Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese

Definitions

• the invention relates to the use of a steel alloy for pipes for the production of stabilizers for Motor vehicles, a stabilizer from such Steel alloy and method for producing stabilizers.
• Stabilizers are components used in automotive engineering to reduce the curvature of the body and to influence self-steering behavior, e.g. to Reduction of oversteer can be used. she stiffen the suspension with one-sided loading, for example when driving over one-sided obstacles.
• Stabilizers are usually designed as torsion bars are mounted in the main part of the vehicle transversely to the direction of travel and via U-shaped legs on the wheel suspensions attack. For stabilization you do that Use the material's resistance to twisting.
• the ends of the stabilizer are each rigid with one Connected side of the axis and act as a lever arm. Becomes the vehicle body when cornering due to centrifugal force inclined to the side, the inside wheel bends more strongly one as the outer. This will twist the stabilizer and acts through its spring force of the side inclination opposite.
• Stabilizers of the usual type have so far been predominantly made from solid bars. They are available in straight and curved versions.
• WO 93/18189 describes the manufacture of vibrating bars or torsion stabilizers from high-strength steels.
• steels with an oriented course of the microstructure are used. The forming takes place either warm below the recrystallization temperature or cold below a temperature of 149 ° C.
• the steels described there have a yield strength Re of at least 620 N / mm 2 and a tensile strength R m of at least 827 N / mm 2 . They have a carbon content of 0.3% to 1%, manganese from 2.0%% to 2.5%% and up to 0.35% vanadium.
• the bars used to manufacture the stabilizers are hot rolled or cold drawn.
• the surface quality of the outer and inner surface of the pipes used is of the utmost importance.
• the pipes with longitudinal seams have the best surface quality from rolled steel strip. This will make the seamless drawn tubes occurring defects, such as wrinkles etc. avoided.
• the previously used steels for pipes Manufacture of stabilizers have a high carbon content and sometimes have a toughness that is too low.
• the low toughness of the steels has an effect especially with seamless pipes mainly due to the reduced surface quality negatively on the fatigue strength out.
• the required strength is a complex remuneration process with high tempering temperatures of approx. 600 ° C necessary. Due to the high tempering temperatures it is necessary that the stabilizers during the starting process to avoid warping in special devices be clamped. However, this effort leads to a Increase manufacturing costs.
• the invention is therefore based on the object Steel alloy to specify pipes in their mechanical Properties meet the high requirements for manufacturing of stabilizers. Keep aiming the invention on an economical production of high quality stabilizers from such tubes from.
• the alloy engineering part of the task is performed by the Use of the alloy specified in claim 1 solved.
• the invention adopts the knowledge that for the manufacture of stabilizers from pipes, with the high demands on the mechanical properties, a pipe material is required which, depending on the tempering temperature, tensile strengths R m of 1100 to 1600 N / mm 2 , 0.2 % Yield strengths R p0.2 from 900 to 1300 N / mm 2 and an elongation at break A 5 of 6 to 15%.
• the most important advantage of the steel alloy according to the invention is therefore seen in the fact that the proposed alloy, compared with the use of the known alloys from which tubes for stabilizers are produced, achieves the specified values of tensile strength, yield strength and elongation at break, and that, in addition, when they are used only one alloy can cover a wide range of required mechanical characteristics. For this purpose, the alloy components are optimally coordinated.
• the carbon content ensures sufficient Strength and hardenability.
• the silicon content determines the tensile strength and the yield strength, the Toughness properties are only slightly affected.
• the manganese also increases the strength of the Steel alloy, the elongation at break is only slight is reduced. In addition, the manganese has a favorable effect on weldability. In connection with the Carbon content, it improves wear resistance.
• the titanium content is mainly used for Stabilization against intergranular corrosion used.
• the boron improves the hardening and increases the core strength.
• the steel alloy according to the invention is inexpensive. Pipes made of such a steel alloy can also be used in existing systems for the production of stabilizers made of solid material can be used without any problems. Compensation systems are already in place here.
• Stabilizers according to claim 3 have a - compared to known Stabilizers made of solid material, reduced weight on. The heavy loads when used in motor vehicles withstand these stabilizers reliably.
• the pipes treated in this way then become stabilizers in terms of metal forming with the usual process steps manufactured. This is followed by water hardening of the stabilizers. Water hardening is preferred in the tool itself, so that an additional pick-up the stabilizers for the purpose of hardening are omitted.
• a clamping of the stabilizers when starting to avoid is in delay in this tempering temperature range not mandatory.
• the ends of the stabilizers upset (claim 6). This is followed by a quenching process on. This is preferably done with water of temperatures above 800 ° C. To be particularly advantageous has quench hardening above a temperature of 920 ° C.
• untreated pipes can also be used, as provided for in claim 7.
• the bending takes place at a temperature above the upper transition temperature, the A C3 point in the iron-carbon diagram. After the bending process, quench hardening is again carried out in the tool. A message is then not necessary.
• heating is Stabilizers after curing to a temperature below the transformation temperature advantageous.
• the tempering temperature should therefore not exceed 350 ° C.
• Another solution to the procedural part of the task includes claim 9. Thereafter, those from the invention Alloy-manufactured tubes, and that before the forming process to stabilizers. A Remuneration after bending can be omitted. This approach is particularly pragmatic and economical.
• the tempering of the tubes comprises the double step of hardening and tempering. This will cause the tube to bend before great strength and high yield strength as well as great toughness.
• Hardening consists of heating to hardening temperature, holding and quenching. Then it starts warmed up again and finally quenched or slowly cooled down.
• the pipes can be bent afterwards Stress relievers are made to stabilizers, as provided for in claim 10. This can cause structural changes or residual stresses are reduced.
• this annealing process is limited to the area the arches of a stabilizer.
• the annealing temperature is included chosen so that the remuneration strength of the Stabilizer is not reduced.
• a production line for the manufacture of stabilizers made of welded pipes and a production line for the production of stabilizers from seamless tubes according to the inventive method is technical generalized in the accompanying Figures 1 and 2.
• FIG. 1 it should be pointed out that with welded pipes depending on their diameter stretch reduction is not absolutely necessary is.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Vehicle Body Suspensions (AREA)
• Heat Treatment Of Articles (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Springs (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=7766123

Family Applications (1)

Country Status (4)

Cited By (5)

Families Citing this family (24)

Family Cites Families (4)

• 1996
  • 1996-06-25 ES ES96109631T patent/ES2159662T3/es not_active Expired - Lifetime
  • 1996-06-25 EP EP96109631A patent/EP0753595B1/de not_active Expired - Lifetime
  • 1996-06-25 DE DE59607441T patent/DE59607441D1/de not_active Expired - Lifetime
  • 1996-07-04 CZ CZ19962015A patent/CZ287707B6/cs not_active IP Right Cessation

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