Form of steel strapping coils: oscillated, ribbon, Jumbo coils

Steel strapping is availabe on two coil forms: oscillated wound and ribbon wound. These two forms of coil can be differentiated along the following criteria:

• # of strap layers per coil: oscillated wound steel strapping has always three layers whereas ribbon wound coils only has a single layer. Hence, width of coil is for ribbon wound the same as the strap width.
• Weight: Oscillated coils always have appr. 50 kg per coil; for ribbon wound coils, weight per coil depends on the strap width: 13 mm steel strap on ribbon wound coils weights ~ 19 kg per coil, 16 mm weights ~ 25 kg, 19 mm approximately 29 kg etc.
• Core diameter: for oscillated wound steel strap, inner core diameter is  ~ 406 mm, outer core diameter around 600 mm; for ribbon wound coils, core ID is ~300 mm whereas core OD is the same with ~ 600 mm
• Required steel strapping dispenser: strapping dispensers for oscillated wound coils have an axis, whereas dispenser for ribbon wound coils have a slot where the coil is put in.

Oscillated wound steel strapping coils	Ribbon wound steel strapping coils

A specific form of oscillated wound coils are the so-called Jumbo coils that are characterized by extremely long length per coil. They are intended for use with automatic strapping machines only.  

Steel strapping for load securing of heavy goods

Strapping with steel has the longest "tradition“ and has substituted binding wire in many industries several years ago. Later on, PP and PET strapping, followed by polyester textile strapping came to the market. Plastic strapping had the advantage of being a lot cheaper than steel strapping - without risk of damaging the packaged good by sharp edges or rust. But for some applications, steel strap is still indispensable.

Steel strap quality grades: bright, blue, black- and zinc-painted

Steel strapping can be differentiated along several criteria: strap width and thickness have an impact on tensile strength, finishing is responsible for rost protection. Basically, there are three different qualities available Bright steel strapping, quality/coated steel strapping and high tensile steel strapping. Bright steel strapping has the lowest parameters in terms of tensile strength and elongation, high tensile steel strap the highest. For quality and high tensile steel strap, three different grades of rust-protection are available: blue-annealed, black-painted and zinc-painted:

bright	blue-annealed	black-painted	zinc-painted

Some steel strapping suppliers use specific names for their steel strap in order to differentiate standard from high tension quality, for example. „Mega-Band“, „Magnus-Band“, or „Ultra-Band“ (like ultra-blue annealed, ultra-black-painted, or ultra-zinc-painted) are used for high tensile steel strapping.

Fields of application for steel strapping

Especially for very heavy packaging goods, steel strapping is often still required: with a 32x0.8 mm high tensile steel strap for example, breaking strengths of more than 26,000 N are reachable. In contrast, the strongest PET strap reaches only half of this strength. Steel strapping is also indispensable when packaging goods have very sharp edges or when they are heated after strapping or still hot before being strapped. In those cases, plastic strapping would simply melt away.

If only a small surface is available, as it is the case for coils, tubes or profiles etc., there is almost no alternative to steel strapping. The strap is put around the packaging good according to the so called "lasso method"; sealing is done by a metal seal in this case.