HR (hot rolled) trimming is the cut off from the slitting machines which process coils for industrial manufacturing use. When new HR coils are processed, they are cut to customer specifications and the off cut from the cutting die is know as HR trimming scrap.
This type of scrap metal is classed as secondary material used by manufacturers mainly in Pakistan and India. HR trimming contains iron and has a low carbon content of 3-5% so it can be re-used in many applications such as new wire manufacture. This scrap metal also has high strength and good ductility, making it durable and extremely light weight.
HR coils are stored in a circular wound reel, so when they are slit, the HR trimming also reverts to a coil shape. The shape makes it easy to process for the manufacturing plant, as they get a clean rolled coil, which they can then un-wind and manufacture new wire. If the HR trimming coil is scattered and loose, it makes it difficult to re-use and the coil would have been used a melting scrap instead.
The thickness and width of the HR trimming scrap is very important. If the trimming is too thick or too wide, then it becomes difficult to be used in the machinery. The ideal thickness of HR trimming should be around 2-6mm and the width should be in the range of 8-20mm. The profile should not be round or oval, but flat which makes it ideal to run through the rollers when re-using.
To sum up the ideal specification :
– Well rolled, not scattered/loose material
– Thickness 2-6mm
– Width 8-20mm
– Free of any coating
The main reason that HR trimming scrap is re-used is that it is cheaper to purchase this scrap metal rather than purchase new hot-rolled coils, or new coil strips to manufacture with.
However, there is also the risk that the specification supplied by the HR trimming scrap supplier is not correct and this would have a negative impact on the overall price. Unusable material would have to be sold or used as melting scrap which has a lower price point. Wastage can also occur when the coils are damaged, tangled, coated and too short.
When HR trimming is exported, it is usually loaded into 20ft containers. Due to its dense nature and if the coils are tightly wound, the average loading weight can be around 22-25mt per container. If the coils are tightly wound even when loaded and transport the HR trimming will stay compact and can be easily unloaded by the importer in Pakistan or India.