• The solution to Newton's GEXACT VALUE & FORMULA
  • The theory controlling planetary spinTHE MATHEMATICAL LAW
  • The pressure at the centre of a massEARTH'S CORE PRESSURE (calculation procedure)
  • Proof of the non-exitence of Dark MatterDOES NOT EXIST
  • The atom as Newton and Coulomb describe itNO NEED FOR A UNIFICATION THEORY
The solution to Newton's G1 The theory controlling planetary spin2 Pressure at the centre of the Earth3 Proof of the non-exitence of Dark Matter4 The atom as Newton describes it5
Materials Carbon Steel SAE Steel Grading Plain Carbon Steels Special Carbon Steels Alloy Carbon Steels Stainless Steels Uses Utilisation

SAE AISI Alloy Carbon Steels

CalQlata's term 'alloy carbon' steels refers to what is generally known as 'high-alloy' steels
They comprise the same alloying elements as special carbon steel along with additional alloying elements⁽¹⁾

Moreover, these steels have the same alloying elements as the equivalent plain carbon steel with the same last two digits, but perhaps in different quantities, along with additional alloying elements to facilitate work hardening and heat treatment.

See Physical Properties below to obtain physical properties for each of steel grade

All the alloy steels on this page contain the following:
Sulphur (S) <0.04%⁽²⁾, Phosphorus (P) <0.035%, Silicon (Si) 0.02%<0.035%

2XXX (Nickel Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Ni (%)
min<max
2330 0.3 0.8 3.6
25XX ??<?? ??<?? 5

3XXX (Nickel-Chromium Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Cr (%)
min<max
Ni (%)
min<max
3140 0.4<0.5 0.5<0.8 0.45<0.75 1<1.5
32XX ??<?? ??<?? 1.07 1.75
33XX ??<?? ??<?? 1.5<1.57 3.5
34XX ??<?? ??<?? 0.77 3

4XXX (Molybdenum Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Mo (%)
min<max
Cr (%)
min<max
Ni (%)
min<max
4012
4023
4024⁽²ᴬ⁾
4027
4028⁽²ᴬ⁾
4037
4047
0.09<0.14
0.2<0.25
0.2<0.25
0.25<0.3
0.25<0.3
0.35<0.4
0.45<0.5
0.75<0.1
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.15<0.25
0.2<0.3
0.2<0.3
0.2<0.3
0.2<0.3
0.2<0.3
0.2<0.3
4118
4130
4137
4140
4142
4145
4147
4150
4161
0.18<0.23
0.28<0.33
0.35<0.4
0.38<0.43
0.4<0.45
0.43<0.48
0.45<0.5
0.48<0.53
0.56<0.64
0.7<0.9
0.4<0.6
0.7<0.9
0.75<1.0
0.75<1.0
0.75<1.0
0.75<1.0
0.75<1.0
0.75<1.0
0.08<0.15
0.15<0.25
0.15<0.25
0.15<0.25
0.15<0.25
0.15<0.25
0.15<0.25
0.15<0.25
0.25<0.35
0.4<0.6
0.8<1.1
0.8<1.1
0.8<1.1
0.8<1.1
0.8<1.1
0.8<1.1
0.8<1.1
0.7<0.9
4320
4340
E4340⁽²ᴮ ⁴⁾
0.17<0.22
0.38<0.43
0.38<0.43
0.45<0.65
0.6<0.8
0.65<0.85
0.2<0.3 0.4<0.6
0.7<0.9
0.7<0.9
1.65<2.0
4419 0.18<0.23 0.45<0.65 0.45<0.6
4615
4620
4621
4626
0.13<0.18
0.17<0.22
0.18<0.23
0.24<0.29
0.45<0.65
0.45<0.65
0.7<0.9
0.45<0.65
0.2<0.3
0.2<0.3
0.2<0.3
0.15<0.25
1.65<2.0
1.65<2.0
1.65<2.0
0.7<1.0
4718
4720
0.16<0.21
0.17<0.22
0.7<0.9
0.5<0.7
0.3<0.4
0.15<0.25
0.35<0.55 0.09<0.12
4815
4817
4820
0.13<0.18
0.15<0.2
0.18<0.23
0.4<0.6
0.4<0.6
0.5<0.7
0.2<0.3 3.25<3.75

5XXX (Chromium Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Cr (%)
min<max
5015
50B44
50B46
50B50
50B60
0.12<0.17
0.43<0.48
0.44<0.49
0.48<0.53
0.56<0.64
0.3<0.5
0.75<1.0
0.75<1.0
0.75<1.0
0.75<1.0
0.3<0.5
0.4<0.6
0.2<0.35
0.4<0.6
0.4<0.6
5117
5120
5130
5132
5135
5140
5145
5147
5150
5155
5160
51B60
E51100⁽²ᴮ ⁴⁾
E52100⁽²ᴮ ⁴⁾
0.15<0.2
0.17<0.22
0.28<0.33
0.3<0.35
0.33<0.38
0.38<0.43
0.43<0.48
0.46<0.51
0.48<0.53
0.51<0.59
0.56<0.64
0.56<0.64
0.98<1.1
0.98<1.1
0.7<0.9
0.7<0.9
0.7<0.9
0.6<0.8
0.6<0.8
0.7<0.9
0.7<0.9
0.7<0.95
0.7<0.9
0.7<0.9
0.75<1.0
0.75<1.0
0.25<0.45
0.25<0.45
0.7<0.9
0.7<0.9
0.8<1.1
0.75<1.0
0.8<1.05
0.7<0.9
0.85<1.15
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.9<1.15
1.3<1.6
1.3<1.6

6XXX (Chromium-Vanadium Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Cr (%)
min<max
V (%)
min<max
6118
6150
0.16<0.21
0.48<0.53
0.5<0.7
0.7<0.9
0.5<0.7
0.8<1.1
0.1<0.15
0.15

7XXX (Tungsten-Chromium Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Cr (%)
min<max
W (%)
min<max
72XX ??<?? ??<?? 0.75 1.75

8XXX (Nickel-Chromium-Molybdenum Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Mo (%)
min<max
Cr (%)
min<max
Ni (%)
min<max
81B45 0.43<0.48 0.75<1.0 0.08<0.15 0.35<0.55 0.2<0.4
8615
8617
8620
8622
8625
8627
8630
8637
8640
8642
8645
8655
0.13<0.18
0.15<0.2
0.18<0.23
0.2<0.25
0.23<0.28
0.25<0.3
0.28<0.33
0.35<0.4
0.38<0.43
0.4<0.45
0.43<0.48
0.51<0.59
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.7<0.9
0.75<1.0
0.75<1.0
0.75<1.0
0.75<1.0
0.75<1.0
0.15<0.25 0.4<0.6 0.4<0.7
8720
8740
0.18<0.23
0.38<0.43
0.7<0.9
0.75<1.0
0.2<0.3 0.4<0.6 0.4<0.7
8822 0.2<0.25 0.75<1.0 0.3<0.4 0.4<0.6 0.4<0.7

9XXX (Silicon-Manganese Steels)

AISI
No
C (%)
min<max
Mn (%)
min<max
Mo (%)
min<max
Cr (%)
min<max
Ni (%)
min<max
9255⁽³⁾
9260⁽³⁾
0.51<0.59
0.56<0.64
0.7<0.95
0.75<1.0
94B17⁽⁵⁾
94B30⁽⁵⁾
0.15<0.2
0.28<0.33
0.75<1.0 0.08<0.15 0.3<0.5 0.3<0.6

Alloy Carbon Steels

These are not ''stainless' steels. The term; 'Alloy Carbon Steel' refers to carbon steels 'alloyed' with elements that can be used to significantly improve their physical properties by:
a) increasing mechanical strength and hardness prior to heat treatment
and
b) responding better to heat treatment and/or work hardening processes
and
c) retaining their mechanical properties at much higher temperatures than it otherwise would

Therefore, whilst carbon is still the dominant alloying element in these steels with regard to their mechanical properties, and chromium, vanadium, nickel and tungsten all increase the hardness and strength of carbon steels prior to heat treatment, the principal benefits of these alloying elements is that alloy steels will retain these properties at much higher temperatures than plain or special carbon steels and that they will (mostly) exist right through the material thickness.
For example: AISI 4130 grade steel, with 0.28% to 0.33% carbon, equates to the plain carbon steel AISI 1030, the respective mechanical properties of which are as follows:

AISI No SMYS (ksi) UTS (ksi) Elongation(%)
1030 45<75 55<85 16.8<29.4
4130 95 148 17.7
Physical properties for AISI 4130 in normalised condition are shown above

The AISI 4130 is stronger because of the chromium, but it is made considerably tougher (less susceptible to brittle fracture) due to the molybdenum.

Physical Properties

Whilst the above Tables contain only chemical composition, you can use this information to obtain the properties of all of the above steel grades as follows:
1) extract the carbon content of your steel grade from the appropriate Table above
2) select the physical properties for the plain carbon steel with similar carbon content
3) modify hardness and strength according to the alloying elements present
4) apply the effects of heat treatment (hardening & tempering, annealing or normalising)
or
5) use CalQlata's carbon steel calculator to predict its mechanical properties
Note: Item 4 is necessary because it is unlikely that any of these alloy steels will be employed without heat treatment of some kind

Alloying Elements

See special carbon steels for the attributes of manganese, phosphorus and sulphur.

Molybdenum

About 0.3% Molybdenum reduces temper-brittleness in hard alloy carbon steels such as chromium and/or nickel making them much more resilient to impact.

Chromium

Chromium is a carbide stabiliser in that it forms the very hard Cr�‚‡C�‚ƒ & Cr�‚‚�‚ƒC�‚† carbides with the carbon atoms in the steel preventing their movement under deformation with the effect of significantly increasing its hardness but if chromium is kept to less than about 1% (as is the case with virtually all alloy carbon steels) its strength will remain largely unaffected. However, chromium promotes grain growth, so continued use at relatively high temperatures can lead to a reduction in strength.
The Brinell hardness number of carbon steel increases by �‰ˆ8 for each additional 0.1% chromium

Chromium also improves corrosion resistance.

Nickel

In addition to increasing tensile strength and toughness of carbon steels nickel has a grain refining effect. However, used on its own in carbon steels nickel will destabilise relatively unstable carbides into graphite making this alloying element more suitable for low carbon steels.
The Brinell hardness number of carbon steel increases by �‰ˆ3 for each additional 0.1% nickel

Nickel is therefore excellent for case hardening low carbon steels and is normally used with other elements that form very stable carbides (e.g. chromium) in high carbon steels.

Tungsten

Tungsten combines with carbon to form the very stable WC & Fe�‚„W�‚‚C carbides and in doing so inhibits grain growth and raises the temperature at which carbon steels loose their strength and hardness making them very suitable for high-speed tool steels; e.g. drills, taps, reamers, dies, formers, etc.

Vanadium

Vanadium, which is rarely used in carbon steel without another alloying element, combines with carbon to form the carbide V�‚„C�‚ƒ, stabilises martensite and improves hardenability. Chrome-vanadium steels are similar to nickel-chrome steels but they are easier to form and machine into smaller sections.
The Brinell hardness number of carbon steel increases by �‰ˆ9 for each additional 0.1% vanadium

Silicon

Silicon generates fluidity in steel improving material flow during forming and is especially useful in steels intended for casting. Silicon also improves corrosion resistance.
Its quantity must be kept below 0.3% as silicon destabilises cementite, which may decompose into graphite and ferrite

Notes

  1. CalQlata has generated a predictive calculator for carbon and alloy steels
  2. Sulphur: 1A 0.035%<0.05%, 1B 0%<0.025%
  3. Silicon: 1.8%<2.2%
  4. Prefix 'E' (e.g. E52100) refers to steel manufactured by electric furnace
  5. 'B' inserted between the 2nd and 3rd characters (e.g. 50B60) refers to a Boron steel (0.0005%<0.005%)

Further Reading

You will find further reading on this subject, incl. heat treatment, in our carbon steels web page

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