Low Alloy Steel - European Standards
Low alloy steel (LAS) is a type of steel that has been alloyed with elements such as nickel, molybdenum, vanadium, and chromium. Moreover, these alloys add properties such as strength, improved response to heat treatment, and excellent resistance to wear, abrasion, and corrosion. As such, LAS is used in numerous applications ranging from agricultural equipment to automotive parts and from construction components to aircraft parts. This article focuses on the European standards for LAS.
The European Standards are the set of technical guidelines and specifications regarding the classification, structure, chemical composition, and mechanical properties of low alloy steel. These standards were developed and maintained by the European Committee for Standardization (CEN) and the European Committee for Iron and Steel Standardization (ECISS). The CEN and ECISS standards for LAS are available for both wrought and cast products.
The first set of standards, EN 10020 and EN 10025, pertain to the definition, classification, and chemical composition of LAS. EN 10020 defines the steel as an alloy of iron, carbon, and other elements with a maximum allowed amount of elements other than iron, carbon, and manganese. EN 10025 outlines the minimum allowable amount of elements allowed within the LAS. The classification of LAS is based on the type and quantity of elements used and EN 10025 includes five different product standards for LAS.
The second set of standards covers the mechanical properties of LAS. The mechanical properties of LAS are typically tested using standard test pieces, such as tensile and hardness tests. These tests are typically carried out in accordance with the EN 10002-1 general requirements. The two major categories of mechanical properties outlined in the standard include static mechanical properties and dynamic mechanical properties. Static mechanical properties refer to the response to static load or force, such as tensile test or tensile strength, whereas dynamic mechanical properties refer to the response to repeated load or force, such as fatigue strength.
The third set of standards pertains to the evaluation of LAS welds. These tests evaluate the strength and soundness of a welded joint. The test can also be conducted to determine the joint’s effect on its surrounding properties. The tests are usually done in accordance with the EN ISO 17637 series of standards. This series focuses on the qualification of welders and procedures, which is important because any welding defect may lead to significant mechanical and physical properties problems later on.
Finally, the last set of standards focuses on the quality requirements for the production and delivery of LAS. The EN ISO 6892 series of standards provides requirements, such as approved tolerance, level of machinability, permissible surface flaws, and packaging, among others. The standards also require a full chemical analysis of the steel on incoming and delivered goods.
In summary, European standards for low alloy steel (LAS) cover four main areas: definition and classification, chemical composition, mechanical properties, and evaluation of welds. These standards help ensure the maximum efficiency and quality of LAS products and ensure that the materials purchased meet their specifications. When buying LAS products, it is important to always check if the products meet the European standards.
