Stainless Steel Plate

The properties of stainless steel are corrosion resistance, high ductility, attractive appearance and low maintenance.

Stainless steel contains chromium which provides the properties of corrosion resistance at high temperatures. Stainless steel can withstand corrosive or chemical environments due to its smooth surface. Stainless steel products are safe for long-term use with excellent resistance of corrosion fatigue.

Product Specification and Size

ASTM JIS AISI EN Mill’s Standard
Specification A240
SA240
G4304
G4312
10088-2
17224, 17440, 17441
Grade S30400
S30403
S31603
S43000
SUS304
SUS304L
SUS316L
SUS430
304
304L
316L
430
1.4301
1.4306
1.4401
1.4016
202
204Cu3

Other specifications are also available up to request

Available Size

Thickness Width Length Surface Finish
15~85 mm 914, 1219, 1524 mm 3048, 6069 mm
10 M
Black
3~8 mm 20~1524 mm Container Loading:
Max. 10M
Bulk: as request
No.1
8 up ~ 60 mm 30~1524 mm Max. 6096 mm No.1

Application

Stainless steel plate is an extremely popular mills processed material that offers good corrosion resistance for numerous types of applications. Stainless steel plate is widely used in internal equipment, walls, pressure vessels and marine applications. 430 stainless steel plate is suitable for dry or internal environment equipment. 304 stainless steel plate is suitable for outdoor walls or windows. 316 stainless steel plate is suitable for the pressure vessel of industrial and marine applications.

Dimension and Shape Tolerance

Thickness Tolerance: According to 1/2 JIS G4304

Thickness Tolerance
8.0 mm < T ≦ 10.0 mm ±0.32 mm
10.0 mm < T ≦ 25.0 mm ±0.34 mm
25.0 mm < T ≦ 85.0 mm ±0.40 mm

 

Length Tolerance: According to 1/2 JIS G4304

Thickness Tolerance
T ≦ 10.0 mm -0 / +60 mm
10.0 mm < T ≦ 85.0 mm -0 / +65 mm

Width Tolerance: Max. Aim ±10 mm
Edge Crack: Max. 5 mm per side

Chemical Composition & Mechanical Property

Chemical Composition

Steel Grade C% Max. Si% Max. Mn% Max. P% Max. S% Max. Cr% Max. Ni% Max. Mo% Max. Ti% Max. Other
SUS 304 0.08 1.0 2.0 0.045 0.03 18.0~20.0 8.0~10.5
SUS 304L 0.03 1.0 2.0 0.045 0.03 18.0~20.0 9.0~13.0 Cu:1.0~3.0
SUS 316L 0.03 1.0 2.0 0.045 0.03 16.0~18.0 12.0~15.0 2.0~3.0
SUS 430 0.12 0.75 1.0 0.04 0.03 16.0~18.0

ASTM Specification

Steel Grade C% Max. Si% Max. Mn% Max. P% Max. S% Max. Cr% Max. Ni% Max. Mo% Max. Ti% Max. Other
S30400 0.08 0.75 2.0 0.045 0.03 18.0~20.0 8.0~10.5 N:0.1Max
S30403 0.03 0.75 2.0 0.045 0.03 18.0~20.0 8.0~12.0 N:0.1Max
S31603 0.03 0.75 2.0 0.045 0.03 16.0~18.0 10.0~14.0 2.0~3.0 N:0.1Max
S43000 0.12 1.0 1.0 0.04 0.03 16.0~18.0 0.75 Max.

Mechanical Property

Steel Grade N/mm 2 MIN.
Tensile Stress
N/mm 2 MIN.
Proof Stress
Elongation MIN. HRB MAX. Hardness Bendability:Bending Angle Bendability:Inside Radius
SUS 304 520 205 40 90 No Require
SUS 304L 480 175 40 90 No Require
SUS 316L 480 175 40 90 No Require
SUS 430 450 205 22 88 180° 1.0 time the thickness
ASTM Specification
Steel Grade N/mm 2 MIN.
Tensile Stress
N/mm 2 MIN.
Proof Stress
Elongation MIN. HRB MAX. Hardness Bendability:Bending Angle Bendability:Inside Radius
S30400 515 205 40 92 No Require
S30403 485 170 40 92 No Require
S31603 485 175 40 95 No Require
S43000 450 205 22A 89 180°

What is the difference between sheet and plate?

Stainless steel sheet

Our range of thicknesses starts at 0.5mm thick and we can stock some thicknesses up to 4000mm long.

Plate and sheet are words used to describe the classification of metal depending upon its thickness. While sheet metal is less than 3 mm thick, plate metal is obviously thicker than 3 mm. Many people become confused because of classifications such as plate, sheet, foil and others, but there is no need to be, as their differences are clearly spelt out. It is mostly in terms of metal aluminum that we hear words like plate and sheet.

The thickness of the product decides the category into which it falls or belongs. Plate is defined as a thickness of more than or equal to 0.25 inches, while a sheet has a thickness of 0.006 inches or more but less than 0.25 inches. At the extreme of this continuum is a foil that has a thickness of less than 0.006 inches.

Application
Stainless sheet is used for industrial sectors and components for processing equipment for foodservice, medical device, chemical, petrochemical and power transmission industries.

Stainless Steel Composition

Below is a table detailing the chemical composition of some of the stainless steel grades that are supplied by stainless materials

Austenitic Grades

Grade EN Specification Carbon (C) Silicon (S) Manganese (Mn) Phosphorus (P) Sulfur (S) Chromium (Cr) Molybdenum (Mo) Nickel (Ni) Nitrogen (N) Iron (Fe)
301 1.4310 0.05 – 0.15 2.00 2.00 0.045 0.015 16.0 – 19.0 0.80 6.0 – 9.5 0.10 Balance
304 1.4301 0.07 1.00 2.00 0.045 0.015 17.5 – 19.5 8.0 – 10.5 0.1 Balance
304L 1.4307 0.03 1.00 2.00 0.045 0.015 17.5 – 19.5 8.0 – 10.5 0.1 Balance
201 1.4372 0.15 1.00 5.5 – 7.5 0.045 0.015 16.0 – 18.0 3.5 – 5.5 0.05 – 0.25 Balance
316 1.4401 0.07 1.00 2.00 0.045 0.015 16.5 – 18.5 2.0 – 2.5 10.0 – 13.0 0.1 Balance
316L 1.4404 0.03 1.00 2.00 0.045 0.015 16.5 – 18.5 2.0 – 2.5 10.0 – 13.0 0.1 Balance

Ferritic Grades

Grade EN Specification Carbon
(C)
Silicon
(Si)
Manganese
(Mn)
Phosphorus
(P)
Sulfur
(S)
Chromium
(Cr)
Titanium
(Ti)
Niobium
(Nb)
Molybdenum
(Mo)
Nickel (Ni)
409 1.4512 0.030 1.00 1.00 0.040 0.015 10.5 – 12.5 [6 x (C + N)] to max 0.65
430 1.4016 0.080 1.00 1.00 0.040 0.015 16.0 – 18.0
434 1.4113 0.080 1.00 1.00 0.040 0.015 16.0 – 18.0
439 1.4510 0.050 1.00 1.00 0.040 0.015 16.0 – 18.0 [4 x (C + N) + 0.15] to max 0.8 (3 x C + 0.3) to max 1
4509 1.4509 0.030 1.00 1.00 0.040 0.015 17.5 – 18.5 0.1 – 0.6
436 1.4513 0.025 1.00 1.00 0.040 0.015 16.0 – 18.0 [4 x (C + N) + 0.15] to max 0.8 0.80 – 1.40 0.020

Martensitic Grades

Grade EN Specification Carbon (C) Silicon (S) Manganese (Mn) Phosphorus (P) Sulfur (S) Chromium (Cr) Nickel (Ni) Nitrogen (N) Iron (Fe)
410 1.4006 0.08 – 0.15 1.00 1.50 0.040 0.015 11.5 – 13.5 0.75 Balance
420 1.4021 0.16 – 0.25 1.00 1.50 0.040 0.015 12.0 – 14.0 Balance
420 1.4031 0.07 1.00 2.00 0.045 0.015 17.5 – 19.5 8.0 – 10.5 0.1 Balance

What is Stainless Steel?
The term stainless steel refers to a wide variety of grades of metal which contain an alloy that has at least 10.5% of chromium. The most popular grades of stainless steel are 304 and 430. Each of the different grades of stainless steel contains different alloying elements that contribute to its properties such as resistance to corrosion, strength, and flexibility.

Because it’s a low-cost material, has a great appearance, has a high resistance to corrosion, and is durable, stainless steel has become very popular, and a preferred material in different applications.

Why is it Stainless?
The word simply means the metal does not stain. This valuable attribute is a result of the addition of the alloying element chromium which reacts with oxygen in the air forming a layer of chromium oxide which protects the surface of the metal.

If scratches or contact with aggressive chemicals destroy the layer, it repairs itself as soon as the metal is exposed to the air again, forming a constant protective coat on the steel.

Mechanical properties of stainless steel

The mechanical properties of stainless steel vary depending on the chemical composition of each grade. For example austenitic grades generally have a higher tensile strength than ferritics.

Austenitic Grades

Grade EN Specification Form Max Thickness (mm) 0.2% – Proof Strength (min MPa)a 1% – Proof Strength (min MPa)a Tensile Strength (MPa)
304 1.4301 Cold rolled strip 6.0 230 260 540 – 750
304 1.4301 Hot rolled strip 13.5 210 250 520 – 720
304 1.4301 Hot rolled plate 75.0 210 250 520 – 720
304L 1.4307 Cold rolled strip 6.0 220 250 520 – 700
304L 1.4307 Hot rolled strip 13.5 200 240 520 – 700
304L 1.4307 Hot rolled plate 75.0 200 240 500 – 700
316 1.4401 Cold rolled strip 6.0 240 270 530 – 680
316 1.4401 Hot rolled strip 13.5 220 260 530 – 680
316 1.4401 Hot rolled plate 75.0 220 260 520 – 670
316L 1.4404 Cold rolled strip 6.0 240 270 530 – 680
316L 1.4404 Hot rolled strip 13.5 220 260 530 – 680
316L 1.4404 Hot rolled plate 75.0 220 260 520 – 670

a – If, in the case of strip in rolling widths < 300 mm, longitudinal test pieces are taken, the minimum values are reduced as follows:
– proof strength – minus 15 MPa,
– elongation for constant gauge length – minus 5 %;
– elongation for proportional gauge length – minus 2 %.
For continuously hot rolled products, 20 MPa higher minimum values of Rp0,2 and 10 MPa higher minimum values of Rp1,0 may be agreed at the time of enquiry and order.

Ferritic Grades

Grade EN Specification Form Max Thickness (mm) 0.2% – Longitudinal Proof Strength (min MPa) 0.2% – transverse Proof Strength (min MPa) Tensile Strength (MPa)
409 1.4512 Cold rolled strip 8.0 210 220 380 – 560
409 1.4512 Hot rolled strip 13.5 210 220 380 – 560
430 1.4016 Cold rolled strip 8.0 260 280 430 – 600
430 1.4016 Hot rolld strip 13.5 240 260 430 – 600
430 1.4016 Hot rolled plate 25.0 240 260 430 – 600
439 1.4510 Cold rolled strip 8.0 230 240 420 – 600
439 1.4510 Hot rolled strip 13.5 230 240 420 – 600
4509 1.4509 Cold rolled strip 8.0 230 250 430 – 630

Martensitic Grades

Grade EN Specification Form Heat treatment condition Max Thickness (mm) 0.2% – Proof Strength (max MPa) Tensile Strength (max MPa)
420 1.4031 Cold rolled strip Quenched and tempered 3.0
420 1.4031 Cold rolled strip Annealed 8.0 760
420 1.4031 Hot rolled strip Annealed 13.5 760

Stainless Steel Plate FAQs

Question: Why is stainless steel plate such a popular manufacturing material?
Answer: There are numerous reasons manufacturers come to Sunny Steel for stainless steel plate. The corrosion resistance of stainless steel is excellent. When combined with other benefits—ease of fabrication, strength-to-weight advantage, aesthetic appearance, easy cleaning ability, impact and heat resistance – stainless steel plate becomes the material of choice for a variety of applications.

Question: What grades of stainless steel plate does Sunny Steel carry?
Answer:

  • 303
  • 304
  • 304L
  • 316/316L

Question: What are the specific differences between 304 and 316 stainless steel?
Answer: Specific differences pertain to the makeup of the material. 316 contains 16% chromium, 10% nickel and 2% molybdenum. 304 contains 18% chromium and 8% nickel. Molybdenum adds corrosion resistance to substances such as salt found in highway de-icing salts and ocean water.

Question: Is stainless steel magnetic?
Answer: Yes and no. 300 series stainless steel contains nickel and does not have magnetic properties. 400 series stainless steel, which does not contain nickel, is magnetic.

Question: Is stainless steel suitable for welding?
Answer: Many of our customers weld with stainless steel. However, welding stainless steel varies from welding carbon steel, since “filler” rod or electrode must be of the same material (stainless steel).

Question: What about hardening stainless steel – can this be done?
Answer: It is possible to harden 300 series stainless steel. This can be done by cold-working the metal, cold-rolling down to lighter gauges, or by other size-altering means. Talk to us about your specific needs.

Question: What does an “L” signify in a stainless steel grade?
Answer: This pertains to carbon content. For example, the use of the letter L in the grade number 317L means that the carbon content does not exceed 0.03%. Lower carbon level stainless steel is often used in welding applications.

Question: Does stainless steel perform well in temperature extremes?
Answer: Stainless steel performs well in hot and cold temperatures. It may be used in applications with high heat of up to 1,800 degrees, as well as extreme cold, such as liquid nitrogen transport.

Question: What kind of machine finishing can you do on stainless steel?
Answer: We can machine finish your stainless steel project with a coarse or fine grain, or bring it up to a high luster, mirror-like finish.

Question: How can I get more information?
Answer: Contact us at +86 21 3378 0199 or sales@sunnysteel.com

5 Frequently Asked Questions about Stainless Steel

Stainless steel permeates so many aspects of life of today. The singular properties of this metal make it well suited for a wide range of applications – especially ones where conditions are demanding. From corrosion resistant cutlery and surgical tools, to food and pharmaceutical tanks, to water-tight watch housings and tools that can handle extreme temperatures; it’s safe to say that the world would be a different place without stainless steel.

Given its wide range of uses, it’s no surprise that there are some unique questions that are frequently asked about this metal. We have selected the top five questions, and compiled here a list of interesting facts about stainless steel, by way of a response.

To clarify, stainless steel is not a single type of metal, but more like a family of metals. There are generally five different categories with multiple grades contained in each. Each has its own different properties and uses.

1. What is special about food grade stainless steel?

Food-grade stainless steel is special not only because it can withstand extreme temperatures, but also because it resists corrosion and is able to be easily sanitized. This ease of sanitization is due to the electropolishing process and the protective oxide layer of the metal. The electropolishing process strips away the outer layer of the stainless steel, leaving behind a microscopically smooth surface. Most typically, type 304 and 316 are the ideal choices for food grade stainless steel.

2. Is stainless steel really stainless?

Because stainless steel is nearly rust proof, it is considered to be stainless. Its chromium atoms bind so securely with its oxygen atoms that a nearly impenetrable and rust-resistant layer is formed. The oxygen atoms are captured by this layer before they can bind to the iron that is in steel so rust is never given the chance to form.

3. How is stainless steel better than aluminum?

As we have already mentioned, stainless steel holds up well in extreme conditions. Aluminum can be used in several similar applications, like cookware. In terms of longevity, steel is harder than aluminum. This means it is less likely to bend, warp or otherwise deform due to force, heat or weight. Another huge difference is electrical conductivity. Stainless is a poor conductor of electricity, whereas aluminum is relatively conductive. Stainless is a great choice for projects requiring low conductivity.

4. Can stainless steel be successfully welded?

Yes! Fabricators weld stainless steel for all kinds of projects. With some small adjustments to the standard equipment, stainless can be welded. In order to weld austenitic stainless, the electrode or filler rod used must be stainless steel. Stainless can be welded to stainless, or to other metals, as long as the proper welding process, shielding gas and filler rod are selected.

5. Is stainless steel stored and handled differently than other metals?
If your small shop or home project requires you to store quantities of stainless steel, handling procedures are good to know. It’s best to store stainless steel away from other metals. Especially in acidic or damp environments — stainless can cause galvanic corrosion in other metals. This type of corrosion typically leaves the stainless steel unaffected. Even with the strength and resistance to the elements, it is still possible to scratch, dent, and even cause corrosion (extended exposure to chlorine) to stainless. Care should be taken with the surface, and proper safety precautions should always be used.

Stainless steel is a versatile metal found in every industry today. The above questions are just the beginning when it comes to learning about its different properties.

Properties of Stainless Steel

Stainless steel has different corrosion properties which includes being non-corrosive, rust-resistant steel, which is simply designated as stainless steel. In comparison with aluminium, stainless steel is approximately 3 times heavier.

Stainless steel, like steel itself, is an alloy. An alloy always consists of different materials. Among the most frequent alloying elements in non-corrosive stainless steel is chrome, where nickel, molybdenum and further elements are used for special requirements.

The magnetisability, as well as the corrosion resistance, are two of these requirements which are controlled by the different alloys.

Stainless steel is a metal alloy, made up of steel mixed with elements such as chromium, nickel, molybdenum, silicon, aluminum, and carbon. Iron mixed with carbon to produce steel is the main component of stainless steel.

Chromium is added to make it resistant to rust. The addition of nickel enhances corrosion resistance properties in case of aggressive usage. The addition of molybdenum gives localized corrosion resistance against scarring. Other alloying metals like copper, titanium and vanadium are also added in order to improve the properties and structure of stainless steel. In all, there are more than 150 grades of steel, but only 15 are used regularly.

Stainless steel is preferred for making kitchen utensils because it does not affect the flavor of food and is easy to clean. It is used to manufacture cookware, surgical instruments, plates, sheets, bars, wire, kitchen cutlery, industrial equipment, building construction materials and hardware. It is also used in commercial kitchens and food processing plants.

Stainless steel is a hard and strong substance, it is not a good conductor of heat and electricity, it is ductile, magnetic, retains its strength and cutting edge regardless of temperature. There are five major types of stainless steel: Ferritic, Martensitic, Precipitation Hardening, Austenitic and Duplex.

Ferritic stainless steel contains 30% chromium that has a crystal structure. It is known to have ferromagnetic properties as well as malleability and ductility. Ferritic stainless steel lacks in high-temperature mechanical properties.

Martensitic stainless steel is a mixture of carbon and 18% chromium. It can be hardened by heat treatments. It is known to have ferromagnetic properties and less corrosion resistance.

Precipitation Hardening stainless steel contains a mixture of nickel and chromium. It is very strong.

Austenitic stainless steel is formed by using nitrogen, manganese and nickel. It contains about 16-26% of chromium and less than 35% nickel. Austenitic stainless steel is tough, ductile with cryogenic and high temperature strength properties.

Duplex stainless steel constitutes a combination of austenite and ferrite crystal structures. Chromium and nickel are the main alloying elements in duplex stainless steel. It is corrosion resistant.

Uses and properties
Steel with a chromium content of more than 10.5%, as well as various other elements in smaller quantities, is considered to be stainless. In combination with oxygen chromium forms a thin, sealed, fixed-adhering, chromic-oxide layer – the so-called passive layer. It is exactly this passive layer which is responsible for the resistance of the material. Due to its corrosion resistance, the metal is used for example for washing drums.
Rust-resistant stainless steel can be very well compared to anodised aluminum with regard to its properties. If the exterior skin of the material is impaired, the material and its surface mostly suffer damage.

Stainless steel applications

  • Automotive and transportation
    Stainless steel was introduced in automotive in the 1930s by Ford to manufacture their concept cars. Since then, it is used to produce a variety of automotive parts such as exhaust systems, grills, and trims. With advancing technology, stainless steel is being favoured by manufacturers to make structural components.
    It is also heavily featured in other fields of transportation like freighting to make shipping containers, road tankers and refuse vehicles. It’s resistance to corrosion makes it ideal to transport chemicals, liquids and food products. The low maintenance of stainless steel also makes it an easy and cost-effective metal to clean and sustain.
  • Medical technology
    Stainless steel is preferred in clean and sterile environments as it is simple to clean and does not easily corrode. Stainless is used in the production of a wide range of medical equipment, including surgical and dental instruments.
    It is also used in building operation tables, kidney dishes, MRI scanners, cannulas, and steam sterilizers.
    Most surgical implants, such as replacement joints and artificial hips are made from stainless steel, as well as some joining equipment like stainless steel pins and plates to repair broken bones.
  • Building trade
    Due to its strength, resistance, and flexibility, stainless steel application has become a vital element of the building trade. It is commonly featured in the interior on countertops, backsplashes, and handrails, and is also used externally in cladding for high impact buildings.
    It is a common feature in modern architecture due to its weldability, easy maintenance and attractive finish, which is used in the Eurostar Terminal in London and the Helix Bridge in Singapore.
    With the movement towards sustainable building, stainless steel, which is a highly recyclable metal, is becoming increasingly preferable to use in construction. With a polished or grain finish, it has aesthetically pleasing properties and can aid in improving natural lighting in the building.
  • Aircraft construction
    The aviation industry also has a preference for stainless steel. It is used in various applications including the frames of aeroplanes because of its strength and ability to withstand extreme temperatures. It can also be applied in jet engines as it can help prevent against its rusting.
    Stainless steel is also an essential part of the landing gear. Its strength and rigidity can handle the weight of the landing aircraft.
  • Food and the catering industry
    In the food and catering industry, stainless steel is used to manufacture kitchen accessories, cookware, and cutlery. Utensils such as knives are made using less ductile grades of stainless steel. The more ductile grades are used to make grills, cookers, saucepans, and sinks.
    Stainless steel can also be used to finish freezers, dishwashers, refrigerators, and countertops. In food production, stainless steel is ideal because it doesn’t affect the flavour of the food. It is also corrosion resistant, and hence able to hold acidic drinks including orange juice. The ease of cleaning stainless steel makes it difficult to harbour bacteria, adding to its usefulness in food storage.
  • Tanker manufacture
  • Vessel manufacture

Benefits of Stainless Steel

  • Strength
    A fundamental property of stainless steel is its strength. It remains incredibly strong at very high or low temperatures, making it a highly sought after metal for demand applications like aviation.
  • Easy to clean
    As it is one of the most hygienic materials, its use in catering and medical applications is suitable. It doesn’t support the growth of bacteria and is easy to clean and sterilize, hence is low maintenance. It can be cleaned using a swab and an all-purpose cleaner, making it beneficial for use in kitchens and hospitals.
  • Aesthetics
    Strength is not the only property of stainless steel. It also looks great which is why it is commonly featured in architecture. It adds a sleek and contemporary look to classic and modern spaces, without compromising on functionality.
  • Corrosion resistance
    Stainless steel can fend off rust and water stains as it is highly resistant to corrosion. This is why stainless steel applications extend to outdoor as well as indoor applications at various pressure and temperature extremes. This property of stainless steel comes from the addition of chromium to the metal, which when exposed to oxygen, creates a fine film over the steel to protect it.
  • Recyclable
    Most of the stainless steel is made from recycled steel. Impressively, its qualities do not deteriorate once the metal is recycled, allowing it to be reused continuously and benefit the environment.

Common grades provided
Stainless Steel is a widely used material across industries because of its corrosion resistance and high versatility. Notably, this tough metal requires relatively low maintenance.
The grades vary depending on the amounts of Carbon, Silicon, Manganese and other elements used in the properties. It is commonly referred to by its grade numbers. We offer a wide range of grades including 301, 303, 304, 304L, 310, 316, 316L, 321, 410, 416, 420, 430 and 440. The grade of steel required depends on your application and use.
We are also able to call upon the unrivalled range of stainless steel products that are available from our extensive network of European warehouses to ensure that we can offer the products that our customers require, no matter how diverse.
Properties of a few common grades are listed below.

Designations
Density
Modulus of
elasticity
Mean coefficient of
thermal expansion
[10−6·K−1]
Thermal
Conductivity
Specific
Heat
Electrical
resistivity
EN
[N°]
AISI/ASTM
at 20 °C
[kg/dm3]
at 20 °C
[GPa]
20 °C
200 °C
20 °C
400 °C
at 20 °C
[W/(m·K)]
at 20 °C
[J/(kg·K)]
at 20 °C
[(Ω·mm2)/m]
Austenitic stainless steels
1.4301
304
7,9
200
16,5
17,5
15
500
0,73
1.4401
316
8,0
200
16,5
17,5
15
500
0,75
Duplex stainless steels
1.4462
2205
7,8
200
13,5
14,0 (g)
15
500
0,80
1.4362
2304
7,8
200
13,5
14,0 (n)
15
500
0,80
1.4501
7,8
200
13,5
(n.r.)
15
500
0,80
Ferritic stainless steels
1.4512
409
7,7
220
11,0
12,0
25
460
0,60
1.4016
430
7,7
220
10,0
10,5
25
460
0,60
Martensitic stainless steels
1.4021
420
7,7
215
11,0
12,0
30
460
0,60
1.4418
7,7
200
10,8
11,6
15
430
0,80
Precipitation hardening stainless steels
1.4542
630
7,8
200
10,8
11,6
16
500
0,71

Stainless steel families

There are four main families, which are primarily classified by their crystalline structure: austenitic, ferritic, martensitic and duplex.

  1. Austenitic stainless steel
    Austenitic stainless steel is the largest family of stainless steels, making up about two-thirds of all stainless steel production. They possess an austenitic microstructure, which is a face-centered cubic crystal structure. This microstructure is achieved by alloying with sufficient nickel and/or manganese and nitrogen to maintain an austenitic microstructure at all temperatures from the cryogenic region to the melting point. Thus austenitic stainless steels are not hardenable by heat treatment since they possess the same microstructure at all temperatures.
    Their yield strength is low (200 to 300MPa), which limits their use for structural and other load bearing components. Duplex stainless steels tend to be preferred in such situations because of their high strength and corrosion resistance.
    Their elongation is high, which allows very important deformation in fabrication processes (such as deep drawing of kitchen sinks)
    They are weldable by all processes. The most frequently used is electric arc welding.
    Thin sheets and small diameter bars can be strengthened by cold working, with an associated reduction of elongation. However, if they are welded, the welded area will return to the low strength level of the steel before cold working. This limits the use of cold-worked austenitic stainless steels.
    They are essentially non-magnetic and maintain their ductility at cryogenic temperatures.
    They can be further subdivided into two sub-groups, 200 series and 300 series:
    200 Series are chromium-manganese-nickel alloys, which maximize the use of manganese and nitrogen to minimize the use of nickel. Due to their nitrogen addition they possess approximately 50% higher yield strength than 300 series stainless steels. Type 201 is hardenable through cold working; Type 202 is a general purpose stainless steel. Decreasing nickel content and increasing manganese results in weak corrosion resistance.[40]
    300 Series are chromium-nickel alloys, which achieve their austenitic microstructure almost exclusively by nickel alloying; some very highly alloyed grades include some nitrogen to reduce nickel requirements. 300 series is the largest group and the most widely used. The best known grade is Type 304, also known as 18/8 and 18/10 for its composition of 18% chromium and 8%/10% nickel, respectively. The second most common austenitic stainless steel is Type 316. The addition of 2% molybdenum provides greater resistance to acids and to localized corrosion caused by chloride ions.
    Low-carbon versions, for example 316L or 304L, are used to avoid corrosion problems caused by welding. The “L” means that the carbon content of the alloy is below 0.03%.
  2. Ferritic stainless steels
    Ferritic stainless steels possess a ferrite microstructure like carbon steel, which is a body-centered cubic crystal structure, and contain between 10.5% and 27% chromium with very little or no nickel . This microstructure is present at all temperatures, due to the chromium addition, and like austenitic stainless steels these are not hardenable by heat treatment. They cannot be strengthened by cold work to the same degree as austenitic stainless steels. They are magnetic like carbon steel.As they do not contain Nickel, they cost less than austenitic grades and are now present in a wide range of industries. Common grades are 409 and 409Cb (Cb is the US name for Nb) with about 10.5%Cr, the latter being used mostly for automobile exhaust pipes in North America, 430 (17%Cr) for architectural applications, for kitchenware, sinks, slate hooks, roofing, etc…). Additions of Nb, Ti, Zr to grade 430 allow a good weldability and such grades are used for automotive exhaust pipes, for white goods (dishwashers, refrigerator doors, chimney ducts, solar water heaters etc.).
    Higher Cr ferritics (22%Cr) are now used for power plates for Solid Oxide Fuel Cells (SOFC) operating at temperatures around 700 °C.
    Electrical resistance ferritic grades Fr-Cr-Al are not included in these groups, as they are designed for oxidation resistance at elevated temperatures.[41]
  3. Martensitic stainless steels
    Martensitic stainless steels offer a wide range of properties and are used as stainless engineering steels, stainless tool steels, and creep resisting steels. They fall into 4 categories (with some overlap):Fe-Cr-C grades:
    They were the first grades used and they are still widely used in engineering and wear-resistant applications.
    Fe-Cr-Ni-C grades: In these grades, some of the carbon is replaced by nickel. They offer a higher toughness and a higher corrosion resistance. Grade EN 1.4303 (Casting grade CA6NM) with 13%Cr and 4%Ni is used for most Pelton, Kaplan and Francis turbines in hydroelectric power plants [43] because it has good casting properties, a good weldability and a good resistance to cavitation erosion.
    Precipitation hardening grades: Grade EN 1.4542 (a.k.a. 17/4PH), the best known grade, combines martensitic hardening and precipitation hardening. It achieves high strength and good toughness and is used in aerospace among other applications.
    Creep-resisting grades: Small additions of Nb, V, B, Co increase the strength and creep resistance up to about 650 °C.
    Heat treatment of martensitic stainless steels
    Martensitic stainless steels form a family of stainless steels that can be heat treated to provide the adequate level of mechanical properties.
    The heat treatment typically involves three steps:
    Austenitizing, in which the steel is heated to a temperature in the range 980 – 1050 °C depending on the grades. The austenite is a face centered cubic phase.
    Quenching (a rapid cooling in air, oil or water). The austenite is transformed into martensite, a hard body-centered tetragonal crystal structure. The as-quenched martensite is very hard and too brittle for most applications. Some residual austenite may remain.
    Tempering, i.e. heating to around 500 °C, holding at temperature, then air cooling. Increasing the tempering temperature decreases the yield strength and ultimate tensile strength but increases the elongation and the impact resistance.
    Nitrogen-alloyed martensitic stainless steels
    Replacing some of the carbon in martensitic stainless steels by nitrogen is a fairly recent development. The limited solubility of nitrogen has been increased by the pressure electroslag refining (PESR) process in which melting is carried out under a high nitrogen pressure. Up to 0.4% nitrogen contents have been achieved leading to higher hardness/strength and higher corrosion resistance. As the PESR is expensive, lower but significant nitrogen contents have been achieved using the standard argon oxygen decarburization (AOD) process.[45][46][47][48][49]
    They are magnetic. They are not as corrosion resistant as the common ferritic and austenitic stainless steels due to their low chromium content.
  4. Duplex stainless steel
    Duplex stainless steels have a mixed microstructure of austenite and ferrite, the aim usually being to produce a 50/50 mix, although in commercial alloys the ratio may be 40/60. They are characterized by high chromium (19–32%) and molybdenum (up to 5%) and lower nickel contents than austenitic stainless steels. Duplex stainless steels have roughly twice the yield strength of austenitic stainless steels. Their mixed microstructure provides improved resistance to chloride stress corrosion cracking in comparison to austenitic stainless steels Types 304 and 316.
    Duplex grades usually divided into three sub-groups based on their corrosion resistance: lean duplex, standard duplex and super duplex.
    The properties of duplex stainless steels are achieved with an overall lower alloy content than similar-performing super-austenitic grades, making their use cost-effective for many applications. The pulp and paper industry was one of the first ones to use extensively duplex stainless steel. Today, the oil and gas industry is the largest user and has pushed for more corrosion resistant grades, leading to the development of super duplex and even so-called hyper duplex grades. More recently, the less expensive (and slightly less corrosion-resistant) lean duplex has been developed, chiefly for structural applications in building and construction (concrete reinforcing bars, plates for bridges, coastal works) and for the water industry.
  5. Precipitation hardening stainless steels
    Precipitation hardening stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths than the other martensitic grades.

There are based on 3 types:

    • Martensitic 17-4 PH,(AISI 630 EN 1.4542) contains about 17% Cr, 4%Ni, 4%Cu and 0.3% Nb.
      Solution treatment at about 1040 °C followed by quenching results in a relatively ductile martensitic structure. Subsequent ageing treatment at 475 °C precipitates Nb and Cu-rich phases that increase the strength up to above 1000 MPa yield strength. This outstanding strength level finds uses in high tech applications such as aerospace (usually after remelting to eliminate non-metallic inclusions and thereby to increase fatigue life). Another major advantage of this steel is that ageing, unlike tempering treatments, is carried out at a temperature that can be applied to (nearly) finished parts without distortion and discoloration.
    • Semi Austenitic 17-7PH (AISI 631 EN 1.4568) contains about 17%Cr, 7.2% Ni and 1.2%Al.
      Typical heat treatment involves first solution treatment and quenching. At this point, the structure remains austenitic. Martensitic transformation is then obtained either by a cryogenic treatment at -75 °C or by severe cold work (over 70% deformation, usually by cold rolling or wire drawing). Ageing at 510 °C, which precipitates the Ni3Al intermetallic phase, is carried out as above on nearly finished parts. Yield stress levels above 1400 MPa are then reached.
    • A286 [52](ASTM 660 EN 1.4980) has the following typical analysis Cr 15%, Ni 25% Ti 2.1% Mo 1.2% V 1.3% and B 0.005%
      The structure remains austenitic at all temperatures.
      Typical heat treatment involves solution treatment and quenching, followed by ageing at 715 °C. Ageing forms Ni3Ti precipitates and increase the yield strength to about 650MPa at room temperature. Unlike the above grades, the mechanical properties and creep resistance of this PH steel remain very good at temperatures up to 700 °C.
      A286 is in fact a Fe-based superalloy, used in jet engines and gas turbines, turbo parts, etc.
      The designation “CRES” is used in various industries to refer to corrosion-resistant steel. Most mentions of CRES refer to stainless steel, although the correspondence is not absolute, because there are other materials that are corrosion-resistant but not stainless steel.

Production process

  • Most of the world stainless steel production is produced by the following processes.
  • EAF (Electric Arc Furnace) in which stainless steel scrap, other ferrous scrap and ferro alloys (Fe Cr,Fe-Ni, Fe Mo, Fe Si …) are melted. The molten metal is then poured into a ladle and transferred into the AOD
  • AOD (Argon Oxygen Decarburization) allows the removal of carbon in the molten steel and other composition adjustments to achieve the desired chemical composition of the steel
    CC (Continuous Casting) in which the molten metal is solidified into slabs (typical section is 20 cm thick and 2 m wide) for flat products or blooms (sections vary widely but 25cmx25cm is about the average).
  • HR (Hot Rolling): The slabs and blooms are reheated in a furnace and then hot rolled. Hot rolling reduces the thickness of the slabs to produce about 3mm thick coils. Blooms on the other hand are hot rolled into bars (that are cut into lengths at the exit of the rolling mill) or wire rod which is coiled.
  • CF (Cold finishing): This is a very simplified overview.

Hot rolled coils are pickled in acid solutions to remove the oxide scale on the surface, then subsequently cold rolled (Sendzimir rolling mills), annealed in a protective atmosphere, until the desired thickness and surface finish is obtained. Further operations such as slitting, tube forming, etc. can be carried out in downstream facilities.

  • Hot rolled bars are straightened, then machined to the required tolerance and finish.
  • Wire rod coils are subsequently processed to produce
  • cold finished bars on drawing benches
  • fasteners on boltmaking machines
  • wire on single or multipass drawing machines

Steel Plates Weight (Metric Sizes)

The article shows the dimensions and weights of steel plates for general use (weight per linear meter depending on steel plate thickness and width)

Plate Thickness (mm) Weight (kg/m) kg/meter (width 1200mm) kg/meter (width 1500mm) kg/meter (width 1800mm) kg/meter (width 2400mm)
3 23.55 28.3 35.3 42.4 56.5
4 31.4 37.7 47.1 56.5 75.4
5 39.25 47.1 58.9 70.7 94.2
6 47.1 56.5 70.7 84.8 113
8 62.8 75.4 94.2 113 150.7
10 78.5 94 118 141 188
12 94.2 113 141 170 226
16 125.6 151 188 226 301
20 157 188 236 283 377
22 172.7 207 259 311 415
25 196.25 236 294 353 471
28 219.8 264 330 396 528
32 251.2 301 377 452 603
36 282.6 339 424 509 678
40 314 377 471 565 754
45 353.25 424 530 636 848
50 392.5 471 589 707 942
55 431.75 518 648 777 1036
60 471 565 707 848 1130
65 510 612 765 918 1224
70 549.5 659 824 989 1319
75 588.75 707 883 1060 1413
80 628 754 942 1130 1507
90 706.5 848 1060 1272 1696
100 785 942 1178 1413 1884

Weight of Steel Plates by Thickness/Width
Weights are expressed in kilogram per linear meter

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