Steel tubes for mechanical engineering, parts of machines and general use

Steel tube specifications and steel grades

Steel tube sizes acc. to EN, DIN, BS, NF A, UNI, STN, ČSN and PN-H standards

Steel tube sizes acc. to ASME standard

Steel tube sizes acc. to ASTM standard

Steel tube sizes acc. to GOST and TU standards

Steel tube sizes acc. to JIS standards



Tubes for mechanical engineering and parts of machines are used for manufacturing in various types of machine parts and at the same time they can be used in many other industrial areas. Tubes are made by using the hot rolling process. Specifications, dimensions and the types of steel are shown in a separate overview. Tube dimensions that are produced by the cold drawing process, according to the dimensional specifications for the precision tubes, are placed in the section called “precision seamless steel tubes”.

Tube dimensions and tolerances for mechanical engineering

Range for the tube dimensions and tolerances for mechanical engineering is between 10.2 mm to 139.7 mm. The tube dimensions meet the requirements of the following standards: EN 10294-1, EN 10297-1, EN 10305-1, DIN 2448, BS 6323/3, NF A 49-311, NF A 49-312, UNI 4991, UNI 7729, STN 42 5715, STN 42 5716, ČSN 425715, ČSN 42 5716, GOST 8732, PN-H 74219, ASTM A 53, ASTM A 519 and JIS G 3445. A detailed dimensional overview is shown in the tables according to EN, DIN, BS, NF A, UNI, STN, ČSN and PN-H standards, ASME standards, ASTM standards, GOST standards, TU standards and JIS standards. Means of tubes production – hot rolling or cold forming (besides its own precision tubes) depends upon the standards, tube dimensions and the agreement when ordering the tubes. The tube tolerances meet the appropriate standards requirements. Orientation data is shown in the dimensional tables. The tube tolerances for mechanical engineering correspond to condition after the tube production.

Steel for tubes which are destined for mechanical engineering

The tubes are manufactured from the following steels, in conformity with EN 10294-1: E355, E355J2, E420J2, E470, 20MnV6; ASTM A 53: Grade A, Grade B. Additional grades according to EN 10 297-1, EN 10083, EN 10084, DIN 1629, DIN 1630, DIN 17 200. DIN 17 204, DIN 17 210, BS 6323/1,3, NFA 49-311, NF A 49-312, UNI 663, UNI 7729, GOST 8731 and JIS G3445 and their chemical composition and mechanical properties are shown in a separate overview.

Tubes length for mechanical engineering

Usually the tubes are supplied in the production length (5 to 6 meters). A precise length may be supplied upon request.

Tube straightness

1.5 x 1000 is the required straightness for the tubes that have diameter up to 33.7 mm and which are destined for manufacturing parts of machines. For tubes that are going to be mechanically machined the required straightness is 1: 1000, i.e. 0.001 x L.

The tubes ends

The ends of the tubes are vertical to the longitudinal axis and are without burrs.

The condition, delivery and surface of the tubes for mechanical engineering

Hot rolled tubes made out of carbon steel do not go through further heat treatment and their condition is the same as the condition of normally annealed tubes. After forming, the cold drawn tubes are heat treated in such way that they would meet the requirements of the appropriate standards as far as the condition of delivery and the mechanical values are concerned. The inner and outer surface of the tubes corresponds to the manufacturing means.

Marking of the tubes and tube bundles

The tubes for the parts of machines or for mechanical engineering are marked based on the requirements of the appropriate standards and Upon request when ordering the tubes and they may be as follows: (a) without marking, (b) marked with colored stripes on the tubes (tube bundles), (c) marked with spray either by a white or black color using InkJet (d) marked by stamping the data (this applies for D > 22 mm and T >2.3 mm). Bundles of tubes are marked either with one or more labels with the required data.

Tubes surface protection

While ordering, it is necessary to agree upon the way and means of temporary protecting the surface of the tubes during transportation and storing. The tubes may be supplied without temporary preservation of the surface, or with the preservation of the surface with an agreed upon preservative.

Packaging of tubes for mechanical engineering and the parts of machine

Tubes are supplied in packages with a circular or hexagonal diameter with weight of 300 to 3500 kilograms. The tubes are bound with a steel band. It is possible to arrange for tubes to wrapped in plastic sheets, burlap or in wooden crates.


Tubes testing

According to EN 10294 – 1 Standards the tubes are tested with specific testing which consists of: cast analysis, tensile test and notched impact strength test (if the testing is possible to make), dimensional inspection, visual inspection, according to the EN 10297 – 1 it can be about (a) nonspecified testing for the steels grade 2.1.1 if by choice there is no agreement about a specific test or (b) specific testing is made for other grades of steel. The mandatory tests for nonspecified testing are in concurrence with the EN 10294-1, the optional tests are shown in the standards.

Certified test reports

Certified test reports are issued according to the appropriate TDC standards:
EN 10204, for EN 10294 – 1 certificate 3.1.B, for EN 10297 – 1 Certified test reports: (a) nonspecified testing 2.1 and 2.2, specified testing – 3.1.B or others

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