Steel pipes having different national or international designations are produced and used in various countries. In Europe, steel pipes normally referred to as “tubes are (mainly) designated as per EN standard designation system. Steel grade designation of different standards e.g. EN, DIN, JIS differs. For various application, different standards of pipes and tubes with respective steel grade designations are used.
In Europe different standards are available and most of them are applicable in the application of welded steel pipe. Following are most common standards used in Europe;
•EN 10217-1
•EN 10217-2
•EN 10217-3
•EN 10220
•EN 10255
•EN 10226
EN 10217 is mainly for welded steel tubes for pressure purpose, containing different specifications for different materials and different diameters. There are different parts of EN 10217 including 10217-1, 10217-2, 10217-3; each part composes different material grades, dimensions and coating techniques of pipes and tubes.
EN 10217-1 was mainly for non-alloy steel tubes with specified room temperature properties, it is made of number of grades, some famous grade are S195T, P235T, P275T etc, which range of yield strength (355N/mm2 to 400N/mm2) and tensile strength (490N/mm2 to 530N/mm2). It covers with electrical-resistance welding, arc welding, and fusion welding. Depending on different welding process and for different applications (e.g. low, medium and high pressure) different steel grades including P195TR1, P235TR1, P275TR1, P195TR2, P235TR2 etc are available according to EN 10217-1 standard.
EN 10217-2 was mainly for electric welded non-alloy and alloy steel tubes with specified elevated temperature properties. It covers steel grades P195GH , P235GH, P265GH, 16Mo3, 10CrMo5-5, 13CrMo4-5. It is also used for pressure purpose with butt-welding process by using different dimensions and properties according to EN 10217 and with wall thicknesses which range from 17,2 mm to 90 mm.
EN 10217-3 is also a part of EN 10217, this part specifies the usage of 10117-2. However, it covers pipes and tubes having non-alloy and alloy steels with specified elevated temperature properties, this part specifies the technical delivery conditions of normalised and normalised formed welded tubes for wet heating systems and for welding process, such as arc welded, submerged arc welded and electrically fused welded tubes. It also defines suitable steel grades including P355NH, P355NL1, P355NL2, P275NL1, P275NL2, P355N (S1), P355N (S2).
EN 10220 generally covers pipes and tubes having nominal dimensions and having pressure purpose. It generally uses steel grade S235 JrG2, S275 JrG2 and S355 JrG2 having values of yield strength of minimum 235N/mm2, 275N/mm2 and 355N/mm2 respectively and with specified range of wall thickness.
EN 10255 specifies the technical delivery requirements for seamless and welded steel tubes having nominal sizes not exceeding 127 mm and 127 mm. It covers tubing having wall thickness as per various schedules and/or groups/classes.
EN 10226 specifies the threaded pipe fittings (of nominal sizes from DN 6 to DN 150) such as taper threads ISO 7/1 and parallel threads ISO 228/1 for welded steel pipes. To meet these threaded requirements different types of threads are used in Europe. These threads are called taper pipe threads, parallel pipe threads and special pipe threads. Taper pipe threads are also used for threaded fittings and for valves for small pipe sizes for machines.
For European welded steel pipe application, a variety of designations and steel grades are available. Generally all these standards covers non-alloy, alloy and stainless steel pipes and supply pressure purpose. Depending on the application, certain European standards e.g. EN 10255, EN 10220, EN 10226, etc are used while selecting appropriate steel grade. The variety of steel pipes available in the market make it important to understand the difference between the respective steel pipes and to match these with the application requirements to get the right material application.
