Coastal Wire Co. offers the following technical help to provide our customers the ability to determine their baling wire needs, and help them with common technical problems that may occur with their baling wire:
Why the wire elongation and the annealing process are so important?
A number of manufacturers sell balers with automatic tiers that use black-annealed wire either from 50 lb or 100 lb. coils in boxes or from 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.
Premature wire breakage due to surface scoring during wire "tungsten" is pluralized feeding
Black-annealed automatic baling wire for use with automatic tiers can break prematurely due to surface scoring while feeding to the tier. With 50 lb or 100 lb. coils in boxes, and coils on carriers, the wire has to be fed over a number of pulleys and through a number of steel pipes before it reaches the tier.
From experience, we have noticed that both the pipes and pulleys wear over a period of time and these wear grooves can cause scoring or scratching of the baling wire. (In extreme cases the wire will even “hang up” in these grooves and break before it gets to the tier.)
Surface scoring of the wire weakens the wire and causes premature wire breakage either during tying or afterwards as the bale expands.
As a service to our customers, the Coastal Wire Company provides round steel guide tubes with tungsten carbide inserts which can be welded to the mild steel pipes through which the wire normally feeds. The tungstens carbide guide tubes are sold for $5.50 each, which is at our cost. If you feel that these tubes would be of benefit to your wire feeding process, please call us and we will be happy to ship them out of our stock.
Standard procedure for measuring wire elongation
Black annealed automatic baling wire for use with automatic tiers requires an elongation of greater than 25% in order to reduce the incidence of wire breakage as much as possible. (The reasons for this are explained in our Technical Help #1)
Elongation, which is a measure of the wire ductility, is generally determined in the tensile test. The elongation is measured by marking with paint a distance on the wire between the jaws of the tensile machine holding the wire sample (called gauge length), and then comparing this distance after fracture by fitting together the two broken pieces.
The amount of stretch is converted to percent elongation by the following formula:
new length after fracture – original length
% elongation = ——————————————————– x 100
Elongation at fracture is not distributed uniformly along the length of the wire sample, and will, therefore, vary with gauge length. Therefore, when comparing the elongation of different wire samples, it is most important that the same gauge length is used. The standard gauge length in the wire industry is 10 inches.
If you would like us at any time to check the elongation and tensile strength of your wire, please send us two samples each, 12 to 14 inches long. Samples sent for testing should not be bent or previously used. There is no charge for this service and we will not ask for the source of you wire samples.
Why does wire untwists at the knot?
Balers with automatic tiers that use black-annealed, high-strength baling wire can incur problems in which the wire unties at the knot after the bale is produced.
It is our opinion that the primary cause of this problem is that the wire tensile strength is too low in either one or both of the wires making the knot. The wire specifications require a tensile strength of 65,000 – 75,000 psi in order for the knot to remain tied.
From experience, we have observed knots untying where one wire has a tensile strength of 75,000 psi while the other wire making up the knot has a tensile strength considerably less than this, for example, 60,000 psi. Under these conditions, the lower strength wire pulls out or unties from the higher strength wire. In some cases, by checking the tensile strength of all coils, the baler operator can “match up” wires with similar tensile strength, even if they are of lower tensile strength than normal, and thereby produce a satisfactory knot.
If you are having problems with your baling wire untwisting at the knot and would like us to check the tensile strength of your wire, please send us two, 12″ to 14″ samples of unused wire. We will test the wire for tensile strength and elongation free of charge, even if the wire was not produced by us.
How can customers reduce the cost of their baling wire?
How can customers reduce the cost of their baling wire?
One of Coastal Wire Company’s goals is to assist customers through the use of technical help sheets. This one shows how a customer can, in many cases, save money by selecting the correct wire size, strength and elongation.
Use of a Higher Strength Wire with European Balers
Most European balers (e.g. MacPress) are designed to use a 10 gauge super soft wire with a tensile strength of 50,000 psi. The breaking strength of a 10 gauge soft (50,000 psi) tensile strength wire is identical to that of Coastal Wire Company’s 11 gauge high strength (70,000 psi) automatic baling wire.
This means that owners of these types of European balers can use our smaller 11 gauge wire instead of the 10 gauge wire and save 25% in the cost of baling wire!!
We invite our customers to call us so that we can arrange for a test comparison. As with all of our products the risk is on us — all we ask is that you pay us for the wire after it meets your approval.
Our Guarantee is quite simple: If there are ANY problems with our wire, we will replace it immediately at our expense.
Why wire breakage may occur in cold weather.
In a few circumstances an increase in the frequency of wire breaks may occur in cold weather when baling materials with excessive memory.
We have been asked if the black annealed wire properties change as the temperature decreases during the winter. One customer even asked us if we had any “winter wire” instead of “summer wire”.
The answer to this problem lies not with a change in the properties of the wire as it gets colder, but in an increase in the memory or retained pressure in the baled product. As the temperature gets colder more pressure is required to compress the product being baled, and this results in more memory in the bale. This, in turn, puts more pressure on the baling wire after the bale has been ejected from the chamber. This problem is particularly relevant in the baling of plastic, e.g. plastic milk jugs and soda bottles.
The following suggestions should help to reduce this problem:
- Make sure that the correct wire size is being used and the wire has been FULLY annealed with at least 25% elongation.This high elongation will allow the bale to expand slightly without the wire breaking. (For additional information on the need for high elongation in wire see Technical Help #1.)
- Try to schedule the baling of high memory materials later in the day when the temperature normally warms up.
- Reduce the bale length by a few inches to lower the bale pressure.
- Use a heavier gauge FULLY annealed wire, for example 9.5 gauge instead of 10 gauge.
- Check to see that the pulleys in the wire feeding system to the baler are not binding because of the cold weather causing the automatic tier to make poorly tied knots.
Finally, if the problems still exists, send us a couple of 10″ long wire samples showing the wire breaks for our free metallurgical evaluation. We will report back to you with our findings within a few days.
Wire breakage at the knot due to dry or poorly oiled wire
Poorly or improperly oiled black-annealed automatic baling wire can cause major problems at the auto tie assembly on the baler often resulting in excessive wire breakage.
Poorly oiled wire increases the back pull on the tier because the wire drags as it goes over the pulleys and through the guide tubes. Wire dragging puts added load to the tier and often prevents sufficient wire being delivered to the tier to make a correct knot.
This condition can often be observed by examining the broken wire knot. If the knot looks particularly dry and shiny and the twists very tightly wound there is a good chance that the wire has not properly oiled.
Some manufacturers of black annealed automatic baling wire shortcut the oiling process by spraying a light oil film on the outside of the wire on the carriers.
At Coastal Wire Company, we understand that it is necessary to FULLY oil the coil–inside and outside. All of our wire is dipped into a tank of oil, which is vigorously stirred by compressed air for a minimum of ten minutes. This process gives sufficient time for the oil to penetrate the entire coil, and to be absorbed by the porous black oxide skin on the wire surface. The wire coil is then set on a draining table where it drains for at least two hours in order to remove the excess oil.
We believe that the cost of making a properly oiled product is money well spent when you consider the cost and aggravation of bales breaking apart due to wire knot failures.
If you are not using Coastal Wire Company’s FULLY oiled wire, check with your current wire supplier to find out how they oil their wire–you may want to reconsider your wire source.
Why does Coastal Wire uses waterborne rust preventive oils?
Even though waterborne rust preventive oil is more expensive than conventional mineral oil, it is used exclusively at Coastal Wire Company to coat our black annealed baling wire and bale ties because it gives a better coating.
Waterborne rust preventive oils are prepared by mixing the oil with water to form a milky-white emulsion into which the coils are fully dipped. (The importance of properly oiling baling wire is covered in the Technical Help #8.)
Unlike mineral oils, waterborne oils do not contain hazardous ingredients such as sodium nitrate, amines, or flammable volatile vapors. Continuous breathing in a mineral oil environment can cause health problems and contact with certain mineral oils can cause skin irritation. Waterborne oils do not vaporize and can be washed off the skin easily with ordinary soap and water.
Waterborne oils produce a drier type of coating making the wire cleaner to handle.
If the wire is stored where the humidity is high, the waterborne oil residue can absorb this moisture without any detriment–it just dilutes the anti-rusting properties slightly.
Mineral oils, however, are wet to the touch and do not mix with water. This means that drops of water can remain in place on the wire under high humid conditions and eventually cause spots of rust to form.
Problems with baling with four wires instead of five
Four Wire Balers
Some balers are designed to use only 4 horizontal wires of Black Annealed Baling wire. When ordering wire, it is important to remember that in this case only 4 wires are carrying the full pressure of the expanding bale as it is ejected from the baler’s chamber.
We recommend that in this situation a one gauge thicker wire should be used. For example, if 12 gauge wire is used with a 5 wire system, then for the same product being baled with a 4 wire system an 11 gauge wire is recommended.
In this situation, a FULLY annealed wire with over 25% elongation (compared to a partially or strand annealed wire with lower elongation) is an absolute requirement or excessive wire breakage will occur.
Five Wire Balers
The following information relates to balers designed for 5 horizontal wires where the operator has decided to use only 4 wires.
With five wires in use, the middle wire takes the most pressure and the bottom wire (next to the ground) takes the next highest pressure. The top wire takes the least pressure.
However, it is most important to remember that if a baler is designed for using 5 wires, yet only 4 wires are used, then considerable over-stressing of the wires can occur and this significantly increases the risk of wire breakage. We consider this practice to be dangerous and do not recommend it.
Solutions to help prevent payoff problems
To minimize payoff tangling and potential wire breakage, the following suggestions will prove beneficial.
The first and most important is the use of a slinger ring. This device fits on top of the wire carrier and opens the cast of the wire as it pays off the wire carrier. This helps to separate the rings of wire and any over-lapping that may occur in manufacturing or transportation.
Another way to reduce tangling is to take a handful of wire from the top of the carrier and lift it above the carrier about two feet. Then, strand by strand, place the wire back on the carrier until you have the last ring of wire in your hand. This should help to eliminate any tangling that may have occurred on the top of the wire carrier during transportation.
A weighted object should be placed around the wire to offer resistance as the wire is fed from the carrier. (This could be an old bearing, a used wire die, or a piece of a logging chain.) This object cannot be too heavy as it will drag the wire from the top of the carrier to the floor. It must rest on top of the wire. As the wire is pulled from the top of the carrier, this will also help to eliminate tangling problems.
If your payoff rack uses guide tubes, these tubes will wear from usage and will eventually form a groove in the tube. As the wire is pulled through this tube, it will score the wire, and this scoring will cause the wire to prematurely break due to the reduced area of the wire. Coastal Wire Company can supply a carbide insert that can be welded in this guide tube for a permanent fix.
By following this information, you should have trouble free operation using wire from any manufacturer.