Need yield strength for 4" dia sch 40 pipe from 1957

[mantonas]

I am trying to calculate the capacity of a duct support consisting of a cantilevered carbon steel 4" diameter schedule 40 pipe. The building was constructed in 1957. If I were specifying a pipe member today, I would call out ASTM A53. After doing a little trial-and-error web sleuthing, I discovered that there was actually a 1952 edition of ASTM A53. I have a copy of a 6th edition AISC Manual of Steel Construction (MSC) that was printed in 1963, and it lists ASTM A53 for steel pipes. However, I have a copy of a 5th edition MSC that was printed in 1961, and the only reference it gives for a material specification for piping is at the bottom of the "Allowable Concentric Loads in Kips" table for steel pipe columns, which states that the pipes are assumed to be made of steel conforming to ASTM A7. I don't know that it makes much difference, because the yield strength for A7 was 33 ksi, and the yield strength for A53 today is 35 ksi; chances are it was less in 1952, but I'm in one of those "every little bit helps" situations. So what spec was most likely followed for my 4" pipe, and what would the yield strength have been?

 

[msquared48]

In the 1949 edition of the "Steel Construction Manual", page 248 at the note at the bottom of the page, it states that for the tabulated values, the material for the pipe is assumed to be A7 steel, and that "If the pipe is made of other steel, safe loads should be suitably modified." I could find nowhere in this publication where the yield stresses are listed.

Still looking.

Mike McCann
McCann Engineering

 

[msquared48]

If you look on page 285 of the actual AISC code covering "Allowable Unit Stresses", it does list some values, generally in the order of 20,000 psi. On page 287, under section 15(b) for cast steel, which your column may be, it mentions that the "Compression and Bearing are the same for Structural Steel. Other Unit Stresses, 75% of those for Structural Steel."

Mike McCann
McCann Engineering

 

[msquared48]

You may have to go so far as to search any ASTM Standards that may have existed at the time to get the Fy values. I do not see them listed in the Code I referred to.

Mike McCann
McCann Engineering

 

[mantonas]

MSQUARED, it seems like you took almost the same path I did. In my original post, the column load table I referred to is the same one that you found on page 248. My copy of the 5th edition MSC also includes a copy of ASTM A7 (maybe yours doesn't), on page 326, and it gives a minimum "yield point" of 33,000 psi, under tensile properties, section 9.

As for searching any ASTM standards, I would love to, but how does one get their hands on ASTM standards from the 1950s? As I wrote earlier, there is evidence that a 1952 version exists, but even if I wanted to pay $65 or whatever for a copy of a "historical standard" from ASTM, the ones for ASTM A53 only go back as far as 1999! I might start another post about that.

 

[msquared48]

I have the same note on the 33,000 yield value on the same page.

Regarding the ASTM's, I do not know.



Mike McCann
McCann Engineering

 

[msquared48]

This is getting interesting to trace - possibly too much information.

In my 1936 copy of the "Handbook of Engineering Fundamentals" by Eshbach, on page 11-25 in the bottom table, he lists "Structural Steel with an ultimate value of 60,000 psi, and a yield strength of 38,000 psi. "Soft Steel", whatever that was or is, is listed at 50,000 and 30,000 psi respectively.

The note at the bottom of the table reads: "The figures in this table are representative of the properties of steel in commercial shapes. Variations may be expected relative to size and shape. The values given are not suitable for a basis for purchase specifications asthey are not assured minima."

Is the water muddy enough yet?

Mike McCann
McCann Engineering