Steel Tube Handbook - 2018

3 Standardization companies and standards International, globally valid standards are issued by two stan- dardization organizations based in Geneva: ISO (International Standards Organization) – issues general standards. IEC (International Electrotechnical Commission) - Issues standards for electrical engineering. ISO standards apply globally and therefore usually they are not taken into the system of national standards. For steel tubes they are not frequently used. However, just for information, we show them in this handbook. European standardization it is organized like the global one, however has up to three com- missions. The first two are based in Brussels, the third in Sophia Antipolis (France): CEN (Comité Européen de Normalisation) - issues general standards in Slovak referred to as European standards (EN). These EN standards can not be equated with previously issued EuroNorms. Standards for iron and steel are issued by the Euro- pean Committee for Standardization of Iron and Steel (ECISS) and the relevant Technical Committees (TC) and subcommitte- es (SC). CENELEC (Comité Européen de Normalisation Electrotech- nique) - issues electrotechnical Standards ETSI (European Telecomunications Standards Institute) - publishes standards for telecommunications. National standard institutes (offices) Issues national standards. In the context of enlargement of the European Union, the EN standards are accepting (implementing) into the system of national standards (technical harmonization of standards). Unlike ISO standards EN standards are implemented without modification and nowadays they must repeal all conflic- ting national standards. In this context, there also has been a ma- jor change in the philosophy of the use of standards. In the past, compliance with the provisions of standards was man- datory. Now two concepts appear to stand out: the validity and obligation of standard. The standard is valid, but, besides few ex- ceptions its observance is not mandatory/binding. The standard specifies the recommended technical requirements which they do not have to be used. On the other hand two circumstances are standing out: • if the standard is specified into the contract between the seller and the buyer then it becomes part of the contract and its requ- irements must be met • if damages incurred as a result of solution, which have not met the requirements of the harmonized standards, the responsibili- ty rests with those who did not meet the requirements of gene- rally formulated by government regulation, because by the law, if STN assumes harmonized EN, it also become harmonized, and after its publication in the Bulletin, this standard can be used for assessing compliance with the technical requirements laid down by the government. Other standards Under consideration comes mainly the company standards. They can not be in conflict with national standards. Another group are the standards of professional societies, e.g. in the USA (AISI, ASTM, ASME, API, SAE). Trading partners among themselves can enter into bilaterally bin- ding technical and delivery conditions or technical specifications. Technical Standards They are part of the legislation in force for the given area of industrial products. Specifically the linking of regulations set out for the individual tube groups. Steel tubes - Classification, terminology and definitions Referred concepts for steel tubes are in STN (ČSN) 42 0044, 42 0045, 42 0046, EN 10079, ISO 6929 standards. Tube classification is based on a number of points of view: the production method, the cross-sectional shape, treatment of tubes ends, and range of application of tubes. According to EN 10079 tubes belong to so-called long products. It is a product that has along the entire length permanent circular, or other hollow cross-section, it is open at both ends and has a relatively large length (ISO 6929). According to the production method we distinguish between two large groups of tubes - seamless and welded. Each of this group can be divided according to the method of tube produc- tion (hot rolled and cold rolled production). Part of tube group is also so called hollow profiles . They are sea- mless or welded tubes of circular, square or rectangular cross-sec- tion, used for production of steel structures for building industry or even for machine parts. Hollow bars are seamless tubes of circular cross-section intended for the manufacture of machine parts by chip machining. From the first two groups of tubes they differ in qualitative and dimen- sional parameters that are chosen to meet the requirements for workability, heat treatment and surface quality components. In this manual the products are classified by application , taking into account the method of production. Similarly are set up also the new EN steel tube. Technical standards for steel tubes Technical characteristics of the steel tubes are concentrated in the relevant technical standards. Tube parameters can be divided into three main groups: • dimensions and their tolerances (depending upon production method of tubes) • type of steel and steel conditions (supply) • technical delivery conditions Individual national standardization bodies use different procedu- res for data standardization for steel tubes. In practice, three op- tions are used: • each main group of parameters is contained in a single stan - dard. Standards are linked by references to related standards. Dimensional standard includes a table of dimensions and their tolerances, steel standard contains its chemical composition and mechanical properties for various methods of tube manufactu- ring and condition of steel. The third standard of the technical delivery conditions (TDC) establishes all other requirements for tubes such as testing, acceptance, certificates, packaging, mar- kings and the like. At the same time includes references to addi- tional standards, where these activities are described (e.g. STN, ČSN standards). • the second option is, when steel and its characteristics are inclu - ded in the TDC standard and this includes the dimensional tole- rances. The tube is described by two standards - dimensional, con- taining dimensional table and TDC standard (e.g. DIN standard). • the third option - tube parameters are in one standard which contains also the dimensional table or selection from the gene- ral table of dimensions, which is the content of general dimen- sional standard (e.g. NFA, EN standards). In practice, there are also cases where the seller and buyer enter into bilateral or TDC or the tubes are supplied according to the technical specifications of the buyer.