common processing methods of steel
Steel is an important raw material for industry and construction. There are many types of steel and a wide range of applications. Of course, there are many types of steel mainly due to different treatment processes, so what is the common method of steel treatment technology? What are the specific operations of the processing technology? What is the temperature of the processing process?
What are the common processing methods and steps of steel?
Hot rolling is the heating of the steel material to about 1000 ° C to 1250 ° C, and the rolling mill is used to roll the material.
The traditional hot rolling production process is usually divided into two steps:
The first step is to roll the ingot, billet or continuous casting billet to a certain shape and size with a blooming mill. This process is often referred to as semi-finished product processing, also known as rough processing.
The second step is to use a different finish mill to roll the billet to the appropriate shape and size of the finished steel. This process is called finished product processing and can usually be divided into two stages: roughing and finishing. In roughing, a larger reduction is used to increase the yield; Then enter the finishing rolling stage, using a small amount of reduction for finishing, in order to get a good surface and accurate size.
With the development of continuous casting production, many companies are currently using continuous casting billets as raw materials, producing steel only in the second step above, and moving towards continuous casting and rolling.
Forging is the forging of steel ingot into steel, billet or forging blank with a forging hammer, precision forging machine, fast forging machine or hydraulic press. Forging is the older treatment method, divided into two types: free forging and model forging, which can obtain finished steel with better mechanical properties and shapes that are not easily obtained.
Extrusion is when the billet is loaded into the extrusion cylinder of the extrusion press to pressurize it, and then it is extruded through the hole of the extrusion cylinder to form a profile, tube or hollow material with a specific cross-section shape. Extrusion is used to produce products that are difficult to produce with hot rolling (e.g., complex cross-sectional steels, stainless steel pipes, etc.).
The cold rolling method is mainly used to produce cold steel plates, cold rolled steel pipes and cold rolled steel bars.
Hot-rolled steel rolls are used as raw materials, which are pickled to remove scale and then cold rolled. The finished product is a rolled hard coil. Due to cold hardening caused by continuous cold deformation, the strength and hardness of the rolling hard roll increase, and the toughness and plasticity index decrease, so the stamping performance will decrease and it can only be used for parts with simple deformation. Hardened rolls can be used as raw materials in hot-dip galvanizing plants because hot-dip galvanizing units are equipped with annealing lines. The weight of the hardened roll is usually 6 to 13.5 tons, and the hot-rolled pickled roll is continuously rolled at room temperature. The inner diameter is 610 mm.
Cold-rolled steel plates can be produced by two-high rolling mills, four-high reversing rolling mills, multi-high reversing rolling mills and cold tandem rolling mills. Although there are still only two work rolls in four-roll and multi-roll mills, each work roll is supported by one or more large-diameter support rolls to prevent deflection of the work rolls. This enables the production of wider and thinner steel plates.
Cold-rolled steel pipes are produced using two-roller periodic cold-rolled pipe mills and multi-roller cold-rolled pipe mills.
Cold-rolled steel bars are produced using Y-shaped roller mills.
Cold-rolled steel plates can be produced by two-high rolling mills, four-high reversing rolling mills, multi-high reversing rolling mills and cold tandem rolling mills. Although there are still only two work rolls in four-roll and multi-roll mills, each work roll is supported by one or more large-diameter support rolls to prevent deflection of the work rolls. This enables the production of wider and thinner steel plates.
Cold-rolled steel pipes are produced using two-roller periodic cold-rolled pipe mills and multi-roller cold-rolled pipe mills.
Cold-rolled steel bars are produced using Y-shaped roller mills.
Cold drawing is mainly used to produce steel sections and steel pipes. Cold drawing uses a cold drawing machine to perform steel and steel pipes. It can be divided into mandrelless drawing, long mandrel drawing and short mandrel drawing.
Cold bending is mainly used to produce cold-formed steel sections and welded pipes.
Cold bending is to process steel strips or steel plates into steel materials of various cross-sectional shapes through a cold bending machine. If steel pipes formed from circles, squares and other hollow shapes are welded with appropriate welding methods, they are welded pipes.
Advantages of cold bending:
(1) It is light in weight and has a large load-bearing capacity. Using it instead of hot-rolled steel can save metal.
(2) It can produce various kinds of special thin, special wide and complex cross-section steel sections.
Cold piercing and cold extrusion are basically deformation processes under the same conditions, but they are different in the way they operate. Cold piers are forging deformations of smaller workpieces and are commonly used in the fastener industry. However, cold extrusion belongs to the extrusion deformation of larger workpieces and is widely used. Cold heading is also a branch of cold extrusion. It is carried out at multiple workstations at the same time, with the transfer of the robot or the transposition of the upper mold added in the middle to achieve multiple extrusion deformations of the workpiece in a short period of time. At the same time, it also has some high-speed impact capabilities that cold extrusion does not have, so the cold heading machine can further reduce the volume under the same kinetic energy.
In order to enhance the corrosion resistance and decorative properties of steel, plating or coating on the surface of plastic-processed steel has become an important part of the steel production method. Protective layer materials are divided into two types: metal and non-metal. The metal protective layer adopts electroplating, hot plating and chemical coating. The metals used for coating are mainly zinc, tin, copper, aluminum, chromium, etc. Among them, galvanizing and tin plating are the most common.
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