alloying elements
TRANSCRIPT
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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