Stuff 101 – Four Ways Of Cold Rolling Metal Pipes
There are two types of rolling process when it comes to metalworking, cold rolling and hot rolling, this article will explain the cold rolling process.
There are four main cold rolling processes, and each one has a different function. Cold rolling is a metalworking process that is used to reduce the size and thickness of a metal. As the name suggests the process happens while the metal is cold, usually at room temperature, and it not only decreases the thickness of the metal but it will also increase the metal’s strength and hardness. A metal slab is passed through two or more rollers that can be set to different levels of pressure depending upon the desired thickness and applications of the finished metal sheet.
Finished cold rolled metal can be used in many different applications but it is typically made into three finished products, these are metal foil, sheet metal, and plate metal. Although hot rolling can produce the same finished metal the ones created with the cold rolling process are typically smaller than the same metal products that are produced through hot rolling. The three types of cold rolling finished metal products are:
(1) Foil Metal
Metal foil is the thinnest type of cold rolled metal, measuring in at less than 0.2mm in thickness. Metal foil is used mainly in the packaging industry and as consumer products such as aluminum foil. Foil metal is also used in the construction industry for building insulation and electrical applications.
(2) Sheet Metal
Sheet metal, the second thinnest finished cold rolled metal ranges from 0.2mm to 6mm in thickness. Sheet metal is used in a wide variety of industries including construction, where it is used as aluminum siding, duct work and roofing, in the consumer packaging industry as aluminum cans and in the automotive sector where it is usually used for making automobile body panels.
(3) Plate Metal
The thickest form of cold rolled metal is called plate metal and is usually over 6mm in thickness. Plate metal is used in a wide variety of functions, from construction such as building components for high-rise buildings and bridges to transportation applications and even on military vehicles.
Now that we know how the finished cold rolled metal is used it is time to learn a bit about the four cold rolling processes, which are skin-rolling, quarter hard, half hard and full hard.
(1) Skin-rolling
Skin-rolling is used to reduce the thickness of a metal by only 0.5 to 1 percent. This process will result in a smooth metal sheet that is more ductile than the other processes.
The next three cold rolling processes, Quarter Hard, Half Hard and Full Hard, can reduce a metal up to 50 percent in size, which will increase the strength and hardness of the metal.
(2) Quarter Hard
Metal cold rolled with the Quarter Hard process is typically turned into metal pipes and can be bent or rolled on to itself without fracturing.
(3) Half Hard
Metal cold rolled with the Half Hard process is also formed into pipes or tubes, however this finished metal can only be bent to a 90-degree angle.
(4) Full Hard
Cold rolled metal with the Full Hard process is much like the Half Hard process but the finished product can only be bent to 45 degrees.
Resources:
Corey Rozon is a freelance writer from Ottawa, Canada.
This article about the four types of cold rolling processes was written for Paramount Roll, a company specializing in steel bending.
Author: crozon
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