Precision steel seamless tubes for the automotive industry

We offer a wide range of precision tubes for the automotive industry within the following parameters:

Dimensions of precision tubes for the car industry

OUTER DIAMETER (OD)	4.0 - 125.0 mm (1/4 - 4 3/4)
WALL THICKNESS (WT)	0.5 - 13.0 mm (0,020 - 0,454)
Tubes for various car components are delivered according to
EN 10305-1; DIN 2391; BS 6323/4; NF A 49-310, 49-312; UNI 7945;	See tube sizes acc. to European standards.
ASTM SAE	See tube sizes acc. to ASTM A 519 See tube sizes acc. to ASTM A 450 See tube sizes acc. to ASTM A999 min wall See tube sizes acc. to ASTM A999 avg wall

Tolerances of precision tubes

Tolerances of the precision tubes are in accordance with the appropriate dimensional tables of standards. Usual value for the outside diameter (OD) is less than 0.5% of OD in no heat treatment process used. For the heat treated tubes, tolerance values are depended upon the relation of the wall thickness and the tube diameter (WT/OD) and are larger (up to a single or twofold). In tolerances of the outside diameter (OD) the allowed deviation of circularity is included. When ordering based on the wall thickness, the tolerance is 10% from the wall thickness. Eccentricity of precision tube is included in the wall thickness tolerance.

Reduced tolerances for metrical sizes - European standards.
Tolerances for imperial sizes acc. to ASTM A 519

Steel grades for precision tubes for the automotive industry

EN 10305-1	E215, E235, E255, E355, E410, 26Mn5, 26Mo2 C35E, C45E, 25CrMo4, 42CrMo4; 25CrMo4 Marking system for steel grades according to EN
ASTM 519 SAE	1008, 1010, 1012, 1015, 1016, 1017, 1018, 1019, 1020, 1021, 1022, 1025, 1026, 1030, 1035, 1040, 1045, 1050, 1518, 4130, 4140, 4142, 8617

Chemical composition and mechanical properties of steels acc. to EN, ASTM, BS, DIN and NF A

Length of precision tubes for the automotive industry

Types of supplied lengths are:	(a) random length, in the range of 3 – 7 (9) m
	(b) fixed length, ± 500 mm,
	(c) exact length, – 0 / + x mm (x upon agreement)
	(d) tubes can be supplied as cut tubes

 

 

Precision tubes ends

The ends are vertical to the longitudinal axis and are without burrs.	The tubes with deburred ends or ends customized for welding.

Deburring applies to

Tube OD	19.0 - 90.0 mm
Tube WT	2.0 - 10.0 mm
Tube lengths	3 - 7 meters
Deburring angle, a	30°+ 5, 37°± 2.5 and 45°± 2.5
Dimension, c	1.6 ± 0.8 mm

Marking of the precision tubes and tube bundles

(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 to OD > 22 mm and WT >2.3 mm).

Bundles of tubes are marked with one or more labels with the required data

Packaging of the precision tubes

Standard precision tubes are supplied in packages with a circular or hexagonal outline with maximum weight of 2 000 kg

(a) tubes bound with a steel band

(b) tubes wrapped in plastic sheets, burlap,

(c) tubes in wooden crates.

Testing of tubes for the automotive industry

Mandatory testing	cast / chemical analysis
	tensile test,
	dimensional inspecti
	visual inspection of the tubes surface.
Optional testing	selection according to standards,
	flattening test or drift expanding test
	roughness measurement
	NDT to find longitudinal defects
eddy current (STN 01 5054, PRP 02-74, SEP 1925, ASTM E 309, EN 10246-3 Gr.E3), stray flux (STN 01 5047, ČSN 01 5047, SEP 1913, ASTM E 570, EN 10246-5 Gr.F3), ultrasound (STN 01 5028, ČSN 01 5028, SEP 1915, ASTM E 213, EN 10246-7 Gr.U3),
NDT as a proof of tightness or leakage test by eddy current EN 10246-1.

Certified test reports for precision tubes for the automotive industry

EN 10204	2.2 nonspecified testing (only mandatory tests),
	3.1 specific testing,
	3.2 after agreement .

Straightness of standard precision tubes

Straightness of the tubes is influenced by the mechanical properties of the tubes. For material having the yield point ReH <= 500 MPa is straightness 0,0015 multiple of the tube length maximum, allowed straightness for one meter length is 1.5 milimeters. For material with the yield point ReH > 500 MPa the allowable straightness for the whole length of the tube is 0.0020 multiple of the tube length, allowed straightness of one meter is 2 milimeters.

Delivery condition and precision tubes surface

Precision tubes are supplied in condition that is presented in the table below. It is marking for thermal processing according to EN 10305-1.

+C	Cold drawn / hard. After the last cold forming no heat treatment.
+LC	Cold drawn / soft. After the last heat treatment follows the cold drawing there is a light finishing pass.
+SR	Cold drawn and stress relieved annealed. After the final cold drawing process the tubes are stress relieved annealed in a controlled atmosphere.
+A	Annealed. After the last cold drawing process the tubes are annealed in a controlled atmosphere.
+N	Normalized. After the last cold drawing process the tubes are annealed in a controlled atmosphere.

Marking for material condition according to DIN 2391-2 and ASTM 519 may be found here.

Surface condition of a tube meets the appropriate standards and depends upon the process of manufacturing the tube and its thermal processing. Precision tubes must have smooth outer and inner surface. The roughness value (Ra) is less or equals to 4 micrometers (0.004 mm) for the outer surface in the tubes in the +SR, +A and +N condition and is less or equals to 4 micrometers (0.004 mm) for the outer and inner surface of the tubes in the +C and +LC condition.

Standard precision tubes surface protection

While ordering, it is necessary to agree upon the method and means of temporarily protecting the surface of the tubes during transportation and storiage.