Module 2

Question 1

Steel,f 2 primary chemicals

Answer 1

Iron + Carbon

Question 2

as carbon content increase so does (3)____decrease (1)

Answer 2

1. strength
2. hardness
3. brittleness
4. decrease weldability

Question 3

> 2% carbon =

Answer 3

cast iron

Question 4

Carbon Equivalence (CE) of a steel alloy refers to method of measuring the

Answer 4

weldability of the alloy, based on the chemical composition of the alloy.

Question 5

Higher concentrations of CARBON and other alloying elements such as manganese, chromium, silicon, molybdenum, vanadium, copper, and nickel tend to increase the ________________and decrease_____________

Answer 5

hardness of the heat affected zone (HAZ) / the weldability of the material.

Question 6

steel generally contain what range of carbon content?

Answer 6

0.03% to 0.35%

Question 7

carbon steel generally contain what range of carbon content?

Answer 7

0.15% to 0.35%

Question 8

Cast iron contain what range of carbon content?

Answer 8

2.1-4%

Question 9

Pros of killed steel? (3)

Answer 9

1. Greater uniformity,
2. Minimal voids and inclusions, and
3. More corrosive resistant

Question 10

how to make killed steel

Answer 10

deoxidizing agent is added to remove gases as it is being poured in the mold

Question 11

what are deoxidizing agent? (2)

Answer 11

1, Aluminum
2. Silicon -larger grain

Aluminum (Al) is a better grain refining element than Silicon (Si) (it makes tighter/smaller grains)

Question 12

SS contains atleast ___Cr?

Answer 12

11.5%

Question 13

4 categories of SS? and example of metals?

Answer 13

1. Austenitic - 300 SS / Not Magnetic
2. Ferritic - found in carbon and low alloy steels and many 400SS
3. Martensitic - structure found in some 400 SS. (heat treatment and/or welding followed by rapid cooling can product this structure in CS and low alloy steel.
4. duplex - mixed austenitic - ferritic structure.

Question 14

what happen when steel is produce?

Answer 14

carbon dissolves in the iron.

Question 15

cast iron flakes pros and cons?

Answer 15

The Good – The flakes provide a cushioning effect for iron when it receives high compression loads

The Bad – The flakes make the material more brittle than steel, and has very poor strength when stretched in tension.

Question 16

PWHT process?

Answer 16

This is a time and temperature dependent operation, which is followed by slow cooling to avoid
creation of new stresses.

DOES NOT CHANGE grain size

Question 17

Quenching (6)

Answer 17

➢ Rapid cooling process.
➢ Hardens and strengthens metal.
➢ Causes brittleness.
➢ Causes internal stresses.
➢ Increases chances of cracking and distortion
➢Small grain size

Question 18

Annealing / Normalizing

Answer 18

➢ Slow cooling process.
➢ Softens and weakens metal.
➢ Causes ductility.
➢ Reduces internal stresses.
➢ Helps prevent cracking and distortion.
Annealing --> Large Grain Size
Normalizing --> Medium Grain Size

Question 19

What kind of grain sizes exist

in and around the HAZ?

Answer 19

small size because it is quenching by the base metal and HAZ = harder

Question 20

What does that do to hardness?

Answer 20

becomes more brittle

Question 21

Dehydrogenation (2)

Answer 21

applied to steels prior to repair welding of refinery
equipment exposed to services that can cause Hydrogen-Induced Cracking (HIC).

bake-out any residual atomic hydrogen in the steel by heating it to 600°F (316°C) and holding for 1.5 – 2 hours. The procedure is intended
to help avoid delayed hydrogen cracking during or after repair welding

Question 22

What does the “L” mean in material grades such as 304L and 316L?

Answer 22

low carbon content

Question 23

what is ionic species

Answer 23

positive charge are called cations.

Question 24

CE (Carbon Equivalent) equation, what element will have more impact on weldability?

Answer 24

carbon (reduce weldability)

Question 25

What is the recommended water to use in the desalter?

Answer 25

Deoxygenated water

Question 26

Amine units remove CO2 and H2S. It will also remove which of the following?

Answer 26

mercaptans, Co2 , H2s

Question 27

The regenerator reboiler and the regenerator are areas where the temperature and __________ of the amine stream are the highest.

Answer 27

turbulence

Question 28

Who controls the operations of the Desalter?

Answer 28

Crude Unit Operators