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Hardenable manganese-boron steel – good forming properties and high strength for precision steel tubes

Precision steel tube made of manganese-boron steel for stabilizers in automotive engineering

Manganese-boron steels made by thyssenkrupp are delivered with excellent forming properties and are used among other things for the production of precision steel tubes.

MnB steels are characterized by high strength and homogeneity of mechanical properties after quenching and termpering. The good strength properties are obtained by carbon and manganese and by a small boron content. Segregation-optimized MnB steels with even greater strength and enhanced ductility in the quenching and temping are being developed.

Apart from MnB alloyed steels in accordance with DIN EN ISO 683-2 (previously DIN EN 10083-3), our range of products includes the steel grades of the tubor® range - our application-optimized MnB steels for precision steel tubes.

Premium material for lightweight automotive manufacturing: tubor® – our application-optimized MnB steel for the production of precision steel tubes

Precision steel tubes made of MnB steels for piston rods in shock absorbers.
Precision steel tubes made of MnB steels for piston rods in shock absorbers.

Owing to their excellent forming behavior, steels of the tubor® range are very well suited for welded, cold-rolled or cold-drawn precision steel tubes. The material features a homogeneous and fine-grained microstructure with a low sulfur and phosphor content. Segregations in the microstructure are significantly reduced by means of special technical processes. Thanks to the combination of an optimized manufacturing process on the one hand and chemical analysis attuned to the end application on the other, the tubor® steel grades offer greater strength and a improved ductility after quenching and tempering.

Application examples of precision steel tubes made of MnB steels

In automotive manufacturing, precision steel tubes offer great potential for cost and weight reduction and are used among other things for stabilizers, piston rods in shock absorbers or driving shafts and camshafts.

thyssenkrupp supplies the steel grades as per the product information or the reference steel grades in accordance with the respective standards.

tubor® – special MnB steels for precision steel tubes

Steel grade designation Standard designation1 THICKNESS2
from _ to in mm
WIDTH2
max. mm
tubor® 26 26MnB5 1.95 – 13.00 2,030
tubor® 34 34MnB5 1.75 – 18.00 1,630
1. According to DIN EN ISO 683-2 (previously DIN EN 10083-3). | 2. Not all thickness and width combinations possible. |

Chemical composition

Steel grade ­ C [%] ­
Si [%]
max.
Mn [%] ­ P [%]
max.
S [%]
max.
Al [%] ­ Cr [%] ­ Ti [%] ­ B [ppm] ­
tubor® 26 0.23 – 0.27 0.15 – 0.35 1.15 – 1.40 0.020 0.006 0.015 – 0.055 0.05 – 0.20 0.015 – 0.045 15 – 40
tubor® 34 0.33 – 0.37 0.15 – 0.35 1.15 – 1.40 0.020 0.006 0.015 – 0.055 0.05 – 0.20 0.020 – 0.050 15 – 40
Mass fractions in ladle analysis.

Manganese-boron steel according to DIN EN ISO 683-2 (previously DIN EN 10083-3)

Steel grade designation Reference grade Material no. THICKNESS1
from _ to in mm
WIDTH1
from _ to in mm
20MnB5 20MnB5 1.5530 2.00 – 13.00 70 – 1,630
30MnB5 30MnB5 1.5531 2.00 – 13.00 70 – 1,630
39MnB5 389MnB5 1.5532 2.00 – 13.00 70 – 1,630
27MnCrB5-2 27MnCrB5-2 1.7182 2.00 – 13.00 70 – 1,630
33MnCrB5-2 33MnCrB5-2 1.7185 2.00 – 13.00 70 – 1,630
39MnCrB6-2 39MnCrB6-2 1.7189 2.00 – 13.00 70 – 1,630
1. Not all thickness and width combinations possible.

Chemical composition

Steel grade C [%]
Si [%]
max.
Mn [%]
P [%]
max.
S [%]
max.
Cr [%]
Mo [%] ­max. / - B [ppm]
20MnB5 0.17 – 0.23 0.40 1.10 – 1.40 0.025 0.010 0.10 8 – 50
30MnB5 0.27 – 0.33 0.40 1.15 – 1.45 0.025 0.010 - 0.10 8 – 50
39MnB5 0.36 – 0.42 0.40 1.15 – 1.45 0.025 0.010 - 0.10 8 – 50
27MnCrB5-2 0.24 – 0.30 0.40 1.10 – 1.40 0.025 0.010 0.30 – 0.60 0.10 8 – 50
33MnCrB5-2 0.30 – 0.36 0.40 1.20 – 1.50 0.025 0.010 0.30 – 0.60 0.10 8 – 50
39MnCrB6-2 0.36 – 0.42 0.40 1.40 – 1.70 0.025 0.010 0.30 – 0.60 0.10 8 – 50
Mass fractions in ladle analysis.
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