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Steel fabrication involves creating steel products using various secondary metalworking processes, including cutting, bending, and joining. It also encompasses additional processes like finishing and heat treatment to enhance the metal's properties. This vital trade serves nearly every industrial sector, with steel products being crucial for construction, transportation, energy, mining, agriculture, and consumer goods manufacturing.
The steel fabrication process is carried out by skilled professionals who specialize in cutting, bending, and shaping steel. These licensed experts are highly trained and possess in-depth knowledge of steel's characteristics and properties.
To understand steel fabricating better, it is important to determine the difference between primary and secondary metal manufacturing processes. Primary manufacturing processes create simple, semi-finished metal products such as plates, sheets, tubes, and bars. These metal products are created by casting, forging, rolling, extrusion, wire drawing, and sintering. All of these processes transform raw metal ingots or billets into metal products that will be used for secondary manufacturing processes. Primary manufacturing processes are done in foundries and steel mills.
Secondary manufacturing processes, also known as fabrication, are performed by steel fabricators who transform metal products from primary processing into finished parts or structures. In these processes, a fabricator reshapes semi-finished metal products to meet specific customer specifications and requirements. Examples of fabricated steel products include steel trusses, storage tanks, automotive chassis, and metal enclosures. Fabricators operate in machine shops, "fab shops," or on-site, depending on the type of fabrication needed and customer needs.
Steel is an iron-based metal alloyed with carbon, making it one of the most commonly used metals due to its affordability and availability. While other metals like aluminum, copper, and nickel alloys are also frequently used in fabrication, steel remains the most popular choice. Despite aluminum being more abundant, the process of smelting iron requires less energy, which contributes to steel's lower cost.
One of the special steel alloys is stainless steel that has a variety of uses and can be fabricated in the same way as steel. Like steel, stainless steel has various grades each of which is ideal for use in different applications. Grades 300 and 400 are the most commonly used with grade 304 being the most popular and widely used. For high temperature exhaust applications, stainless steel grade 321 is ideal since part of its alloy is titanium, which ensures very little weld decay.
Steel is an iron-based metal alloyed with carbon, making it one of the most commonly used metals due to its affordability and availability. While other metals like aluminum, copper, and nickel alloys are also frequently used in fabrication, steel remains the most popular choice. Despite aluminum being more abundant, the process of smelting iron requires less energy, which contributes to steel's lower cost.
The space exploration industry, which once favored composite metals, is now witnessing a renewed interest in stainless steel, appreciating its unmatched durability.
These metal products are created by melting and solidifying metal ingots. Castings are formed to match the shape of the final product but often have dimensions that may be slightly out of tolerance. To achieve the final specifications, secondary processes such as machining, finishing, and heat treatment are employed.
Blooms are metal stocks with a nearly square cross-section, measuring at least 6 x 6 inches. They are produced from the initial breakdown of metal ingots.
Slabs are created by rolling metal ingots in a steel mill. These slabs typically have a rectangular cross-section and are generally 8 inches thick or more.
Billets are akin to blooms but feature a square cross-section, typically ranging from 2 x 2 inches to 5 x 5 inches. They are essentially blooms that have undergone additional processing through rolling, forging, or extrusion.
These semi-finished products are created by rolling blooms and slabs further. Plates have a thickness exceeding a quarter of an inch, while sheets and strips are thinner. Sheets are distinguished from strips by their larger width-to-thickness ratio.
These are durable metal products with square, round, or rectangular cross-sections. They are created by rolling billets into smaller dimensions, with typical cross-sections ranging from 0.5 to 2 inches.
Rods resemble bars but have a smaller cross-section, usually ranging from 0.2 to 0.5 inches. Due to their narrower dimensions, rods are more flexible and can be easily bent. They are commonly available in rolls or coils.
These metal products have irregular cross-sections and are created from blooms through a progressive rolling process. The process involves grooved rolls positioned with a gap between them. As the metal passes through this gap, it gradually takes shape.
Tubes and pipes are hollow metal products that come in square, rectangular, or round shapes. They are typically categorized into two types: welded and seamless. Welded tubes and pipes are created by rolling a metal slab or plate into a coil, then welding the coil's edge together using electric resistance welding. Seamless tubes and pipes, on the other hand, are produced by rolling a round bar and piercing it with a rotating cone, forming the tube at high temperatures close to the metal's transition temperature.
These metal products have cross-sections that are significantly reduced through a process called drawing. In this metalworking technique, a metal rod is pulled through a die to form wires. Drawing is considered a cold working process because it is performed at room temperature.
Before starting the actual fabrication processes, it's crucial to understand the preliminary steps. This includes conceptualizing and planning the design and features of the final product. Proper preparation of the workpiece is essential to avoid errors and minimize material wastage.
Design and drafting are the initial stages of the fabrication process, encompassing:
In the past, design and drafting were performed manually, resulting in hand-drafted engineering drawings and manual calculations. Today, most design work is done using computer software. Programs like AutoCAD, SolidWorks, and Tekla Structures handle both design and drafting, allowing for advanced calculations and modeling. This technology enables faster design iterations and streamlines the entire process.
Sub-finished metal products usually come with a protective coating to prevent corrosion. However, this protection may not be entirely effective, and some rusting might still occur. Additionally, handling, transfer, and storage can lead to debris accumulation on the surface. It's crucial to remove coatings, scales, oils, old paint, rust, dirt, or any other contaminants that could interfere with fabrication processes and impact the quality of the final product.
Common methods for preparing workpieces include pneumatic blasting, waterjet cleaning, mild pickling, scraping, and brushing.
Marking involves transferring measurements from the design onto the workpiece, often as part of the preparation phase. This process includes scribing edges, fold lines, and hole centers onto the surface of the workpiece, ensuring these marks remain visible throughout fabrication. Common marking tools include metal scribers, pencils, chalks, dividers, and punches. In addition to measuring devices, tools such as rulers, center squares, and T-squares assist with accurate marking.
Cutting is a crucial step in metal fabrication. This process involves removing or separating excess material from the primary workpiece or product. The removed material, which includes metal chips and scraps, is collected and recycled.
Cutting can also be performed with a scrap-less approach, where no material is wasted and is instead used for recycling. This technique is often applied in sheet metal cutting. To maximize material efficiency, metal from both sides of the cut is utilized, resulting in the production of a new part with each cut.
Cutting techniques can be categorized into four main types: shear cutting, wedge-action cutting, abrasion, and non-traditional methods.
Shear cutting, also known as shearing, involves using two moving cutting tools to make a cut. The process works by sliding these tools past each other with the material positioned between them. As the tools press against the material, the stress applied overcomes its shear resistance, initiating a crack or tear. This crack then extends through the material, creating a cutting line that divides it into two separate pieces.
Shearing is further categorized into several distinct cutting processes, as listed below.
Blanking is a shearing process carried out using a punch and die. In this process, the cutting line is a closed-loop that shapes a distinct region. The resulting cut-out is the workpiece, which is the inner part of the metal stock, while the surrounding material is discarded as scrap. Blanking is commonly used with sheet or strip metal.
Piercing is similar to blanking in that both processes involve a cutting line that fully encloses an area. The key difference is that in piercing, the cutting line outlines the edges of internal features within the workpiece, while the scrap generated is the central portion of the metal stock.
This is a unique blanking process where the metal stock is securely clamped during punching, resulting in a clean cut with minimal burrs.
This method involves shearing with a cutting line that does not close upon itself. Parting separates a metal stock into two distinct pieces.
This shearing process involves cutting the metal stock without fully separating it, allowing one side or section to be bent or shaped.
Another open-ended cutting technique employed to form features (such as notches) along the edges of metal stock.
Trimming is a shearing process that involves removing excess material from the edge of a stock to achieve the final dimensions of the workpiece.
This cutting process involves using a tool with a sharp tip or edge to remove material from stock. The tool partially penetrates the material and moves along the cutting line, gradually removing material until the final dimensions of the workpiece are achieved. The metal stock used in these processes typically includes solid blocks like bars, rods, and slabs.
Wedge-action cutting can be categorized into several distinct types, as outlined below.
This process involves rotating the stock while a cutting tool moves laterally across its outer surfaces, shaping the external features of the workpiece. As the stock spins, the cutting tool makes slight, controlled cuts. This turning operation is commonly performed on a lathe machine.
This process is similar to turning, but instead of the cutting tool moving around the outer surface, it moves along the inside surfaces of the metal stock. Boring, usually performed after drilling, is used to create larger holes with precise dimensional accuracy.
Drilling is a process used to create holes in solid materials by using a tool with multiple cutting edges that rotate against the material. It is frequently combined with other machining techniques, including boring, trepanning, reaming, and countersinking, to achieve precise results.
Trepanning is a process where a circular groove is cut into the surface of round stock. This can be achieved by either rotating the stock or revolving the cutting tool. Trepanning is commonly used to create large circular holes and round disks.
This is similar to a boring operation, but the cut is shallower. It enhances the dimensional accuracy of the bored hole.
This process enlarges drilled holes to fit the heads of fasteners like bolts and screws.
This process involves removing material with a rotating cutting tool that has multiple cutting edges. Milling processes are primarily categorized into two types: face milling and peripheral milling. In face milling, the cutting edges are arranged on one side of the cutter, while in peripheral milling, they are positioned radially around the circular edge of the cutter. Milling is versatile and can create various types of cuts, performing tasks comparable to other machining processes.
Planing is a machining process that removes excess material by moving a cutting tool back and forth against a stationary workpiece. This method is commonly used to flatten surfaces or create straight contours on large pieces.
Sawing is a cutting technique that involves partially or entirely slicing through solid materials using tools that reciprocate or rotate, such as power band saws, hack saws, and circular saws.
This process involves using materials with high hardness and rough surfaces to scratch, erode, rub, or wear down the surface of a workpiece. During fabrication, abrasion is carefully controlled to gradually remove excess material. Below are the different types of abrasion processes.
Grinding involves applying an abrasive material to the workpiece surface with a force perpendicular to the contact area. Relative motion, either parallel or tangential (for circular grinding tools), occurs between the two surfaces.
Honing is a precision process that involves low-speed abrasion, typically applied to cylindrical surfaces. It employs both rotating and reciprocating motions to produce a crosshatch pattern. The primary goal of honing is to achieve high dimensional accuracy and a smooth, refined finish.
Lapping is similar to honing but typically involves lower speeds and pressures. It produces components with a superior surface finish and precise dimensions. In lapping, a workpiece is paired with a tool known as a lap or another workpiece, with the rubbing surfaces separated by a layer of abrasive mixture.
These methods of cutting are unconventional as they don't rely on mechanical action to remove material. Instead, they utilize electrical, electromagnetic, chemical, thermal, acoustic, or specialized mechanical phenomena to achieve metal cutting. They are often favored over traditional techniques due to their precision and the ability to produce burr-free cuts. Examples of these methods are listed below.
This technique employs high-speed water jets to slice through various materials. A specialized form, called abrasive jet cutting, combines water with abrasive substances to cut through tougher materials like metals. Waterjet cutting works by gradually eroding the material's surface along the designated cutting line.
Laser cutting is a technique that uses a highly focused beam of light, known as a laser, to precisely cut through various materials.
This process eliminates material by electrolytically dissolving the unwanted sections. ECM is commonly employed for machining hard metals like titanium, Inconel, and other high-strength alloys.
Bending is a fabrication technique that shapes metal by applying pressure to it while it is supported at two or more points. This process deforms the metal stock into its final shape based on the profile of the press or punch and the arrangement of the supports or dies. It is widely used to shape metal sheets, plates, strips, rods, and bars.
The bending process produces angle bars, channels, V-shaped and U-shaped bars, profiled sheets, and rounded plates.
Bending processes can be categorized based on how the bending load is applied, as outlined below.
Air bending, also known as free bending, is a widely used method in metal fabrication. In this process, the workpiece is supported at two points by a die, while a punch applies pressure from above. The underside of the workpiece remains unsupported, allowing it to bend freely without touching the die. This technique creates three points of contact. The position and movement of the punch are adjusted based on the desired shape of the part's cross-section.
In bottom bending, the workpiece is supported at two points, much like in air bending. However, in bottom bending, the workpiece is pressed fully until its bottom side makes contact with the die. The final bend radius is determined by the punch tip radius and the degree of spring back. This method is commonly used to create V-shaped cross-sections.
Coining is a process that involves pressing the workpiece firmly against the die with enough force to cause the metal to flow. This method requires higher forces compared to air and bottom bending because it fully deforms the material in contact. The final cross-section is determined by the shape of the punch and die. Coining is known for its precision and repeatability, as it effectively eliminates springback.
Roll bending involves passing metal stock through a set of three rolls. Typically, this setup includes two stationary lower rolls and a movable upper roll. The movement of the upper roll bends the metal, creating a radius that is determined by the radii of the rolls and the distances between them.
At this stage of metal fabrication, all the cut and shaped components are combined and integrated to create a larger structure. Initially, the parts are assembled piece by piece to visualize the overall structure. This preliminary assembly is performed using temporary joints, like tack welds or bolted connections, to ensure each part fits correctly with the others. This step is crucial for verifying that all components align properly before final assembly.
After the metal components are accurately aligned and positioned, permanent joints are formed. Permanent joints include techniques such as final or full welds and adhesive-bonded surfaces. Among metal fabrications, welding is the most frequently used joining method, with bolting, screwing, and riveting being common alternatives. These joining processes are described below.
Welding is a fabrication technique used to join metals by heating and melting them. The process involves melting the metal joints along with a filler metal to create a weld pool. This molten metal is then allowed to cool and solidify, forming a strong, durable joint. Welding methods vary based on how heat is applied, the type of shielding used, and the thickness of the materials being welded. Common welding processes include shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW/TIG), gas metal arc welding (GMAW/MIG), and electroslag welding (ESW).
Soldering and brazing are joining techniques that involve melting a filler metal to bond parts together. Unlike welding, these methods do not melt the base metals of the workpieces. Fundamentally, soldering and brazing operate on the same principle, but brazing employs filler metals that melt at higher temperatures. Typically, brazing uses brass as a filler, while soldering utilizes tin-lead alloys and silver alloys.
Bolting and screwing create joints with threaded machine elements, resulting in semi-permanent connections that can be disassembled without damaging the components. These processes involve making holes for inserting the fasteners and require access to one or both sides of the joint. Regular inspection of bolts and screws is essential, as vibrations can cause them to loosen over time.
This is another type of semi-permanent joint commonly used for joining sheet metals. Similar to bolting and screwing, it does not result in permanent deformation or damage to the workpiece.
Steel fabricators enhance steel products by refining and altering both their external and inherent characteristics. The specific fabrication processes used vary based on the product’s original design and its intended use. Here are some common fabrication techniques:
Heat treatment is a secondary process that alters the microstructure of metal parts. It can enhance a material's ductility, strength, and hardness, and also alleviate residual stresses from initial manufacturing and welding processes.
Coating refers to the process of applying a layer of material to a part's surface. This material is usually a curable polymer and can be in either powder or liquid form. Common coating methods include powder coating and painting. The application of a coating enhances the surface's quality, durability, appearance, texture, and chemical resistance.
This process entails applying a layer of zinc to a metal surface to protect it from rust. The most prevalent method is hot-dip galvanizing, where the metal is immersed in a bath of molten zinc.
This process enhances the thickness of the oxide layer on a metal's surface by passing an electric current through the material while it is immersed in an electrolyte bath. It is commonly used for aluminum components.
Deburring improves the final product quality by eliminating raised edges and unwanted material, called burrs, left over from the initial machining processes. Burrs are formed during operations such as shearing, bending, cutting, piercing, and compressing metals.
In the United States and Canada, a range of machines are utilized for steel fabrication. These machines play a crucial role in modern industry, facilitating the efficient and accurate production of steel components essential for construction, infrastructure, manufacturing, and transportation. Their impact extends to fostering economic growth and technological progress. Below, we explore several of these key machines.
The HSFDB-C is a cutting-edge CNC plate processing system designed for drilling, cutting, and thermal treatment of steel plates. It boasts high-speed drilling with multiple tool heads, which minimizes processing time and boosts productivity. Constructed with a durable steel frame and precise linear guides, the machine ensures stability and accuracy during operations. It also includes an intuitive control interface and advanced software for efficient part programming and nesting.
The MetalMaster Xcel is a highly adaptable CNC plasma cutting system renowned for its precision and superior cut quality. Capable of handling various steel plate thicknesses, it is ideal for diverse steel fabrication needs. The system features automatic torch height control to ensure the perfect cutting distance from the workpiece. With Messer's Global Control Plus software, programming is straightforward, and material use is optimized. Built with durability in mind, the Messer MetalMaster Xcel withstands even the most demanding operating environments.
The TruLaser series features a variety of CNC laser cutting machines crafted for precise and efficient steel cutting. Leveraging advanced fiber laser technology, these machines deliver high cutting speeds with reduced energy consumption. Equipped with Trumpf's TruTops software, they offer robust programming and nesting tools to optimize material use and minimize waste. TruLaser machines handle various steel thicknesses, include automatic nozzle changing and piercing detection, and are celebrated for their reliability and ease of maintenance.
Accurpress produces a range of hydraulic press brakes popular in steel fabrication shops for their precision and repeatability in bending steel plates and sheets. These press brakes feature advanced CNC controls for straightforward programming and accurate control of bending parameters. Built with a robust frame and high-quality components, Accurpress press brakes are designed for durability and stability. They are available in various bending lengths and tonnage capacities to meet diverse fabrication requirements.
Although not solely focused on steel fabrication, Haas VF Series CNC machining centers are extensively utilized for precise milling and drilling of steel components in the metalworking industry. These vertical machining centers provide high spindle speeds and rapid traverse rates for efficient metal removal. Renowned for their reliability and ease of use, Haas machines are favored in numerous fabrication shops. Equipped with Haas' intuitive CNC control and user-friendly software, these vertical machining centers facilitate straightforward programming and operation. Additionally, their robust construction and precise ball screws enhance overall accuracy and stability.
Keep in mind that the popularity of each machine may vary based on specific fabrication needs and company preferences. Before making a purchase, it's crucial to conduct thorough research and consult with manufacturers or industry experts to identify the most appropriate machine for your particular application.
When discussing steel, it's common for people to use the term "metal" interchangeably, as many assume steel and metal are the same. While some metals may resemble steel and share similar characteristics, they are distinct. Steel stands apart with unique properties and attributes that set it apart from other metals.
A metal is composed of various elements found naturally in the Earth's crust. Common examples include titanium, copper, and nickel. Unlike steel, which requires blending with other elements to form an alloy, metals can be extracted and used in their natural state. Steel, on the other hand, is an alloy made from iron ore, a naturally occurring metal that is essential for its creation and one of the most abundant metals in the Earth's crust.
Alloying steel enhances its strength and resilience compared to naturally occurring metals. While natural metals, which are often used for jewelry, decorations, and surgical implants due to their malleability, are relatively soft, processed steel demands extensive tooling and labor to shape.
Steel production involves purifying iron ore by eliminating impurities like silica, phosphorus, and sulfur. After purification, carbon is added to the ore to improve the steel's durability, strength, and machinability.
Metal fabrication is a process that uses flat metal sheets that are formed and shaped. The sheets are about a quarter inch thick or less, which makes them pliable enough to be shaped and configured. Much like steel fabrication, the sheets of metal are subjected to cutting, stamping, folding, welding, and other processes to reach the necessary shape.
To enhance the strength and resilience of metals, various processes can be employed. These might include plating, expanding, wiring, and incorporating different hardware, fittings, and castings. The choice of method depends on the intended application of the final product. Often, fabrication shops start with multiple types of metals and combine them into a single piece.
While metals are generally more pliable and adaptable than steel, they are fabricated using similar methods. Unlike steel, which demands intense and forceful operations for shaping, metals can be molded with the same techniques but with less intensity.
Precision sheet metal fabrication is a common manufacturing process where the structure of a metal workpiece is cut, bent, and assembled by machining. There are any number of operations that are performed in the creation of a finished sheet metal product...
Sheet metal fabrication is metal that has been formed into thin and flat sheets which is then cut and bent into various shapes. Different metals, brass, steel, copper, tin, titanium, aluminium, etc., can be made into sheet metal...
Stainless steel can be fabricated using any of the traditional forming and shaping methods. Austenitic stainless steel can be rolled, spun, deep drawn, cold forged, hot forged, or stippled using force and stress...
Laser cutting is a non-traditional machining method that uses an intensely focused, coherent stream of light called lasers to cut through the material. This is a type of subtractive machining process where the material is continuously removed during the cutting process...
Water jet cutting is a manufacturing process that uses high pressure jets of water provided by pressurizing pumps that deliver a supersonic stream of water to cut and shape various types of materials. The water in water jet cutting is...