The difference between a tube and a tube
Definition of pipe
The tube is an empty container with a circular cross section that has a specific diameter, thickness and length that is used to move and transfer fluids and is composed of different materials such as: steel, concrete, fiberglass and …..
Pipes are divided into two categories in terms of construction, Seamless pipes and Welded pipes.
Examples of common pipes in the industry are:
ASTM A53 Specification for pipe, steel, black and hot-dipped, zinc coated, welded and seamless
ASTM A106 Specification for seamless carbon steel pipe for high-temperature service
ASTM A333 Specification for seamless and welded for low-temperature service
* Seamless Pipes
These pipes are made of ingots with full and circular cross-section and with the force of heat and tension by rollers. Seamless pipes are usually made up to 16 inches in diameter.
* Welded Pipe
To make this type of pipe, they are made of steel sheets and using welding. Seamed pipes are usually produced by two methods of submerged arc welding (SAW) and electric resistance welding (ERW). The categories are divided into:
1. Straight seam pipe
2. Spiral seam pipe
Dimensional specifications of pipes
NPS Nominal Pipe Size
OD Outside Diameter
Thickness t Wall Thickness
Tube head makeup End preparation
Concepts NPS, OD, ID for pipes
The pipes have a definite OD, although their thickness varies. A pipe with a fixed nominal diameter for different thicknesses, its outer diameter is the same. For example, the outer diameter (OD) of an 8-inch pipe is the same as Sch60, Sch40, etc. and is equal to 8.625 inches.
Up to the size of NPS≤12 ”the nominal diameter is not the same as the outer diameter and the value of the outer diameter is greater than the nominal diameter. For example, a pipe with a nominal diameter of 10 inches has an outer diameter of 10,750 inches.
From size 14 inches up, the nominal diameter of the pipe is equal to its outer diameter.
Tube Thickness Class (Schedule No)
The pipe thickness class is used to facilitate the pipe trade.
Approximate calculation formula Sch. Pipe
Sch. = (3 + ID) / T where ID = Inside diameter and T = Thickness.
Note: In order to facilitate the use of commercial common thickness classes are called as follows.
STD = Standard XS = Extra Standard XXS = Double Extra Standard
High thickness pipes such as XXS, Sch160, Sch140, Sch120 are also called HEAVY WALL pipes.
Definition of tube
Tubes are commonly used for high heat transfer and high pressure applications. They are resistant to creep and are used in boilers, oil furnaces and heat exchangers.
The tubes do not have a specific length. The thickness of the tubes is the same throughout them, while this thickness in the tube has a tolerance. Common examples of tubes in the industry are:
ASTM A178 Specification for Electric-Resistance Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tube
ASTM A179 Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
ASTM A192 Specification for Seamless Carbon Steel Boiler Tubes for High-Pressure Service
ASTM A209 Specification for Seamless Carbon-Molybdenum Alloy-Steel Boiler and Superheater Tubes
Technical specifications of tubes
* The nominal diameter of the tubes is equal to their outer diameter.
* The thickness class of the tubes is determined by BWG = Birmingham Wire Gauge.
* As the BWG increases, the thickness of the tube decreases.