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Chayce Lewis
Mrs. Oorlog
English IV
20 December 2010
Metalworking
Metalworking is the process of working with metals to build and create projects
or parts to build machinery. The art of metalworking has been around for hundreds of
years and has helped manufacture and build machinery and parts in the trade industry .
There are many different types of metalworking since there are many types of different
metals. The most common types of metals are: iron, steel, aluminum, copper,
magnesium, nickel, titanium, and zinc.
Steel is the easiest of all metals to weld and to work with . Steel is made of
mostly iron and consists of anywhere between 0.2% to 2.1% carbon. Carbon acts as a
hardener in steel and gives it its strength. Iron comes from the Earth’s crust in a state
known as iron ore. The creation of steel is known as smelting. This process is when iron
is extracted from iron ore by removing oxygen and adding carbon. The iron and carbon
mixture is melted, and once cooled, it turns into steel. When molten, the steel is poured
into slabs which can then be cold rolled into steel sheet or plate by the use of a press
brake. Modern day foundries use raw ore to produce the steel and end up with a
finished steel product. Steel can also be made by taking recycled steel and melting it
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down to reuse the product. This process saves on iron ore use and gets rid of unwanted
scrap metal messes.
In my grill guard I used all cold-rolled A500 grade B steel. This steel tubing has
high strength to weight ratio and is relatively low in cost and is easily weldable, formed,
punched, and drilled. The minimum mechanical properties of this type of steel are a
58,000 psi tensile strength rating and a 46,000 psi yield strength rating. Tensile strength
is the maximum stress that a material can be stretched or pulled. Yield strength is the
stress that a material begins to deform in shape and size.
The two different sizes of tubing I used were square 2x2x1/8 and rectangular
10x2x3/16. The 2 inch square tubing weighs about 3 pounds per foot (Ryerson ).
Whereas the 10x2 weighs 14.5 pounds per foot (Ryerson ). Square and rectangular
tubing are made with a process called cold forming. Cold forming gets its name from
working the steel at room temperature or when it is not heated to form the structure . In
the process of cold forming, a flat sheet of steel is formed using a series of tooling rolls
to gradually form the tube shape. After the steel is formed to the desired shape or size
the steel is then welded together at the seam using an automated welding process. The
steel tubing comes off of the line in 20 to 40 foot lengths depending on the
manufacturer.
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Steel sheet and plate can be formed using a press brake. A press brake is a
hydraulic press that uses punch and die tooling to form a bend radius in the steel. A
bend radius is the rounded edge found on the edges of steel products. Thicker materials
require larger bend radii to prevent the material from cracking. The bend radius of the
material is determined by the radius machined into the punch and die tooling . Bend
angles are determined by how much hydraulic pressure is exerted on the material. Less
pressure results in a smaller bend angle and more pressure is required for larger bend
angles. Softer materials such as aluminum and brass require far less hydraulic pressure
to bend than harder materials such as steel and stainless steel.
There are many ways to cut metal. Cutting There are two different types of
metal cutting: chip producing, and burning. Chip producing would be machining,
turning, sawing, threading, and grinding. Burning would include lasers, oxy-fuel torches,
and plasma cutters.
Machining is the use of a milling machine to shape metal by using spinning
cutters. End-mills, corner radius mills, face mills, and boring heads are different types of
cutters used on a milling machine. These cutters are used to machine the metal surface,
radius corners, create chamfers, and bore holes in the metal. CNC milling machines are
a computer run machine that will automatically machine a part from specifications
programmed into it from a CAD drawing which is a computer program that blueprints
and sketches out projects.
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Turning is the use of a lathe to make radiuses such as chamfering, threading,
boring, drilling, and knurling on round shaped objects such as shafts or bolts. There are
also CNC turning lathes that produce parts automatically. Some lathes can automatically
feed the material to produce one part after another without a machine operator .
Sawing uses a cutting blade or abrasive wheel to cut steel to specifications that
you need. Types of saws include band saws, chop saws, hacksaws, reciprocating saws,
and hole saws. Band saws, hacksaws, reciprocating saws, and hole saws all use a toothlike cutting edge to cut through the metal whereas a chop saw uses an abrasive cutoff
wheel like a grinder, except on a larger scale. A band saw uses an electric motor to turn
a thin metal toothed blade, and it uses leverage to cut through metal. A hacksaw is
more of a hand tool where you use your own strength to cut the steel using back and
forth motion. Reciprocating saws are an electric hand tool that runs the saw blade back
and forth in a very quick motion. Hole saws are used in a drill to cut a perfectly round
hole in metal.
Threading is also another type of cutting. Threading is used to mount bolts or
screws into metal by the use of a tap or die. Taps and dies come in many different sizes
either standard or metric, coarse or fine thread. Taps are used to cut internal threads in
a drilled hole. Dies are used to cut external threads on a shaft or bolt.
Grinding is a process of using an abrasive cutting wheel to remove metal and
produce a desired finish. There are several different types of grinders. Angle grinders
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are a hand held power tool with a spinning abrasive wheel or grinder disc. Grinder discs
come in different sizes ranging from 4 to 9 inches in diameter. A larger grinding wheel
will remove more material in less time than a smaller wheel, but it requires more
power. Angle grinders can be equipped with a grinding disc, a thinner cutting disc, or a
wire brush for cleaning a metal surface. Bench grinders and belt sanders are a pedestal
mounted power tool and can be used to alter the surface of a metal object or for
sharpening tools.
A surface grinder is a metal cutting tool that produces a desired finish on a flat or
curved metal surface. A surface grinder uses a stationary grinding wheel that is powered
by an electric motor. The metal object to be ground is mounted to a table similar to a
milling machine table that moves back and forth beneath the grinding wheel . Surface
grinding has several advantages over a milling machine. One advantage of a surface
grinder is that it can remove metal on very hard metals without a loss of efficiency.
Another advantage is it can also produce more accurate and finer finishes than a milling
machine. Surface grinding tooling is far less expensive than milling machine tooling.
Because it is an abrasive tool instead of a drill type tooling.
Laser cutting uses a high-power laser to cut materials. The laser is directed by a
computer program into which you program what you want cut. Laser cutting produces a
more accurate cut compared to using a torch method. Lasers can cut many different
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materials including mild steel, aluminum, stainless steel, titanium, paper, wax, plastics,
wood, and fabrics. However, they are limited to materials less than a half inch thick.
Oxy-fuel torches use a flammable gas along with oxygen to cut through harder
materials such as steel. There are three main gases used along with oxygen in these
torches: propane-air, propane-oxygen, and acetylene-oxygen. A propane-air mixture
burns at about 3,630 degrees Fahrenheit which is the coolest of the three combinations .
A propane-oxygen torch burns at about 4,530 degrees Fahrenheit. The hottest of the
torches, acetylene-oxygen burns at approximately 6,330 degrees Fahrenheit. When
cutting materials with a torch you first heat the metal to a melting temperature and
then add the oxygen mixture to make the flame hotter to cut through the steel by
pressing down the oxygen trigger on the torch.
Plasma cutting is a process of cutting through metals of different thicknesses by
the use of a plasma torch. In this process a gas (usually compressed air) is blown at high
speed out of a nozzle. An electrical arc travels through that gas to the surface that is
being cut. This electrical arc initially turns the gas into plasma which is hot enough to
cut through the material. Plasma cutters can also be used as CNC machine which is an
automated machine that cuts the steel according to the specifications you put into it.
Regular plasma cutters are becoming more advanced and use a smaller nozzle with a
thinner plasma arc that makes the cuts laser like and much more precise.
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Water jet cutting is a new process to cut metal and other materials . This uses a
jet of water, or a water and abrasive mix at a very high pressure to cut through the
steel. Water jet cutting is better for materials that are sensitive to high temperatures
because it keeps the temperature of the material cool. Abrasives that can be added are
usually garnet or aluminum oxide. The width of the cut can be changed by changing
nozzles on the machine. They can be as narrow as 0.003 inches (the width of a human
hair) up to 0.05 inches. Therefore the accuracy of water jet cutters is very high.
Joining metals is a very common practice to build machinery or other objects.
Metals can be joined in different ways such as welding, brazing, and soldering. Welding
is a process that uses an electric current to melt the material and add a filler metal that
creates a bond. Different types of welders are arc, mig, and tig. Arc welders often
known as stick welders, use an electrode that has a flux coating over the filler metal. As
the electrode melts the filler metal is used to fill the joint and the flux removes
impurities in the metal. Mig welders use a wire-feed method to join metal together.
They are the most commonly used in today’s manufacturing business because they are
easy to use and produce cleaner, better looking welds. The wire used in mig welders
acts as the filler metal. Mig welders require a gas that is run into the weld to remove
impurities. A tig welder is used to weld metals that aren’t as easy to weld such as
aluminum, or stainless steel. In tig welding you use a tig torch that heats the metal and
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creates a molten pool while you use a filler metal rod to create the weld. Tig welders
also use a shielding gas that does the same job.
Brazing is a metal joining process that uses a non-ferrous filler metal which is
heated between two different parts which are then joined by capillary action . The filler
metal is heated and then put on the base metal and then is cooled to join the two pieces
together. Brazing and soldering are similar but brazing is at a higher temperature.
Brazing is typically used to join metals such as stainless steel, cast iron, titanium, and
aluminum.
Soldering joins two materials together by melting and flowing a filler metal
(solder). Soldering filler metals have a relatively low melting point. Just like brazing,
soldering uses capillary action to join the two materials. Metals that can be soldered are
copper, aluminum, brass, and silver.
Metalworking is a very complicated and creative process that requires a lot of
work and a lot of time to create a genuine product . Without metal in today’s world we
wouldn’t be where we are. We use metal everyday in our cars, homes, workplaces and
many other products. Almost everything that has been invented has some type of metal
in it. Metal has so many different uses that the list is never ending . If it weren’t for
metal I wouldn’t be able to have typed this paper or get to school every day or even
cook my food that I need to survive. So when you use something with metal in it, be
thankful for all the work that was put into that.