Process for Manufacturing Cold-Formed Precision Steel Pipes
AssigneeMhp Mannesmann Prazisrohr GmbH
InventorsJosef Siekmeyer, Wolfgang Mussmann, Lothar See, Sven Herzing
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Abstract
The invention relates to a process for manufacturing cold-formed, in particular cold-drawn, precision steel pipes for application in particular as pressure-operated cylinder pipes with optimum addition of one or several alloying elements as well as impurities caused by melting. A seamless, hot-formed pipe blank or welded pipe blank made from a hot strip with defined starting condition is hereby drawn in one pass or in several passes into a finished pipe, and the pipe undergoes a heat treatment before the finishing pass.
Claims14
1-10. (canceled)
A process for manufacturing a precision steel pipe having the following chemical composition (in weight-%):
- C =
- 0.05-0.25
- Si =
- 0.15-1.0
- Mn =
- 1.0-3.5
- Al =
- 0.020-0.060
- V
- max. 0.20
- N
- max 0.150
- S
- max 0.030
- and impurities caused by melting, said process comprising the steps of:
- drawing a pipe blank with defined starting condition in at least one pass;
- subjecting the pipe blank to a heat treatment;
- and
- subjecting the pipe blank to a finishing drawing step to produce a finished pipe.
Dependencies are inferred from the claim text.