05-METALS

Question 1

FERROUS METALS

Answer 1

the chief ingredient of the metals known as iron and steel is the chemical element iron (ferrum), from which iron-based alloys get the generic name “FERROUS METALS”

Question 2

BENEFICIATION

Answer 2

Any process that improves (benefits) the economic value of the ore by removing the gangue minerals, which results in a higher grade product (concentrate) and a waste stream (tailings). –the BENEFICIATION OF ORE consists of two things:

1 / grinding and concentrating them to increase the iron content

2 / agglomeration, which increases the ore’s particles to a size suitable for blast furnace use

Question 3

COKE

Answer 3

form of coal often used in blast furnaces

Question 4

FLUXES

Answer 4

minerals that have an affinity for the impurities in iron ore or pig iron. they combine with these impurities and separate them from the molten metal in a furnace by forming a liquid slag.

limestone and dolomite are examples of basic fluxes

sand, gravel, and quartz rock are acid fluxes

Question 5

PIG IRON

Answer 5

Pig iron, also known as crude iron, is an intermediate product of the iron industry in the production of steel which is obtained by smelting iron ore in a blast furnace.

Pig iron has a very high carbon content, typically 3.8–4.7%,[1] along with silica and other constituents of dross, which makes it very brittle and not useful directly as a material except for limited applications.

Question 6

REFRACTORIES

Answer 6

nonmetallic materials with superior heat and abrasion resistance used as linings of steelmaking furnaces, flues, and vessels.

the most common basic refractory material is magnesia

Question 7

ALLOY

Answer 7

a metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion.

Question 8

MANGANESE

Answer 8

all steel contains manganese both as a scavenger to remove oxygen from molten metal and as an alloying element to improve hardness and wear.

~12lbs per ton of steel

Question 9

CHROMIUM

Answer 9

added in amounts of 1%-5%

provides stainless steels with resistance to heat, rust, and corrosion.

also an important coating in metal

Question 10

NICKEL

Answer 10

cryogenic steels (those produced at low temperatures) use nickel to increase their hardness.

steels containing nickel are especially suitable for case hardening.

Question 11

SILICON

Answer 11

silicon serves as a deoxidizer in steel and as an alloying element.

when used in large percentages silicon enables cast irons to withstand highly corrosive acids.

Question 12

NONFERROUS METALS

Answer 12

metals or alloys are materials that are not iron-based like their ferrous counterparts. Ferrous metals contain iron making most of their metals a magnetic property.

HEAVY NONFERROUS MTLS: copper, zinc, lead, and nickel-based metals

LIGHT NONFERROUS MTLS: aluminum and magnesium-based metals

Question 13

BRASS, COPPER, AND BRONZE

Answer 13

copper alloys have good thermal and electrical conductivity, corrosion resistance, and easy forming and joining.

disadvantage: low strength-to-weight ratios and strength reduced at elevated temperatures

Question 14

BRASS

Answer 14

copper with zinc as its principal alloying element

Question 15

REFRACTORY MATERIALS

Answer 15

A refractory material or refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures.

often used in the lining of smelting furnaces

Question 16

METAL CORROSION

Answer 16

caused by galvanic action, occurs between dissimilar metals or between metals and other materials when sufficient moisture is present to carry and electrical current.

Question 17

PITTING

Answer 17

is a form of extremely localized corrosion that leads to the creation of small holes in the metal. The driving power for pitting corrosion is the depassivation of a small area, which becomes anodic (oxidation reaction) while an unknown but potentially vast area becomes cathodic (reduction reaction), leading very localized galvanic corrosion. The corrosion penetrates the mass of the metal, with a limited diffusion of ions.

Question 18

CARBON STEELS

Answer 18

residual elements, such as carbon manganese, phosphorus, sulfur, and silicon, are controlled, but in which no alloying elements are added to achieve special properties

up to 1.2 percent carbon

more than 90 percent of steel manufactured into finished products is carbon steel

poor resistance to corrosion

Question 19

STEEL CLASSIFICATION

Answer 19

American Iron and Steel Institute: AISI designates steel with code numbers that indicate the chemical composition and steelmaking process of various types of steel

ASTM: carbon steels typ used in bldg construction conform to ASTM standards A6, A36, A53, A82, A185, A283, A497, A500, A501, A615, A663, A675, A767, and A996. Most common for construction is A36. These standards indicate certain partial chemical compositions and specified minimums for strength and ductility.

UNI (Unified Numbering System): alloy and carbon steels have been assigned a designation in UNS for Metals and Alloys. UNS est 1975 by ASTM. Consist of a single letter prefix followed by five digits.

Question 20

ALLOY STEELS

Answer 20

when the content of alloying elements exceeds certain limits or when a definite range of alloying elements is specified.

*does not cover stainless steel, tool steel, specialty steel, even though they contain specified amounts of alloying elements.