No minimum hardness value for SA213 - 2004 2

[replica]

Hi all,

I just wondering why only maximum hardness is specified for all materials in ASTM SA213 - Table 4 and not the minimum hardness. I think minimum hardness is also very important to look for material deterioration due to spheriodization as well as creep especially on low alloy steel when subjected high pressure and temperature . Any one can clarify on this?

 

[metengr]

Yes. There was no agreement or consensus as to what the values should be.

 

[mrfailure]

There is not a minimum hardness (in most cases), but there are minimum tensile and yield strengths. These provide the limiting conditions. As a practical matter, you can estimate minimum hardness (for the ferritic steels in the table) by converting minimum UTS to hardness using the table in ASTM A370.

 

[metengr]

Also, maximum hardness can be well defined because it impacts forming, weldability and corrosion resistance in service.

 

[replica]

metengr and mrfailure ...thank you very much for clarification, I really appreciate that...

 

[replica]

What about the hardness for weldment. Where can i get the information on maximum and minimum hardness for weld deposit and HAZ? Is it depending on application?

 

[metengr]

The hardness for weldments can be obtained for carbon and low alloy steels from ASM B31.3. I found this has been the best source for maximum hardness.

 

[replica]

Thank you very much metengr

 

[replica]

Hi metengr..when I go through ASME B31.3. ..I could not find the said weldments hardness value. Is it ASM B31.3 or ASME B31.3?..Is it the same? Sorry I am not familiar with this code....Appreciate your comment......

 

[metengr]

replica
Look at Table 331.1.1 in ASME B31.3 Process Piping Code over to the right in the column are maximum hardness values. See Note 4 below, these values apply to bending and after PWHT, see Note 4 below

331.1.7 Hardness Tests. Hardness tests of production
welds and of hot bent and hot formed piping are
intended to verify satisfactory heat treatment. The hardness
limit applies to the weld and to the heat affected
zone (HAZ) tested as close as practicable to the edge of
the weld.
(a) Where a hardness limit is specified in Table 331.1.1,
at least 10% of welds, hot bends, and hot formed components
in each furnace heat treated batch and 100% of
those locally heat treated shall be tested.
(b) When dissimilar metals are joined by welding,
the hardness limits specified for the base and welding
materials in Table 331.1.1 shall be met for each material.

 

[replica]

metengr......thank you very much for an excellent post....

 

[weldstan]

If memory serves correct, B31.3 does not address hardness for carbon steel. It defines hardness for maximums for specific low alloy steels but only in the PWHT condition.