Method and device for producing a hollow metallic billet from a metallic billet

Abstract

The present invention is directed to a method for producing a hollow metallic billet ( 10 ) from a heated metallic billet ( 1 ) by a piercing operation (for example with the use of a piercing mandrel ( 4 )). The method is characterized in that a local temperature change is effected at least at the hole initiation end ( 11 ) of the billet ( 1 ) in at least one zone ( 110, 112 ) and the zone is rotationally symmetrical to the central axis (M) of the billet ( 1 ). Also described is a device for producing a hollow metallic billet ( 10 ) from a metallic billet ( 1 ) and comprising a holder ( 3 ) for the billet ( 1 ), characterized in that the device includes at least one temperature adjusting device or a projection element ( 2 ) operative to change the temperature of the billet ( 1 ) in the holder ( 3 ) at least zonewise and directed at a subzone of at least one of the end sides of the billet ( 1 ).

1 . A method for producing a hollow metallic billet ( 10 ) from a heated metallic billet ( 1 ) by a piercing operation, characterized in that a local temperature change is effected at least at the hole initiation end ( 11 ) of the billet ( 1 ) in at least one temperature change zone ( 110 ,  112 ) and the temperature change zone is rotationally symmetrical to the central axis (M) of the billet ( 1 ). 
     
     
         2 . The method as in  claim 1 , characterized in that the temperature change is effected in a temperature change zone ( 112 ) that is spaced apart radially from the central axis (M) of the billet ( 1 ). 
     
     
         3 . The method as in  claim 1 , characterized in that the temperature change is a decrease in temperature. 
     
     
         4 . The method as in  claim 1 , characterized in that the temperature change zone ( 110 ) in which the local temperature change is effected encompasses the central axis (M) of the billet ( 1 ) and the temperature change is an increase in temperature. 
     
     
         5 . The method as in  claim 1 , characterized in that the local temperature change occurs as a result of action on a portion of one of the end faces of the billet ( 1 ). 
     
     
         6 . The method as in  claim 1 , characterized in that the local temperature change occurs as a result of action on a portion of one of the end faces of the billet ( 1 ) and a segment, adjacent to said end face, of the length of the circumferential surface of the billet ( 1 ), the length of the segment of the circumferential surface being less than the length of the billet ( 1 ). 
     
     
         7 . The method as in  claim 1 , characterized in that the temperature change zone ( 110 ,  112 ) in which a temperature change is effected extends for no more than ⅓, particularly no more than ¼, the length of the billet ( 1 ). 
     
     
         8 . The method as in  claim 1 , characterized in that the billet ( 1 ) is a round billet. 
     
     
         9 . The method as in  claim 1 , characterized in that the billet ( 1 ) is rotated about the central axis (M) at least before the effectuation and/or during the effectuation of the local temperature change. 
     
     
         10 . The method as in  claim 1 , characterized in that the temperature change is effected by projecting at least one jet ( 21 ) onto one of the end sides of the billet ( 1 ), and a projection element ( 2 ) that is spaced apart from the billet ( 1 ) is preferably used for said projection. 
     
     
         11 . The method as in  claim 1 , characterized in that least at one water jet is directed at the end side of the billet ( 1 ). 
     
     
         12 . The method as in  claim 1 , characterized in that least at one jet ( 21 ), particularly an oxygen jet, is directed at the end side of the billet ( 1 ) to generate an exothermic reaction at the end face or in the billet ( 1 ). 
     
     
         13 . The method as in  claim 1 , characterized in that least at one electromagnetic beam ( 21 ) is directed at the end side of the billet ( 1 ) and is reflected from the end side by at least one reflector ( 22 ). 
     
     
         14 . The method as in  claim 1 , characterized in that a temperature change is also effected at the hole exit end ( 12 ) of the billet ( 1 ), i.e., the opposite end from the hole initiation end ( 11 ). 
     
     
         15 . A device for producing a hollow metallic billet ( 10 ) from a metallic billet ( 1 ) and comprising a holder ( 3 ) for the billet ( 1 ), characterized in that said device includes at least one projection element ( 2 ) operative to change the temperature of the billet ( 1 ) in the holder ( 3 ) at least zonewise and directed at a subzone of at least one of the end sides of the billet ( 1 ). 
     
     
         16 . The device as in  claim 15 , characterized in that the projection element ( 2 ) is aligned with the central axis (M) of the billet ( 1 ) in the holder ( 3 ). 
     
     
         17 . The device as in  claim 15 , characterized in that the projection element ( 2 ) includes at least one nozzle ( 20 ) or at least one reflector ( 22 ). 
     
     
         18 . The device as in  claim 15 , characterized in that the projection element ( 2 ) is disposed at the hole initiation end ( 11 ) and/or at the hole exit end ( 12 ) of the billet ( 1 ). 
     
     
         19 . A device for producing a hollow metallic billet ( 10 ) from a metallic billet ( 1 ) and comprising a holder ( 3 ) for the billet ( 1 ), characterized in that said device includes at least one proiection element ( 2 ) operative to change the temperature of the billet ( 1 ) in the holder ( 3 ) at least zonewise and directed at a subzone of at least one of the end sides of the billet ( 1 ), characterized in that it is designed to carry out the method as in  claim 1 .