Technical Help
Why are wire elongation & the annealing process so important in high-strength, black-annealed automatic baling wire?
A number of manufacturers sell balers with automatic tiers that use high-tensile (75,000 psi) black-annealed wire either from 50lb or 100 lb. coils in boxes or from 1,500 lb. coils on carriers. As baler manufacturers produce more powerful balers, greater demands are put on the wire used to contain the bale. It has been our experience that wire elongation of greater than 25% is a necessity for these balers for the following reasons:
First, a bale expands after it is ejected from the baling chamber and the amount of expansion depends primarily on the products being baled. The baling wire must have sufficient elongation to allow for this expansion or the wire will break.
Second, whenever a metal is worked, i.e. twisted, it hardens and loses some of its original elongation. Therefore, the wire at the knot has less elongation than the wire around the bale. If the original baling wire has low elongation, for example - 15% or less, then the wire adjacent to the knot will have insufficient elongation to withstand the normal bale expansion and wire breakage will take place.
For this reason, Coastal Wire employs a batch annealing process for heating its wire as opposed to a strand annealing process. Steel wire can be annealed (or softened) by strand annealing or by batch annealing. In strand annealing the wire is heated for a matter of minutes and then rapidly cooled. In batch annealing, the wire is heated for several hours and then slowly cooled. It is a metallurgical fact that wire annealed by the batch annealing process has much greater elongation than wire annealed by the strand annealing process.
The Coastal Wire Company batch anneals all of its baling wire and achieves a typical elongation of 25%. There is no extra charge for this additional elongation because we believe it is a necessity to avoid wire breakage - and we know how costly the retying of bales can be!
If you would like us at any time to check the elongation of your wire, please send us two 12-14" samples of unused wire. We mark off a 10" length and measure its extension when pulled to fracture in our tensile test machine. There is no charge for this service and we will not ask for the source of your wire samples.
