What is Sherardizing?

The surface finishing industry hopes you will be following in his footsteps, Minna.

Regards,

A. I am also a motor engineering student in Devon. I have found a bit of info on sherardizing. Sherardizing is a diffusion process in which articles are heated in the presence of zinc dust ⇦ this on eBay or Amazon [affil links] . The process is normally carried out in a slowly rotating closed container at temperatures ranging from 320-500 °C Hope this helps.

A. It is apparently a finishing process that nobody but the British are interested in :-)

Bravo, Ted.. that was too damned funny!

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Ed. note: We deleted the many RFQs we've received for Sherardizing shops & consultants over the years as they are no longer of current interest. But we left this one so readers could realize that people have been looking for this process since at least 1998.

A. Keystone Steel & Wire in Peoria IL does some Sherardizing. The process consists of tumbling small parts with sand, flux, and zinc dust and heating it until the zinc fuses to the surface of the part, followed by a quench.

A. Sherardising, it is called. I work in a small company that sherardizes. It is a method not known very well. In 1901 Sherard Cooper founded this method in England. You put metal products, sand and zinc dust in a closed iron box. This box you put in an oven an heat it until about 410 °C. At about 380 °C. the zinc dust will melt into/onto the metal products that has to be sherardized. This method has a lot of positive things. It is better harmed to corrosion, salt spray test results are better than galvanized. In Europe only a few companies use this method. In The Netherlands one, Germany one, France two and England two or three companies. In other countries, I don't know. In US, I don't know.

You don't have to seek a company that makes equipment. You will not find anyone. Just make the equipment yourself. If you need the machines you want, just go to a constructor and tell your wishes. The owner just developed some machines, and some he could buy.

A. The simple answer to your question is that it depends. The zinc requirement depends on the surface area of the product you coat. The smaller the coated item is the more zinc you'll require. The larger it is the less zinc you'll require.
To be more specific, I'm familiar with a new Sherardizing system, and they use about 2%-9% zinc proportional to the weight of the coated items, i.e. if you coat small parts then you'll use 36 kg zinc for 400 kg steel, however, if you do larger parts you'll use 8kg zinc for 400 kg steel.

A. Up to my knowledge sand is used for distribution of heat. Some two thirds of the drum have to be filled by steel or sand.

Q. Who knows something about physical basics as diffusion coefficients or metallurgic analysis of the layer. Thanks for answering.

A. Hi Arturo. Hi Phillip.
The March 2004 edition of Metal Finishing Magazine contains an article by Dr. Benu Chatterjee on sherardizing, page 40. There are a number of used and inexpensive books about Sherardizing at this link at Amazon.

Regards,

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Ed. note-- Readers: to the extent practical, please try to keep this discussion about generic metal finishing technologies like sherardizing/thermodiffusion rather than purported advantages of a brand, a source, or a proprietary (why?)
Also, bear in mind that salt spray testing of galvanizing can be quite silly because its corrosion resistance depends upon the development of glassy tenacious self-sealing zinc carbonate corrosion products over the months & years. In practice, hot dip galvanizing can often last 50-75, even 100 years without maintenance whereas it rapidly dissolves away in a salt spray cabinet :-)

A. Dear Sir,

Distek is an Israeli company who designs and sells lines for thermodiffusion zinc coating. Distek has today a better technology than Sherardising, but in principle it is the same technology of thermodifussion coating.

Best regards
Sigve

A. You can try Distek web site or just google "Distek thermo diffusion".

A. I'm very familiar with this system. I know that DiSTeK® coated product is being sold under their American trademark UnStain® 1500 and is guaranteed for 1000 hours in ASTM B117 salt spray test.

A. I know that DiSTeK is the owner of the DiAv-93 process and that their American subsidiary have test results by independent 3rd parties, such as US EPA, Michigan State University, and Dade County (FL) approved lab. Their American company posts the test results on their web site. I am sure that through a search on Google you can find the information. Or you can contact them and they will send you copies of these test results.

A. Hi, Sena. Hi, Norbert.

1. If you search our site for "sherardizing" you will find several threads on what it is and its history.
2. The March 2004 edition of Metal Finishing Magazine contains an article by Dr. Benu Chatterjee on sherardizing, page 40.
3. Distek NA can probably help you with your questions or refer you to the proper contacts in Turkey.
4. You may wish to listen to our podcast interview with Martin Straus of Chemplate Industries about Sherardizing and the DiSTeK® process.

Regards,