Sheet metal fabrication is a multifaceted process of creating metal parts or structures out of sheet metal.
Cutting: Cutting metal into pieces of precise dimensions or dividing large sheets into several parts are examples of sheet metal processing. You can cut sheet metals manually using power tools, metal saws, lasers and waterjet saws.
Blanking: Blanking involves cutting out a portion of the sheet metal based on a stencil. Excess material is discarded or recycled.
Bending: Depending on your specific design, you may need to bend portions of the sheet metal pieces you have made. You can do this using press brakes and other tools.
Galvanizing: Corrugated roofing panels, for example, are a great example of this type of use. Zinc coated materials works effectively in prolonging the life of your roof.
Milling: If the metal work piece is still too thick and further reducing its thickness through rolling or stretching is impractical, milling is the next best course of action. It requires the use of a rotary cutter.
Welding: Joining together two pieces of metal by applying heat and pressure with gas or electricity can be used to build structures and create parts.
Crafting brass is a complex journey that involves more than meets the eye. It takes both science and artistry to transform raw materials into beautiful objects. Creating brass involves several processes before it can become its recognizable bright gold appearance. Each step adds something special until we finally have one of mankind’s most enduring materials — brass.
Melting brass begins by heating the metal until it reaches its low melting point at 1,999 degrees Fahrenheit. Once the metal has reached its melting point, it will liquefy at the edges first before flowing towards the center of the container where it is heated.
Gradually increasing the temperature throughout this process, to avoid uneven heating or cooling, is critical. Without a gradual climb in temperature, cracks may be present in the final product. The zinc present in a brass alloy gives the finished product a yellowish tint and increases its strength, while in copper alloys produce a deeper color and add elasticity to the alloy.
Cold Rolling and Annealing
Cold rolling is a process that involves passing the brass through a series of rollers at different temperatures. This process reduces the thickness of the sheet, as well as increases its length. Cold rolling improves the material’s flexibility, tensile strength, hardness, and yield strength.
The annealing process helps improve the mechanical properties of brass. Annealing means heating brass to a specific temperature for a specific amount of time. After cold rolling or annealing operations have been performed, it will be ready for further processing according to your specific needs.
Hot rolling is used to produce flat products, like sheet or plate, by passing them through a series of rollers under high pressure. The pressure causes the material to elongate and become thinner as it moves through each successive pair of rollers until it reaches its desired thickness.
This process can occur at room temperature or above 1,832 degrees Fahrenheit. In brass manufacturing, hot rolling produces large coils of material that is then further cut-to-size into pattern sizes.
It’s one of those pieces of information that we all seem to misplace…what really IS the difference between Aluminum Association, American Standard and Sharp Corner products?
First, let’s name that shape! The base, or depth, is often noted as the first dimension of the shape. The thickness, or web, is the thickness of the base/depth. Lastly, the legs or flanges are the uprights of the channel.
Each of the different types, Aluminum Association (AA), American Standard (AS) and Sharp Corner (often called Architectural) have a different combination of leg and interior corner types.
Aluminum Association (AA) has curved (radius) interior corners and straight legs with flat ends.
Need help remembering? We like to make a connection between letters AA in Aluminum Association, and the flat ends of the legs.
American Standard (AS), on the other hand does not have ANY flat or sharp corner in its interior or legs. The legs taper from thick to thin and have rounded ends. You can almost see the shape of an “S” between the rounded legs and the radius interior corner.
Everything about “Sharp Corner” is what it sounds like! 90 degree interior corners and straight legs with flat ends make everything angular. Sharp Corner, or Architectural also only comes in aluminum alloy 6063.
Aluminum, whether or not you know, is present in our daily lives in some fashion. But how did it get that way?
Let’s step back to look at how aluminum is made.
The first step in aluminum production is mining. Mining takes place in Bauxite-rich regions of the world such as the Caribbean, Australia and Africa. Bauxite is a naturally occurring ore that contains aluminum silicates that took millions of years to create from the natural chemical weathering of rocks.
After mining comes refining. Bauxite alone does not create aluminum, it’s the process of grinding the Bauxite and adding it to a mix of caustic soda and lime to which high heat is applied. After this intense process of heat and pressure occurs, aluminum oxide is created and precipitated out of the mix. It is washed and heated again. Now the mix looks like a white powder and is called ‘Alumina’. Alumina is also known as ‘aluminum oxide’.
Alumina is then smelted, which is an electrolytic reduction process. Electric current is passed through the bath of dissolved alumina and the aluminum metal is created and separates from the original chemical solution.
We aren’t done yet! After the aluminum is created it goes back into a furnace and is mixed with other metals or elements according to a precise scientific recipe in order to create a molten metal that is chemically suitable for certain applications. Purification then occurs and the molten metal is cast into ingots or molds and cools, awaiting its final processing.
Lastly, the ingot or cast material is either rolled, forged, drawn or extruded into its final form: sheet, plate, bar, tube or custom extrusion.
Bar stock can end up as the screws you buy from a hardware store and sheet products could be formed into a filing cabinet you use for important documents.
Next time you use or see something in your daily life that is aluminum- remember the long process it took to get that way and all the people and processing that happened along the way.
Aluminum is naturally a soft, low-density metal – too soft to be used for any structural applications in its pure form. Yet we see aluminum used regularly in high stress applications: construction, aircraft, even space shuttles. So how does such a ductile metal become so strong? The first step is creating an aluminum alloy. Adding alloying elements such as copper, silicon and magnesium modify the mechanical properties of aluminum to produce a stronger metal. Further processing can then be done to add even more strength and durability to aluminum. One of the most popular methods of doing this is through tempering.
What is Tempering? With controlled application of heat, metal is raised to nearly its critical temperature – a temperature just short of melting, high enough to alter a metal’s mechanical properties and relieve its internal stresses. The heat treatment is used to increase the hardness and ductility, while it decreases brittleness to prevent cracking and breakage. There are several different methods to produce the desired result, but the overall process is known as tempering.
What is an Aluminum Tempering Designation? Once the tempering process is complete, the metal’s hardness is referred to as its temper. Its tempering designation identifies exactly what kind of heat treatment the metal has undergone. This is helpful in identifying the strength of a particular type of aluminum, and mechanical applications it is best suited for. Two pieces of aluminum alloy may have the same chemical composition, but if they have different tempering designations, their uses can be quite different.
What are the Tempering Designations? The tempering designation is a two-character code attached after the aluminum alloy designation. The first character is a letter which identifies the type of tempering treatment used on the aluminum:
F: As fabricated. These are known as ‘semi-finished’ products, and often used in creating other finished tempers. H: Strain hardened, used for wrought aluminum types which are non-heat treatable. O: Annealed, which results in the lowest strength of tempered aluminum that has greater workability. T: Thermally treated. These types of aluminum are heat-treated, quenched, and aged.
The second character of the tempering designation is a digit from 1-10, which helps to specify exactly how the tempering method was done. For instance, all T-series aluminum are thermally treated, but a naturally aged aluminum will have a different digit assignment than an artificially aged one. This level of detail helps to easily classify the type of aluminum and how it might best be used.
The T-series tempering designation is the most commonly used for aluminum, which can serve as an example showing the different tempering methods:
T1: Naturally aged after cooling from high temperatures during the forming process T2: Cooled after a high-temperature forming process, cold worked, then naturally aged T3: Solution heat-treated, cold worked, then naturally aged T4: Naturally aged after a solution heat treatment T5: Artificially aged after cooling from high temperatures during the forming process T6: Artificially aged after a solution heat treatment T7: Solution heat-treated, then overaged T8: Solution heat-treated, cold worked, then artificially aged T9: Solution heat-treated, artificially aged, then cold worked T10: Cooled after a high-temperature forming process, cold worked, then naturally aged
Once familiar with these designations, it’s possible to quickly identify an aluminum alloy’s composition, tempering, and processing. Rather than looking up every type and grade, the tempering designation helps a buyer narrow their search for the strongest and hardest aluminum they need for the intended application.
Given its assets of strength, corrosion resistance, and easy weldability, it’s no wonder stainless steel is so widely used across many industries. Each stainless steel family – austenitic, martensitic, ferritic, duplex, and precipitation hardening – is determined by the alloying elements in its chemical structure and the crystal structure of the steel itself. While all stainless steels share the same basic characteristics, each family has an asset making it particularly good for certain uses. For example, the low carbon found in ferritic stainless steel makes it highly malleable and excellent for welding. On the other hand, stainless steels in the martensitic family contain a high percentage of carbon, greatly increasing its tensile strength and impact resistance. Duplex steel is unique because it combines two of those families, austenitic and ferritic, to create a stainless steel with the benefits of both. Austenitic stainless steel has good corrosion and impact resistance, but the nickel used in its alloy adds to the production cost. Ferritic stainless steel is known for its ability to resist stress cracking, but the alloys used in ferritic steel’s composition make it more susceptible to corrosion. By combining these to make duplex steel, you can reap the performance benefits of both types while keeping costs down.
How is Duplex Steel Made? Duplex steel production begins like all stainless steel: the iron ore is smelted and combined with alloying elements such as nickel, molybdenum, chromium, and others. However, duplex steel’s chemical composition has a higher level of chromium than most stainless steels (typically 25% or more) and a lower percentage of nickel (less than 9%). It also contains a small amount of nitrogen, which helps improve the weldability of the finished steel. Once combined, the molten steel alloy is forged and left to cool. As the steel solidifies, the grain structure of the steel is formed into ferritic crystals; at this point, the entire product is ferritic steel. However, as it continues to cool to room temperature, more and more grains will begin to convert to austenitic steel until it becomes roughly 50-50 of each type. The reason duplex steel is so strong is due to the intermixing of these grains, much like the fat marbling on a prime steak. If the austenitic and ferritic steel were in distinct layers, that would leave one type more prone to cracking or corrosion, which risks weakening the other. In duplex steel, the interspersing of the grains means they reinforce the steel’s strength while minimizing each other’s weaknesses.
Advantages of Duplex Stainless Steel While duplex steel makes up a fairly small part of the global stainless steel market, it has some clear advantages compared to other families of stainless steel:
• Strength: Stainless steel is already a strong material on its own, but duplex steel can be 2 to 3 times stronger than austenitic or ferritic steels.
• Corrosion resistance: Duplex stainless steel has comparable or even higher levels of corrosion resistance than austenitic steels. Additionally, its high level of chromium provides more protection against crevice corrosion and pitting.
• Cost: Perhaps the greatest appeal of duplex steel is that it offers so many benefits while requiring less molybdenum and nickel, which keeps costs low. The strength and durability of duplex steel can also contribute to a longer lifetime use with less required maintenance, which helps money.
Disadvantages of Duplex Stainless Steel You might wonder, with all the benefits of duplex steel, why is it not in greater demand? There are a few disadvantages which limit its use: • Production: Due to its unique chemical composition, advanced knowledge is needed to produce this steel.
• Performance at low temperatures: Duplex steel has excellent impact resistance, except at very low temperatures. The ferrite in the duplex steel becomes brittle and prone to cracking.
• Performance at high temperatures: The structure of duplex steel can be negatively altered by very high temperatures, even with brief exposure. This includes the heat produced during welding, although the addition of nitrogen and a skilled welder can help prevent damaging the steel.
One of the best ways to ensure worker safety in industrial environments is by preventing falls. Proper footwear with non-skid soles is a must, but there will still be a risk of slipping on stairs and walkways. A textured surface in these areas will produce more friction while walking, providing better traction to prevent worker falls. One of the most common methods to improve slip resistance is the use of diamond plate in these high-traffic areas.
What is Diamond Plate? Diamond plate goes by many names, including tread plate, checker plate, and deck plate. Whatever the name, it all refers to the same thing: metal flooring with a raised diamond pattern on one side. It can be made of various types of materials from metals to plastic, but is most often produced from aluminum, hot rolled steel, and stainless steel. Because aluminum is naturally corrosion resistant, aluminum diamond plate is a favored choice for outdoor areas or other environments where the plate is in contact with water. Industrial kitchens, loading docks, and fire escapes often make use of aluminum diamond plate. The surface is able to withstand corrosion and abrasions, and can be easily cleaned. Steel has the strength advantage over aluminum, making steel diamond plate even more hard-wearing and strong. For this reason, diamond plate made from steel is often used in structural applications such as stairs and ramps. While it offers less corrosion resistance than aluminum, steel diamond plate’s sturdiness holds up well through regular use and cleaning chemicals. It is ideal for indoor location usage such as shop floors and walkways.
Production of Diamond Plate Although diamond plate may look intricate with its raised interlocking patterns, the process of making it is fairly straightforward. Using a combination of heat and pressure, metal can be made into diamond plate by stamping or hot rolling. With the stamping method, the metal (generally aluminum) can be used at room temperature. The aluminum is run through a series of large rollers, with each pair of rollers having one raised side and one smooth. As the metal passes through each roller, the massive pressure of the patterned roller embosses those shapes onto the aluminum’s surface. Once finished, the diamond pattern will be firmly stamped into the raised side while leaving the other side smooth. For steel diamond plate, hot rolling is the usual method of production. A steel slab is flash heated to just above its recrystallization point, and quickly passed through the rollers to produce the diamond pattern and desired thickness. Afterwards the steel is allowed to cool slowly, which helps prevent any major alternations to its mechanical properties. Once cooled to room temperature, the steel plate will have the raised diamond pattern on its surface.
Why Use Diamond Plate? Diamond plate is most often found in any area where extra traction is needed to help reduce slips and falls. This safety practice applies most importantly to workers, but benefits their usage of industrial vehicles as well. A warehouse loading dock surface made of diamond plate keeps workers steady on their feet, but also provides better traction for forklifts. Finally, the extra strength and durability of the metal plate allows the dock to withstand the heavy weight of forklifts without damage.
The forging of metal sheet and plate is often just the first step in its overall processing. Sawing will give you the desired size, but depending on the intended purpose of the metal, further operations will need to be done. Material removal services enable metal producers to create the exact customer specifications for components, using hole punching, drilling, and notching. Each process results in material removal, but the choice of method can depend on the metal’s thickness, the location of where the removal will take place, and other factors.
The Material Removal Process Hole Punching This shearing process involves a tool with sharp edges capable of punching through a piece of metal. Think of a cookie cutter: no matter what the shape, if the cutter is pressed quickly and firmly into the dough, you’re left with precise edges once the piece is removed. Hole punching works the same way on metal sheet and plate. Whether done using electrical, hydraulic, or pneumatic power, if sufficient force is applied, any shaped hole can be made in the metal.
Notching Much like hole punching, notching is a shearing operation using a sharp-edged tool. The difference lies in the removal’s location. While hole punching can take place anywhere on the metal, notching occurs only on its edges. Once those notching cuts are performed on the metal’s perimeter, additional bending or forming can be done.
Drilling This type of material removal uses a drill bit rather than a shearing tool. As the drill is applied to the metal, it continually removes the material until the bit pierces through. While a hand drill can be used, more often this process involves a machine known as a drill press. The operator uses the machine handles to lower the bit onto the metal, which helps enable more precise drilling.
Advantages and Disadvantages Hole Punching Hole punching is an appealing option for several reasons, but especially because of its speed. The presses used for hole punching can be incredibly quick, allowing multiple metal pieces to be processed within a short period of time.
Quick processing means a higher production volume, making this highly cost-effective. The other advantage is flexibility, since hole punching easily creates shapes other than round. Whatever the shape needed – round, square, triangular – the hole punching press can cut that into the metal. However, successful hole punching is limited to metal pieces with a thinner diameter. It is also dependent on the sharpness of the press, and punching through metal wears on the tool. If not kept sharp, a worn tool leads to punches that are incomplete or have sloppy, rough edges.
Notching Since notching is a shearing process like hole punching, they share similar pros and cons. The notching tool is fast, and while the process often involves creating vertical cuts, it can be modified to create different shapes. And like hole punching, this type of material removal is best done on thinner pieces of metal. Greater ease of cutting helps ensure the notches will be clean-edged and precise. Thicker metal can be processed, but requires greater force which is tough on the notching tool. The tool wear requires more supervision and maintenance to best help keep it sharp for notching.
Drilling Unlike hole punching and notching, which cut through the metal, drilling gradually pierces through it to remove material. While slower than a shearing method, drilling helps to prevent distortion of the metal part. The force needed for punching or notching tools can sometimes leave the metal bent around the location of the cut. Drilling is much better at keeping the surrounding area unaffected, and can be done successfully even on very thick pieces of metal. In addition, drilling is much more affordable since the necessary equipment is less expensive than the tools needed for other material removal options. However, the use of a drill bit does have its issues. This process can only create a round hole, unlike notching and punching. There is more friction involved due to drilling being a longer process, and friction produces heat which can negatively affect the metal. The friction also wears away at the drill bit, which may need replacement or sharpening to keep the hole precise.
The word “metallic”: a term synonymous with adjectives such as bright, gleaming, and reflective. However, newly-produced metal straight from the mill isn’t very shiny; in fact, it looks and feels rather rugged. Its appearance is referred to as “mill finish”, and it has a rough and irregular surface texture. The finish is dull, and its color often patchy due to metal oxidation or contamination from mill oil. While it looks unrefined, depending on its use mill finish can be acceptable. Why spend extra time and money to make unfinished metal look better when appearance is unimportant? However, the majority of consumers prefer their metal products to be smooth and shiny. Beyond the look of mill finish, other processes such as shearing can leave metal with rough or sharp edges. To improve the overall quality of the metal, polishing is often done to create a smooth and shiny surface. But when a finer degree of finishing is needed for certain applications, additional processing such as superfinishing is done.
Superfinishing Simply put, superfinishing is a level beyond the typical processing done to metal products. The metal has already gone through some type of finishing such as polishing or another surface modification process. To the naked eye, polishing leaves a gleaming surface and metallic shine, but the process can actually result in microscopic structural irregularities on its surface. These irregularities are referred to as the residual amorphous layer. Unlike the rest of the metal which retains its crystalline structure, the amorphous layer has scattered atoms creating a disordered surface. Superfinishing is necessary for situations where removal of that amorphous layer is critical to the metal component’s use.
The Superfinishing Process During a primary finishing process like polishing, a great deal of friction is needed to smooth away any pits or bumps marring the metal’s surface. On the other hand, the secondary process of superfinishing is a much more precise operation using lower friction. The best way to create lower friction is by the use of a very fine abrasive agent. The height of a superfinishing abrasive agent may only measure from 5 to 8 micrometers: too small for successful polishing, but effective in wearing away the amorphous layer. After the selection of stone or sandpaper with an extremely fine grit, the abrasive is applied on the metal’s surface while the item rotates in the opposite direction. This is done one small section at a time, both for precision and to keep friction to a minimum. Additional thermal protection is provided by using a lubricant, which helps reduce any heat produced from friction.
Advantages of Superfinishing Superfinishing is useful for both functional and aesthetic purposes: • Appearance: the metal is left with tiny crosshatch marks, creating an attractive brushed-metal finish.
• Low Tolerances: the amorphous layer removal performed during superfinishing means the metal’s measurements are much more precise. Polishing may leave metal looking shiny, but on a microscopic level, the surface is still uneven. Superfinishing ensures that the metal’s surface is uniform, because the crosshatching is the same height on every part of the component. The metal’s dimensional accuracy is improved, creating better seals and more precise assembly when the part is used in applications.
• Prolonged Use: precise assembly allows for less friction created during use, because pieces are less likely to press and slide against each other. This reduces wear on the metal, which then requires less maintenance and enables a longer period of use. Automotive parts like rods and shafts are typically superfinished to help extend the lifetime of the part.
Disadvantages of Superfinishing • Finish: depending on the consumer’s taste, a polished finish may be considered more appealing than a superfinished one.
• Cost: additional equipment is needed to perform superfinishing, adding to the metal’s overall cost.
• Time: while superfinishing is not a particularly lengthy process, the operation does add to the overall processing period for that part. This prolongs the time before a finished product can be shipped or sold.
It’s likely almost everyone has heard of rebar, and seen pieces of it sticking out of a concrete wall or pillar under construction. However, it’s probably also safe to assume most people are not familiar enough to explain exactly what rebar is. Could they describe how is rebar made, and its intended use? We’ll take a closer look at rebar to help answer these questions.
What is Rebar? Rebar, short for “reinforcement bar”, is a metal bar used to increase the tensile strength of concrete. Concrete is quite hard and has great compression strength, but it is much weaker when it comes to tensile strength. Simply put, this means concrete is prone to cracking or toppling over from its own weight when used for building. A concrete sidewalk rests on the ground, which provides enough support for concrete to stay whole and strong. But when building up for the walls of a stadium, or building across for lengths such as a freeway overpass, the concrete requires reinforcement. The insertion of rebar within the structure helps the concrete to withstand great amounts of pressure and tension. Rebar is available in several types of metals, and can even be made of fiberglass, but the most commonly used is produced out of carbon steel. This is because steel possesses thermal properties similar to concrete, which means both the structure and the rebar buried within it will react the same way to temperature changes. As the temperature rises and falls, the concrete and steel will expand or constrict together, which helps to prevent cracking.
How is Rebar Made? Steel rebar is almost always made of recycled steel, taken from the frames of cars, appliances, and machinery which are too old for continued use. These steel pieces are melted down and cast as billets, the term used for long unfinished steel bars. The billet shape allows the pieces to be easily stacked away in storage until needed. To make rebar, the billets are heated to a very high temperature just short of the steel’s melting point. The red-hot billets are then fed into extrusion machines, squeezing the steel out like toothpaste from a tube. This process is repeated with a series of smaller and smaller extrusion diameters, until it results in steel rods of the desired size. From there, tooling machinery is used to create the distinctive corkscrew ribbing found on rebar rods. These ribs help to anchor rebar within the concrete, preventing the rods from slipping or bending. The final step is shearing the rebar rods to cut them down to the desired lengths.
How is Rebar Used? Concrete is an incredibly resilient material – some ancient concrete structures such as the Roman Colosseum are still standing, thousands of years later. However, most concrete does begin to degrade as it ages and begins to form cracks. Cracks allow moisture and air to seep into the concrete, speeding the process and weakening the material’s structural integrity. If left untreated, the cracks can allow oxidation of the steel rebar, causing rust and weakening the steel. Compromised rebar can lead to serious consequences, because the steel is no longer providing the strong degree of strength and reinforcement to the structure as intended. Not only does it provide building strength, but rebar can also help to prevent cracks from forming. And if cracks do form, the placement of rebar helps experts to predict where they’re most likely to occur, and those spots can be reinforced. For best effect, rebar is often laid in a grid pattern. The carbon steel’s strength is maximized in grid formation, allowing it to reinforce the concrete despite tensile forces coming from many different directions. Ordinarily, non-heat treated carbon steel would be considered too brittle for construction use. Heat treatments such as hardening or annealing allow steel to retain much of its hardness while making it less breakable. However, this is not a concern when carbon steel is used for rebar, so the alloy can be left untreated. The steel is extremely hard and brittle, and highly vulnerable to rust, but once embedded within the concrete, these qualities are no longer liabilities. The extreme hardness of untreated carbon steel is a benefit, giving the structure added strength and stability.