Steel

Question 1

What is steel?

Answer 1

An alloy of iron containing less than 2% carbon.

Question 2

What is mild steel?

Answer 2

A common type of steel with less than 0.3% carbon and beneficial elements like manganese and silicon.

Question 3

What are the impurities commonly found in mild steel?

Answer 3

• Phosphorus
• Sulfur
• Oxygen
• Nitrogen

Question 4

How does cast iron differ from steel?

Answer 4

Contains 3-4% carbon and more impurities, making it hard but brittle.

Question 5

What is wrought iron?

Answer 5

Contains even less carbon than most steel alloys, resulting in a malleable but weaker material.

Question 6

How does carbon content affect iron-based metals?

Answer 6

Significantly influences their properties; optimal carbon levels in mild steel enhance structural properties.

Question 7

What is the primary process used to produce most steel?

Answer 7

Basic oxygen process.

Question 8

Describe the basic oxygen process.

Answer 8

A lance introduces high-pressure oxygen into molten iron and scrap steel to remove excess carbon and impurities.

Question 9

What additional metallic elements may be added to steel?

Answer 9

• Manganese for abrasion resistance
• Molybdenum for strength
• Vanadium for strength and toughness
• Nickel and chromium for corrosion resistance, toughness, and stiffness

Question 10

What is ASTM A992 used for?

Answer 10

Preferred for standard wide-flange structural shapes.

Question 11

What is the significance of ASTM A36?

Answer 11

Historically the most common steel used in building frames.

Question 12

What is stainless steel?

Answer 12

Produced by adding nickel and chromium, offering enhanced corrosion resistance.

Question 13

What is galvanization?

Answer 13

A process that involves applying a zinc coating to protect steel from corrosion.

Question 14

What is weathering steel?

Answer 14

Designated as ASTM A588, it develops a protective oxide coating when exposed to the atmosphere.

Question 15

What is the structural mill process?

Answer 15

Beam blanks are reheated and passed through rollers to shape the metal into the desired form and size.

Question 16

What are wide-flange shapes?

Answer 16

Shapes that have largely replaced older American Standard shapes due to superior structural efficiency.

Question 17

What is a rivet?

Answer 17

A steel fastener with a cylindrical body and a formed head.

Question 18

What process is used to install a rivet?

Answer 18

Heating it to white heat, inserting it through holes, and forming a second head using a pneumatic hammer.

Question 19

True or False: Riveting is still the dominant fastening technique in modern steel frame construction.

Answer 19

False.

Question 20

What types of bolts are used in steel frame construction?

Answer 20

• High-strength bolts (ASTM A325 and A490)
• Lower-strength carbon steel bolts (ASTM A307)

Question 21

What are bearing-type connections?

Answer 21

Bolts are installed to a snug-tight condition, primarily stressed in shear under normal load conditions.

Question 22

What are slip-critical (friction-type) connections?

Answer 22

Bolts are preloaded to create friction, resisting movement and stressed in tension.

Question 23

Fill in the blank: Bolts are inserted into holes that are _______ larger than the bolt diameter.

Answer 23

1/16 inch (2 mm)

Question 24

What is the primary advantage of welding in steel construction?

Answer 24

Allows for the joining of steel frame members as if they were a single, monolithic structure.

Question 25

True or False: Welded connections are weaker than the members they join.

Answer 25

False.