Alloying Elements and Properties of Steel

Here is a comprehensive list of are a few major alloying elements for steel, what they do, and what they are used for.
For clarity, there are no links. Look up these modules for explanations:
 
Element Stabilizes.... Hardness Increase
Mechanism		 Tendency to form hard Carbides Major / Minor Functions
Manganese
Mn		 Austenite
Open g-field		 Moderate increase
Powerful solution strengthener		 Middle 1. Takes care of Sulphur (S).
2. Makes special steels in high concentrations
3. Cheap increase of hardenability.
Silicon
Si		 Ferrite
Closed g-field		 Hardens, but reduces ductilityModerate increase None 1. Deoxidation ("killing") of liquid steel.
. 2. Increases electrical resistivity (important for transformer cores).
3. Improves oxidation resistance.
Aluminum
Al		 Ferrite
Closed g-field		 Small
Grain size hardening		 No carbides but nitride. 1. Deoxidation ("killing") of liquid steel.
2. Improves oxidation resistance.
Chromium
Cr		 Ferrite
Closed g-field		 Moderate increase
(Secondary) prec. hardening
 Strong 1. Corrosion resistance.
2. Strength + oxidation resistance at high T.
3. Abrasion resistance (needs high C, too).
Titanium
Ti		 Ferrite
Closed g-field		 Strong increase;
Prec. hardening
Grain size hardening
 Extremely strong 1. Oxygen, nitrogen and sulphur scavenger.
Forms hard carbides. prevents grain growth.
2.Prevents local depletion of carbon in stainless steels due to Cr-carbide formation
Vanadium
V		 Ferrite
Closed g-field		 Very strong increase
Prec. hardening
Grain size hardening

Moderate solid solution hardening
 Very strong 1. Restricts grain coarsening of austenite.
2. Increases hardenability.
3. Delays softening during tempering.
Nickel
Ni		 Austenite
Open g-field		 Mild increase
 None 1. Enables austenitic steels.
2. Enables Invar steel
Molybdenum
Mo		 Austenite
Open g-field		 Strong increase
Prec. hardening
Grain size hardening		 Very strong 1. Improves corrosion resistance of stainless steels.
2. Prevents embrittlement of certain Ni/Cr steels.
3. Keeps strength at higher T. 4. Provides high abrasion resistance.
Boron
B		 ? Major changes i at very small concentrations Strong increase
Prec. hardening
Grain size hardening		 Very strong 1. High strength steel
2. Nitrogen scavenger
3. Replacement for expensive elements without compromising properties
 

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go to Overview of Major Steels

go to 9.2.2 Designing Low Alloy Steels

go to Alloying Elements in Detail

go to Science of Alloying

go to Inhomogeneous Deformation

go to Overview of Major Steels: 1. Classifying Steels

go to 9.2.1 A Closer Look at Low Alloy Steels

go to Overview of Major Steels

go to Steel Properties

© H. Föll (Iron, Steel and Swords script)