A123 / A123M - ASTM International

[m sleem]

I cannot understand the meant by min average ref to table title, as per the code requirements A123 / A123M ? ASTM & ref to the material category the steel thickness range shall be min 65 but the contractor and the supplier say that must be the average, please help to interpret correctly. Thanks in advance.

 

[m sleem]

I really appreciate your help!

 

[GoldDigger]

I really appreciate your help!

If the words have their common English language meaning, it means this:

1. Look at the average thickness of the coating. Not the maximum thickness or minimum thickness, although if the coating thickness is zero in some places, that is probably not OK.
2. Once you find the average value, that value must be greater than or equal to the thickness listed in the table.

 

[m sleem]

So, in general the meant is the average value, and the average value shall be equal or greater than the listed value in table.

 

[GoldDigger]

That is how I read it, yes.

Tapatalk!

 

[m sleem]

That is how I read it, yes.

Tapatalk!

I don't have a much experience in such material but Don't you think there is could be risk when consider the average of the coating thickness e.g the piece of cable tray is 6 meter=9' & divided into #6 segments all of them well coated except one with bad coating may be 20, if the reference value is average that means it would suffice while the 20 value is really wrong.

 

[mgookin]

The average thickeness has to be that stated minimum or more.

Think hot dipped galvanized nails. They're rough on their surface. To scratch in the thinnest place you can find and put it under a microscope and measure it is not practicle. But knowing how much the nails weighed before plating and knowing how much they weigh afterwards and knowing the density of the hot zinc and the surface area of the nail, you can calculate the average thickness of the coating and that average thickness must meet or exceed the minimum prescribed.

Make sense?

 

[mgookin]

I don't have a much experience in such material but Don't you think there is could be risk when consider the average of the coating thickness e.g the piece of cable tray is 6 meter=9' & divided into #6 segments all of them well coated except one with bad coating may be 20, if the reference value is average that means it would suffice while the 20 value is really wrong.

The standared is expecting quality control in the plating process. You're looking at the standard which prescribes the thickness. There are other process control standards related to the plating operation (please don't ask me where though). If you have plated material with a "bald spot" that material does not meet standards regardless of meeting the minimum average thickness.