3.1 885 °F (475 °C) Embrittlement

Question 1

Embrittlement Is a loss of

Answer 1

Dusctility and fracture toughness

Question 2

Occur in stainless steels containing a ferrite phase result of

Answer 2

Ferrite phase result of exposure in the temperature range 600 °F to 1000 °F (315 °C to 540 °C)

Question 3

The affected materials are?

Answer 3

SS Ferritic 400 series and SS duplex

Question 4

The critical cactors are?

Answer 4

chromium content, amount of ferrite phase, and operating temperature

Question 5

The lower-chromium alloys are _____ and The higher chromium ferritic stainless steels and duplex stainless steels are ______

Answer 5

Less suceptible ; More susceptible

Question 6

Duplex stainless steels need to be _______ after welding to avoid formation of embrittling phases.

Answer 6

cooled rapidly

Question 7

The effect on toughness is not pronounced at the operating temperature but is significant at lower temperatures experienced during

Answer 7

Plant shutdowns, start-ups, or upsets.

Question 8

Embrittlement can also result from heat treatment if the material is

Answer 8

held within or cooled slowly through the embrittlement range.

Question 9

885 °F (475 °C) embrittlementcan be found in any unit where susceptible alloys examples

Answer 9

• fractionator trays and internals in high-temperature vessels used in crude,
• vacuum, fluid catalytic cracker (FCC), and coker units
• Duplex stainless steel heat exchanger tubes

Question 10

metallurgical change that is _______ apparent with metallography?

Answer 10

not readily

Question 11

can possibly be identified by an increase in hardness in affected areas. However, the he most positive indicator of 885 °F (475 °C) embrittlement is

Answer 11

bend testing or impact testing

Question 12

Most cases of embrittlement are found in the form of cracking during

Answer 12

turnarounds or during start-up or shutdown

Question 13

The best way to prevent 885 °F (475 °C) embrittlement is

Answer 13

avoid exposing the susceptible material to the embrittling range or to use a non-susceptible material.

Question 14

Cracking of embrittled material can often be avoided through temperature controls during

Answer 14

start-up and shutdown.

Question 15

885 °F (475 °C) embrittlement is reversible by heat treatment followed by rapid cooling treatment temperature is typically __________ (de-embrittled). However, if the component is exposed to the same service conditions, it will re-embrittle _______ than it did initially.

Answer 15

1100 °F (595 °C) or higher ; Faster

Question 16

Metallographic
examination is typically

Answer 16

Not efective

Question 17

Field hardness testing may distinguish embrittled from non-embrittled material, but hardness testing alone is generally _____ . the hardness test itself may produce ______, depending on the degree of
embrittlement.

Answer 17

Not definitive ; Craking

Question 18

Hammer testing (“field impact testing”) is considered a ________ test. might confirm that a component is not badly embrittled, if it does not crack, or that it is embrittled, if it does crack.

Answer 18

Destructive Test