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Up Topic Welding Industry / General Welding Discussion / Hss assembly
- - By jsimon514 Date 05-10-2004 20:14
Hi every body ,
i'm taking welding class and i almost finish my formation thrue our
program we have assembly class wich is to read plans prepare our pieces and weld the final product .But when i'm asking my teachers about the way to caculate the structural force of an H.S.S. assembly they cannot answer my questions .
It pretty obvius that a 1/4 wall tickness is stronger than a 1/16
but i want to understand ,learn the whole process so i can make an accurate structure without having too much ecessive weight.

Thank you very much
Parent - By GRoberts (***) Date 05-10-2004 22:07
A good book on this is "Design of weldments", or "Design of welded structures" by Omer Blodgett. You can get them inexpensively from Lincoln Electric.
Parent - - By billvanderhoof (****) Date 05-11-2004 04:04
What does H.S.S. stand for in this context?
Bill
Parent - By swnorris (****) Date 05-11-2004 12:19
Bill,

Obviously I can't speak for him, but since jsimon514 mentioned wall thickness, my guess is that HSS means hollow structural section (tubes), as designated by the AISC. I've also heard and seen references to HSS that mean high strength steel.
Parent - - By jwright650 (*****) Date 05-11-2004 12:35
Hi Bill,
Like Scott said, HSS is a designation they changed recently to designate round, square or rectangular structural tubing. The way it is spelled out in the shopbill determines exactly which tubing you are asking for. HSS10.00 would be a 10" pipe, HSS4 x 4 x 1/2 would be a 4" square tube with 1/2" wall. I'm not certain how you properly designate the wall thickness of the pipe though, I still see STD or XSTRG / and Schedules listed in the shopbill here at work to designate wall thickness for pipe.
John Wright
Parent - - By swnorris (****) Date 05-11-2004 14:51
John,

All I've ever seen pipe billed out as is schedule 40 (standard), schedule 80 (extra strong), or schedule 120 (double extra strong), which among other things designates the wall thickness. We just list the diameter on the cutting list and either std., xs, or xxs. I don't know if schedule 120 is correct or not. In the green AISC Steel Construction Manual in dimensions and properties, in the far right I see schedule 40 for standard, and schedule 80 for extra strong, but nothing for double extra strong. I looked in my old red eighth edition and my old blue seventh edition and the schedules were not listed.
Parent - By jwright650 (*****) Date 05-11-2004 15:13
Hi Scott,
Purchasing converts the schedules listed to get the proper wall thickness. I just see them listed as such on the details over in the shopbill portion of the sheet. You just can't imagine what sort of info gets billed out sometimes. We end up having to call and ask, "What is it exactly that you call out over here in the shopbill?". When it comes to wall anchors, whether channel slots or wire ties are to be furnished, we get HB, Weston, or Heckman stock numbers and have to cross them over to the brand we end up purchasing. All sorts of crazy things get billed out in our shopbills. What fun.
John Wright
Parent - - By Pascal (*) Date 05-12-2004 06:02
I used to work for a Pipe Systems Distribution company in Aus and my understanding was that double extra strong always ment sch160. Sch120 was just sch120 as it had very limited uses there.

Pascal.
Parent - - By jwright650 (*****) Date 05-12-2004 10:42
Hi Pascal,
I was looking at a ANSI Pipe schedule chart and take for instance a 8" pipe. w/ 8.625 o.d.
Schedule / Wall Thickness" / WT in #/Ft
5 / .109 / 9.914
10 / .148 / 13.40
20 / .250 / 22.36
30 / .277 / 24.70
40 / .322 / 28.55
STD/ .322/ 28.55(same as SCH 40)
60 / .406 / 35.64
80 / .500 / 43.39
XH / .500 / 43.39(same as SCH 80)
100 / .593 / 50.87
120 / .718 / 60.63
140 / .812 / 67.76
160 / .906 / 74.69
XXH / .875 / 72.42(a little lighter than the SCH 160)

Some sizes don't seem to come in all the schedules listed like the 8" does. And in most cases it looks like the XXH is heavier than the SCH 160, but the XXH 8" is actually a little lighter than the SCH 160. I don't know, Go figure.
John Wright
Parent - By Pascal (*) Date 05-12-2004 22:50
Thanks John, I know there's some discrepancy between using ERW and seamless pipe im unsure of the details at the moment.
Parent - By billvanderhoof (****) Date 05-12-2004 04:26
Thanks to all- the only expansion I could think of was "high speed steel" which is used for cutting tools. I didn't think he was asking about a drill bit.

jsimon- to be legally acceptable stresses must be computed by an engineer. The failure of these sections can be from yielding or buckling and buckling is difficult to predict. There are some simple cases, like a short axially loaded column, Stress=load/cross sectional area. Symetrical bending in a rectangular member isn't too bad (there are tables of maximum bending allowable, sometimes free from steel suppliers). If you have an intense interest in this I would suggest further study. Perhaps a course in mechanics for starters.
Bill
Parent - - By JTMcC (***) Date 05-13-2004 18:20
Round HSS and pipe are two different things.

Round HSS is designated by the nominal diameter and the wall thickness, to 3 decimal places. An example would be: HSS 8.338 X 0.375

J Wright, it sounds like you are specifying pipe, but calling it HSS, using a hybrid designation.

Feel free to correct me if I'm wrong : )


JTMcC.

Parent - - By jwright650 (*****) Date 05-13-2004 20:35
Hi JT,
You could very well be right, but I'm reading this right off a structural shape chart. It may have Pipe dimns listed, but it's right there along side the Wide Flanges, Angles, Channels, Square Tubing, Flats and Rounds. It lists Pipe from 1/8" - 48". Long about the 14" sections they are listed as OD from there on up to the 48". Under 14" they are listed as nominal sizes. Does this info help determine if it's a Pipe or HSS chart? I'm asking because I don't know.
John Wright
Parent - - By swnorris (****) Date 05-13-2004 22:38
There's a really good article in this past January's Modern Steel Construction magazine, published
by the AISC titled Are You Properly Specifying Materials? Here's the link to the online version:

http://www.aisc.org/Content/ContentGroups/Modern_Steel_Construction3/January_2004/30725_materials.pdf

It has ASTM specifications and information for most everything used in structural fabrication.
It covers W, M, S, HP, C, L, WT, HSS, plate, all types of fasteners, anchor bolts, etc. Definitely worth checking out.

jsimon514: HSS is available in rectangular and round in the commonly used ASTM A500 Grade B,
but are also available in ASTM A500 Grade C and ASTM A501, which are all carbon steel. In addition, HSS rectangular and round are available in ASTM A618 Grades 1,2, and 3, which are high strength low
alloy steel. Rectangular HSS is available in ASTM A242 and ASTM A588, which is corrosion resistant high strength low alloy steel, and rectangular and round HSS are available in ASTM A847, which is corrosion resistant high strength low alloy steel. The charts on the link provide tensile and yield properties, which may assist in your calculations, if you know the material grade.
Parent - By jwright650 (*****) Date 05-14-2004 10:13
Hey Thanks Scott,
I sent a copy over to our detailing department for their reference. That article covers more than just Pipe and HSS!
John Wright
Parent - By JTMcC (***) Date 05-14-2004 22:18
It sounds to me like they are specifying pipe rather than round HSS.

JTMcC.
Up Topic Welding Industry / General Welding Discussion / Hss assembly

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