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US 6,808,103 B2Granted
Method for continuous high-speed welding of double-ply metal tubes and welding furnace for performing the same
OwnerYukito Nomurainventor
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Abstract
The present invention is a method and apparatus for making a double-ply metal tube such as those used for automobile brake tubes by producing the tube continuously in a single process. The present invention is characterized by using a high-temperature reducing molten salt with high heat capacity as the heating medium, whereby the welding speed can be increased and the balance with the tube-making speed can be kept.
Claims2
A method for the continuous high-speed welding of a double-ply metal tube, comprising:
- immersing the double-ply metal tube in a bath comprising at least one neutral or reducing molten salt selected from the group consisting of BaCl2, and mixtures of BaCl2 with one or more of NaCl, MgF2, B2O3 and Ca—Si as a heating medium and maintaining the molten salt bath at 900 to 1200° C. to bond the tube.
A method for the continuous high-speed welding of a double-ply metal tube, comprising the steps of:
- forming a double-ply metal tube by feeding a strip-shaped metal material that has been subjected to metal plating on both sides into a tube-making apparatus;
- feeding the formed double-ply metal tube into a continuous heating furnace with a neutral or reducing molten salt bath as the heating medium and immersing the double-ply metal tube in the molten salt bath at a temperature of 900 to 1200° C. using at least one neutral or reducing molten salt selected from the group consisting of BaCl2, and mixtures of BaCl2 with one or more of NaCl, MgF2, B2O3 and Ca—Si to bond the tube;
- thereafter feeding the double-ply metal tube into a high-temperature auxiliary furnace with a reducing atmosphere;
- and
- cooling the resulting double-ply metal tube.
2 more elements
Dependencies are inferred from the claim text.