Multi-chapter guide to Metal Grating describing: what metal grating is, how metal grating is used, types of metal grating, how it is made, types of metals used.
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Metal grating is a metal product produced by perforating metal sheets or joining bars of metal to form a grid. They are a metal product that is widely used in various industries as stairs, platforms, scaffolding, and protective coverings. The different processes used to produce metal gratings include expansion, perforation, molding, and welding.
Nearly any metal can be used to make metal gratings. The most common types are iron, carbon steel, aluminum, and stainless steel. Metal gratings are commonly used as a non-slip safe surface for applications that require a secure work platform.
The environment and type of building determine the kind of grating that will be used. Engineers and designers work to develop metal grating solutions that exactly fit the parameters of a structure. Part of their considerations includes thickness, metal bar dimensions, and the configuration or pattern of the gaps or openings, which include oval, square, and diamond shapes.
Some of the factors examined when designing metal grating are the amount of allowable light, air, and sound that needs to pass through with its aesthetic value dependent on how visible the grating may be. Exceptionally heavy gratings are made of welded steel or pressure locked interlocked bars.
Expanded metal grating gets its name from the process that is used to produce it, which includes puncturing slits in a metal sheet. After the slits are cut, the metal sheets are stretched and pulled to expand them. The resulting effect is a diamond shaped pattern. The completed sheets can be cut to fit the needs of any application. All of the various types of metals are used to create expanded metal gratings.
Standard expanded metal grating is used where a slip resistant surface is required. Flattened expanded metal grating is made using the standard expanded process but is cold rolled to flatten the surface to a smooth even finish.
Bar metal grating is the most common and the one people envision when discussing metal grating. It consists of parallel bars connected to perpendicular bars that are attached using a variety of methods with welding being one of the most common. Other connecting types include riveting, close meshing, and press locking.
The type of joining process is determined by the metals to be joined. Bar metal grating is made from aluminum or steel, has a high strength to weight ratio, and is used for industrial flooring. Due to the strength and durability of bar metal grating, it is also used for fire escapes, street drains, and bridges.
The many names for wire mesh metal grating include wire fabric and wire cloth. It is a form of grating that has rows and columns of intersecting wires. It is very easy to install, exceptionally durable, and has applications in many industries. The flexibility, versatility, and variations of wire mesh metal grating have made it extremely popular.
Wire mesh metal grating can be welded or woven, depending on the manufacturer. Welded wire metal grating is welded where the columns and rows intersect. Woven wire metal grating is woven like cloth with columns and rows going over and under at their connecting points.
Perforated metal grating is produced by stamping, punching, or deforming metal sheets by placing holes in them of a specific size, pattern, and shape. The metal sheets are made of exceptionally sturdy metals, including stainless steel, carbon steel, and aluminum. The perforations are placed in the metals by rotary pinning, die punching, and laser cutting.
There are a wide variety of uses for perforated metal grating, including sound reduction, ventilation, and screening.
The purpose of safety grating is to provide a firm, solid, and skid-resistant surface. It is designed to increase traction and prevent stumbling and falling. Safety metal grating is made with diamond protrusions for greater grip and traction. For increased safety and to prevent the accumulation of liquids, safety metal grating has large openings for drainage and air flow. The increased grip of safety metal grating is created by serration of the edges of the diamond openings, which are produced by cold stamping.
Compound metal grating combines two forms of grating and includes bar grating and steel plate grating. It is composed of a checkered plate that is sealed to the surface of a steel bar metal grating, with the steel plates having thicknesses of 3 mm to 6 mm or 0.12 inch to 0.24 inch.
Compound metal grating comes in a wide assortment of sizes and types of materials, with some forms using wire mesh metal grating while others have multiple layers of bar metal grating and perforated metal grating. To prevent deformation during zinc coating, heavy gauge steel is used to manufacture compound steel grating.
Press locked metal grating is a form of bar grating, distinguished by the method used to join the perpendicular and parallel bars. The cross and bearing bars are notched and pressed together, the result of which is a smooth even surface across the joined bars.
This type of bar metal grating connection creates an aesthetically appealing appearance that fits into architectural designs. Press locked metal bar grating is available in steel and aluminum as well as a wide variety of sizes and bar openings.
The term grating refers to any type of covering or frame used to cover holes, offer support, serve as a platform, or provide protection. There is an endless number of materials that are used to manufacture grating, from various types of sturdy plastics to heavy duty steel and stainless steel. When choosing a grating material, the main concerns are where it will be used, how strong it needs to be, and whether it will be required to add to the ambiance of a structure.
Metal gratings are used in a variety of conditions and environments as a safety precaution or means of protection. Specialized metal gratings are used at airports, industrial operations, and manufacturing facilities and are very strong and durable.
Aluminum metal gratings are malleable, corrosion resistant, ductile, and have thermal and electric conductivity. It is lightweight, nontoxic, nonmagnetic, and is resistant to bacterial propagation. Aluminum metal grating can withstand extreme cold without becoming brittle. The wide use of aluminum metal grating is mainly due to its pleasing appearance, which makes it useful for industrial applications and decorative ones as well.
Light duty steel metal grating is used for pedestrian traffic and some types of rolling traffic, such as carts and hand trucks. It is produced as bar metal grating, which can be swaged, riveted, dovetailed, or welded. In most cases, light duty steel metal grating has load bearing bars with perpendicular cross bars and is made from carbon steel with an open grid structure. Due to its cost efficiency and low maintenance, it is widely used for highway platforms, safety barriers, and machinery floors.
Several grades of stainless steel are used for producing metal grating, which include grades 304, 304L, 316, and 316L. Stainless steel metal grating is exceptionally strong, long lasting, and capable of withstanding corrosive, humid, and high moisture conditions. It is produced using a wide variety of bar sizes using swage or welding methods.
The special characteristics of stainless steel make it an ideal grating for water treatment plants, chemical processing plants, and oil and gas production. It is highly resilient and capable of enduring harsh weather and extreme variations in temperature.
Galvanized steel is carbon steel that has received a zinc coating for protection against rust and corrosion. As with stainless steel, it is an ideal solution for grating that is installed outdoors or in highly moist and damp environments. The zinc protection ages slowly, which extends the lifespan of galvanized steel metal grating.
The majority of galvanized steel metal gratings have a b load class, able to hold 28,000 lbs. or 125 kilonewtons (kn) as classified by Deutsches Institut für Normung (DIN).
Heavy duty carbon steel metal gratings use deeper and thicker steel bars that are joined at high temperatures to form a permanent, secure, and solid joint. This type of metal grating is designed to carry heavy loads and offers optimum performance for many years.
Every form and type of grating is produced using a different process depending on the materials being used and the production method. Some common production methods are welding, dovetailing, stretching, and swaging, with welding being the most common. The chosen process depends on the thickness and weight of the material as well as how it will be used.
Regardless of which of the manufacturing methods chosen, the first step is selecting the metal, which is determined by the environmental conditions and how sturdy and strong the metal grating has to be.
Expanded metal grating begins with sheets of metal that have a diamond shape cut into them. The process for expanded metal grating is completed in one operation where diamond shapes slits are cut into the metal surface as the sheets are stretched.
Piercing and stretching of expanded metal grating result in a raised surface with bonds and strands at a uniform angle to the plane of the metal sheet. The outcome is a metal grate with exceptional strength and rigidity. For applications that require a smooth surface, the stretched metal sheets are flattened between two rollers.
Swaging is a cold metal working process where metal for one part is deformed to fit into another metal part by force. The swaging process for metal gratings begins with load bearing metal bars, evenly spaced for strength and design. Next, tubular bars are positioned across the load bearing bars at an equal distance from each other and electrode welded. The depth of the bars and the distance between them can vary depending on how the grating will be used.
Dovetailing is an ancient manufacturing method that has been used for centuries to join two types of material. In metal grating, the process begins by precision slotting the load bearing and cross bars. The slots are precisely cut such that the cross bars fit snuggly and tightly into the load bearing bars. Next, a hydraulic press forces the close tolerance pieces of metal together.
The pressure placed on the metal bars creates a permanent lock between them. The result is a tightly locked and rigid flat uniform surface.
Welded metal grating is produced using an electro forging process where rectangular load bearing bars are welded to cross bars. By welding the metal bars, a positive fused connection is formed between the bars that lasts for many years. Bearing bars for welded metal grating have a thickness of 0.125 in to 0.5 in or 0.3175 cm to 1.27 cm.
Welded metal grating is the most common form of metal grating and is used for a wide variety of applications.
Riveted metal grating is produced using carbon steel, 6000 series aluminum, and 300 series stainless steel. The process for riveting metal grating involves riveting crimped flat bars in a reticuline pattern to load bearing bars. The process results are metal gratings with superior resistance to impact, fatigue, and heavy loads. The reticulated cross bars provide excellent strength and durability when they are required to endure stress and pressure.
As with all forms of industrial products, there are standards that have been established to guide manufacturers in the production of their products. Though there are a wide assortment of metal grating standards, the two most commonly followed are those from the American National Standards Institute (ANSI) and Deutsches Institut für Normung (DIN) or the German Institute for Standardization.
DIN divides their classifications with the letters from A to F, while ANSI’s classifications are descriptors for the type of work metal grating will perform.
ANSI standards are divided into five groups: light, medium, heavy, extra heavy, and special duties. The determination for each group is decided by weight.
Grates that can handle a load under 2000 lbs. or 900 kg. This level of grate is for pedestrian traffic only.
Metal grating that can support loads between 2000 lbs. and 5000 lbs. or 900 kg and 2250 kg. It is a metal grating that is available for light pneumatic traffic, sidewalks, and residential parking lots.
The load for heavy duty metal grating is between 5000 lbs. and 7500 lbs. or 2250 kg and 3375 kg. This type of metal grating is capable of supporting commercial traffic and tractor trailers.
Extra heavy duty metal grating can be used for roads, highways, and bridges and has an H-20 load rating capable of handling 10,000 lbs. or 4500 kg of load.
Special duty metal gratings are designed to handle airport traffic and endure loads of 10,000 lbs. or 4500 kg or greater.
Load class A is for pedestrian traffic and capable of handling loads of 3370 lbs. or 15 kilonewtons (kn).
Class B is for parking lots, sidewalks, and light vehicular traffic with a load rating of 28,000 lbs. or 125 kn.
Load class C is for commercial applications capable of handling loads of 56,000 lbs. or 250 kn.
Load class D metal grating is for exceptionally large heavy duty loads and has an H-20 load rating. It is capable of handling loads of 90,000 lbs. or 400 kn.
Class D metal grating can support forklifts, roads, bridges, and highways.
Load class E can handle a wide variety of manufacturing and transportation conditions that include high impact steel struts and metal wheels. It has a weight rating of 134,000 lbs. or 600 kn.
Load class F is designed for airport traffic with a load bearing rating of over 200,000 lbs. or 900 kn.
A common application for metal grating is as a safety measure to protect workers by providing a stable, secure, and firm work surface with excellent traction. As a further safety measure, metal grating can be placed as a barrier to prevent accidents in unsafe or hazardous situations.
The uses for metal gratings are determined by the material used to produce it with aluminum and stainless steel being ideal for corrosive and moist conditions, while carbon steel can provide strength and support for heavy duty work.
The aesthetic appeal of metal gratings can be found in their use as flooring, walkways, platforms, and mezzanines. The safe, strong, and durable structure of metal gratings makes them the ideal choice for adding an extra dimension to any type of structure. The unifying nature of metal gratings can add a cohesive quality that provides a sense of continuity as well as being a protective barrier.
Metal gratings are used in water filtration systems due to their resistance to corrosion and exceptional strength. Though these characteristics are impressive, metal gratings are mainly used for filtration systems because of their high processing ability with less material consumption and long service life. The pressed metal gratings are used to capture large materials in water destined for processing such as plastic bags, boxes, and other forms of garbage.
One of the main uses of metal grating is as flooring, which can be made from an assortment of alloys in configurations to exactly fit the needs of an application. Aluminum floor grates are used in marine and wastewater conditions. Since aluminum is lightweight, it can easily be maneuvered and positioned in small and confined spaces.
Steel metal floor grating is normally used for heavy duty applications where strength is necessary and a coarse hard surface. Production facilities depend on steel flooring for its exceptional performance and safety.
Metal grating fencing has an appealing appearance with the necessary strength and rigidity to provide a high level of security. The secure connection between the metal grating panels is ideal for locations that require protection from intruders. Metal grating fencing can be shaped, fabricated, and designed to fit any location since every installation is uniquely designed to fit the dimensions of the location.
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