Grade or Thickness

What is the thickness for X56 and the thickness for X52 ??

x 52 thick 17.5 mm

x56 thick 15.8

the last post is from me.

Welcome galal_elden,

• May be the proper choice depends on an economy study, and it is easily to do that by getting a price list from the suppliers for both grades with the different thicknesses (schedules).

• And the economy study may includes the weldability of both grades, because the higher strength grade may require special WPS's & PQR's.

• Also - in case of underground piping - may be the higher resistance for soil and other external/impact loadings is preferred which may be established in case of using higher thicknesses piping.

• May be the MDMT and need to impact test of piping material is the governing point, which depends on the material and its grade and its thickness, which determines its curve on MDMT-Thickness Curve. Please refer to the applied piping code to find MDMT and need for impact test.

Are you sure you need 90 bar pressure? That's about 1300psi - usually potable piping is rated in the region of 100-125psi for that diameter.

There are a few considerations as under to enable choice/decision:

1.Higher grade, lesser thickness gives weight reduction leading to transport and handling cost reduction. Lower Initial installation cost slightly offsetting higher cost of higher grade.

2.Lower grade, higher thickness gives higher weight of line leading to reduction in holding down/anchoring cost.

3.Lower grade, higher thickness gives higher longevity of line leading to reduction in overall cost.

I'd recommend Lower grade.

Add to 3. Underground pipe is subject to corrosion. Thicker pipe will resist this longer.

Good answer

A 900 mm diam steel pipe at 60 bar pressure with the wall thicknesses you gave is in the realm of fantasy. The pipe will not hold. I recommend to have the calculations re-checked by PROFESSIONALS.

He said 90 Bar which is even worse , he must have hie figures confused.

i mean 60 bar sorrrrrrrrrrrrrrrrrrry,

For mild steel pipe at 60 Bar that leaves you about 8 bar head room from maximum working pressure, not a great deal of leeway [ that is for 17,5mm wall ].

Hello Garth

It's normal to design pressure vessels as close as that to the allowable stress, so why not pipe? I suspect designing the pipe connections is more of an issue than the pipe itself - including taking account of thrust loads (depending on connection type)

But I can't see why the OP is asking us. As he has the 2 thicknesses he can presumably cost both options. Things like handling and installation costs might be different, but he should be in a better position to assess that than anybody here.

Cheers.........Codey

The X52 and X56 pipes otherwise are so similar (except the strength) that i don't think anything except the cost will matter.

The corrosion behaviours of both are same as per literatures. As are welding and other features.