Duplex steels consist of a combination of austenitic phases and ferrites, which gives them higher strength and good corrosion resistance compared to austenitic steels.
The price chart of stainless steel and duplex are not much different and they are weldable like austenitic steels. This steel has special applications in cases where strength is required, such as pressurized pipes.
By adding nickel (8 to 20 percent) to iron and chromium alloys, it is possible to produce steels that remain austenitic at room temperature. This steel resists corrosion when exposed to a magnetic field and is magnetic, but not a permanent magnet.
They are weldable due to their low carbon content. 304 steel is an economical example of this type for general applications. The modified corrosion-resistant version is 316 steel, which is used for industrial purposes and is the most corrosion-resistant steel of this group.
Adding the letter L to this group of steels indicates improved weldability. Thermal resistance can be improved by adding titanium to austenitic stainless steels, such as 321 steel used in the aerospace industry.
By adding carbon (up to 2%) to ferrochrome alloy, its hardness can be increased to become martensitic steel. This steel has a wide range of properties. It is magnetic, although not as corrosion resistant as austenitic and ferritic stainless steels.
This type of steel is used in many applications that require high strength and hardness and wear resistance in addition to corrosion resistance.
Martensitic steel is used for making knives and scissors because of its good wear resistance and high hardness. By adding 12 to 18% chromium, the resistance of this steel can be significantly increased and it can be used to make turbine blades, razor blades and surgical instruments.
410, 403 and 416 are the most widely used grades of this type of stainless steel. 416 steel has the best machinability of all steel grades.
410 steel is used to make pump shafts and parts of food processing machinery. 403 steel is also used where the metal is exposed to high temperatures, e.g. in turbines
Ferritic stainless steels are alloys of iron and chromium (more than 17% chromium). The structure of these alloys remains ferritic under normal heat treatment conditions and therefore they are called ferritic steels.
This steel has high corrosion resistance, but it is cheaper than nickel-containing alloys because it does not contain nickel in its composition.
Compared to austenitic steels, this type of steel has a limited field of application due to its inflexibility and poor weldability. Heat treatment cannot be used to harden this type of steel, but cold forming and hammering can help.
Ferritic stainless steel is widely used in making kitchen appliances and decorative and architectural applications due to its reasonable price.
It is also used where corrosion resistance, malleability, ductility and cost are important, but strength is not so important.
Stainless steel is an alloy of iron and chromium that contains 10 to 30 percent chromium and has high corrosion resistance. Although there are many grades of stainless steel, only a few are commonly used in industry.
For example, AISI type 304 stainless steel, which uses a combination of chromium, nickel, and low carbon, is popular in products such as kitchen sinks for its corrosion resistance, cleanability, and ductility, and AISI type 316 stainless steel Contains molybdenum. which is more resistant to 304 chemicals and is ideal for environments where the product comes into contact with sea water, sulfuric acid or salt water.
Stainless steel is an alloy made mainly of iron and carbon. Stainless steel differs in that other alloying elements such as chromium (chromium) and nickel (nickel) are added to create a corrosion-resistant product.
When chromium is added to steel, chromium oxide is formed, which protects the surface from air and moisture corrosion like normal steel. There are over 100 different grades of stainless steel.
Corrosion resistance is the main advantage of stainless steel, but it is not its only advantage. Stainless steel includes:
Resistant to high and low temperatures
Strong and sturdy
It has an aesthetic appeal
Eco-friendly and recyclable
In addition to chromium, stainless steel is also made of silicon, nickel, carbon, nitrogen and manganese alloys. For example, nitrogen improves tensile properties such as ductility. Nickel is added to austenitic steels to make them more ductile.
These alloys are used in different amounts and compositions for specific applications, which is why it is important for stainless steel manufacturers to verify the percentage of alloy used.
Stainless steel is a versatile material. It was initially used in services and quickly found its way into the chemical industry due to its corrosion resistant properties.
Today, corrosion resistance is still very important and there is a growing understanding of the mechanical properties of materials. Stainless steel is available as coil, plate, rod, tube and wire. as follows:
Kitchen use
sinking
knife and fork
Kitchen appliances
Surgical instruments and medical equipment
Hemostatic agent
Surgical implant
temporary crown (dental)
bridge construction
Monuments and statues
Airport roof
Automotive and aerospace applications
Body
Subway
level
Kitchen use
The best known use of stainless steel is in dinnerware and kitchen utensils. The best type of cutlery is 304 steel, which contains (18% chromium, 8% nickel).
The most demanding industries that use stainless steel are the chemical, oil and gas industries, which creates a large market for stainless steel tanks, pipes, pumps and valves.
First success with 304 stainless steel; Storage of dilute nitric acid, as it can be used for thinner sections. Several special grades of stainless steel have been developed for higher corrosion resistance over a wide temperature range.
Stainless steel and other corrosion-resistant alloys are widely used in the power generation industry to combat corrosion, especially at high temperatures.
In particular, nickel alloys are used for high temperature resistance and oxidation resistance in fossil fuel power plants. Nickel alloys and other stainless steels are widely used in flue gas descaling devices.
The nuclear power industry uses large amounts of stainless steel, often characterized by low cobalt content, for power generation and radiation control. Steam and gas turbines use stainless steel due to its resistance to corrosion and heat.
Large amounts of stainless steel are used in food production and preservation. The most common stainless steels are 304 and 316. In general, 316 stainless steel is used in environments with higher hardness.
One of the main advantages of stainless steel in this application is that it does not impart any taste to the food it comes in contact with and is easy to wash.
Architecture, building and construction
Stainless steel is used in most modern buildings for cladding, roofs and facades. Airport roofs are often used to build bridges, buildings and sculptures.
Surgical instruments and medical equipment
Stainless steel is used as a standard material for most medical equipment, orthopedic beds and examination equipment due to its hygienic quality and ease of cleaning.
Pharmaceutical companies use stainless steel for pill funnels, piping solutions, etc.
The automotive industry
In car manufacturing, they mainly use stainless steel for exhaust systems and catalytic converters, as well as for the body.
The stainless steel market continues to improve with greater focus on achieving long-term maintenance costs, reducing environmental impact and increasing focus on life cycle costs.
