4 Sheet, Plate and Shapes
Sheet Metal
Sheet metal is formed in a long continuous roll or is cut into individual sheets of various dimensions.
The sheets are formed in a rolling mill where the almost white-hot slabs of steel are passed through a succession of rollers. Each pair of rollers is set slightly closer to each other than the previous pair. The metal is squeezed thinner as it passes through each pair of rollers. Rolling continues until the metal is the desired thickness or gauge.
Sheet metal may be made from many different metals, including steel, aluminum, copper or brass. It may be rolled hot or cold, depending on the properties desired. For cold rolling, the metal is rolled hot at first, then cooled before the final rolling processes. Cold rolling increases the strength and hardness of the metal by work hardening, as well as producing a more accurate thickness than hot rolling.
Sheet metal may be used for roof covering, heating and cooling ducts, door cladding and work surfaces on benches. Sheet metal is widely used in the manufacturing of simple items such as instrument panels, as well as more complex items such as automobile bodies and engine covers. When sheet steel requires protection from corrosion it is usually galvanized (coated with zinc).
Sheet goods are commonly be stored in horizontal racks. However, storing sheets this way requires quite a bit of floor space and may lead to surface damage as the sheets are dragged from the pile. Sheet metal can also be stored on edge, in racks that permit you to tilt each sheet to expose both faces. The rack should allow you to lift or slide out any sheet you choose. Lifting light sheets may be done by hand, but clamps and an overhead crane or forklift should be used if the sheets are too heavy.
If sheet metal is supplied in rolls, it should be stored mounted on its horizontal axle to permit the desired amount to be removed. Avoid storing rolls on end, as this makes unrolling difficult.
Almost all types of metals are subject to corrosion. Even stainless steel or galvanized metal will show discolouration and corrosion if allowed to sit in water. One of the prime concerns with storing ferrous metals is to prevent moisture accumulation. If storing ferrous metals on racks outdoors, a light coating of oil can temporarily protect the metal from rusting. This is usually done from the factory.
Specialty Sheets
Perforated Sheet Metal
Perforated sheet metal is sheets of metal that have holes or shapes punched into it. Most commonly, a series of round holes in a specific pattern are used. Perforated sheets can be used for many applications such as decorative panels, screens/filters, or in duct work for sound attenuation.
Expanded Metal
Expanded metal is sheet material which has been slit in a particular pattern and then stretched. It can be either flat or profiled. It is seen commonly for stair treads, walkways and fan housings. It can be very sharp and caution should be taken with handling expanded metal.
Attention must be taken when shearing perforated and expanded metal as small pieces may stick to shear blades. These must be cleaned off with extreme caution and the machine must be “locked-out” before doing so. It is a good idea to block the upper blade with wood so it is impossible for it to come down.
Plate
Metal is also available in a form known as plate. Plate is similar to sheet metal, but thicker. Sheets of metal are considered plate if they are at least [latex]\frac{3}{16}″[/latex] thick. Like sheet metal, plate is available in sheets of various widths and lengths.
Plate is formed by the same rolling process as sheet. Hot-rolled steel plate has a dark blue, scaly surface, while cold-rolled steel plate is smoother and has a sheen. Plate is used in heavy industry and manufacturing. It is used for equipment manufacturing, truck decks and general fabrication.
Solid Stock-Round and Flat Bar
Many different shapes are available as solid stock. Round bar and flat bar are the most common and available in many different metals. Most are available in lengths up to 2′. Small diameter round bar is commonly referred to as rod.
Flat bar is similar to plate except it is never wider than 6″. Flat bar is available either hot rolled or cold rolled.
Solid stock is used in a wide range of manufacturing and construction processes such as shafts and brackets.
They should be stored in horizontal racks to prevent the round bar from rolling. Sometimes the sides of the racks are marked off at 1′ intervals to allow for quick identification of each item’s length. Stock of different sizes and metal types should not be stored in the same rack. Once the lengths are too short, stand them vertically in racks. This method of storage permits quick and easy selection of required lengths.
Structural Shapes
Structural metal shapes can be extremely heavy and have potential to cause serious injury. Always make sure that you wear the appropriate safety equipment. Protect your hands by wearing gloves and always keep your hands out of areas where they could be pinched by shifting material. Never attempt to lift structural shapes by hand, always use proper lifting devices and correct rigging practices.
Storage of these structural shapes depends on their size and how long they must be stored. Large sections may be too cumbersome to (replace picture) place in racks. It is just as convenient to store large sections of I-beams and channel on dunnage (wood blocking) on the floor.
Smaller sections can be stored in horizontal or vertical racks in much the same way as flat bar stock. Care should be taken to nest one section into another to prevent any shifting of the stock during removal.
Angle
Angle-shaped metal is also available in many different metals, including steel, aluminum, and wrought iron. The shape is used in manufacturing and fabricating and is more rigid than round or flat bar. Angle may be ordered in a variety of leg dimensions and lengths.
Channel
Channel is available in many different materials and various dimensions and lengths. Channel is used extensively in construction and manufacturing.
I-beam
The I-beam shape is a structural shape used mostly in large steel structures such as buildings.
The shape provides rigidity in two directions while keeping weight to a minimum. Structural shapes include standard I-beam and wide flange I-beam.
Pipe and Tubing
Pipe and tubing are commonly referred to as the same, but they are not. They are similar in the sense that they are hollow shapes, but it is in the shape and the way they are sized which makes them different. Tubing is measured “outside” and pipe is measured “inside.” As well, pipe is always round and tubing is available in different shapes, such as round, square or oval.
Tubing is available made from many different materials in different wall thickness. It is commonly used for such items as handrails and table legs. Tubing is always measured to an accurate outside dimension.
Pipe is commonly available in steel and aluminum. It is measured by a “nominal” inside dimension. Like lumber, a 2×4, which actually measures [latex]1\frac{1}{2}″\times3\frac{1}{2}″[/latex], pipe doesn’t necessarily measure exactly what you think it will. We must refer to a chart to get the true measurements. The thickness of pipe is referred to as “schedule.” Pipe has many uses such as structural components, like roll cages.
Storage of Metals and Metal Shapes
The purpose in storing any product is to:
- Provide easy access to materials
- Provide easy identification of materials
- Protect the products from damage
- Protect personnel from injury by materials
- Facilitate inventory of stock
- Protect the finish of the product
- Prevent theft
- Prevent loss
Depending on the type and shape of metal, different storage practices may be followed to achieve the above goals.
Media Attributions
- “Steel Coils” by Arosset is licensed under a CC BY-SA 4.0 licence.
- “Perforated Sheet Metal” by rkit is licensed under a Pixabay licence.
- “Expanded Metal” is CC0 public domain.
- “Steel Bar” by Tudor Barker is licensed under a CC BY-NC-SA 2.0 licence.
- “Angle-shaped metal” is CC0 public domain.
- “Steel Channel” by justincobb1 is licensed under a Pixabay licence.
- “I-beam raw material at WP Welding” by W.carter is CC0 public domain.
- “Geometric Stairs” is CC0 public domain.
- “Pipe” is CC0 public domain.
The strength different materials display when placed under tension. In the imperial system, tensile strength is measured in pounds per square inch (PSI).
The degree to which a metal can endure mechanical indentation or abrasion without deformation.
A process of hardening a material by means of forming. Bending or rolling done without heating will harden the material. The degree of hardening depends on the process and material. Each time we form a piece of metal, it becomes "work hardened" or "strain hardened" in the area of the forming.