Every country has its own designations for steels. The European standard EN10027 classifies four different categories of steels:
Let us distinguish the “standard” steels (non alloyed steels or low alloyed steel) and the stainless steels. Standard steel is less expensive than stainless steel, but it is not corrosion resistant. This has a direct impact on the conveyed fluids such as food, beverage, drugs or pure gas.
Stainless steel has become essential for many purposes, applications and products: kitchenware, everyday objects, medical and chirurgical tools, construction and public works, ship construction, the automotive and aeronautical industry, tooling, the mechanical industry, food and beverage, chemical works, transport and so on. These markets have a large number of standards and they cannot take a standard steel as the sensitive fluids could be contaminated.
>> Which welding process to use to meet health standards?
The lifetime of stainless steel installations is longer when stainless steel has been used for construction. Due to its composition, they do not corrode, or don’t corrode much. So they are more resistant than standard steels. Standard steels are mostly used by construction enterprises and for buildings. They are used for external works when corrosion and oxidation are permitted.
Stainless steel is alloyed steel (with a minimum of 1.2% of carbon and more than 10.5% of chrome). This alloy has the property of not being corrosive and does not rust.
Having more than 10.5% of chrome creates a protective layer made of chromium oxide; this is the reason why stainless steel does not corrode.
Generally speaking, stainless steel alloys are made in order to resist to corrosion, to oxidation and “creep behaviour” (distortion). The classification of the four types of stainless steels enables us to decide in which industry they can be used.
How to choose your welding process?
There is no official science or rules, as it will be the final use of the tube that has to be taken into account, but we can define the general uses as following:
They are used in order to form a resistance barrier for corrosion. They can also be used to equip the sides and panels) of pressure equipment made of steel in the petrochemical and chemical industries. They are equally used for the food and beverage industry.
They are used when high mechanical resistance is required. Remember the example of the importance of hardening the steel for the hammer and the nail in order to understand the interest in martensitic steels for a huge number of industries.
Due to their chemical resistance and their ductility – compared to copper – and their excellent mechanical characteristics they are the most used of stainless steels. They can also be used at very low temperatures (up to – 200°C), which is a good solution for cryogenic applications. You will also find marine applications with austenitic steels.
They have a biphasic structure as they belong to the austenitic/ferritic steels. This grade of steel was initially produced as the chlorine and other aggressive chemicals present in the coolant water caused corrosion in the tubes inherent to the fabrication process. Duplex steel is also used in the paper and textile industry, for chemical, petrochemical and marine applications, for the pharmaceutical industry as well as for seawater desalinations or anti-pollution equipment.
Our machines are perfectly adapted to weld standard steels as well as stainless steels, which is perfect for companies who use both grades. About 80 % of our customers use them for stainless steel as the conveyed fluids are often precious and need high quality welds, as well as repeatability and traceability - imperative in compliance with the quality standards requested in these industries.
We are most active in the food- and beverage industry (liquids, food components, beverage, and milk), the pharmaceutical industry (drugs and components), the semi-conductor market (gas or pure water), the aeronautic industry (tubes made of titan, low weight of components), the chemical and petrochemical industries (having most corrosive fluids).
Have a look at following examples of our equipment used for a multitude of industries and applications:
This is just a short list of applications. Do not hesitate to contact us directly. Together we will find the solution for your project.