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Archive for the ‘Gray Cast Iron’ Category

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.

Welding cast iron can be easy

There are certain elements and materials that are difficult to weld. Cast iron is one such item. But with little effort and application of right strategies, it can also be welded. In most of the cases, welding on this item includes casting to repairs. In the foundry, the repair work is done. It is done where the casting operation is performed. The casting defects may be repaired after the portioned is machined. Mis-machined cast iron portion or part may require some repair welding, especially when holes are drilled or made in the wrong area. Welding technology is used for repairing broken cast iron parts. Broken cast iron parts are common. It is due to the brittle nature of the cast iron.

There is a wide variety of cast iron. Gray cast iron is one of the most popular types. There are some information regarding this variety of cast iron. It will definitely prove to be helpful for you to understand the welding challenges. Cast iron has 2%-4% carbon content. It is ten times much than the steel. Due to the high carbon content the carbon forms into flakes of graphite.

Molted iron is allowed to cool after it is poured into a mould. This is done during the preparation of casting. Castings that are free from any crack can be made when high carbon element is permitted to cool slowly. This is one of the most important information for you. It will be of great help while welding cast iron, especially during and after the completion of welding operation. You may allow the casting to be too slow or keep it cool so that the rate of cooling is not so crucial.

Most of the cast iron has a critical temperature of 1450 degrees F. this temperature condition can cause cracking. The arc will definitely heat the casting iron to temperatures above this point. So, it is very crucial on your part to check whether the casting is done for long periods at this temperature. It is one of the most important areas that you need to look at.

There are two common techniques of welding. One is welding through pre-heating procedure ad another is without pre-heating. In most of the cases, cast iron is welded through the pre-heating technique. In fact, it is the coon method used by most of the welding experts. Another method is to weld the cast iron by cooling it.

So now that you know the methods make sure that you find out what your requirements are and select the best method as per your needs.

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How about the cast iron & pig iron prices in China

As a metal foundry in China, we always keep our eyes on the updated pig iron prices. At the same time, we also provided the updated cast iron prices on Dandong Foundry’s website. In this way, our clients and visitors can learn about the latest prices about grey iron casting, ductile iron casting and pig iron in China.

As for the pig iron prices, we got them from those websites we often used. We have compared their prices with our purchased prices. So, these prices are accurate and representative.

As for the cast iron prices, we have quoted them by gray iron castings by green sand casting process and resin sand casting process. And likewise for the ductile iron castings.

However, you must know that these prices are just average prices, which are just for your reference. There are many factors will affect the prices of iron castings. Such as the unit weight, the annual demand, the structure complexity, material requirements, surface and inside requirements, dimensional requirements etc. So, if you need accurate quotations, you should contact the manufacturers and send the drawings and requirements to them. The incautious inquiry and quotations will affect the both profits for the buyer and seller.

What is the relations between cast iron and pig iron?

There are direct relations between them. In other words, if the pig iron rises 100 USD/ton, then the cast iron prices will rises 100 USD/ton too. Therefore, pig iron prices will largely affect the iron casting prices.

By the way, the different degrees for the gray iron and ductile iron will also affect their prices. The higher degrees will require higher costs. As for the gray iron, the GG 15, GG20, GG25 should have similar prices, but the GG30 and GG35 should have higher prices. As for the ductile iron, the GGG50 should have higher price than GGG40. The GGG60 and GGG70, GGG80 will have more higher prices. Why? The higher degrees will require higher requirement and technical capability. Moreover, the higher degrees will mean the difficulty to recycle the materials. In other words, as for the GG20 materials, we can reuse their casting head (gate and feed) to make GG20 again. Since we make GG20 materials everyday, so the inferior products can be our raw materials again. However, the higher degree materials have to wait for making the same materials again.

For the updated cast iron & pig iron prices, please check Dandong Foundry.

Basics of cleaning and maintenance of cast iron cookware. I will post several videos on seasoning, removing rust, ect… This is just the basics on how to keep your cast iron looking good and well seasoned. At the end of the video, it cut-off at “What is seasoning” – This is a message I sent to fellow YouTuber, MinhSaChau, explaining the term: When a cast iron pan is completely bare – with no oil or anything on it – It will be gray in color, like gun metal. When it is in this unprotected state, any small amout of moisture, humidity or water will cause it to rust… and rust rather quickly. “Seasoning” means that layers of oil have been allowed to bond to the metal. The more layers of oil, the better the bond is… This is what seasoning is… The more you cook with your pans, the more of these layers of oil/coating will build-up and protect that gray metal. A pan that is well seasoned will be very black and smooth in color. It will be as good or better than teflon-coating as far as non-stick performance. : ) I have another video that will help show this – what seasoning and non-stick performance of even just a little seasoning can do.
Video Rating: 4 / 5