Stainless Steel Cable Ladder Grade Test?

By | December 22, 2014

Stainless Steel Cable Ladder Grade Test?

Getting the right Stainless Steel Grade from your manufacturer.

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Can you use Magnet to test if the material used is Stainless Steel Grade?

Addressing The Myth that Stainless Steel does not have magnetic characteristic unlike normal mild steel.

The Truth is SS304 or SS316 may still response to magnetic test depending on the Cold Work Done on the materials. as Quoted below from ASSDA Website:

Magnetic response

A widely accepted but sometimes misunderstood test is with a magnet. Duplex, super duplex, martensitic and ferritic stainless steels are strongly attracted to a magnet while annealed austenitic stainless steels are not. However, cold worked austenitic stainless steels can develop magnetic response, so cold formed ends to a vessel, cold formed bolts and particularly cold drawn wire or bar may be affected by a magnet. This applies to both the conventional CrNi 300 grades and CrMn 200 austenitic grades.

The strength of the magnetic effect is related to the relative permeability. The graph shows the different effect of the same level of cold work (e.g. by drawing) on various austenitic grades. For austenitic grades, more deformation or cold work results in higher strength.

The austenitic grades with higher nickel or other austenitising elements (310 or 316) show much lower magnetic response. Mild steel has a relative permeability between 200 and 2000. Relative permeability of duplex and ferritic stainless steels is in the hundreds

Taken from: http://www.assda.asn.au/technical-info/technical-faqs/testing-for-grade-confirmation.

This means that the test of Stainless Steel Grade using a Magnet is incorrect method and cannot be used as a reference of non-compliance to the Stainless Steel Grade Required by Clients.

It is therefore needed for clients or end user to understand the basis of testing for Stainless Steel Grade instead of the magnetic cube that we found regularly use by Quality Inspectors of the end users.

Stainless Steel Cable Ladder and Stainless Steel Cable Tray is fabricated using Cold Forming such as Rolling, Stamping and Bending and this may add to the strength of the magnetic effect of the materials.

"The magnetism of stainless steel is affected by its alloying elements, atomic grain structure, and the amount of cold-working during fabrication."

Quoted from Techinal Bulltetin: http://www.pencomsf.com/

There is now a Simpler Way to Differentiate between SS316 and SS304, and it is a better test than using a magnet:

Watch the video Below.

Hope this article provide you with a better understanding on the more reliable test to be done to determine Stainless Steel grade.

 

 

 

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