High-speed wire rod rolling apparatus and method

Abstract

A wire rod rolling plant constituted by three distinct, independent rolling units ( 10, 20, 30 ), wherein there are provided four rolling stands, arranged in oval-round-oval-round sequence, in the first two rolling units, and there are provided at least two rolling stands, in oval-round sequence, in the third rolling unit. One motor ( 12, 22 ) is provided in the first two rolling units ( 10, 20 ) for actuating the two round steps arranged in even positions and one motor ( 11, 21 ), independent from the first one, is provided for actuating the two oval steps arranged in odd positions. Two motors ( 31, 32 ), mutually independent, which actuate each rolling step respectively are provided in the third rolling unit.

1 . Wire rod rolling apparatus, defining a rolling direction, comprising two or more rolling units, arranged in sequence in the rolling direction, each rolling unit comprising two or more rolling stands and at least one first motor and at least one second motor for actuating the two or more rolling stands, each of said rolling stands having a pair of rolling rings with respective either oval or round section gauge, the rolling stands being arranged along the rolling direction so as to display in succession a rolling stand with oval section gauge followed by a rolling stand with a round section gauge, characterized in that in at least one of said rolling units the respective first motor actuates the rolling stands with oval section gauge and the respective second motor actuates the rolling stands with round section gauge. 
     
     
         2 . Apparatus according to  claim 1 , wherein in each rolling unit the respective first motor actuates the rolling stands with oval section gauge and the respective second motor actuates the rolling stands with round section gauge independently from the first motor. 
     
     
         3 . Apparatus according to  claim 2  comprising three rolling units wherein a first rolling unit comprises four first rolling stands arranged, in sequence so that the respective gauges are oval, round, oval and round in the rolling direction, and a respective first motor and a respective second motor,
 wherein a second rolling unit comprises four second rolling stands arranged in sequence so that the respective gauges are oval round, oval and round in the rolling direction, and a respective first motor and a respective second motor, 
 wherein a third rolling unit comprises at least two third rolling stands arranged in sequence so that the respective gauges are oval, round in the rolling direction, and a respective first motor and a respective second motor. 
 
     
     
         4 . Apparatus according to  claim 3 , wherein the third rolling unit comprises a further third rolling stand having a pair of rolling rings with round gauge, arranged downstream of said at least two third rolling stands and actuated by a third motor. 
     
     
         5 . Apparatus according to  claim 2  comprising two rolling units, wherein a first rolling unit comprises six first rolling stands arranged in sequence so that the respective gauges are oval, round, oval, round, oval, round in the rolling direction, and a respective first and a respective second motor,
 wherein a second rolling unit comprises four second rolling stands arranged in sequence so that the respective gauges are oval, round, oval, round in the rolling direction, and a respective first and a respective second motor. 
 
     
     
         6 . Apparatus according to  claim 5 , wherein the second rolling unit comprises a fifth rolling stand having a pair of rolling rings with round gauge, arranged downstream of said four second rolling stands and actuated by a third motor. 
     
     
         7 . Apparatus according to  claim 3 , wherein in at least one of the rolling units there are provided kinematic coupling means, that can be engaged and disengaged, between transmissions of the first motors and transmissions of the second motors, so as to cinematically couple even rolling stands with odd rolling stands of said at least one rolling unit with one of said first and second motors, in particular operating conditions. 
     
     
         8 . Apparatus according to  claim 5 , wherein in at least one of the rolling units there are provided kinematic coupling means, that can be engaged and disengaged, between transmissions of the first motors and transmissions of the second motors, so as to cinematically couple even rolling stands with odd rolling stands of said at least one rolling unit with one of said first and second motors, in particular operating conditions. 
     
     
         9 . Apparatus according to  3 , wherein a water box is provided between the first rolling unit and the second rolling unit. 
     
     
         10 . Apparatus according to  claim 5 , wherein a water box is provided between the first rolling unit and the second rolling unit. 
     
     
         11 . Apparatus according to  claim 3 , wherein at least one water box and at least one first equalizing channel are provided between the second rolling unit and the third rolling unit. 
     
     
         12 . Apparatus according to  claim 5 , wherein at least one water box and at least one first equalizing channel are provided between the second rolling unit and the third rolling unit. 
     
     
         13 . Apparatus according to  claim 11 , wherein a prebox and a second equalizing channel are provided upstream of the first rolling unit. 
     
     
         14 . Apparatus according to  claim 12 , wherein a prebox and a second equalizing channel are provided upstream of the first rolling unit. 
     
     
         15 . Wire rod rolling plant comprising a wire rod rolling apparatus, defining a rolling direction, comprising two or more rolling units, arranged in sequence in the rolling direction, each rolling unit comprising two or more rolling stands and at least one first motor and at least one second motor for actuating the two or more rolling stands, each of said rolling stands having a pair of rolling rings with respective either oval or round section gauge, the rolling stands being arranged along the rolling direction so as to display in succession a rolling stand with oval section gauge followed by a rolling stand with a round section gauge, wherein in at least one of said rolling units the respective first motor actuates the rolling stands with oval section gauge and the respective second motor actuates the rolling stands with round section gauge. 
     
     
         16 . Wire rod rolling method by means of a wire rod rolling apparatus, defining a rolling direction, comprising three rolling units, arranged in sequence in the rolling direction,
 each rolling unit comprising two or more rolling stands and at least one first motor and at least one second motor for actuating the two or more rolling stands,   each of said rolling stands having a pair of rolling rings with respective either oval or round section gauge,   the rolling stands being arranged along the rolling direction so as to display in succession a rolling stand with oval section gauge followed by a rolling stand with a round section gauge,   wherein in each rolling unit the respective first motor actuates the rolling stands with oval section gauge and the respective second motor actuates the rolling stands with round section gauge independently from the first motor,   wherein a first rolling unit comprises four first rolling stands arranged in sequence so that the respective gauges are oval, round, oval and round in the rolling direction, and a respective first motor and a respective second motor,   wherein a second rolling unit comprises four second rolling stands arranged in sequence so that the respective gauges are oval, round, oval and round in the rolling direction, and a respective first motor and a respective second motor,   wherein a third rolling unit comprises at least two third rolling stands arranged in sequence so that the respective gauges are oval, round in the rolling direction, and a respective first motor and a respective second motor;   
       the method comprising the following steps:
 a) rolling the product in first rolling unit with an oval, round, oval, round rolling sequence, 
 b) rolling the product in the second rolling unit with an oval, round, oval, round rolling sequence, 
 c) rolling the product in the third rolling unit with an oval, round rolling sequence, 
 
     
     
         17 . Method according to  claim 16 , wherein the rolling of the product in the third rolling unit includes a further rolling pass with round gauge. 
     
     
         18 . Method according to  claim 16 , wherein:
 a thermal treatment is provided before step a) by means of a prebox and first temperature equalizing channel upstream of the first rolling unit;   between step a) and step b) a thermal treatment of the rolled product by means of a first water box is provided,   between step b) and step c) a thermal treatment of the rolled product by means of at least one second water box and at least one second temperature equalizing channel is provided,   after step c) a final cooling of the rolled product is provided until a temperature comprised between 850° C. and 900° C. is reached.