NON-FERROUS METALS

STAINLESS STEELS

NON-FERROUS METALS

STAINLESS STEELS

The term stainless is a general term for stainless steel that requires a minimum of 10.5% Chromium. The chromium content in steel is very important as it forms a thin layer of chromium oxide on the metal surface to prevent corrosion of the metal.

What is Stainless Steel?

 
Stainless steels are a group of steels with a minimum chromium content of 10.5% and resistant to corrosion. This is considered in the stainless category for other steels, including some tool steels that contain chromium levels. The major difference between these steels and stainless steels comes from the addition of a certain amount of chromium in stainless steels mainly to improve corrosion resistance.
 
The European standard for stainless steels EN 10088 (published in the UK as BS EN 10088) defines stainless steels as steels with a minimum (Chromium value) of 10.5% for use in applications where corrosion resistance is required.
 
Many commercially available stainless steels contain more than this minimum level of chromium, and also nickel, molybdenum, titanium, niobium, etc. They contain varying amounts of other alloying additions, including These additions are used not only to increase the corrosion resistance of the steel, but also to improve mechanical strength, hardness, toughness, magnetic properties, etc. It is added to improve other properties or to modify working properties, including formability, machinability, and weldability.
 
Stainless steels can also be used in heat resistant and cryogenic applications as they have excellent oxidation resistance. These special steels often have enhanced chromium levels to improve their heat resistance properties. They are covered by the BS EN 10095 standard.
 
The behavior of various stainless steels during manufacture and use depends not only on their chemical composition, but also on the design and surface quality of the manufactured parts. Being careful in this regard, selection of the most suitable steel grade, design and surface finish is vital for the successful application of stainless steels.

Products

Products

Qualities
301 (1.4310) 302 (1.4310) 303 (1.4305)
304 (1.4301) 304L (1.4307) 310 (1.4845)
316 (1.4401) 316L (1.4404) 420 (1.4021)
431 (1.4057) 440M (1.4116N) 630 (1.4542) 17-4 PH
1.4545 PH 13-8 Mo (1.4534)

301 (1.4310)

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302 (1.4310)

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303 (1.4305)

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304 (1.4301)

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304L (1.4307)

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310 (1.4845)

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316 (1.4401)

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316L (1.4404)

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420 (1.4021)

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431 (1.4057)

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440M (1.4116N)

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630 (1.4542) 17-4 PH

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1.4545

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PH 13-8 Mo (1.4534)

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What are the types of Stainless Steels?

Stainless steels have “family” names that reflect their metallurgical (atomic) nature.

These groupings, often referred to as families, are:

  • Ferritic
  • Austenitic
  • Duplex (ferritic-ausenitic)
  • Martensitic and precipitation hardening

The main characteristics of each family are:

Ferritik (Ferritic)

  • Magnetic
  • low carbon
  • Chromium major alloying element, typically in the range of 10.5-17%
  • Cannot be hardened by heat treatment
  • Typical grades 409 (1.4512), 430 (1.4016)
 

Austenitic

  • Non-magnetic (when fully softened)
  • Low carbon Chromium content typically 16-20%
  • Nickel content is typically 7-13%
  • Cannot be hardened by heat treatment, but becomes significantly stronger during cold working
  • Typical grades 304 (1.4301), 316 (1.4401)

Duplex

  • Magnetic

  • low carbon

  • Chromium content typically 21-26%

  • Nickel content is typically 3.5-6.5%

  • Nitrogen content, typically 0.05-0.40%

  • Cannot be hardened by heat treatment but exhibits higher annealed strength levels than ferritic or austenitic stainless steels

  • Typical grade 2205 (1.4462)

Martensitic and precipitation hardening

  • Magnetic or non-magnetic
  • Carbon can be up to 0.95%
  • Chromium content typically 12.0-17%
  • Nickel content is typically 2-7%
  • Precipitation hardening types also contain aluminum or copper Can be hardened by heat treatment
  • Typical grades 420 (1.4021), 17/4PH (1.4542)

What are the Physical Properties of Stainless Steels?

In addition to corrosion resistance, certain stainless steel grades have other properties that can be useful in service or during fabrication. These characteristics can vary greatly between families and various degrees and include:

Mechanical Strength

The mechanical strength of ferritic (about 500 MPa) and austenitic (about 600 MPa) stainless steels is similar to that of low alloy steels. Austenitic steels retain their strength with temperature increases better than ferritic stainless steels or non-stainless structural steels. This makes austenitic stainless steels good choices for fire and heat resistant applications.

Duplex steels have about twice the strength of these other steels, with a yield strength of about 450 MPa and a tensile strength of 700 MPa. Their mixed structure of ferritic and austenitic mixture together with their nitrogen content enhances these high levels of strength.

The strength of martensitic and precipitation hardening steels can be varied over a wide range by heat treatment. The precipitation hardening types in particular have very high strength levels up to 1100 MPa.

Hardness

Hardness, resistance to indentation or scratching is similar for all “softened” steels such as ferritic, austenitic and duplex family grades. Only martensitic grades with enhanced carbon levels can be hardened. Grades such as 440C (1.4125) can be hardened to approximately 60 HRC (Rockwell C). In contrast, precipitation hardening grades, despite their name, are used primarily for their heat treatable strength rather than hardness.

Corrosion Resisdance

All stainless steels can withstand some degree of corrosion. There is a wide variety of service environments, different formats and locations where a corrosion attack can take place. This is the main reason why there are four main types of stainless steel and each has its own grade range. All stainless steels have a corrosion resistant, tightly adherent, chromium-rich passive layer.

Hardening

Hardening is the gradual increase in strength and hardness of a material (as it is “cold” worked). Most metals harden to some degree during processes such as cold forming, bending or machining.

The hardening rate of austenitic stainless steels is higher than most other metals. This is because some of the austenite turns into the stronger martensite component. These are structural changes in steel.

Hardening can be both a disadvantage and an advantage. It is undesirable during machining, but advantageous during some cold drawing operations where it can delay premature failure during operation.

Interstage annealing operations are often needed, but when producing severely drawn or complex shaped parts. The effects of cold working can be reversed by annealing heat treatments at about 1050°C.

Magnetic Permeability

Magnetic permeability is a measure of the attractiveness of a permanent magnet. Most materials, including many metals, are not attracted to a magnet. The common exception comes from iron and most steels, which can also be converted into magnets, i.e. magnetized and demagnetized by electric fields.

Softened austenitic steels do not behave this way. They have very low magnetic permeability with relative permeability values ​​of around 1.005. Ferritic and martensitic stainless steels, by contrast, have relative permeability values ​​of around 15. With this very low relative permeability, austenitic stainless steels can be used in equipment that is very sensitive to magnetic field interference but also needs to be corrosion resistant.

These applications include medical body scanner bodies and marine minesweeper equipment. With its additional nitrogen content, grade 316LN (1.4406) is well suited for such applications. It should be noted that hardened austenitics can be somewhat magnetic.

 

Click the button below for the tables containing the technical and physical features of our Stainless Steel products!

Ferritic ve Martensitic

Standarts
Chemical Composition
Mechanic Characteristics
DIN 17440/17441
W. Nr German
AISI American
BSI English
JIS Japanese
C (max.)
Cr
Ni
Mo
Diğer
Tensile strength (N/mm²)
Yield strength (N/mm²)
Elongation (%)
Hardness(HB) max.
X10 Cr13
1.4006
410
410S21
SUS4105
0.12
13
450-650
220
20
185
X20 Cr13
1.4021
420
420S29
SUS420J1
0.20
13
420-560
225
14
220
X6 Cr17
1.4016
430
430S15
0.08
17
450-600
270
20
180
X10 Cr AL24
1.4749
446
SUS430
0.18
25
500-700
230
20
180
X5 CrNi 18.10
1.4301
304
304S15
SUS304
0.07
18.5
9.5
500-700
230
45
180

Austenitics

Standarts
Chemical Composition
Mechanical Characteristics
DIN 17440/17441
W. Nr German
AISI American
BSI English
JIS Japanese
C (max.)
Cr
Ni
Mo
Other
Tensile strength (N/mm²)
Yield strength (N/mm²)
Elongation (%)
Hardness(HB) max.
X2 CrNi 19.11
1.4306
304L
304S12
SUS304L
0.03
19
11
460-680
215
40
202
X6 CrNiTi 18.10
1.4541
321
321S12
SUS312
0.08
18.5
10.5
460-680
210
45
183
X6 CrNiNb 18.10
1.4550
347
347S17
SUS347
0.08
18.5
11
500-750
205
35
217
X5 CrNiMo 17.12.2
1.4401
316
316S16
SUS316
0.07
17
11.50
2.25
510-710
205
40
190
X5 CrNiMo 17.13.3
1.4403- 1.4436
316
316S18
SUS316
0.07
17
12
2.75
510-710
205
40
217
X2 CrNiMo 17.13.2
1.4404
316L
316S12
SUS316L
0.03
17
12
2.25
490-690
190
40
217
X2 CrNiMo 18.14.3
1.4435
316L
316S14
SUS316L
0.03
17
12.50
2.75
490-690
190
40
217
X6 CrNiMoTi 17.12.2
1,4571
316Ti
320S17
Add New
0.08
17
11.50
2.25
500-730
210
40
217
X2 CrNiMoTi 17.16.4
1.4438
317L
317S16
SUS317L
0.03
18
14.50
3.50
500-700
195
34
217
X6 CrNi 23.14
1.4833
309S
309S24
SUS3O9TB
0.08
23
13
500-750
210
26
180
X12 CrNi 25.21
1.4845
310S
310S24
SUS310TB
0.08
25
20
500-750
210
26
192