Process for the continuous hardening of tubes

Abstract

The process for the continuous hardening of tubes comprises helically advancing a plurality of tubes arranged end to end in a horizontal direction and externally heating said tubes. A further step includes simultaneously or successively heating internally the said tubes and subsequently cooling said tubes both externally and internally. A further step includes temporarily accelerating the feeding of said tubes to divide the substantially continuous line of tubes into individual tubes. An additional step before externally and internally heating the tubes includes preheating said tubes to a temperature in the range of 500.degree. to 600.degree. C. Apparatus for the continuous hardening of tubes includes a roller table for the longitudinal helical transport of the tubes arranged end to end. An external heat source is provided for heating the tubes and an external spraying ring is arranged axially in advance of the heat source for the external cooling of the tubes. An internal electrical heat source internally heats the tubes and a forwardly advanced internal spraying head is provided for internally cooling said tubes successively. A tubular support is disposed axially of said tubes and mounts upon its inner end a heat source for internal heating of the tubes and internal spraying head for internal cooling of the tubes. A pair of spaced two-part clamping devices are spaced forwardly of the spraying head and displaceable transversely relative of the tube axis and adapted when opened to loosely receive said tubes. A source of electrical energy is connected to said clamps for transmitting power to the tubular support for energizing said internal heat source and internal spraying head.

Dependencies are inferred from the claim text.