THE ALLOYING ELEMENTS AND

THEIR EFFECT ON THE PROPERTIES

OF STEEL

TOPIC

GROUP MEMBERS

• BSME01143062 Ali Rehman

• BSME01143060 Uzair Irfan

WHAT IS ALLOY?

Alloy is the metal made by the combination of two or more metals or elements combined to attain certain chemical or mechanical properties

DIFFERENCE BETWEEN ALLOY AND COMPOSITE

A Brief Description Alloy is a mixture of two or more elements where at least one

of them is metal. Steel is an example for alloy. It is made up of iron and

carbon. Composite is a material made out of two or more constituent

materials which are chemically or physically different. Concrete is the composite of gravel and cement.

A BRIEF HISTORY OF ALLOYS

Historically, the earliest alloys created by man was brass, a simple alloy of copper and zinc known to be in use from as early as 3000 BCKing Croesus of Lydia during the years 560-546 BC desired and developed the first official government coinage system using a naturally occurring alloy of gold and silver, known as Electrum

ALLOY STEEL

Alloy steel is basically mixture of Iron and Carbon and other trace elements (Silicon Manganese Sulphur etc)Carbon %age in steel is about 0.12 - 2%

CarbonChromiumSiliconManganeseNickelVanadium

ALLOYING ELEMENTS IN STEEL

MolybdenumTungstenAluminumTitaniumBoron

CARBON

Percentage range 0.12 - 2%Increases hardnessIncreases Strength

The basic metal, iron, is alloyed with carbon to make steel and has the effect of increasing the hardness and strength by heat treatment but the addition of carbon enables a wide range of hardness and strength.

CHROMIUM

Percentage range 0.5 - 18%Increases hardenability of steel (0.5-2%)Provides Corrosion Resistance (4-18%)

Chromium is added to the steel to increase resistance to oxidation. This resistance increases as more chromium is added. 'Stainless Steel' has approximately 18% chromium and a very marked degree of general corrosion resistance when compared with steels with a lower percentage of chromium. When added to low alloy steels, chromium can increase the response to heat treatment, thus improving harden ability and strength.

CHROMIUM PROTECTION

Percentage Range 0.2 – 2%Increases Strength (0.2 – 0.7%)Spring Steels (0.7 – 2% )Improve Magnetic Properties (Higher Percentages)

SILICONThis metalloid improves strength, elasticity, acid resistance and results in larger grain sizes, thereby, leading to greater magnetic permeability. Because silicon is used in a deoxidizing agent in the production of steel, it is almost always found in some percentage in all grades of steel.

The addition of 2% silicon changes the behavior of the steel drastically for use in a katana. This spring steel is most commonly seen in application on fencing foils where it needs to withstand a high degree of bend and still be able to return to center.

SILICON USE

Percentage Range 0.25 – 1%When combined with Sulfur Improves Brittleness (0.25-0.40%)Increases Hardenability (>1%)

MANGANESE

Increases strength at high temperatures by eliminating the formation of iron sulfides. Manganese also improves hardenability, ductility and wear resistance. Like nickel, manganese is an austenite forming element and can be used in the AISI 200 Series of Austenitic stainless steels as a substitute for nickel.

Percentage Range 2 - 20%Provide Toughness (2-5%)Provides Corrosion Resistance (12-20%)

NICKELNickel is added in large amounts, over about 8%, to high chromium stainless steel to form the most important class of corrosion and heat resistant steels. These are the austenitic stainless steels, typified by 18-8, where the tendency of nickel to form austenite is responsible for a great toughness and high strength at both high and low temperatures. Nickel also improves resistance to oxidation and corrosion

NICKEL APPLICATIONS

Nickel stainless steel alloy Environmental Protection Agency (EPA) eliminates a stronger and thicker corrosion-resistant.

Percentage Range 0 - 0.15%Stable Carbides-Increase Strength While Retaining DuctilityPromotes fine grain structure (FGS)

VANADIUM

vanadium can produce stable carbides that increase strength at high temperatures. By promoting a fine grain structure, ductility can be retained.

high carbon high chromium die steel with added carbon and vanadium for abrasion resisting qualities.

VANADIUM USE

The first large-scale industrial use of vanadium in steels was found in the chassis of the Ford Model T, inspired by French race cars.(1927)

Percentage Range 0.2-5%Stable Carbides Inhibits Grain Growth

MOLYBDENUMFound in small quantities in stainless steels, molybdenum increases hardenability and strength, particular at high temperatures. Often used in chromium-nickel austenitic steels, molybdenum protects against pitting corrosion caused by chlorides and sulfur chemicals.

Percentage Range Hardness at high temperatures

TUNGSTENProduces stable carbides and refines grain size so as to increase hardness, particularly at high temperatures

Many high speed steels - those used in cutting and machining tools like saw blades - contain around 18 percent tungsten

Tungsten-steel alloys are also used in the production of rocket engine nozzles, which must have high heat resistant properties. 

TUNGSTEN USES

Percentage Range 0.95 – 1.30%Increase ductility in steel alloyscommonly used in draw quality steels. Helps in removing the dissolved oxygen from the liquid steel. This process is known as killing.

ALUMINUM

ALUMINUM USE

Aluminized steel in different parts of a car

Percentage RangeImproves StrengthReduces martensitic hardness in chromium steels

TITANIUMImproves both strength and corrosion resistance while limiting austenite grain size. At 0.25-0.60 percent titanium content, carbon combines with the titanium, allowing chromium to remain at grain boundaries and resist oxidization.

TITANIUM USE

EOS has expanded its metal materials portfolio with EOS titanium Ti64ELI and EOS stainless steel 316L.EOS titanium Ti64ELI is a light metal alloy that is corrosion resistant and bio-compatible 

Percentage range 0.001-0.003%Powerful hardenability agent

BORON

A hardenability agent that improves deformability and machinability. Boron is added to fully killed steel and only needs to be added in very small quantities to have a hardening affect. Additions of boron are most effective in low carbon steels.

Hot-stamping boron-alloyed steels for automotive parts

BORON USE

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