LONG PRODUCTS BULLETIN - SMS Meer GmbH

42 Newsletter No. 3/2009
Long-product mills
Thermomechanical rolling of all wire-rod dimensions
New cost-efficient
wire-rod mill concept
A wire-rod finishing block consisting of a sixstand
plus a four-stand rolling unit enables
thermomechanical rolling of wire rod in all
standard dimensions at low costs and high
productivity. This innovative concept has
been successfully implemented by SMS Meer
in two wire rod mills for Weifang Iron & Steel,
China, which have meanwhile been put on
stream.
Six-stand and four-stand rolling units. Thermomechanical
rolling of wire rod at small dimensions and high productivity cannot
be attained with a conventional ten-stand finishing block. Due to
the required number of passes, the heating up is too much to realize
the desired metallurgical properties. By separating the conventional
wire-rod finishing block into a six-stand and a four-stand
unit, a wire rod of any dimension can be finish-rolled on the second
unit at a maximum number of four passes.
Loop technology reaches temperature reduction down to
750 °C. By means of sufficient cooling and perfect temperature
equalization over the cross-section, thermomechanical rolling can
also be achieved with a high production volume, and the loop
technology from SMS Meer which we have successfully applied
already in several wire rod mills also offers a good precondition.
Consequently, the temperature can be reduced to 750 °C when
the wire rod enters the first finishing block i.e. at temperature deviations
of less than 50 °C.
This is a significant precondition to reach
again 750 °C prior to the last four shaping
passes in the case of dimensions which
still have to be produced in a total of ten
passes. This enables a normalizing or thermomechanical
rolling even for smaller
cross-sections.
View on both wire rod mills at Weifang Iron & Steel.
Loop on a wire rod mill.