Use of sheet steel: applications and parameters

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sheets stainless steel cover Chrysler building Microscopic close-up of mild steel sheet metal

Sheet metal

is a metal formed by an industrial process into thin, flat pieces. Sheet metal is one of the basic shapes used in metalworking and can be cut and bent into a variety of shapes. Countless household items are made from sheet metal. Thickness can vary significantly; very thin sheets are considered foil or sheet, and pieces thicker than 6 mm (0.25 in) are considered sheet steel or "structural steel".

Sheet metal is available in flat pieces or rolled strips. Coils are formed by passing a continuous sheet of metal through a slitter.

In most countries around the world, sheet metal thickness is always specified in millimeters. In the United States, the thickness of sheet metal is usually determined by a traditional nonlinear measure known as its thickness. to measure. The higher the caliber number, the thinner the metal. Typically, steel sheet is used with a thickness of 30 to 7 gauge. The gauge varies between ferrous metals (iron-based) metals and non-ferrous metals such as aluminum or copper. The thickness of copper, for example, is measured in ounces, which corresponds to the weight of copper contained in an area of ​​one square foot. Parts made from sheet metal must be of uniform thickness to achieve ideal results.[1]

There are many different metals that sheet metal can be made from, such as: aluminum, brass, copper, steel, tin, nickel, and titanium. Some important sheet metals for decorative use include silver, gold, and platinum (platinum sheet metal is also used as a catalyst).

Sheet metal is used in car and truck bodies, airplane fuselages and wings, medical tables, building roofs (architecture), and many other applications. Sheet metal of iron and other high magnetic permeability materials, also known as laminated steel cores, has applications in transformers and electrical machines. Historically, sheet metal was used in the plate armor worn by cavalry, and sheet metal still has many decorative uses, including in horse armor. Sheet metal workers are also known as "tin hammers" (or "tin hammers"), a name derived from the rattling sound of panel seams when installing tin roofs.[2]

Content

• 1. History
• 2 Materials 2.1 Stainless steel
• 2.2 Aluminum
• 2.3 Brass

Story

Hand-forged metal sheets have been used for architectural purposes since ancient times. Water-powered rolling mills replaced the manual process in the late 17th century. The process of flattening metal sheets required large rotating iron cylinders that pressed the metal parts into sheets. Suitable metals for this were lead, copper, zinc, iron and then steel. Tin was often used to coat iron and steel sheets to prevent them from rusting.[3] This tin-coated sheet metal was called “tin.” “Sheet metal originated in the United States in the 1870s when it was used for shingle roofing, stamped decorative ceilings and exterior sidings. Sheet metal ceilings were only commonly known as "tin ceilings" later, as manufacturers of the period did not use the term. The popularity of both tiles and ceilings stimulated widespread production. With the further development of steel sheet metal manufacturing in the 1890s, the promise of being cheap, strong, easy to install, lightweight, and fire resistant generated significant interest in sheet metal products among the middle class. It was not until the 1930s and World War II that metals became scarce and the sheet metal industry began to collapse.[4] However, some American companies, such as WF Norman Corporation, were able to stay in business producing other products while Historic Preservation projects contributed to the revival of decorative sheet metal.

Where else is sheet steel used?

Sheet metal has many different uses in interior and exterior design. It is capable of soundproofing and optimizing air, so it is excellent for ceilings and also for dividing spaces. In addition, elements such as tables, shelves, partitions, railings, drawers, containers, etc. are made from sheet steel. The small thickness of the product makes it possible to bend it, creating a variety of bent or profile products.

Thick sheets are used to create metal frames, in the construction of welded structures, and in the manufacture of various parts.

Materials

Stainless steel

A score of 304 is the most common of the three scores. It provides good corrosion resistance while maintaining formability and weldability. Available ends are No. 2B, No. 3 and No. 4. Grade 303 is not available in sheet form.[5]

Grade 316 has greater corrosion resistance and elevated temperature strength than 304. It is commonly used for pumps, valves, chemical equipment and marine equipment. Available finishes: #2B, #3 and #4.[5]

Grade 410 is a heat-treated stainless steel, but it has lower corrosion resistance than other grades. Commonly used in cutlery. The only finish available is matte.[5]

Grade 430 is a popular and inexpensive alternative to the 300 series alloys. It is used when high corrosion resistance is not a primary criterion. A common grade for household appliances, often with a matte finish.

Aluminum

Aluminum, or aluminum in British English, is also a popular metal used in sheet metal due to its flexibility, wide range of capabilities, cost-effectiveness and other properties.[6] The four most common grades of aluminum available as sheet metal are 1100-H14, 3003-H14, 5052-H32, and 6061-T6.[5][7]

Grade 1100-H14 is a technically pure aluminum with high chemical and weather resistance. It is plastic enough for a deep pattern to be welded, but has low strength. It is commonly used in chemical processing equipment, light reflectors, and jewelry.[5]

Grade 3003-H14 is stronger than 1100 while maintaining the same formability and low cost. It is corrosion resistant and weldable. Often used in stamping, curled and painted parts of mailboxes, cabinets, tanks, and blade fan.[5]

Grade 5052-H32 is much stronger than 3003, but still maintains good formability. It maintains high corrosion resistance and weldability. Common applications include electronic chassis, tanks, and pressure vessels.[5]

Rating 6061-T6 is a conventional heat treated structural aluminum alloy. It is weldable, corrosion resistant and stronger than 5052, but not as ductile. When welded, it loses some of its strength.[5] Used in modern aircraft designs.[8]

Brass

Brass is an alloy of copper that is widely used as sheet metal. Compared to copper, it has greater strength, corrosion resistance and formability while maintaining its conductivity.

In sheet hydroforming, changing the properties of the incoming sheet roll is a common problem in the forming process, especially with automotive materials. Although the incoming sheet coil may meet tensile test requirements, production often experiences high scrap rates due to the inconsistent behavior of the material. Thus, there is a strong need for a discriminating method to test the formability of incoming sheet material. The hydraulic sheet bulge test simulates the biaxial deformation conditions commonly found in manufacturing operations.

For forming extreme curves in aluminium, mild steel and brass. The theoretical analysis is performed by deriving the governing equations to determine the equivalent stress and equivalent strain based on spherical swelling and Cod's yield criterion with the corresponding flow rule. For experiments, circular grid analysis is used.[9]

Main characteristics of hot-rolled sheets

The popularity of hot-rolled steel coils is explained by their excellent properties, namely:

• large production volumes and availability in warehouses;
• high weldability rates;
• good anti-corrosion properties;
• resistance to temperature changes;
• uniform surface;
• wide application in all industries;
• low cost and availability;
• resistance to mechanical damage, impact resistance.

This is interesting: Electric welded pipe - characteristics and scope of application

To measure

Many international standards organizations do not recommend the use of gauge numbers to indicate sheet metal thickness. For example, ASTM states in ASTM Specification A480-10a: “The use of calibration number is not recommended because it is an archaic term of limited usefulness with no general agreement on meaning.”[10]

Manufacturers' standard gauge for sheet steel is based on an average density of 41.82 pounds per square foot per inch of thickness.[11] equivalent to 501.84 lb/cu ft (8,038.7 kg/m3). Gauge is defined differently for ferrous (iron-based) and non-ferrous metals (such as aluminum and brass).

The gauge thickness given in Column 2 (decimal inch (mm) for sheet and plate iron in the US) seems somewhat arbitrary.
The sequence of thicknesses is clearly visible in column 3 (U.S. standard for sheet and plate iron and steel 64 in. (delta)). The thickness changes first by 1/32 inch as the thickness increases, and then gradually decreases to 1/64 inch, then 1/128 inch, with a final decimal increment of 1/64 inch. Standard sheet metal thicknesses[12]

Tolerances

During rolling, slightly handle the bend of the rollers, causing the sheets to become thinner at the edges.[5]
Tolerances in the table and appendices reflect current manufacturing practices and commercial standards and are not representative of a manufacturer's standard gauge, which does not have tolerances. Tolerances of steel sheet metal[5][16]

Tolerances for sheet aluminum[5]

Tolerances for stainless steel sheet metal[5]

Types of sheet metal

There are two types of rolled products: hot-rolled and cold-rolled.

• thin - no more than 4 mm, presented in the form of a roll, processed by etching;
• thick - sheet thickness varies from 4 to 160 mm;
• low-alloy - made from low-alloy alloys, characterized by low cost; used in construction and industry;
• structural - made of alloyed carbon alloys, used in mechanical engineering.

Hot-rolled sheets are suitable for metal structures installed outdoors. Barbecues and safes are made from it.

Advantages of hot rolled steel:

• high surface quality;
• simple processing;
• resistance to temperature conditions.

Cold rolled sheets are a type of product that is produced by rolling from ductile steel alloys. Products are obtained in different thicknesses from 0.35 to 5 mm. Rolled sheets for welding metal structures have high accuracy. The product produced by the cold-rolled method can be used for roofing, as well as for the production of corrugated sheets and perforated sheets.

Advantages of cold rolled steel:

• does not require additional processing;
• resistance to thermal deformation;
• excellent quality top layer.

Separately, corrugated sheet metal, galvanized sheet metal and corrugated sheet metal are distinguished.

Corrugated sheets are rolled metal that has a surface deformed in a special way. It is made in the form of diamonds or lentils. Sheets can have single- or double-sided embossing. Carbon steel alloys are used in the production of rolled products. Corrugated sheets are produced in the form of rolls. They are actively used in laying flooring to increase friction force. Also suitable as cladding and ventilation panels.

Galvanized sheets are rolled metal obtained by galvanizing. The products are of high quality and are manufactured using the cold-rolled method. According to the standard, the thickness of the product varies from 0.5 to 2.5 mm, width - from 710 to 1800 mm. Galvanized sheets are in demand in the construction industry: they are used during the installation of roofing and cladding of buildings. In addition, rolled sheets are used in medicine and the food industry.

Advantages of galvanized sheets:

• strength;
• long service life;
• easy installation.

Corrugated sheets are rolled metal in the shape of a wave. They are produced by cold-rolling and galvanizing. Corrugated sheets are used for:

• installation of roofs for industrial enterprises;
• construction of fences;
• wall cladding;
• creating roofing decking;
• as a component of sandwich panels.

Molding processes

Bending

Main article: Bending

Equation for estimating maximum bending force:

F Maximum = k T L t 2 W { displaystyle F_{ text{max)) = k { frac {TLt^{2)){W))} ,

where k

— coefficient that takes into account several parameters, including friction.
T
is the tensile strength of the metal.
L
and
t
are the length and thickness of the sheet metal, respectively.
The variable W
is the open width of the V-die or grinding die.

Curly

Main article: Curly

The curling process is used to shape the edge of the ring. This process is used to remove sharp edges. This also increases the moment of inertia near the bent end. The flare/burr should be turned away from the die. Used for curling material of a certain thickness. Tool steel is commonly used due to wear and tear during use.

Dismemberment

Main article: Dismemberment

It is a metalworking process to remove bending, horizontal bending of strip material. This can be done for a finite length section or coils. This is similar to the flattening process of straightening, but on a warped edge.

Deep drawing

Main article: Deep drawing

Deep drawing example

Drawing is a forming process in which metal is stretched into shape or die.[17] In deep drawing, the depth of the part being produced exceeds half its diameter. Deep drawing is used to make automobile fuel tanks, two-piece kitchen sinks. aluminum cans, etc. Deep drawing is usually done in several steps called drawing cuts. The greater the depth, the more reductions are required. Deep drawing can also be achieved with less reduction by heating the workpiece, for example in sink production.

In many cases, the material is rolled in both directions on the mill to facilitate deep drawing. This results in a more uniform grain structure that limits tearing and is referred to as a "draw quality" material.

Extension

Main article: Expanded metal

Expansion is the process of cutting or stamping slots in an alternating pattern, much like fastening a stretcher into brickwork and then stretching the sheet like an accordion. It is used in applications where air and water flow is required and where light weight due to a hard, flat surface is required. A similar process is used in other materials such as paper to create inexpensive packaging paper with better support properties than just flat paper.

Hemming and Stitching

Main article: Hemming and stitching

Main article: Automotive binder

Hemming is the process of folding the edge of sheet metal back onto itself to reinforce that edge. Stitching is the process of folding two sheets of metal together to form a joint.

Hydroforming

Main article: Hydroforming

Hydroforming is a process similar to deep drawing in which the part is formed by stretching a blank over a stationary die. The required force is generated by directly applying extremely high hydrostatic pressure to the workpiece or cylinder that is in contact with the workpiece, rather than to the moving die portion of a mechanical or hydraulic press. Unlike deep drawing, hydroforming typically does not require draw reduction—the part is formed in one step.

Incremental Sheet Forming

Main article: Incremental sheet forming

Incremental sheet forming or ISF forming process is basically sheet metal processing or sheet metal forming process. In this case, the sheet is given its final shape through a series of processes, in each of which small incremental deformations can be performed.

Ironing

Main article: Ironing

Ironing is the process of working or shaping sheet metal. It uniformly thins the workpiece in a specific area. This is a very rewarding process. It is used to produce parts with uniform wall thickness and high height-to-diameter ratio. It is used to make aluminum beverage cans.

Laser cutting

Main article: Laser cutting

Sheet metal can be cut in a variety of ways, using hand tools called tin snips all the way up to very large power shears. With the advancement of technology, sheet metal cutting has evolved into computers for precision cutting. Many sheet metal cutting operations rely on computer numerical control (CNC) laser cutting or a multi-tool CNC punch press.

A CNC laser involves moving a lens assembly that carries a beam of laser light across the metal surface. Oxygen, nitrogen or air is supplied through the same nozzle from which the laser beam emerges. The metal is heated and fired by a laser beam, cutting the metal sheet.[18] The edge can be mirror smooth, with an accuracy of approximately 0.1 mm (0.0039 inch). Cutting speeds up to 25 m (82 ft) per minute for thin 1.2 mm (0.047 in) sheets. Most laser cutting systems use a CO2-based laser source with a wavelength of about 10µm; Some more modern systems use a YAG laser with a wavelength of about 1 µm.

Photochemical processing

Main article: Photochemical processing

Photochemical machining, also known as photoetching, is a tightly controlled corrosion process used to produce complex metal parts from sheet metal with very fine detail. The photoetching process involves applying a photosensitive polymer to a raw metal sheet. Using CAD-designed photo tools as stencils, the metal is exposed to ultraviolet light to leave a design pattern that is developed and etched from the metal sheet.

Perforation

Main article: Perforation

Punching is a cutting process in which several small holes are punched close together in a flat workpiece. Perforated sheet metal is used to make a wide variety of surface cutting tools such as cutters.

Press brake

Metal Forming on a Press Brake
This form of bending is used to produce long, thin sheet metal parts. The machine that bends metal is called Press the Brake. At the bottom of the press there is a V-shaped groove called a die. At the top of the press is a punch that presses the sheet metal into a V-shaped die, causing it to bend.[19] Several techniques are used, but the most common modern method is air bending. Here the die is at a sharper angle than the required bend (usually 85 degrees for a 90 degree bend) and the upper tool is precisely controlled during its stroke to push the metal down the required amount to bend it 90 degrees. Typically a general purpose machine has an available bending force of about 25 tons per meter of length. The width of the bottom die opening is usually 8-10 times the thickness of the metal being bent (for example, 5mm material can be bent in a 40mm die). The internal radius of the bend formed in the metal is determined not by the radius of the upper tool, but by the width of the lower die. Typically the inside radius is 1/6 of the width V used in the forming process.

The press usually has some kind of back stop to set the depth of the bend along the workpiece. The back gauge can be computer controlled, allowing the operator to make a series of bends on the part with a high degree of precision. Simple machines control only the backstop; more advanced machines control the position and angle of the stop, its height and the position of two control pins used to determine the location of the material. The machine can also record the exact position and pressure required for each bending operation so that the operator can achieve a perfect 90-degree bend when performing various operations on the part.

Stamping

Main article: Stamping

Punching is carried out by placing a sheet of metal blank between a punch and a die installed in the press. The punch and die are made of hardened steel and have the same shape. The punch is designed to fit very tightly into the die. The press pushes the punch toward and into the die with enough force to cut a hole in the workpiece. In some cases, the punch and die "nest" together, creating an indentation in the stock. In a progressive die, a roll of material is fed into a long multi-stage die/punch. In one step you can get several holes of a simple shape, and in several steps you can get complex holes. At the final stage, the part is released from the “web”.

Typical CNC Turret Punch Up to 60 tools can be selected in the "turret" and can be rotated to bring any tool into the punching position. A simple shape (such as a square, circle or hexagon) is cut directly from the sheet. Complex shapes can be cut by making many square or rounded cuts around the perimeter. The punch is less flexible than a laser for cutting complex shapes, but faster for repeating shapes (such as an air conditioner grille). The CNC punch can produce 600 strokes per minute.

A typical component (such as the side of a computer case) can be precisely cut from a blank sheet of paper in less than 15 seconds using any CNC press or laser machine.

Roll Forming

Main article: Roll forming

A continuous bending operation for the production of open profiles or welded pipes of long lengths or in large quantities.

Rolling

Roll bending of sheet metal
Main article: Rolling

Rolling is metal working or forming of metals. In this method, the workpiece is passed through one or more pairs of rollers to reduce the thickness. It is used to ensure uniform thickness. Classified by rolling temperature:[20]

1. Hot rolling: at this temperature is higher than the recrystallization temperature.

2. Cold rolling: This temperature is below the recrystallization temperature.

3. Warm rolling: This temperature is intermediate between hot and cold rolling.

Spinning

Main article: Metal spinning

Spinning is used to make tubular (axisymmetric) parts by fixing a piece of sheet stock in a rotating mold (mandrel). Rollers or rigid tools press the stock against the mold, stretching it until the stock conforms to the shape of the mold. Spinning is used to make rocket engine casings, rocket nose cones, satellite dishes and metal kitchen funnels.

Stamping

Main article: Stamping

Stamping includes many operations such as punching, punching, embossing, bending, flanging and embossing; simple or complex shapes can be formed with high productivity; Tooling and equipment costs may be high, but labor costs are low.

Alternatively, the related repoussé and chase methods have low tool and equipment costs but high labor costs.

Waterjet cutting

Main article: Waterjet cutting

A water jet cutter, also known as a water jet cutter, is a tool capable of controlled erosion of metal or other materials using a high speed and pressure jet of water or a mixture of water and an abrasive.

Wheeling

Main article: Wheeling

The process of using the English wheel is called wheeling. It is basically the process of working or stamping metal. The English wheel is used by the craftsman to create complex curves from a flat metal sheet of aluminum or steel. It is expensive as it requires highly skilled labor. It can produce different panels with the same method. A stamping press is used to produce large quantities of products.[21]

Options

The main characteristics of sheet steel include:

• Steel grade;
• Sheet thickness;
• Length Width;
• Precision manufacturing;
• Uniformity of structure;
• Character of the edge.

Cold-rolled sheets are manufactured according to the GOST 19904-90 standard, hot-rolled - GOST 19903–74 and 19903–2015, galvanized - GOST 14918-80, corrugated - GOST 8568-77, expanded metal - 8706-78. Dimensions, thickness, manufacturing accuracy, edge character and maximum deviations are regulated by these standards.

Recommendations

1. "Design Guide: Sheet Metal Fabrication" (PDF). xometry.com
   .
2. Green, Archie (1993). Hesitators, Pile Butts, and Other Heroes: Studies in Labor
   . Urbana ua.: Univ. Illinois Press. paragraph 20. ISBN 9780252019630. Archived from the original on July 14, 2015. Retrieved July 14, 2015.
3. Simpson, Pamela H. (1999). Cheap, fast and easy: imitation architectural materials, 1870-1930.
   . Knoxville: University of Tennessee Press. paragraph 31. ISBN 978-1-62190-157-0.
4. Staveteig, Kaaren R. "Historic Decorative Metal Ceilings and Walls: Use, Repair, Replacement" (PDF). CONSERVATION
   (49): 1–3. Retrieved March 20, 2022.
5. ^ a b c d f g gram h i j k l
   “Sheet metal”. precisionsheetmetal.com. Archived from the original on June 15, 2009.
6. "Sustainability of Aluminum in Buildings" (PDF). European Aluminum Association. Retrieved June 20, 2013.
7. "Catalogue of the Central Metallurgical Sheet Metal Thickness Gauge". University of North Carolina at Chapel Hill. Archived from the original July 19, 2013. Retrieved June 21, 2013.
8. ^ a b
   Oberg, paragraph 387.
9. ^ a b
   15 USC § 206:
   Standard gauge for sheet and plate iron and steel
10. ^ a b
    Oberg, item 2502.
11. "ASTM-AISI Thickness Tolerance Ranges" (PDF). CoyoteSteel.com. Archived (PDF) from the original August 5, 2012. Retrieved June 20, 2013.
12. Parker, pp. 20, 85
13. Thomas, Daniel J. (August 2011). “The Impact of Laser and Plasma Cutting Process Parameters on the Advanced Performance and Durability of Yellow Goods Vehicles.” Journal of Manufacturing Processes
    .
    13
    (2): 120–132. doi:10.1016/j.jmapro.2011.02.002. ISSN 1526-6125.
14. Parker, pp. 29, 83
15. Parker, paragraph 115
16. Parker, p. 89
17. Parker, p. 70
18. Parker, pp. 17, 22, 29–30, 117

Bibliography

• Oberg, Eric; Jones, Franklin D. (2004). Handbook of Machinery
  (27th ed.). New York: Industrial Press. ISBN 0-8311-2700-7.
• Parker (2013). Victory in Construction: Aircraft Manufacturing in the Los Angeles Area During World War II
  . Cypress, CA. ISBN 978-0-9897906-0-4.