EN 10297 is a European standard that specifies requirements for seamless circular steel tubes used in mechanical and general engineering purposes. This standard plays a pivotal role in ensuring the quality and consistency of steel tubes across various industries.
1. Scope of EN 10297
The EN 10297 standard is divided into several parts. EN 10297 - 1 focuses on non - alloy and alloy steel tubes, covering aspects such as technical delivery conditions, including chemical composition, mechanical properties, and dimensional tolerances. Other parts may deal with specific types of steel tubes or additional requirements.
2. Chemical Composition
Non - Alloy Steel Grades
For non - alloy steel tubes under EN 10297 - 1, different grades exist with varying chemical compositions. For example, Grade E235 has a carbon (C) content typically up to 0.17%, silicon (Si) in an unspecified range (but generally low as it's not a major alloying element in this context), manganese (Mn) ranging from around 0.27 - 1.20%, and maximum sulfur (S) and phosphorus (P) content of 0.030% each. This grade is designed to provide basic strength and formability for general applications.
Grade C45, on the other hand, has a carbon content in the range of 0.42 - 0.50%. With this relatively higher carbon content, it offers increased strength and hardness compared to lower - carbon grades. The manganese content is usually in the 0.50 - 0.80% range, and sulfur and phosphorus are limited to 0.035% each. This makes C45 suitable for applications where higher mechanical properties are required, such as in the manufacturing of shafts and gears.
Alloy Steel Grades
Alloy steel grades covered by EN 10297 also have precisely defined chemistries. For instance, the 41Cr4 grade contains 0.38 - 0.45% carbon, which contributes to its hardenability. Chromium (Cr) is present in the 0.90 - 1.20% range. Chromium addition enhances the steel's corrosion resistance and improves its mechanical properties, especially when combined with heat treatment. Manganese is typically in the 0.60 - 0.90% range, and sulfur and phosphorus are restricted to 0.035% each.
3. Mechanical Properties
Yield and Tensile Strength
The mechanical properties of EN 10297 pipes vary depending on the grade. For non - alloy steel Grade E235, the yield strength (ReH) is 235 MPa for wall thicknesses up to 16 mm. As the wall thickness increases, the yield strength slightly decreases. The tensile strength (Rm) is around 360 MPa. For Grade C45, the yield strength can be as high as 340 MPa (for certain wall thicknesses), and the tensile strength reaches up to 620 MPa.
Alloy steel grades show even more impressive mechanical properties. The 41Cr4 grade, after appropriate heat treatment, can have a high yield strength, often well over 500 MPa, and a tensile strength in the range of 700 - 900 MPa, depending on the heat treatment process.
Elongation
Elongation is an important property as it indicates the ductility of the steel. Grade E235 has an elongation (A) of around 25% for wall thicknesses up to 16 mm, which means it can deform significantly before breaking. Grade C45 has a lower elongation, typically around 14 - 16% for certain wall thickness ranges, as its higher carbon content makes it less ductile compared to lower - carbon grades like E235. Alloy steel grades such as 41Cr4 may have elongation values in the range of 10 - 15%, balancing strength and a certain degree of formability.
4. Manufacturing Process
EN 10297 pipes are manufactured through seamless processes. The most common method is hot - rolling, where a billet of steel is heated and passed through a series of rolling mills to form a hollow tube. This process allows for the production of large - diameter pipes. For smaller - diameter and higher - precision pipes, cold - drawing may be used. In cold - drawing, a pre - formed tube is pulled through a die to reduce its diameter and wall thickness while improving its surface finish and dimensional accuracy. After manufacturing, the pipes may undergo heat treatment processes such as annealing, normalizing, or quenching and tempering, depending on the grade and the desired mechanical properties.
5. Applications
EN 10297 pipes find extensive use in various industries. In the automotive industry, they are used for manufacturing components such as axles and shafts, where high strength and reliability are crucial. In the mechanical engineering field, they are employed in the construction of machinery, including parts like hydraulic cylinders. The energy sector also makes use of these pipes, for example, in oil and gas extraction equipment, where the pipes need to withstand high pressures and harsh environmental conditions. Additionally, they are used in the manufacturing of industrial machinery, such as conveyor systems and power - transmission equipment.
6. Testing and Quality Control
To ensure that EN 10297 pipes meet the required standards, rigorous testing procedures are carried out. This includes chemical analysis to verify the composition of the steel, tensile testing to determine the mechanical properties, and dimensional inspections to ensure that the pipes have the correct diameter, wall thickness, and length. Non - destructive testing methods, such as ultrasonic testing and magnetic particle inspection, are also used to detect any internal or surface defects. Only pipes that pass all these tests are certified as compliant with the EN 10297 standard, guaranteeing their quality and fitness for use in critical applications.
