Metallic Materials

1. Metallic Materials By: Engr. Rizwan Nasir 25th August, 2009

2. Key Concept • There are a number of basic properties that are important to classifying a metal for use with a particular manufacturing process and product application. • These properties are the material’s density, color, electrical conductivity and reaction when exposed to heat.

3. Key Concept • There are a four major types or classifications of metals: Ferrous, Nonferrous, High Temperature Super alloy and refractory. • The two major types of ferrous metals are iron and steel.

4. Ferrous Metallic Materials • The ferrous metallic materials further classified as: • Iron • Steel • Alloys

5. Iron • Iron ore constitutes about 5% of the earth's crust and is easy to convert to a useful form. • Iron is obtained by fusing the ore to drive off oxygen, sulfur, and other impurities. • The ore is melted in a furnace in direct contact with the fuel using limestone as a flux. • The limestone combines with impurities and forms a slag, which is easily removed. More knowledge about Iron.pdf

6. Steps of Purification • There are three steps for iron purification Ores/ Raws Crude Pure

7. Ores • Iron ores are rocks and minerals from which metallic iron can be economically extracted. • The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, deep purple, to rusty red. • Iron is never found or available in nature in its purest form. It has to be extracted from its various ores

8. Types of Iron • The iron is divided into three types on the presence of carbon contents. • Pig Iron • Wrought Iron • Cast iron

9. Pig Iron • The name is derived from the time when the iron ran into molds in sand beds fed from a common runner. • The row of molds was said to resemble a litter of suckling pigs, hence the individual ingots were referred to as pigs and the runner was called the sow. • Pig iron is the most crudest form of iron and contains large number of impurities. • To remove these impurities from iron ores carbon is added with H2SO4 Ores  pig iron

10. Properties • It is hard and highly brittle • Its melting point is low. • It is neither malleable nor ductile. • It is difficult to bend at normal temperature. • The fusion temperature of Pig Iron is 1200oC.

11. Wrought Iron • Wrought iron is so named because it is worked from a bloom of porous iron mixed with slag and other impurities. • The word "wrought" is an old past tense form of the verb to work. • Wrought iron literally means worked iron. • It is define as: It is good type of iron. It is the purest form of iron in which total amount of Impurites does not exceed from 0.5%.

12. Examples

13. Properties • It is tough, can bear shocks and impacts. • It can be welded. • Its melting point is 1500oC. • It corrodes easily. • It can be magnetized.

14. Uses • It is used for sheet making. • It is used for rod making. • It is used for making gas pipelines. • It is used for making boiler tubes. • It is used for making frames of windows.

15. Cast Iron • Cast iron is not a particular strong or tough structural materials, although it is one of the most economical and widely used in industry. • The amount of carbon in cast iron is 2.1 – 4.0%. • Cast iron also contains appreciable amount of silicon 1.0 – 3.0%. • Cast iron is made by remelting pig iron, often along with substantial quantities of scrap iron and scrap steel, and taking various steps to remove undesirable contaminants such as phosphorus and sulfur.

16. Properties & Uses Properties: • It is brittle. • Its melting point is 1150 – 1200oC. • It has excellent machineabilty. • It has wear & tear resistant. Uses: • It is used to make different types of machines • It is used for the manufacturing of parts of car.

17. Steel • Steel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.1% by weight, depending on the grade. • It is the purest form of iron. The impurities present in it are less than 0.5%. • The difference between the wrought iron and steel is due to the amount of carbon contents. • Carbon contents in the steel is 1.5%.

18. Types of Steel • There are five types of steel and we classify it on the basis of carbon contents. • Dead mild steel • Medium carbon steel • High carbon steel • Cast steel • Mild steel

19. Cont… Dead mild steel • If carbon content are less than 0.15% then the steel is known as dead mild steel. Medium carbon steel • If carbon contents are in the range of 0.3 – 0.8% then steel is called Medium Carbon Steel. High carbon steel • If the carbon contents are in the range of 0.8 – 1.5% then steel is called high carbon steel. Cast steel • If the carbon contents are more than 1% then steel is called cast steel. Mild steel • It is also called low carbon steel. It has carbon contents in the range of 0.15 – 0.3%

20. Mild Steel Properties • Its structure is fibrous. • Its color is dark blue. • It is more than tough & elastic than cast and wrought iron. • It corrodes easily but can be protected from corrosion by painting or coasting it. • It can be magnetized. • It can be welded. • It can withstand shocks & Impacts. • Its specific gravity is 3.8

21. Cont… Uses • In construction work it is used as rod structural sections. • It is extensively used in the manufacturing various tools, machine parts, rail tracks, industrial buildings & transmission towers.

22. High Carbon steel Properties • Its structure is granular. • It is more tough and elastic than mild steel. • More difficult to weld. • It can be magnetized permanently. • It can withstand shocks and vibrations. Uses • It is used to make those parts of machinery which needs hard, tough & durable material. • It is used to making the tools for drilling.

23. ALLOYS

24. Definition • Alloys are the combination of different metals or addition of different metals in one metals e.g. Brass, Steel etc. • Alloy is a solid solution of two solids when you add one metal into another metal in molten state and then allow it to freeze

25. Cont… • An alloy is generally prepared to increase strength, hardness, toughness, resistance to corrosion, thermal and electrical conductivity of metal, tensile strength, shear strength and young’s modulus.

26. Types of alloys • There are two types of alloys • Ferrous alloys • Non ferrous alloys

27. Ferrous alloys • Ferrous alloys have iron as a major component. Chromium, nickel, vanadium, tungsten, molybdenum and manganese are all the metals that form ferrous alloys with iron.

28. Types of ferrous alloys • There are five types of ferrous alloys • Stainless steel • Nickel steel • Vanadium steel • Tungsten steel • Manganese steel

29. 1. Stainless steel • In metallurgy, stainless steel, also known as inox steel or inox, is defined as a steel alloy with a minimum of 11% chromium content by mass. • Chromium is the most effective for making resistant to heat and corrosion. • Various brand of stainless steel are present in the market. The types of stainless steel are: • Group A • Group B • Group C

30. Group A • Stainless steel in the first group has chromium content lower than 16% and carbon content lower than 0.4%. Properties • It can be welded. • It can be machined by using special design culturing tools. • It has ability to work at a temperature 800oC.

31. Group B • Stainless steel in the second group has chromium contents higher than 16% and carbon content are not more than 0.4%. Properties • It can be welded but it becomes very weak near the welding point. • Due to its high chromium contents it is good resistant to heat and corrosion as compared to other steel.

32. Group C • Stainless steel in third group contains sufficient amount pf chromium to make it non magnetized. Properties • They are very tough. • It is low resistant to heat. • It can not be machined.

33. 2. Nickel Steel • steel containing up to 6 percent nickel: A steel containing up to six percent nickel, sometimes with other metal added, usually to assist hardening during formation • Steel containing 3 to 5% nickel and 0.2 to 0.5% carbon; the nickel increases the strength and the elastic limit of the alloy • It contains 0.5 – 1% carbon, 3.5% Ni and 93 – 95% iron and small amount of chromium. Properties: • Presence of Ni improves the hardness, toughness and strength of an alloy. Reduce the rusting rate of iron. • If the %age of Ni present in the steel is 30 – 40% then this steel is called Special Steel, which has very low thermal expansion. Uses: • Manufacturing of automobile • Special steel is used for making the delicate & sophisticated equipment.

34. 3. Vanadium Steel • It contains 0.1 – 0.2% vanadium and minute amount of impurities. Properties • It is very strong & ductile. • It is capable of resisting shocks. • Its elasticity is very high.

35. 4. Tungsten Steel • Steel usually containing 5 to 10% (but sometimes as much as 24%) tungsten and 0.4 to 2% carbon. • It contains 14% - 20% tungsten (W) and 3 – 8 % chromium very small quantity of carbon and small quantity of molybdenum. • It is sometime called as high speed steel. Properties • It is very hard. • It is high temperature resistant and corrosion resistant. Uses • It is used to make drilling machine and high speed cutting tools.

36. 5. Manganese Steel • It contains 12 – 15 % manganese. The addition of manganese in a steel make it very hard and non magnetic steel. Uses • It is used to make the machine parts. • It is also use to make the railway tracks.

37. Non Ferrous Alloys • These are the non iron alloys. • We find that over 90% non ferrous alloys are based on the metals like: • Aluminum • Manganese • Magnesium • Copper • Nickel • Titanium • Zinc • These elements are more expansive but each element has specific application because it has unique properties such as corrosion resistant.

38. Types of Non Ferrous Alloys • There are following types of non ferrous alloys. • Brass • Bronze • Duralumin • German silver

39. SEE YOU IN THE NEXT CLASS!!!