Steel Tubing strength

[CIRCLEBFAB]

Any body know if there is any differance in strength between regular mild steel tubing and schedule 40 pipe. I am using 1.625 x .134 wall mild steel tubing for race car roll bars and cages and the cost of steel just keeps going up. I can get a good deal on schedule 40 pipe 1.66 x .126 wall. since NHRA and IHRA only require .118 wall what would be wrong with using the scedule 40? Is there any differance in the metalergy of these. THANKS JIM

[hankj]

Where did you get the size? According to my pipe table, Sch. 40 steel 1-1/4" pipe = 1.66 OD x .140 wall.

Unless you're using 4130 tube, looks like the Sch. 40 would be tougher.

Hank

[Terence638]

Ive also posed that same question and dont remember the answer but i thing the schd 40 is by far stronger but it is harder to work with and id like to build a motor cycle frame from schd 40 because i can get an awsome deal on thew schd 40 pipe (free) so ill keep looking at this post to see for an answer.
Terence

[wrench3047]

hey hank
do you have that pipe chart on the computer where you could post it? If you don't have you seen on online?

[hankj]

Might have to back off here - my reference is actually a Canadian publication, and the table I'm using is Imperial. Gotta see if there's a difference between that and U.S., and I'd betcha there is!

Standby!!

Hank

[yammahoppy]

here is a pipe chart of sorts http://www.sss-steel.com/refpdf/26-30.pdf dont know if it is what you are looking for.

[hankj]

Nope. Same-o same-o.

Here's a link.

http://www.interpipe.com/Pipe_Dimensions_and_Weights.htm#10

Hank

[CIRCLEBFAB]

pipe

hankj, I am sure the schedule 40 probably calls for .140 but the pipe I have on hand measures .126. I think the mills have a little leeway over or under. Thanks for your response. JIM

[Compchassis]

I would be real careful about using water pipe in a car. I have seen it get through tech, but, I have also seen my share of cars rejected because they were built with water pipe. If the car is to be certified, many times the inspecter has a half round gauge he puts on the chassis to check tubing diameters. Water pipe is obviously bigger than 1.625, but smaller than 1.750 and they can reject it. Not to mention, if any thing should happen and someone were to get hurt in a car you built with water pipe, you are opening yourself up for even bigger problems.

Steel is going up, there is no way around it. Just raise your prices the same amount that steel has gone up. I have had to do it myself. I have had several customers come in that I had quoted jobs to 2-3 months back and I just have to tell them that steel has gone up and the price has to go up with it.

[hankj]

Jim,

I'm thinkin that .014 slop is way too much to meet the ASTM cert. Is it Sch. 40 steel or someting else?

Hank

[Teeps]

I would be real careful about using water pipe in a car. I have seen it get through tech, but, I have also seen my share of cars rejected because they were built with water pipe. If the car is to be certified, many times the inspecter has a half round gauge he puts on the chassis to check tubing diameters. Water pipe is obviously bigger than 1.625, but smaller than 1.750 and they can reject it. Not to mention, if any thing should happen and someone were to get hurt in a car you built with water pipe, you are opening yourself up for even bigger problems.

Steel is going up, there is no way around it. Just raise your prices the same amount that steel has gone up. I have had to do it myself. I have had several customers come in that I had quoted jobs to 2-3 months back and I just have to tell them that steel has gone up and the price has to go up with it.

I don't see how putting a stronger pipe in a car, some how puts him at risk.

The welds have to be good with either tube, that goes without mention.
Maybe sched. 40 is not stronger in some way? torsionally? more brittle?
Otherwise I don't see the downside.

[Compchassis]

I dont have specs on water pipe sitting in front of me to compare to mild steel or DOM, but, I can tell you that I have seen the seam on water pipe open up fairly easily when bent. It is not as strong as dom or std mild steel. Also, used to state specifically in the rule book, no water pipe.

[paulrbrown]

1 1/4" pipe should measure 1.660 OD, .140 wall, 1.380 ID for Schedule 40ST or 40S. Data from ANSI/ASME B36. Both 'WaterPipe' and Mild Steel tubing should be made of the same 'LowCarbon" steel and the welds are similar. DOM is more accurate as to OD and ID due to the extra forming process, you also loose the inner weld bead on DOM. Chamfering with endmills also causes more problems due to the odd size of OD and the avaliability of endmills. STRENGTH DIFFERENCE???? maybe a comparison is out there somewhere in Cyberland. hope this helps, Paul

[paulrbrown]

I have been searching the net today, for hours, and can't seem to find Pipe/Tubing specs that tell you the Tensile strengths without having to pay $40.00 for each type........plenty of data on weights/ID/OD. Can someone enlighten us on what ASTM specs the different sanctioning bodies require and give what the specs are on the different materials....I will post the best sites I have found after I do a little more research. Thanks, Frustrated Paul
PS, DOM tubing does gain strength due to the process I found out.

[Terence638]

what about seamless schd.40 pipe would that be tha way to go?
as apposed to seamed?
Terence