Intermediate Wire Processing

Heat treatment

As previously briefly mentioned the wire drawing process is a plastic deformation process. For a material to be possible to draw it must be ductile - and to be ductile a steel wire must have a suitable large grain crystal structure. During drawing the steel work hardens and it is therefore necessary to anneal or stress relief the wire. Through heat treatment it is also possible to alter the steel characteristics to fit the demand of a specific application.

Annealing

The purpose of annealing is:

  1. To soften the steel and improve ductility,
  2. To relieve internal stresses induced by some previous treatment (drawing, cold rolling, or uneven cooling after hot rolling the wire rod)
  3. To remove coarseness of grain.

The operation consists of: heating the steel to a certain temperature, "soaking" at this temperature for a time sufficient to allow the necessary changes to occur and then cooling at a predetermined rate. For more in depth process description and for various types annealing furnaces use this link.http://www.wireworld.com/seminar/intermediate/heattreatment/annealing.htm

Carbon Steel Wire - Patenting

The purpose of patenting is to produce a wire with a uniform austenite grain structure, suitable for production of wire for products like rope construction.

In the patenting operation the wire is passed through tubes in a furnace at about 970 Deg. C. This high temperature treatment produces uniform austenite of rather large grain size. The subsequent cooling – in air or molten lead (lead patenting) – is rapid (e.g. coarse process wire or wire rod), and the patented wire structure will consists of very fine pearlite with little or no separation of primary ferrite.

For more in depth process description use this link http://www.wireworld.com/seminar/intermediate/heattreatment/patenting.htm

Process furnaces