The hardenability curves of several iron alloys are shown in the figure below. In terms of alloying additions, 1040<5140<8640<4140<4340. Explain briefly the effect of alloying addition to the hardenability of the iron alloys. Solution The image is not uploaded sir, you can repost including the image. for the effect of alloying addition to the hardenability of the iron alloys: Iron is a great buildingmaterial but steel (an alloy made by adding small amounts of nonmetallic carbon to iron) is stronger, harder, and rustproof. Aluminum is a very light metal but it\'s also very soft in its pure form. Add small amounts of the metals magnesium, manganese, and copper and you make a superb aluminum alloy called duralumin, which is strong enough to make airplanes. There are two mechanisms that can cause an alloy to form, called atom exchange and the interstitial mechanism. The relative size of each element in the mix plays a primary role in determining which mechanism will occur. When the atoms are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a substitutional alloy. With the interstitial mechanism, one atom is usually much smaller than the other, so cannot successfully replace an atom in the crystals of the base metal. The smaller atoms become trapped in the spaces between the atoms in the crystal matrix, called the interstices. This is referred to as an interstitial alloy. Steel is an example of an interstitial alloy, because the very small carbon atoms fit into interstices of the iron matrix that\'s what makes it more hard Sulfur, when present, forms iron sulfide, which prevents the formation of graphite and increases hardness. The problem with sulfur is that it makes molten cast iron viscous, which causes short run defects. To counter the effects of sulfur, manganese is added because the two form intomanganese sulfide instead of iron sulfide. The manganese sulfide is lighter than the melt so it tends to float out of the melt and into the slag. The amount of manganese required to neutralize sulfur is 1.7 × sulfur content + 0.3%. If more than this amount of manganese is added, then manganese carbide forms, which increases hardness andchilling, except in grey iron, where up to 1% of manganese increases strength and density Titanium is added as a degasser and deoxidizer, but it also increases fluidity. 0.15–0.5% vanadium is added to cast iron to stabilize cementite, increase hardness, and increase resistance to wear and heat. 0.1–0.3% zirconium helps to form graphite, deoxidize, and increase fluidity.[3] In malleable iron melts, bismuth is added, on the scale of 0.002–0.01%, to increase how much silicon can be added. In white iron, boron is added to aid in the production of malleable iron; it also reduces the coarsening effect of bismuth.

1. The hardenability curves of several iron alloys are shown in the figure below. In terms of
alloying additions, 1040<5140<8640<4140<4340. Explain briefly the effect of alloying addition
to the hardenability of the iron alloys.
Solution
The image is not uploaded sir, you can repost including the image. for the effect of alloying
addition to the hardenability of the iron alloys:
Iron is a great buildingmaterial but steel (an alloy made by adding small amounts of nonmetallic
carbon to iron) is stronger, harder, and rustproof. Aluminum is a very light metal but it's also
very soft in its pure form. Add small amounts of the metals magnesium, manganese, and copper
and you make a superb aluminum alloy called duralumin, which is strong enough to make
airplanes.
There are two mechanisms that can cause an alloy to form, called atom exchange and the
interstitial mechanism. The relative size of each element in the mix plays a primary role in
determining which mechanism will occur. When the atoms are relatively similar in size, the atom
exchange method usually happens, where some of the atoms composing the metallic crystals are
substituted with atoms of the other constituent. This is called a substitutional alloy. With the
interstitial mechanism, one atom is usually much smaller than the other, so cannot successfully
replace an atom in the crystals of the base metal. The smaller atoms become trapped in the
spaces between the atoms in the crystal matrix, called the interstices. This is referred to as an
interstitial alloy. Steel is an example of an interstitial alloy, because the very small carbon atoms
fit into interstices of the iron matrix that's what makes it more hard
Sulfur, when present, forms iron sulfide, which prevents the formation of graphite and increases
hardness. The problem with sulfur is that it makes molten cast iron viscous, which causes short
run defects.
To counter the effects of sulfur, manganese is added because the two form intomanganese
sulfide instead of iron sulfide. The manganese sulfide is lighter than the melt so it tends to float
out of the melt and into the slag. The amount of manganese required to neutralize sulfur is 1.7 ×
sulfur content + 0.3%. If more than this amount of manganese is added, then manganese carbide
forms, which increases hardness andchilling, except in grey iron, where up to 1% of manganese
increases strength and density
Titanium is added as a degasser and deoxidizer, but it also increases fluidity.

2. 0.15–0.5% vanadium is added to cast iron to stabilize cementite, increase hardness, and increase
resistance to wear and heat.
0.1–0.3% zirconium helps to form graphite, deoxidize, and increase fluidity.[3]
In malleable iron melts, bismuth is added, on the scale of 0.002–0.01%, to increase how much
silicon can be added.
In white iron, boron is added to aid in the production of malleable iron; it also reduces the
coarsening effect of bismuth