Friday, January 27, 2012

1K / 2K Finish on Stainless Steel sheet and Plate – why is it so important?


Firstly it’s important to look at the BS EN 10088-2 specification with relation to a 1K or 2K surface finish. The 1K refers to a finish applied onto Hot Rolled stainless steel plate, and the 2K refers to a finish produced on either cold rolled plate or sheet – and the sheet can be either 2B or from a 2R (bright annealed) substrate.

The specification and advice from the British Stainless Steel Association reads; “Satin Polish. Similar to 1J / 2J but with maximum specified Ra value of 0.5 microns. Usually achieved with SiC polishing belts. Alumina belts are strongly discouraged for this finish as this will have detrimental effect on corrosion resistance. Recommended for external architectural and coastal environments where bright polish (2P) is not acceptable.”

Having an Ra of less than 0.5 microns (often written as 0.5µm) means that the surface roughness is very fine. The finer the surface finish the less areas there are for contaminates to become trapped and potentially discolour. SiC, or silicon carbide polishing media gives a ‘clean cut’ to the surface finish thus preventing any ‘nooks and crannies’ for debris to sit in. Whilst an alumina (or aluminium oxide) abrasives belts can achieve a surface roughness of less than 0.5µm, they do not give the same ‘clean cut’ finish.
A 1K / 2K finish can be applied to sheet, plate, laser cut profiles and blanks and also long products such as square tube and flat bar.
However there will be some visual differences between the finishes produced on different product as, for example, hot rolled material will require a pre-grind to remove surface scale and defects and long products will of course go through a different product line than, for example, a cold rolled sheet at 3000 x 1500 x 2.5mm

By polishing to a 1K / 2K finish not only is the grain itself fine and smooth but there is a natural lustre to the finish. Not only a technically superior polish but also one with exceptional aesthetic appeal.
When measuring and certifying the less than 0.5µm finish it is often termed ‘Ra’. An ‘Ra’ finish is the universally recognized and most used parameter of surface roughness. It is the arithmetic mean of the departure of the profile from a ‘mean’ or ‘centreline’ and is displayed in microns (µm). The finish should be measured and certified to ensure it meets the measurement required of the 1K / 2K specification.


Source: Professional Polishing Services


9 comments:

  1. Stainless steel Usually 18-20% Chromium and about 8-10.5% nickel. It depends on the type of stainless steel you are referring to. If it is 18-8 stainless steel, then it is 18% chromium and 8% nickel (hence the 18-8). There are several other types, like the 300 series and the 400 series which have slightly different variations of chromium and nickel. If you do a search for "types of stainless steel" you will find that there are several different types.

    ReplyDelete
  2. Very useful information has been shared. You really did an awesome work. Thank you so much. Request you to keep sharing in future also.
    silicon wafer dicing

    ReplyDelete
  3. It was necessary for someone to write on this topic and you grabbed the heart of millions by taking the initiative which is enough to bring the evolution. Thanks for bringing it in light.
    304 stainless steel properties

    ReplyDelete
  4. Your blog held my interest right to the very end, which is not always an easy thing to do!!
    alumina sub micron polishing

    ReplyDelete
  5. Nothing wrong if I say that you are really a wonderful writer. You always raise the social causes in your article which is respectful and admirable for me as an individual.
    Polished silicon wafers

    ReplyDelete
  6. It is a wonderful reply to the question that has been asked since a longer time. Given answers were so immaculate that will open many eyes. I appreciate your work and want you to write more.
    stainless steel 304 properties

    ReplyDelete
  7. It is an inspiring blog post. The issue handles very nicely. I really appreciate the communication skill of yours and definitely come soon by the time you will complete another write-up.
    http://customdicing.com/wafer-dicing.htm

    ReplyDelete
  8. Wow!! This is something I ‘ve been searching for for a while.I’m thankful to you for writing this article.
    wafer dicing services

    ReplyDelete
  9. I would like to thank you for the efforts you have made in writing this article. I am hoping the same best work from you in the future as well.
    Sapphire & Substrate Dicing

    ReplyDelete