Comparing Round & Square Pipes: Strength & OD, Thickness

[raj001]

what are the principles regarding pipe OD, thickness & strength as well regarding round and square which one is more stronger. This matter came up becoz there are certain sizes of OD not available in HR but only available in CR, on the other hand there are certain sizes which we can convert form round to square to save material or increase strength. Pls note that we have to find out the following regarding Pipes -

1. If we make a Hollow Round Tube of 15.88mm OD and 1.2mm Wall Thickness, means a weight of 470gm per mtr. Keeping the same weight per mtr, if we make Holow Tube of 19.08mm OD then its thickness will be 1.0mm.

Now our question is, which Hollow Tube will be stronger? Which will bend less when put same pressure on same length? The Tube with 15.88mm OD or with 19.08mm OD as the material used in both of them is same?

 

[Q_Goest]

1. If we make a Hollow Round Tube of 15.88mm OD and 1.2mm Wall Thickness, means a weight of 470gm per mtr. Keeping the same weight per mtr, if we make Holow Tube of 19.08mm OD then its thickness will be 1.0mm.

Now our question is, which Hollow Tube will be stronger? Which will bend less when put same pressure on same length? The Tube with 15.88mm OD or with 19.08mm OD as the material used in both of them is same?

Stronger in what sense? Generally when we speak of the 'strength' of a pipe, we're referring to its ability to resist internal pressure. But we might also be thinking of using a pipe to make some kind of framework in which it must resist a bending moment.

For the case of internal pressure, a thicker wall and smaller diameter is stronger because there is more material to resist the forces that tend to split the pipe (ie: lower force per unit area of material).

For the case of a bending moment in a pipe, the thinner wall and larger OD is stronger (up to the point where buckling becomes the primary failure mechanism) because there is more material farther away from the point of bending (called a 'neutral axis) and this allows for larger moments to be resisted in the same way that less force is needed on a longer lever arm to produce the same moment around a fulcrum.

 

[oswaler]

The strength of a pipe is dependent on several factors, including its outer diameter (OD), wall thickness, and the material used. In general, a larger OD and thicker wall will result in a stronger pipe. However, when comparing round and square pipes, there are additional principles to consider.

Firstly, square pipes have a larger surface area than round pipes of the same OD and thickness. This means that square pipes have more material and, therefore, can handle more stress and pressure before bending or breaking. This makes square pipes generally stronger than round pipes.

Secondly, square pipes have more structural stability than round pipes. This is because the corners of a square pipe provide additional support and prevent the pipe from buckling or collapsing under pressure. In contrast, round pipes are more prone to bending and buckling due to their circular cross-section.

In the specific scenario described, if we keep the weight per meter the same, the square pipe with an OD of 19.08mm and a wall thickness of 1.0mm will be stronger than the round pipe with an OD of 15.88mm and a wall thickness of 1.2mm. This is because the square pipe has a larger surface area and more structural stability, making it better equipped to handle pressure and resist bending.

However, it is important to note that converting from round to square pipes may not always result in a stronger pipe. This is because the material used also plays a crucial role in determining the strength of the pipe. For example, if the material used in the round pipe is stronger than the material used in the square pipe, then the round pipe may be stronger despite its smaller surface area and less structural stability.

In conclusion, when comparing round and square pipes, it is important to consider the principles of surface area and structural stability in addition to the OD and wall thickness. In the specific scenario described, the square pipe with an OD of 19.08mm and a wall thickness of 1.0mm would be stronger than the round pipe with an OD of 15.88mm and a wall thickness of 1.2mm. However, the material used must also be taken into account in order to accurately determine the strength of a pipe.