Material Classification

Date 12-02-2010 13:46

These to me are interesting questions from an historical perspective but I have never been able to find it written anywhere and there aren't any of the old guys around when this stuff was established to tell us. Somebody knows I'm sure. Not me.
Sometimes these things are actually just 'rectumus extracticus', or in the case of seamless pipe, 'rectumus extrudicus'. It is fascinating to listen to some of the old guys and realize how arbitrary some of these things actually are.
What you have there is as good a guess as I can come up with and actually seems quite likely.

By G.S.Crisi (****)

Date 12-02-2010 19:12

TP means TYPE; i.e., A 312 Type 304. This is because AISI classifies stainless steels in types. For example: type 304, 316, 304 L etc.
As for WP, I don't know. And what about A 234 Grade WPB?
Giovanni S. Crisi
Sao Paulo - Brazil

By fschweighardt (***)

Date 12-02-2010 21:52

WP seems to always be associated with Wrought items
Sometimes you see F for forgings, and C for castings

By ravi theCobra (**)

Date 12-02-2010 22:27

the " WP " designation is wrought product , the " TP " designation is tubular product

The real difference between them is that the chemistries may be different -

By Shane Feder (****)

Date 12-03-2010 11:01

Thanks guys,
I am looking for some "quoteable" evidence as I am in the middle of a heated discussion,
Regards,
Shane

By jrupert (*)

Date 12-03-2010 21:52

I did not find any specific definition of WP or TP, however, the following might be helpful as far as spec references go.

A403 Paragraph 1.2 "Grades are designated with the prefix WP or CR based on the applicable ASME or MSS dimensional and ratings standards respectively."
The references in this standard led me to ASME 16.9 and 16.11 which both state that products that conform to either of these specs are to be labeled with a "WP" prefix. ASME 16.9 has a paragraph "Section 5 Materials - the term wrought denotes fittings made of pipe, tubing, plate or forgings."

I would say that based on the above that the WP stands for wrought product like the others have stated.

As for the "TP", I checked A312 which lists everything there with a prefix of "TP" with a reference to ASME B36.10 which says in the scope that "The word pipe is used, as distinguished from tube, to apply to tubular products of dimensions commonly used for pipeline and piping systems."

I would say that based on the above that the TP stands for tubular products.

.

By ravi theCobra (**)

Date 12-03-2010 23:46

duh -

Is that not what I said ?????????????????????????????

By Shane Feder (****)

Date 12-04-2010 10:10

Guys,
Looks like my original opinion may be wrong.
Found this
"Butt Welding Fittings conforming to the requirements of ASTM specifications A234, A403, A420, B361, B363 and B366 shall use marking symbols consisting of the prefix 'WP" added to the ASTM-specified grade identification symbol.
Examples: WPB, WP304, WPL6, WP6061, WPT1."

Based on the above I am leaning towards "Weldable Pipe" or "Weldable Product" rather than "Wrought Product"

Five of the six specifications noted above are for Wrought Products but B363 throws a spanner in the works because it is not applicable to wrought products.

It is strange that there is so little information available on the internet regarding what these symbols actually mean.
Regards,
Shane

By eekpod

Date 12-04-2010 14:06

You can e-mail ASTM and ask them dirsct, but it takes awhile to get a responce.