Steel material for a torsionally stressed component, method for producing a torsionally stressed component from said steel material, and component made thereof

Patent metadata

Field	Value
Publication number	US-12428693-B2
Application number	US-202017638014-A
Country	US
Kind code	B2
Filing date	Aug 27, 2020
Priority date	Aug 30, 2019
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

A steel material for a torsionally stressed component, such as a driveshaft, having a minimum tensile strength of 800 MPs, and the microstructure consists of more than 50 vol. % of bainite, having an alloy with the following composition in wt. %: C: 0.02 to 0.3; Si: up to 0.7; Mn: 1.0 to 3.0; P: max. 0.02; S: max. 0.01; N: max. 0.01; Al: up to 0.1; Cu: up to 0.2; Cr: up to 3.0; Ni: up to 0.3; Mo: up to 0.5; Ti: up to 0.2; V: up to 0.2; Nb: up to 0.1; B: up to 0.01; where 0.02≤Nb+V+Ti≤0.25, residual iron, and smelting impurities. The steel material is inexpensive and has good torsional fatigue strength when used for a torsionally stressed component. The invention also relates to a method for producing a component made of the material and to such a component.

First claim

The invention claimed is:

1. A tubular component being a drive shaft/cardan shaft, said tubular component produced from a steel material in which the steel material has a minimum tensile strength of 800 MPa and the microstructure comprises more than 50 vol. % bainite, having an alloy with the following composition in wt. %:
C: 0.02 to 0.3;
Si: up to 0.7;
Mn: 1.0 to 3.0;
P: max. 0.02;
S: max. 0.01;
N: max. 0.01;
Al: up to 0.1;
Cu: up to 0.2;
Cr: up to 1.0;
Ni: up to 0.3;
Mo: up to 0.5;
Ti: up to 0.2;
V: up to 0.2;
Nb: up to 0.1; and
B: up to 0.01;
wherein 0.02≤Nb+V+Ti≤0.25 is met, with the remainder being iron and melting-induced impurities.

2. The tubular component as claimed in claim 1 , wherein the microstructure of the steel material consists of at least 90 vol. % bainite and the proportions of residual austenite and martensite and ferrite are <10 vol. %.

3. The tubular component as claimed in claim 2 , wherein with respect to one or more of the following elements the composition of the steel material is in wt. %:
C: 0.02 to 0.11; and/or
Si: 0.01 to 0.5; and/or
Mn: 1.4 to 2.2; and/or
Al: 0.015 to 0.1; and/or
Cr: up to 0.3; and/or
Ni: up to 0.2; and/or
Mo: 0.05 to 0.5; and/or
B: max. 0.004; and/or
wherein 0.05≤Nb+V+Ti≤0.2.

4. The tubular component steel material as claimed in claim 3 , wherein with respect to the following elements the composition is in wt. %, as follows:
C: 0.05 to 0.11; and/or
Si: 0.1 to 0.5; and/or
Mn: 1.5 to 2.0; and/or
N: 0.003 to 0.01; and/or
Al: 0.03 to 0.1; and/or
Ni: up to 0.15; and/or
Mo: 0.1 to 0.3; and/or
Ti: 0.04 to 0.2.

5. The tubular component as claimed in claim 1 , wherein the tubular component is rotated and subjected to torsional stress.

6. The tubular component as claimed in claim 1 , wherein the microstructure of the steel material consists of at least 70 vol. % bainite and the proportions of residual austenite and martensite and ferrite are <30 vol. %.

7. The tubular component as claimed in claim 6 , wherein with respect to one or more of the following elements the composition of the steel material is in wt. %:
C: 0.02 to 0.11; and/or
Si: 0.01 to 0.5; and/or
Mn: 1.4 to 2.2; and/or
Al: 0.015 to 0.1; and/or
Cr: up to 0.3; and/or
Ni: up to 0.2; and/or
Mo: 0.05 to 0.5; and/or
B: max. 0.004; and/or
wherein 0.05≤Nb+V+Ti≤0.2.

8. The tubular component as claimed in claim 7 , wherein with respect to the following elements the composition of the steel material is in wt. %, as follows:
C: 0.05 to 0.11; and/or
Si: 0.1 to 0.5; and/or
Mn: 1.5 to 2.0; and/or
N: 0.003 to 0.01; and/or
Al: 0.03 to 0.1; and/or
Ni: up to 0.15; and/or
Mo: 0.1 to 0.3; and/or
Ti: 0.04 to 0.2.

9. The tubular component as claimed in claim 1 , wherein with respect to one or more of the following elements the composition of the steel material is in wt. %:
C: 0.02 to 0.11; and/or
Si: 0.01 to 0.5; and/or
Mn: 1.4 to 2.2; and/or
Al: 0.015 to 0.1; and/or
Cr: up to 0.3; and/or
Ni: up to 0.2; and/or
Mo: 0.05 to 0.5; and/or
B: max. 0.004; and/or
wherein 0.05≤Nb+V+Ti≤0.2.

10. The tubular component as claimed in claim 9 , wherein with respect to the following elements the composition of the steel material is in wt. %, as follows:
C: 0.05 to 0.11; and/or
Si: 0.1 to 0.5; and/or
Mn: 1.5 to 2.0; and/or
N: 0.003 to 0.01; and/or
Al: 0.03 to 0.1; and/or
Ni: up to 0.15; and/or
Mo: 0.1 to 0.3; and/or
Ti: 0.04 to 0.2.

11. The tubular component as claimed in claim 9 , wherein the microstructure of the steel material consists of at least 70 vol. % bainite and the proportions of residual austenite and martensite and ferrite are <30 vol. %.

12. The tubular component as claimed in claim 1 , wherein the tubular component is configured to be torsionally stressed.

Assignees

• Salzgitter Flachstahl Gmbh
• Mannesmann Prec Tubes Gmbh

Inventors

• Braun Michael
• Zimmermann Steffen
• Meiwes Karl

Classifications

• C21D8/10

  during manufacturing of tubular bodies · CPC title

• F16C2326/06

  Drive shafts · CPC title

• F16C2240/70

  Diameters; Radii · CPC title

• F16C2240/60

  Thickness, e.g. thickness of coatings · CPC title

• F16C2240/06

  Temperature · CPC title