What is Stainless Steel? Definition, Meaning, Properties, Types, Melting Point


Stainless steel was discovered by Harry Brearley, Elwood Haynes, and Robert Forester Mushet. There are many scientists and metallurgists who may be able to claim Brearley’s discovery during the 5-year period between 1908 and 1913.

Rust-less steel was discovered in 1913 by Harry Brearley of Sheffield, UK. Despite many prior attempts, Brearley’s stainless steel with a 12.8% chromium content is considered to be the first true stainless steel.

Brearley made several varieties of his alloys during these experiments, varying the amount of chromium and carbon. A steel with 12.8% chromium and 0.24% carbon was created by Brearley on 13th August 1913, regarded as the first stainless steel ever.

What Do You Mean by Stainless Steel?

Stainless steel is an iron-based alloy with at least 11% chromium, which provides heat resistance and prevents iron from rusting. The three-digit number 304 identifies a specific type of stainless steel, e.g.408 stainless steel.

stainless steel definition meaning properties types melting point
Stainless steel definition meaning properties types melting point

Iron, chromium, nickel, and other metals are used to make stainless steel, which is corrosion-resistant.

A green material par excellence, stainless steel is completely and infinitely recyclable. It is estimated that the construction sector will recover at a rate close to 100 percent.  A green material par excellence, stainless steel is completely and infinitely recyclable. It is estimated that the construction sector will recover at a rate close to 100 percent.

Proper Meaning of Stainless Steel Melting Point

Temperature affects the tensile strength of most metals. Steel becomes more rigid and easier to bend when it is exposed to extreme heat. Stainless steel usually undergoes this process at about 1000°C.

It is the tensile strength of a steel basket that determines how much weight it can support when it is used to hold heavy objects in an extremely hot environment. A basket holding the same weight at 800°C can carry twice as much weight as one at 1000°C. The welded joints on the basket could also be damaged by high temperatures.

A melting point can cause physical changes, as well as determine an object’s resistance to oxidation and sulfurization. Iron will be destroyed by both oxygen and sulfur. Chromium in stainless steel prevents it from oxidizing and sulfidating. When nickel is added, however, the protective power of chromium is diminished and iron is exposed to oxygen or sulfur, which could damage the stainless steel.

A Brief Description of Stainless Steel Composition

Iron and carbon are the main components of steel. Stainless steel is a kind of steel that has an average chromium content of 10.5% and a carbon content of less than 1.2%. Nickel, titanium, niobium, molybdenum, manganese, etc., can further improve the corrosion resistance and mechanical properties of stainless steel.

Surfaces of materials are coated with chromium oxide when they come into contact with oxygen. It is protected by this passive layer and is capable of self-repairing.

Characteristics of Stainless Steel

The stainless steel family of iron-based alloys is known for its corrosion and heat resistance. Steels with a chromium content of less than 10 percent are characterized by their superior corrosion resistance compared with steels with higher chromium content.

  • Stainless steel is primarily composed of iron and carbon, but it is also alloyed with several other elements, the most prominent of which is chromium. 
  • Nickel, magnesium, molybdenum, and nitrogen are also common alloys found in stainless steel.
  • In addition to its high corrosion resistance, stainless steel is ideal for the manufacture of roofs, facades, rainwater recovery systems, and service water pipes that are exposed to adverse weather conditions.
  • As a sustainable building material, stainless steel is long-lasting. Low maintenance, effective assembly, and installation ensure unrivaled service life for the user.

Stainless Steel Properties

In many industrial sectors, stainless steel is widely used in parts and components because of its numerous desirable properties. Most importantly, it is extremely corrosion-resistant due to its chromium content. Steels with a minimum of 10.5% chromium content are approximately 200 times more corrosion-resistant than steels without chromium.

Consumers also enjoy its high strength and durability, high and low-temperature resistance, increased formability and ease of fabrication, low maintenance, long-lasting, attractive appearance, and environmental friendliness. Stainless steel doesn’t need to be treated, coated, or painted once it has been put into service.

Mechanical Properties

Because stainless steel is steel, it has strong mechanical properties at ambient temperatures. A unique combination of ductility, elasticity, and hardness allows it to be used in difficult forming modes, such as deep stamping, flattening, extrusion, etc. while providing resistance to heavy wear such as friction, abrasion, impact, elasticity, etc. Also, at low and high temperatures, it exhibits good mechanical properties.

Resistant to Corrosion

By reacting with oxygen in air or water, chromium forms an oxide layer on the surface of stainless steel that continuously protects it. It regenerates itself if scratched. Stainless steel is corrosion-resistant because of this special feature.

Looks

A variety of finishes are available for stainless steel, including matte, bright, brushed, and engraved. The material can be embossed or tinted, making it aesthetically pleasing. Architecture, interior design, street furniture, and other design applications use it extensively.

Recycling

There is no limit to the amount of recycling you can do with stainless steel. It is the green material. It is close to 100% recovered in the construction industry. It doesn’t release compounds that could change the composition of elements like water when it comes into contact with it, and it’s environmentally neutral and inert.

Fire Resistant

A critical temperature of 800°C is required for stainless steel to be fire-resistant in structural applications. There is no toxic fume emissivity when stainless steel is ranked great for fire resistance.

Easy to clean

The surface of stainless steel objects can be easily cleaned with common cleaning agents such as detergents and soap powder. When it comes to cooking and decorative utensils that need to be washed frequently, stainless steel meets all the requirements.

Types of Stainless Steel

Ferritic

Its low carbon consistency is typically no more than 0.1%, and it typically contains between 10.5% and 30% chromium. The magnetic properties of ferritic stainless steels make them ideal for high temperatures and stress corrosion cracking.

Uses

The ferritic stainless steels found in ferritic stainless steel are commonly used in automotive components, petrochemical plants, heat exchangers, furnaces, and appliances.

Martensitic

Similar to ferritic stainless steel, martensitic stainless steel has a high carbon content of up to 1.2%, which allows it to be hardened to a great extent. Surgical instruments and medical tools can be created with them.

Uses

There are many uses for martensitic stainless steels, including compressor blades and turbine parts, kitchen utensils, nuts, bolts, and screws, pumps and valves, dental and surgical instruments, electric motors, pumps, valves, machine parts, sharp surgical instruments, cutlery, knife blades, and other cutting hand tools.

Austenitic

There are several types of stainless steel in the austenitic group. There is a higher concentration of chromium, molybdenum, and nickel in austenitic stainless steels than in other types. Due to their excellent strength and malleability, they are very versatile materials.

Uses

This alloy has 18% chromium and 8% nickel, and it is frequently used to make kitchen equipment, cutlery, food processing equipment, and structural components for aircraft and cars. Stainless steel grade 316 is another common material. 

There are many products made from it, including food preparation equipment, laboratory benches, medical and surgical equipment, boat fittings, pharmaceuticals, textiles, and chemical processing equipment.

Duplex

Due to its higher strength, duplex stainless steel can reduce weight significantly because it combines austenite with ferrite. The excellent corrosion resistance of this material makes it ideal for marine applications, even in demanding environments.

Uses

Duplex stainless steel of the 2000 Grade series is suitable for applications in chemical, oil, and gas processing, marine, high-chlorine environments, as well as pulp and paper processing. In addition to cargo tanks for ships and trucks, biofuel plants, chloride containment and pressure vessels, transportation, heat exchanger tubes, construction, and desalination plants, there are also locomotives and trucks.

Stainless Steel Melting Point

Melting points for stainless steel range from 2550°F to 2790°F or 1400°C to 1530°C.

The exact chemical composition of stainless steel determines its melting point. There is a melting point for each element. Nickel, chromium, and iron are the primary elements of stainless steel.

The melting point of pure iron is 1535°C, that of chrome is 1890°C, and that of nickel is 1453°C. The temperature range for stainless steel is between 1400 and 1530°C. There is a slight difference in the elements that make up each grade of stainless steel. Therefore, different grades have different melting points.

Determination of Stainless Steel Melting Point

The melting point determination principle is used in this process. Melting points are determined by a material’s change in light conduction capacity. As a solid crystalline substance moves through five points of light conductivity, it finally reaches a clear point when it is liquid.

The capillary method is used by researchers to determine the melting points of elements and alloys. Using a thin-walled capillary melting point tube along with a heat source and an accurate thermometer, they pack a sample of the material. A degree Celsius is added to the temperature each minute by the researchers.

In order to determine the melting point of a material, researchers record the temperature at which the material inside the tube becomes completely liquid.  

Temperature Variation on Various Grade of Stainless Steel Melting Point

Stainless steel comes in different forms or formulations. Stainless steels that are high in carbon include 304, 316, and 317.  Ferritic steels like 430 and 434, and tempered and hardened steels such as 410 and 420. The melting point of each type of group will differ due to its compound composition.

Among the different grades of steel,

  • Grade 304 has a melting point of 1400 -1450°C,
  • Grade 316 has a melting point of 1375 -1400°C,
  • Grade 410 has a melting point of 1480 -1530°C,
  • Grade 420 has a melting point of 1450 -1510°C,
  • Grade 430 has a melting point of 1425 -1510°C, and
  • Grade 434 has a melting point of 1426 -1510°C.

Steel grades are expressed as ranges rather than specific numbers, as you may have noticed. Due to the possibility of tiny variations in alloy formation, the melting point of a specific alloy type can and will vary.

Temperature Concern on Stainless Steel Melting Point

Stainless steel should not be used solely for structural or supporting purposes in heated environments. A certain amount of tensile strength is lost by all alloys at high temperatures, and stainless steel is no exception. 

The experiments show that stainless steel becomes weaker and more brittle even before reaching the critical melting point.

The tensile strength of steel that retains 100 percent of its structural integrity at 850°C is likely to be lost around 50% by 1000°C. Therefore, when exposed to a higher temperature, a structure designed to carry 1000kg could only support 500kg of weight safely. If the structure is loaded with more weight, it could bend significantly.

Do you think Stainless Steel is Immune to Rusting?

A stainless steel alloy consists of a minimum amount of chromium content of 10.5%. It is resistant to corrosion and rust due to the reaction between chromium and oxygen in the air.

The development of rust on stainless steel can be caused by a variety of factors. The corrosion of one stainless steel alloy might not affect another because there are hundreds of different stainless steel alloys.

Galvanic Corrosion

Manufacturers may make the basic mistake of welding dissimilar metals together by accident or design when creating custom steel wire or sheet metal forms.

  • There may be a flow of electrical current when two metals with different properties are connected via an electrolytic material, such as water or weld filler. The less noble metal, i.e., the metal that is more easily corroded due to its capacity to accept electrons, will become an anode.
  • Several factors will influence the speed of corrosion, such as the types of stainless steel used, the welding filler used, ambient temperature, humidity, and the total surface area of the metals in contact.
  • Galvanic corrosion can be prevented by avoiding permanently joining two dissimilar metals. Add a coating to seal off the metals to prevent electrons from flowing between the cathode and anode.
  • In addition, galvanic corrosion may occur at the weld site if the weld filler is too dissimilar to the metals being joined.

Extreme Temperature Application

The melting point of stainless steel alloys is typically well over 1,200 degrees Fahrenheit. Despite not melting at high temperatures, the metal may undergo other changes that affect its corrosion resistance.

  • In many heat treatment and annealing processes, stainless steel alloys are subjected to extreme temperatures that cause scaling. Due to the different compositions of the scales and the base metal, bimetallic corrosion can occur when scales form on hot metal.
  • The loss of the protection provided by stainless steel alloys exposed to extreme temperatures can also increase the risk of corrosion for a period of time, until the oxide layer can be replaced.
  • If your manufacturing processes exceed the recommended operating temperatures for any stainless steel, corrosion will occur as a result of scaling or other issues caused by temperature extremes. In order to design any custom wire basket or sheet metal form for our clients, Marlin’s engineers always ask about their processes’ temperatures.

Raw Iron Transplantation to Stainless Steel

A stainless steel basket or part may be contaminated with particulate residue from a plain steel or iron workpiece. As a result, the protective oxide layer on a stainless steel workpiece can disrupt, causing corrosion and rusting.

  • Contrary to bimetallic corrosion, this corrosion occurs by pure chance and typically without the manufacturer’s knowledge.
  • Steel or iron residue frequently gets transferred to stainless steel parts or workpieces when equipment used for one type of material uses for the other without being cleaned between batches.
  • A wire bending robot can bend plain iron wires for several hours, then switches to bending stainless steel wires. 
  • There is a possibility that some iron particles could be left behind on the robot manipulators, which could then transfer to the stainless steel wires that can bend.
  • The equipment must be thoroughly cleaned and prepared when changing to new material to prevent the transplantation of plain steel or iron. It is never a good idea to share equipment between different types of metal, such as steel brushes.  

Environmental Factors

It is not uncommon for a manufacturer to make a stainless steel wire basket or tray exactly to specification, but for it to corrode due to some previously unaccounted-for environmental factor. An environmental factor that might be overlooked in a design document is the presence of salt and moisture in the air due to the factory’s coastal location.

It’s important to consider as many environmental factors as possible when selecting stainless steel for custom wire and sheet metal forms. Rather than rusting right away, the stainless steel basket, tray, or part will remain corrosion-resistant for as long as possible.

Pitting Corrosion

The corrosion of stainless steel alloys caused by environments that are rich in chlorides, such as salt, can lead to extreme pitting. As a result of contact with salt-rich seawater or salt-enriched sea breezes, grade 304 stainless steel, when used in naval applications, may suffer pitting.

You can use the highest quality stainless steel like grade 316 to avoid pitting corrosion as it is specifically resistant to chlorides. To prevent direct contact with chlorides in the environment, steel can be coated with a specialized coating.

Uses of Stainless Steel

This material has a lot of uses and can be an excellent alternative to steel in many cases.

Due to its resistance to pitting corrosion caused by salt, grade 316 stainless steel is frequently preferred for applications involving salt or other chlorides. For its incredibly high tensile strength, some prefer grade 430 stainless steel that has been hardened and stress relieved. In contrast, grade 304 stainless steel is widely used in many industries for a variety of applications.

In most applications, stainless steel is used because it has unique properties and is corrosion-resistant. In addition to coils, sheets, plates, rods, wire, and tubes, you can find this alloy milled in coils, sheets, and plates. 

  • Kitchen sinks, cutlery, and cookware are all used in the kitchen.
  • Instruments used in surgery and medicine: Hemostats, Surgical implants, Temporary crowns or dental.
  • An architecture builder’s work, such as the Chrysler Building shown above: Bridges, sculptures, and airport roofs.
  • Application areas include auto-bodies, rail cars, and aircraft.

Custom Wire Form

Its strength, corrosion resistance, and temperature tolerance make stainless steel ideal for a wide range of manufacturing applications. It includes material handling, ultrasonic part cleaning, sterilization of medical equipment, and finishing of parts.

A variety of uses can be achieved with stainless steel wire baskets. The type of stainless steel used will, of course, depend on the exact nature of the process. Certain types of stainless steel are better suited for certain applications than others.

Distinguish between Plain steel & Stainless Steel

You can find stainless steel in a number of formulations on the market. Apart from having different component metals in different ratios, what makes stainless steel alloys different from plain steel alloys is the protective oxide layer of film. Steel will retain its shiny surface appearance as long as this oxide layer remains intact.

Define Oxide Layer

In order to understand why stainless steel forms this oxide layer, we must first understand it’s basic. Many forms of stainless steel are made up of specific elements: iron, manganese, silicon, carbon, and chromium.

The oxide layer of stainless steel can be further enhanced by adding nickel or molybdenum. It’s no surprise that chromium is the most important element in terms of stainless steel’s rust resistance, which is why most austenitic stainless steels contain chromium in their composition.

A stainless steel alloy’s resistance to corrosive chemicals can be strengthened by specific additives, such as molybdenum. Stainless steel grade 316, for instance, contains molybdenum, which stainless steel grade 304 does not. Therefore, grade 316 stainless steel is more corrosion resistant than grade 304.

Carbon Steel Melting Point

Steel melts at a temperature of 2500-2800°F or 1371-1540°C. 

Steel is an alloy, not a pure metal like iron. It is the melting point of pure metals that determines their purity. In contrast, alloys are made up of multiple elements with different melting points. Consequently, alloys do not melt at fixed temperatures or freeze.

Toxicity

Hexavalent chromium, a toxic carcinogen, is not present in stainless steel. All forms of life require manganese as a trace nutrient. Whenever manganese levels exceed 500 micrograms, it is considered toxic.

In spite of the lack of acute toxicity studies on stainless steel, long-term use and subacute studies strongly suggest no acute health risks via inhalation, dermal exposure, or oral intake. Acute toxicity is also unknown for any of the constituent metals.

Scratched stainless steel pans may expose you to chromium and nickel, which in higher amounts may cause health issues like dermatitis, particularly for people whose nickel sensitivity is high. Stainless steel cookware that is older or badly burned may also leach chemicals into food.

Highest Quality of Stainless Steel

The most common form of stainless steel in use around the world is 304 stainless steels, which offers excellent corrosion resistance and is quite affordable. Most oxidizing acids will not cause corrosion to 304. As a result of 304’s durability, it can be easily sanitized, making it an ideal material for food and kitchen use.

Cheapest Quality of Stainless Steel

Steels made from ferritic alloys include the inexpensive grade 409 stainless steel and the proprietary grade 430 stainless steel. The combination of low price, corrosion resistance, and excellent formability makes 409 stainless steel the ideal material for automotive exhausts.

Difference between Aluminum & Stainless Steel

A third of the weight of stainless steel makes aluminum ideal for industries like airplanes and bicycles. The automotive industry also uses aluminum sheets extensively.

Corrosion

Iron, chromium, nickel, manganese, and copper are the main elements found in stainless steel.  Chromite is used as a corrosion preventive agent.  In addition, it is non-porous, which increases its corrosion resistance. As a result of its passivation layer, aluminum is highly resistant to oxidation and corrosion.  Aluminum’s surface turns white when oxidized and sometimes pits. Acute acidic or base environments can cause Aluminum to corrode rapidly and catastrophically.

Cost

Stainless steel is typically more expensive than aluminum.

Temperature

It is possible to use stainless steel at much higher temperatures than aluminum, which can become very soft above about 400 degrees Fahrenheit.

Thermal Conductivity

The thermal conductivity of aluminum is much better than that of stainless steel. Car radiators and air conditioning units use it for this reason.

Electrical Conductivity

Most metals are much better conductors than stainless steel. Aluminum conducts electricity very well. Aluminum is commonly used for high-voltage overhead power lines because of its high conductance, lightweight, and corrosion-resistant properties.

Strength

The strength of steel is generally greater than that of aluminum, but aluminum weighs almost one third as much as steel. Aluminum is used in aircraft primarily because of this reason. In other words, aluminum has a higher strength-to-weight ratio than stainless steel, despite being stronger.

Workflow

It is fairly easy to cut and shape aluminum since it is fairly soft. Stainless steel is difficult to work with due to its resistance to wear and abrasion.  As compared to aluminum, stainless steels are harder and are particularly difficult to form. Aluminum is difficult to weld compared to stainless steel.

Stainless Steel Checking

Steel can be identified by grinding a bit of the item on a grinding wheel and seeing a glow of sparks. A 300-series stainless steel item is most likely non-magnetic and gives off sparks if it isn’t magnetic.

In the kitchen, on the stove, in sinks, on fixtures, and in other parts of the house and workplace, it is an excellent choice. The stainless steel on appliances such as microwaves, dishwashers, and refrigerators can be scratched. Scuffed-up steel does not have to stay that way forever.

Define Melting Point Depression

The alloy steel is made up of iron and carbon. Chrome and nickel are also included in stainless steel’s alloy. A lower melting point is achieved by adding each new element. Melting point depression refers to this phenomenon

Wrapping it Up

Aside from being environmentally neutral, stainless steel is also inert, which makes it suitable for sustainable buildings, since it is durable, inert and environmentally friendly. Furthermore, the compounds do not leach when they are exposed to water or any other element, such as air or sunlight.

Aside from its environmental benefits, stainless steel offers a number of other advantages, including hygienic properties, ease of maintenance, durability, and beauty. As a result, stainless steel is used in a wide range of everyday items.

Additionally, these types of metals are used in many industries, such as energy, construction, research, medicine, food, transportation, and logistics.

FAQs for Stainless Steel Melting Point

Is Stainless Steel Water proof?

It is also resistant to rain and many other liquids, in addition to shower water. In the event that it gets wet, all you need to do is thoroughly dry it off. In contrast, don’t wear your jewelry to the swimming pool this summer if you plan on going swimming.
The durability and waterproof properties of stainless steel make it an excellent choice for jewelry. Rain doesn’t need to worry you when caught in it. You won’t have to worry about it rusting or tarnishing. It only takes a few seconds to wipe any water off with a soft lint-free cloth.

Can you describe the main problem of Stainless Steel?

The heat conductivity of stainless steel is significantly lower than that of steel and other iron-based materials. Material-removal tasks, such as removing weld seams, are difficult because of this, since it gets hotter locally when worked on.

Is Stainless Steel Metallic or Not?

Steel is a type of metal that includes stainless steel. Therefore, they contain iron in their chemical composition. Magnetic stainless steel varieties are usually those with iron in their composition. Austenitic crystal structures are not magnetic, so they are not magnetic alloys.

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