In the last article, we introduced hot roll forming and cold roll forming respectively in detail. Steel, for example, is known to come in many grades, sizes, shapes and finishes — the World Steel Association lists more than 3,500 different grades of steel, each with unique characteristics. The variety of types means steel can be used in a wide range of infrastructure, appliances, vehicles, wind turbines and more.
However, optimizing steel performance for each application involves more than just changing chemical composition. The manufacturing and processing of steel can also have a significant impact on steel products — even if they are of the same grade and specification. A key difference between prefabricated steel products is the difference between hot-rolled and cold-rolled steel. So what is the difference between the hot roll forming and the cold roll forming?
The difference between the hot roll forming and the cold roll forming
The main difference between the hot roll forming and the cold roll forming is in their processing mode.
Hot forging is a process in which the material must be significantly heated to form. Hot rolled steel is steel that has been rolled at high temperatures. The hot-rolled forming process can prevent strain hardening of the material at high temperature, thus achieving optimal yield strength, low hardness and high ductility.
Cold rolling, on the other hand, refers to a process that takes place at or near room temperature. The advantage of cold rolling is that we obtain a good surface finish for the product. In essence, the cold roll forming is a hot roll forming that is further processed in the cold rolling material. Below the crystallization point of the material, it is deformed, the material is cooled and then annealed and/or tempered rolling.
Although these technologies affect overall performance and application, they should not be confused with the formal specifications and grades of steel-related to metallurgical composition and performance grades. Understanding the differences between hot roll forming and cold roll forming can help you determine the type that best suits your needs.
The hot roll forming can usually be identified by the following characteristics:
Scaled surfaces — remnants of extreme temperature cooling;
Slightly rounded edges and corners of bar and sheet products (due to shrinkage and less precise finishing);
Slightly deformed, cooling may result in slightly trapezoidal shapes instead of perfect square angles;
The cold roll forming can usually be identified by the following characteristics:
Better, more finished surfaces with smaller tolerances;
Smooth surfaces usually feel greasy;
Bars are real and square, and usually have well-defined edges and corners;
The pipe has better concentric uniformity and straightness.
In short, roll forming makes sense.
Cold roll forming generally results in better, more attractive finished surfaces that are closer to tolerance. It can be formed in a variety of shapes and can be easily galvanized, painted, or powder coated during the molding process.
The key, of course, is to use the right process for the job. If you need to know more about whether roll-forming and hot-forming or alternative processes are suitable for your application, it is best to ask the manufacturer before choosing to use one or the other.
Leading manufacturer of the roll forming machines
Foshan Te Xiang Machinery Co., Ltd is a China leading manufacturer of metallic processing machines, including slitting line, cut to length line, stainless steel polishing line, ERW tube mill line, roll forming machines, embossing line and etc. We grant you the best level of engineering, assembling, and commissioning. If you have any questions about roll forming or are looking for high-performance roll forming machines, please feel free to send an inquiry to contact us. We will do our best to provide you with quality service.
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