Tubes suitable for welding and threading

Standards and steel grades,
Tube sizes acc. to EN 10224 standard,
Tube sizes acc. to ASTM or ASME standards.
Tube sizes acc. to DIN, BS, NF A, UNI, STN, ČSN, GOST, PN-H standards,

Seamless steel tubes for threading and welding are produced by hot rolling. Continuously cast blooms are semi-finished product that is used as the starting material for these tubes. Threaded tubes have a wide range of use especially in the construction field. They are used for water transfer and distribution of all kinds of liquids and gasses. The limits for using this group of tubes as far as the level of pressure is concerned and the type of transfer media is used are given by the appropriate directives that are valid for pipeline construction, distribution and pipes. Tubes are made from carbon and alloyed steel. Overview of dimensional standards and technical-delivery conditions by which these tubes are manufactured and supplied is shown in a separate overview.

Tube dimensions for threading and welding

The outside diameter of the tubes for threading ranges from 1/8 (10.2 mm) to 4 (114.3 mm) according to EN 10255. Tubes for threading may also be supplied by other standards. Detailed overview is shown in tables according to DIN, BS, NF A, UNI, STN, ČSN, GOST, PN-H standards, according to EN 10224 and according to ASTM or ASME standards. Preferably these tubes are supplied with a wall thicknesses of medium and heavy series. Tubes of 10.2 – 17.2 mm diameter (DN 6 -10) are supplied as cold drawn. The drawn tubes after forming are heat treated. Upon request it is possible to deliver these tubes for water lines where the tubes are disassembled (for example according to DIN 2460) with diameter up to 219.1 mm (DN 200, NPS 8 inch), both sides zinc plated and with connecting segments. Water lines of this type may be used for many applications (production of artificial snow, watering etc.).

The types of steel destined for threaded tubes

Tubes are manufactured from the following steels, according to EN 10224: L235, L275, L355, according to EN 10255: LS235JRH and according to STN 42 0250: 11 353. Additional steel grades (according to DIN 2440, 2441, 1629, BS 1387, NF A 49-115, UNI 8863, 6363, GOST 3262, PN-H 74220 and ASTM and ASME) together with its chemical composition and its mechanical properties are shown in a separate overview. Steel is made in electric arc furnace and is fully killed. After an agreement other types of steel may be supplied.

Delivery and surface condition for tubes for threading

Usually the tubes are supplied as hot rolled. Only tubes with DN 6 -10, or possibly tubes of other dimensions may be supplied after an agreement as cold drawn tubes, and after forming, heat treated. Surface of the tubes is appropriate to the way of production. Upon request, tube surface may be taken care of by a definite surface insulation (tar, PVC tape or extruded PVC according to DIN 30670).

Length of the tubes destined for threading and welding

Tubes are supplied in approximate length of 6 meters ± 500 mm, or in precise length of 6 meters –0/+15 mm after an agreement.

Straightness of the tubes for threading

Tubes visually are straight.

Tube ends for threading

Tubes are supplied with smooth ends without thread and sockets.

Marking of the tubes and tube bundles

Tubes are marked by the manufacturers’ logo and a symbol of series, or color marked (medium series – blue, heavy series – red). Bundles are marked by a label with prescribed data.

Protection of the tubes surface for threading

Tubes are supplied without a temporary protection against corrosion. Upon request it is possible to deliver tubes with agreed upon anticorrosion protection.

Packaging of the tubes for threading

Tubes are packed into bundles with the weight of 1500 – 3500 kg.

Testing of the tubes for threading

Tubes are tested with nonspecified test. Tests: leak tightness (pressure 50 bar for 5 seconds or according to EN 10246 – 1), visual inspection, tensile test, bend test and flattening test.

Certified test reports

EN 10204 – 2.1, 2.2
DIN 50049 – 2.1, 2.2
STN, ČSN 42 0250

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