DE19906082C2 - Use of a steel pipe - Google Patents

Description

Pipes are used, for example, in the field of vehicle construction to create vehicle frames. Such pipes are produced according to the prior art by cold forming and electrical resistance welding from hot or cold strip and then annealed. They have a rectangular, quadrati rule or other cross-section. A steel commonly used here has the following composition:

carbon 0.16 to 0.23 silicon ≦ 0.28 manganese 0.40 to 0.75 phosphorus ≦ 0.040 sulfur ≦ 0.040 aluminum <0.020 boron no requirement.

JP 09049050 A discloses a hot strip and a method for its production, which has the following composition:

carbon 0.02 to 0.25 silicon <0.6 manganese <2.5 phosphorus <0.05 sulfur <0.01 aluminum 0.01 to 0.10 titanium <0.1 niobium <0.1 Vanadium <0.1

as well as small amounts of at least one element from the group including nickel, copper, molybdenum, chromium, boron, calcium and Rare earth metals.

This steel is heated to 1000 to 1400 ° C and at a Fi nishing temperature of 70 to 900 ° C rolled into a hot strip. Nothing is said about the further processing of this hot strip.

US 44 10 369 discloses a method for producing a electrically welded steel pipe, in which the pipe consists of a Hot strip is cold formed. Here, the steel block from which the hot strip is rolled, cast in two steps, with im first step the mold mostly with an oxygenhal tigen (non-killed) steel filled and a thin layer on top a low-oxygen calmed (killed) steel is poured. The steel block is then rolled so that the resulting Hot strip along a narrow area made of the killed steel the later welding zone for the cold-formed pipe. There the pipe can be welded better with. About the processing processing of the pipe nothing is said either.

The object of the invention is to create a way to drive to produce tool frames from such pipes more economically.

According to the invention, this object is achieved by using a tube made of steel in the unannealed state for the manufacture of vehicle frames, the steel having the following composition (in% by mass):

carbon 0.12 to 0.16 silicon ≦ 0.03 manganese 0.65 to 1.2 phosphorus ≦ 0.025 sulfur ≦ 0.008 aluminum <0.020 boron ≦ 0.0008.

It has surprisingly been shown in the context of the invention that that such pipes have the same strength values even when not annealed, Show deformability and welding properties like annealed Prior art pipes. By eliminating the glow pre Significant cost savings are achieved at the beginning.

One embodiment of the invention is that the manganese content (in% by mass) is 0.65 to 0.85. This training concerns not directly molded pipes. For directly molded pipes A manganese content of up to 1.2% by weight is permissible.

According to the invention it is provided that the tube as a square tube is trained.

Another embodiment of the invention is that the pipe is designed as a profile tube.

The invention also relates to a vehicle frame which is made from unannealed tubes according to the invention.

The advantages of the invention are essentially that with constant strength values the pipe according to the invention un can be used annealed. As for making a Vehicle frames, especially a bus frame, in large quantities such tubes are needed and the annealing and straightening More costs in a significant amount becomes a significant one Cost savings achieved.

In the following the invention is illustrated by means of embodiments explained:

Embodiment 1 (procedure according to the invention)

Made of steel with the following composition (in% by mass):

carbon 0.12 to 0.16 silicon ≦ 0.03 manganese 0.65 to 0.85 phosphorus ≦ 0.025 sulfur ≦ 0.008 aluminum <0.020 boron ≦ 0.0008

hot or cold strip is produced and pickled. A rectangular, square or other profile tube with a scale-free surface is made from the band by welding and deforming. This pipe has the following strength values:

Yield point (N / mm ² ) ≧ 295 Tensile strength (N / mm ² ) ≧ 440 Elongation at break A5% ≧ 23 Yield strength ratio Rm-Re ≦ 0.8

and is used for the production of vehicle frames, e.g. B. Omnibusgerip pen used.

Embodiment 2 (state of the art)

Made of steel with the following composition (in% by mass):

carbon 0.16 to 0.23 silicon ≦ 0.28 manganese 0.40 to 0.75 phosphorus ≦ 0.040 sulfur ≦ 0.040 aluminum <0.020 boron no requirement

hot or cold strip is produced and pickled. A rectangular, square or other profile tube with a scale-free surface is made from the band by welding and deforming. The tube is then annealed to normalize and straightened in a protective gas atmosphere. This pipe has the following strength values:

Yield point (N / mm ² ) ≧ 295 Tensile strength (N / mm ² ) ≧ 440 Elongation at break A5% ≧ 25

and is used for the production of vehicle frames, e.g. B. Omnibusgerip pen used.

Claims (8)

1. Use of a steel pipe with the following composition (in% by mass):
carbon 0.12 to 0.16 silicon ≦ 0.03 manganese 0.65 to 1.2 phosphorus ≦ 0.025 sulfur ≦ 0.008 aluminum <0.020 boron ≦ 0.0008 in the unannealed condition for the production of vehicle frames. 2. Use according to claim 1, wherein the manganese content (in mass %) Is 0.65 to 0.85. 3. Use according to claim 1, wherein the tube as a square tube is trained. 4. Use according to claim 1, wherein the tube is a profile tube is trained. 5. Vehicle frame made from unannealed steel tubes of the following composition (in% by mass):
carbon 0.12 to 0.16 silicon ≦ 0.03 manganese 0.65 to 1.2 phosphorus ≦ 0.025 sulfur ≦ 0.008 aluminum <0.020 boron ≦ 0.0008 in unannealed condition. 6. Vehicle frame according to claim 5, wherein the manganese content (in Mass%) is 0.65 to 0.85. 7. The vehicle frame according to claim 5, wherein the tubes as a square are designed. 8. The vehicle frame according to claim 5, wherein the tubes as a profile tube are formed.