Steel processing – sometimes called "steel machining" – is a group of processes that focuses on shaping parts (with desired dimensions) out of blocks of steel. Today processing of that alloy relies strongly on the machining processes like milling, turning, grinding, and steel machining (numerically controlled machines).
Such methods differ by the technological process, possibilities, and limitations, yet allow to achieve steel parts within the desired specification. It is worth mentioning that the most common type of that machining is stainless steel processing – due to the popularity of this particular type of alloy. Such a process is similar to machining other types of that alloy (eg. tool steel, construction steel, special steel, duplex stainless steel).
Types of steel processing
Just like in other types of metal machining, types of forming parts from steel blocks can be divided to:
- steel machining – focuses on removing the excess material to achieve the desired form. Such type of steel processing includes milling, turning, grinding, laser cutting, and other types of machining processes,
- plastic steel processing – focuses on forming parts with pressure and utilizes a natural plasticity of alloy, sometimes with the assistance of high temperature. That group of processes includes eg. stamping, bending, forging or pulling,
- temperature steel processing – that focuses on changing (bettering) part/steel mechanical parameters by the influence of temperature differences (heating and cooling). Such processes include impregnation with elements, heat treatment, hardening, or annealing.
Just like with processing other types of materials (metals, plastics, polymers), blocks made of different alloys require different types of machining and parameters of such process. In other words: CNC machining of stainless steel requires different work parameters than the same process performed on the different types of alloy.
To achieve the best possible parts quality it is crucial to adjust the whole process to a particular type of alloy and machined part desired parameters and according to the technical specification. For a better understanding of the complexity of that process, below we describe the most important types of steel forming procedures:
Steel machining (milling, turning, grinding)
Machining steel parts is a very popular – if not the most popular – method of shaping steel parts. It is a loss method – the excess material is removed by special tools (eg. cutters, bits) to achieve the desired shape of the part.
After the whole machining process, the part is lighter than the block it was made of. It is worth mentioning that CNC steel machining requires high-quality tools with blades covered with cemented carbide to improve its hardness.
The machining park for the company that delivers CNC machining services is usually equipped with devices like:
- lathers – devices that allow removing excess material with specialized bits and the block itself is hard-mounted in the turning spindle. Stainless steel turning is a commonly used method of production of steel parts of cylindrical shape (eg. steel sleeves),
- mills – devices that remove material by specialized cutters mounted on the moving spindle. That type of machine allow to create almost any type of shape and even very small parts and elements. That is why steel milling is – today – one of the industry standards, especially combined with CNC technology,
- grinders – devices focused on finishing the surface of machined parts. The grinding itself is usually the last or almost the last step in machining steel parts (sometimes the additional process of surface bettering or additional thermal processing).
Steel CNC machining
CNC machining of steel is – in fact – a form of technological expansion of the types of machining mentioned above. Although similar in form, machining processes are performed by specialized devices, numerically controlled.
CNC steel processing is very similar to traditional forms of machining that alloy – the main difference is in the controlling. Traditional (often: automatic) mills or lathes use templates or manual guidance in the process of machining.
The same work on CNC devices is controlled by a computer that executes the following lists of given commands. Thus the name: computerized numerical control. That technology allows mass manufacturing of almost (if not) identical parts, according to the specification, and the automatization of the whole manufacturing process.
It is worth mentioning that CNC machining can deliver significant savings in time and production costs above production thresholds. Preparations of the whole process can take time which is why significant savings are visible in batches of 100 and more parts. Just like in traditional (automatic) machining, CNC steel processing requires specialized tools and the professional expertise of machining operators (eg. for CNC milling).
Plastic processing of steel (bending, forging, stamping)
Plastic processing and shaping steel is used to modify the shape of steel objects but without changing their weight (pipes, sheets, plates). Among many types of plastic steel processing we can highlight:
- forging – focuses on impacting the element with high force (tools like point, hammer, or mechanical/hydraulic press) to order the crystal structure of metal grain. Eg. forged elements have very high mechanical rigidity but are pretty fragile,
- stamping – focuses on flattening steel elements, usually with a press (hydraulic or mechanical). It is the most popular type of manufacturing sheet metal,
- bending – focuses on changing the shape of a steel element with a high force. It is the simplest (technically) form of steel plastic processing – it requires only force. Bending is an important step in manufacturing pipe constructions.
Each form of plastic steel processing can be performed cold and hot:
- hot steel processing improves the flexibility of the material but can have a negative impact on the rigidity of the shaped part,
- cold steel processing has less flexibility in shaping and forming but improves further mechanical rigidity and increases fragility.
Heat treatment of steel (hardening, saturation with elements)
That type of steel processing focuses mainly on adding features to already manufactured elements. Some of them allow to improve surface rigidity (eg. saturation with elements, like zinking or chroming steel to improve its corrosion resistance), and some of them are focused on part structure (rg. hardening, annealing).
Usually, such a type of processing is the last step in the manufacturing process – the element subjected to that processing usually has its desired shape and should not be machined further.
Processing and machining different types of steel
Industries require different types of steel (also called "steel grades") that can deliver different performances. The types of that alloy differ due to additions that can change its performance or machinability. There many grades of steel but from our perspective the most important alloys are:
- structural steel – used for constructions, eg. low-alloy, bearing, spring types,
- tool steel – used in manufacturing tools due to its high rigidity and good mechanical characteristics (eg. carbon or high-speed alloy),
- specialized steels – eg. acid-resistant, magnetic, or finally: stainless steel – the last one is the most popular in the machining shops and factories.
The most popular stainless steel alloys are:
- austenitic stainless steel – estimated 70% of all resistant to corrosion steels are austenitic, also called "18-10", due to proportions of chrome and nickel addons in the alloy. That steel grade is potent for cold bending and forging. On the other hand, requires high-quality cutting tools for machining – if different forming such alloy can lead to fast degradation of tools and decreasing precision of machining,
- ferritic stainless steel – has very good thermal conductivity but lower mechanical rigidity than "18-10" grade steel. During machining, that type of steel requires a good shavings removal system (shavings can be very long and damage the machine),
- ferritic-austenitic stainless steel – sometimes called a "duplex stainless steel" – is a high-performance type of steel alloy but due to its high hardness is problematic in machining.
Steel processing - contact us
At RADMOT, we can offer CNC milling services, CNC turning services as well as many additional services, including washing, aluminum anodizing, laser marking and assembly.
Contact us and tell us what you need. We have been providing CNC services for 40 years. Our quote is completely free. And if you are in doubt about which technology will work best for you, we are able to advise customers from many industries on machining and quickly determine the price of machining the parts you order - our expertise is at your disposal.