EN 10255 S195T Carbon steel tubes are also called mild steel tubes. These pipes are manufactured to EN specifications and are commercially known as CS or MS pipes. The hardness of low carbon steel tubes is not as good as that of high carbon steel tubes, but carburizing can increase its surface hardness.

This document describes the criteria for circular non-alloy steel tubes suitable for welding and threading, as well as a variety of alternatives for tube end and coating finishes. This document applies to tubes with specified outside diameters ranging from 10.2 mm to 165.1 mm (thread sizes 1/8 to 6) in two series, medium and heavy, and three types of designated thicknesses.

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TUSPIPE places a premium on product quality and rigorous product quality control. In order to maintain good product quality,  the company has established a Test & Inspection Center since 2004. With a series of state-of-the-art tests and inspection equipment, the test & inspection center is able to perform the tensile tests, hydro tests, impact tests, DWTT, etc.

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EN 10255 Grade S195T Properties

The chemical composition of EN 10255 S195T has a considerable impact on its mechanical properties. Among all the elements of S195T. Carbon is a toughening element. Silicon contributes to strength. Manganese is essential austenite stabilizing element that contributes to texture structure creation and increases firmness, strength, and wear resistance. Phosphorus reduces plasticity and toughness, as well as the appearance of cold brittleness. Meanwhile, it may considerably raise the strength of steel and improve the stability of atmospheric corrosion. Sulfur increases the hot brittleness of steel.

Dimensions and Sizes of S195T Steel Pipes

There is a wide range of steel tube dimensions and weight by the European standard EN 10255 “Non-Alloy Steel Tubes Suitable for Welding and Threading” and British Standard BS 1387:1985 “Specification for screwed and socketed steel tubes and tubular, and for plain end steel tubes suitable for welding or screwing to BS 21 pipe threads”. This table allows easy comparison between different types of steel tubes to choose the most suitable one for a particular application. The table shows that the weight of steel tubes can vary significantly, from less than 1 kg/m to more than 30 kg/m. The diameter of the tube also has a significant impact on the weight, with larger diameters generally being thicker and therefore heavier. The table also shows that there are different types of steel tubes available with different thicknesses, which can be selected to suit the required application.


Chemical Composition of EN 10255 S195T

Steel GradeChemical composition
Mechanical Properties
Upper Yield strength
Tensile strength
A min.
Steel NameSteel NumberC
S 195T1.00260,201,400,0350,030195320 to 52020

NOTE The steel specified in this document is weldable, however, when subsequently welding tubes produced according to this documented account should be taken of the fact that the behavior of the steel during and after welding is dependent not only on the steel but also on the conditions of preparing for and carrying out the welding.

Mechanical Properties of EN 10255 S195T

GradeMechanical Properties
S195TYield Strength (Mpa)Tensile Strength (Mpa)Elongation (%)

Other Properties of S195T

Steel GradeAnnealing hardness HBSCold pull hardness HBSPreheating temperature
Quenching temperature
Holding time
Hardening mediumTemper temperature ℃After tempering hardness
Salt-bath furnaceControlled atmosphere furnace
S195T235262788119112045*15Air cooling52260

Tolerances of S195T Piping

- Type L - Dimension Tolerance and Unit Mass


- Type L1 - Dimension Tolerance and Unit Mass


- Type L2 - Dimension Tolerance and Unit Mass


- Wall Thickness

  • ±10%. for M and H series & Type L;
  • -8% with the plus tolerance limited by the mass tolerance, for Types L1 and L2.

- Weight

  • ±7.5% on bundles of 10 tons or more, for M and H series and Type L;
  • +10%, -8% on individual tubes for Types L1 and L2.

- Straightness

  • Straightness shall not exceed 0.002 L.

Test and Inspection of S195T Piping

- Tensile Test

The tensile test shall be performed on a bare tube in accordance with EN 10002-1.

- Bend Test

The quality of our welded tubes is of the utmost importance to us. In order to ensure that they meet the highest standards, we perform a bend test in accordance with EN 10232. This test is applied to bare tubes with specified outside diameters of 17.2mm up to and including 60.3mm, and the tube is bent to an angle of 90°. The groove in the forming tool has a width that fits the tube diameter accurately and a depth not less than half of the diameter. The radius at the bottom of the groove of the former is as given in the table below. Welded tubes shall be bent with the weld at the outside of the bend. The tubes shall show no cracks visible without magnifying aids. By performing this test, we can be confident that our welded tubes meet the highest standards of quality.

Diameter (mm)17.221.326.933.742.448.360.3
Bending Radius506585100150170220

- Flattening Test

The flattening test is an essential part of quality control for welded tubes. By applying pressure to the tube until it reaches 75% of its original outside diameter, the test helps to ensure that the welds are strong enough to withstand the required amount of pressure. The test is conducted with the weld placed alternately at 0 or 90° to the direction of flattening, to ensure that all parts of the weld are tested equally. Any cracks or flaws that are visible without magnifying aids are cause for rejection. Once the distance between platens reaches 60% of the original outside diameter, however, slight premature failure at the edges shall not be considered as a cause for rejection. This test helps to ensure that welded tubes meet the high standards required for use in critical applications.

- Leak Tightness Test

Leak tightness is an important quality for tubes, as even a small leak can cause problems downstream. There are two ways to test for leak-tightness: a hydrostatic test and an electromagnetic test. In a hydrostatic test, the tube is filled with water and pressurized to at least 50 bar for 5 seconds. If there are no leaks, the tube passes the test. An electromagnetic test uses magnetic flux to detect leaks. This method is more sensitive than a hydrostatic test and can detect very small leaks. However, it is also more expensive and less widely available. Manufacturers can choose which test to use, but both methods are effective in testing for leak-tightness.

- Dimensional Inspection

The size and dimension inspection shall be performed.

- Visual Examination

The visual examination shall be performed as per the standard.

Marking on S195T Pipes

The markings should be placed at least once within one meter of one end of the tube, and the tubes shall be marked with the following information by suitable and durable methods:

  • The name or trademark of the manufacturer;
  • The serious symbol (H or M) and the type (L, L1, or L2);
  • The symbol of the manufacturing process (S or W)

Colors can be a helpful way to organize and identify different objects, and this is especially true when it comes to tubes. Tubes are often used in a variety of settings, from construction sites to laboratories, and they come in a wide range of sizes and materials. While each type of tube has its unique properties, they all need to be marked so that they can be easily identified. The manufacturer may opt to use color coding instead of series or type markings. This will make it easy to quickly identify the different types of tubes, saving time and preventing confusion. By using colors to mark tubes, manufacturers can help to ensure that they are used safely and correctly.

RedBlueSee Tolerance Table

The following information shall appear on the label of each bundle:

  • The name or trademark of the manufacturer;
  • The standard code EN 10255;
  • The symbol of the manufacturing process (S or W)
  • The D (outside diameter) or R (thread size);
  • The series or type or specified wall thickness.

Appearance of S195T Pipes

The surface finish of a tube plays an important role in determining its quality. For this reason, manufacturers must take care to ensure that their products are free from defects that can be detected by visual examination. The internal and external surfaces of the tube must be smooth, with no imperfections or marks that would require dressing. Any surface imperfections that encroach on the specified minimum wall thickness are considered defects. It is permissible to dress surface imperfections by grinding or machining provided that the wall thickness in the dressed area is not less than the specified minimum. All dressed areas must blend smoothly into the contour of the tube. By paying close attention to these details, manufacturers can produce high-quality tubes that meet the needs of their customers.

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