluminium and PVC are popular gutters but nothing quite looks as good as the solidity of cast iron. This metal which was first used in Europe in the fourteenth century became the most widely used metal in the manufacture of machines, bridges and ships. Many other metals like the widely used aluminium were not even known to man until the nineteenth and twentieth centuries.

Although steel was being produced in small quantities up until the eighteen fifties it was a very expensive process. At this point an industrialist and inventor in England discovered a process which reduced the cost of converting the iron into steel and began mass production in a method still used today. At almost the same moment in history the first all iron steamship was being built in Bristol. This ship named the Great Britain is now in dry dock in Bristol and is one of the greatest tourist attractions in the country. It wasn’t long before ships were being made of steel and that other metal aluminium which coincidently was also just about being developed at this time. Steel hulls for ships allow them to be built to an almost limitless length whereas there is a finite length that a wooden boat can be built at around a maximum three hundred feet.

Just behind aluminium, iron is the fourth most abundant element on earth and both these materials are used in hundreds of manufacturing processes. Cast iron guttering is just one use for iron but the invention of an efficient way of making steel gave another dimension to iron usage as the metals are both derived from the same material but steel has some better properties over iron. Steel is lighter, tough and crucially it is flexible where iron is brittle and very unyielding. Depending on the amount of carbon introduced into the process of turning iron into steel, it also can have the added property of being rust proof.

There is no reason why gutters cannot be made of steel instead of iron but the extra cost of steel and the fact that it gives no extra advantage means that iron gutters are the better option.

The problems with steel foundries in China

There are three kinds of steel foundries in China. One is the sand casting foundries, then the water glass investment steel casting workshops, and the silica sol investment steel casting workshops. We usually called the investment casting as precision casting process.

What kinds of products can these casting workshops produce?

As for the sand casting workshop, they usually make the steel castings with material of normal carbon steel, and some kinds of alloy steel. The prefer weights are from 5kg to 400kg. With normal surface and inside quality requirements, and simple machining. They usually use the green sand or CO2 gas hardening sand as the materials. The problems with these foundries are their production efficiency is low. Since they use the traditional manual molding process, their annual output is small. They can not meet the delivery time for the large orders. Second problem is their surface quality is not good. This is the common problem for all sand castings. Thirdly, they can not do the high precision machining. These workshops are usually able to make the simple machining. Of course, I do not mean all the steel foundries do not have CNC centers. Some large steel foundries have many good machines for machining.

As for the water glass investment casting workshops, they use the water glass and yellow wax as the material. We also call this casting process as lost wax casting process. This process can keep very good dimensional and surface requirements, and these workshops usually use the medium-frequency induction furnace, therefore, they can make some alloy steels. Their problems are they can not make large or heavy castings. Their prefer size is between 50mm to 300mm, and prefer weight is between 0.3kg to 5kg. This is restricted by the lost wax process.

As for the silica sol investment steel casting workshops, they use the materials of yellow wax and silica solution. So, they can keep the higher level for the surface quality and dimensional requirements. According to the experience of Mr. Galen Wang from Dandong Ruiding Foundry, the silica sol investment casting process can reach the best surface quality and dimensions. Their problems are as same as the water glass investment casting process. They have size and weight restriction. In addition, their production costs are usually three times of water glass investment castings. Therefore, unless you need absolutely high surface quality and dimensions, this process is not your best choice.

By the way, all steel foundries are not willing to make iron castings. It is because the pig iron used for making steel castings is not same as that used for making iron castings. We call this pig iron as steel pig or pig iron for steel making.

We hope this article can help the overseas buyers and purchasers to learn more about the steel foundries in China, so, they can choose the most suitable suppliers for their products.

This article was originally written by Mr. Galen Wang from Dandong Ruiding Foundry

Foundry Equipment, Sand Casting, Sand Core Making, Core Shooting Machines Shell Molding Machines Shell Moulding Machines Sand Core Making Resin Sand Core Making Iron Casting Sand Casting Green Sand Casting Foundry Core Making

13 Minute Video featuring the TEKCAST Spin-casting process – PART 1.

Spin-casting is a quick, low-cost solution for producing a wide variety of metal and plastic items. It is suitable for industrial, novelty, decorative and prototype applications.

Spin-casting is also popular with the fishing lure, gaming miniature, costume jewelry and replacement part industries.

13 Minute Video featuring the TEKCAST Spin-casting process – PART 2.

Spin-casting is a quick, low-cost solution for producing a wide variety of metal and plastic items. It is suitable for industrial, novelty, decorative and prototype applications.

Spin-casting is also popular with the fishing lure, gaming miniature, costume jewelry and replacement part industries.