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API 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry > 4.2.7 Brittle Fracture > Flashcards

4.2.7 Brittle Fracture Flashcards

(80 cards)

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1
Q

Brittle fracture is characterized by ________.

A

A sudden rapid failure under stress

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2
Q

The main concern for brittle fracture is _________

A

during startup and shutdown

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3
Q

Brittle fracture cracks will typically be straight, non-branching, and largely devoid of any associated plastic deformation - True or False?

A

True

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4
Q

One of the properties of mechanical fatigue is that it typically happens _____________.

A

well below yield strength of the material

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5
Q

Fatigue cracks usually initiate on the surface ___________ under cyclic loading.

A

at notches or stress raisers

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6
Q

Heat treatment can have a significant effect on the toughness and hence fatigue resistance of a metal. In general ____________ tend to perform better than __________.

A

Finer grained microstructures - coarse grained

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7
Q

An example of a component that might exhibit mechanical fatigue due to thermal cycling is a ______________.

A

coker drum

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8
Q

NDE monitoring for mechanical fatigue might include

A

PT, MT, and SWUT

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9
Q

Materials that might be affected by atmospheric corrosion include 1.____________.

A
  1. carbon steel
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10
Q

Materials that might be affected by atmospheric corrosion include 2. ____________.

A
  1. low alloy steels
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11
Q

Materials that might be affected by atmospheric corrosion include 3. ____________.

A
  1. copper alloyed aluminum
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12
Q

For piping on supports are often very prone to atmospheric corrosion due to ___________.

A

water entrapment between the pipe and the supports

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13
Q

Materials that might be affected by CUI (corrosion under insulation) including 1. ___________.

A
  1. Carbon Steel
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14
Q

Materials that might be affected by CUI (corrosion under insulation) include 2. ___________.

A
  1. low alloy steels
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15
Q

The method(s) that can be used for inspection to find atmospheric corrosion are ___________.

A

UT and visual

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16
Q

Materials that might be affected by CUI (corrosion under insulation) include 3. ___________.

A
  1. 300 Series SS
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17
Q

Materials that might be affected by CUI (corrosion under insulation) include 4. ___________.

A
  1. duplex stainless steels
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18
Q

It is known that 300 series SS, 400 series SS and duplex SS are subject to pitting and localized corrosion. The 300 series are also subject to what form of attack if chlorides are present?

A

Stress corrosion cracking

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19
Q

Preventing corrosion under insulation calls for careful selection of insulating materials. Therefore ______________ materials will hold less water against the vessel / pipe wall than ________ and, potentially be less corrosive.

A

closed-cell foam glass - mineral wool

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20
Q

The recommended technique for identifying wet insulation and potential corrosion under insulation is ____________.

A

neutron backscatter

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21
Q

The severity of soil corrosion is determined by many factors including 1. ____________.

A
  1. operating temperature
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22
Q

The severity of soil corrosion is determined by many factors including 2.____________.

A
  1. moisture and oxygen availability
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23
Q

The severity of soil corrosion is determined by many factors including 3. ____________.

A
  1. soil resistivity (soil condition and characteristics)
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24
Q

The severity of soil corrosion is determined by many factors including 4. ____________.

A
  1. soil type (water drainage)
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25
The severity of soil corrosion is determined by many factors including 5.____________.
5. homogeneity (variation in soil type)
26
The severity of soil corrosion is determined by many factors including 6. ____________.
6. cathodic protection
27
The severity of soil corrosion is determined by many factors including 7. ____________.
7. stray current drainage
28
The severity of soil corrosion is determined by many factors including 8. ____________.
8. coating type
29
The severity of soil corrosion is determined by many factors including 9. ____________.
9. age
30
The severity of soil corrosion is determined by many factors including 10. ____________.
10. condition
31
Microbiology induced corrosion is a form of corrosion caused by living organisms such as 1. __________.
1. bacteria
32
Microbiology induced corrosion is a form of corrosion caused by living organisms such as 2. __________.
2. algae
33
Microbiology induced corrosion is a form of corrosion caused by living organisms such as 3. __________.
3. fungi
34
Because there are several types, organisms can survive and grow under severe conditions including 1. ___________.
1. Lack of oxygen
35
Because there are several types, organisms can survive and grow under severe conditions including 2. ___________.
2. light or dark
36
Because there are several types, organisms can survive and grow under severe conditions including 3. ___________.
3. high salinity
37
Because there are several types, organisms can survive and grow under severe conditions including 4. ___________.
4. pH range of 0 to 12
38
Microbiology induced corrosion affected materials are most common materials of construction including 1. ________.
1. carbon steel
39
Microbiology induced corrosion affected materials are most common materials of construction including 2. ________.
2. low alloy steels
40
Microbiology induced corrosion affected materials are most common materials of construction including 3. ________.
3. 300 series SS
41
Microbiology induced corrosion affected materials are most common materials of construction including 4. ________.
4. 400 series SS
42
Microbiology induced corrosion affected materials are most common materials of construction including 5. ________.
5. aluminum
43
Microbiology induced corrosion affected materials are most common materials of construction including 6. ________.
6. copper
44
Microbiology induced corrosion affected materials are most common materials of construction including 7. ________.
7. some nickel base alloys
45
Microbiology induced corrosion is most often found in 1. _____________.
1. heat exchangers
46
Microbiology induced corrosion is most often found in 2. _____________.
2. bottom water of storage tanks
47
Microbiology induced corrosion is most often found in 3. _____________.
3. piping with stagnant or low flow
48
Microbiology induced corrosion is most often found in 4. _____________.
4. piping in contact with some soils.
49
Soil resistivity is frequently used to estimate soil corrosivity mainly because ____________.
it is easy to measure
50
soils having high moisture content, high dissolved salt concentrations, and high acidity are usually ___________ corrosive.
most
51
Units or equipment affected by soil corrosion include 1. __________.
1. underground piping and equipment
52
Units or equipment affected by soil corrosion include 3. __________.
3. buried tanks
53
Units or equipment affected by soil corrosion include 4. __________.
4. bottoms of above ground storage tanks
54
Units or equipment affected by soil corrosion include 5. __________.
5. ground supported metal structures
55
Caustic corrosion affected materials are primarily 1.____________.
carbon steel
56
Caustic corrosion affected materials are primarily 2. ____________.
low alloy steels
57
Caustic corrosion affected materials are primarily 3. ____________.
300 Series SS
58
Major contributing factors of caustic corrosion are the presence of caustic (NaOH or KOH). The following are sources of caustic: 1.
1. It is sometimes intentionally added to boiler feed water at low concentrations
59
Major contributing factors of caustic corrosion are the presence of caustic (NaOH or KOH). The following are sources of caustic: 2.
2. may enter inadvertently during regeneration of demineralizers.
60
Affected units or equipment of caustic corrosion include 1. _______
1. boilers
61
Affected units or equipment of caustic corrosion include 2. _______
2. steam generating equipment
62
Affected units or equipment of caustic corrosion include 3. _______
3. heat exchangers.
63
The description chloride stress corrosion cracking is surface initiated cracks caused by environmental cracking of 300 series SS and some nickel base alloys under the combined action of tensile stress, temperature and an aqueous chloride environment. This condition is accelerated by ___________.
increasing temperature
64
Which of the following alloys is highly susceptible to CI SCC?
300 Series stainless steel
65
SCC usually occur sat pH value _______. At lower pH values, uniform corrosion generally predominates. SCC tendency decreases toward the alkaline pH region.
Above 2
66
Inspection for CL SCC can be detected by using which of the following NDE methods?
both methods above (VT PT)
67
Corrosion fatigue is usually found in deaerators by using ______ NDE
WFMT
68
Caustic embrittlement is a form of stress corrosion cracking characterized by surface-initiated cracks that occur in piping and equipment exposed to caustic, primarily adjacent to _______________.
non-PWHT welds
69
Crack propagation rates increase dramatically with temperature and can sometimes grow through wall in ______________.
a matter of hours or days
70
Caustic embrittlement is often found in piping and equipment that handles caustic. It may also be found in a process unit that ______________.
has metacarpans
71
Prevention of cracking in carbon steels can be achieved by PWHT to a temperature of ____________
1150F
72
Corrosion of steel due to acidic sour water containing H2S occurs at a pH between __________.
4.5 and 7.0
73
Sour water corrosion primarily affects ____________.
Carbon steels
74
H2S content, pH, temperature, velocity and ____________ concentration are all critical factors for Sour Water corrosion.
Oxygen
75
Acid sour water corrosion is a concern in overhead systems of FCC and coker gas fractionation plants with ___________.
high H2S levels and low NH3 levels
76
_________________ are susceptible to pitting attack and may experience crevice corrosion and/or chloride stress corrosion cracking
300 Series SS
77
For carbon steel, damage is usually in the form of general thinning but may be highly localized to specific areas of high velocity or turbulence, typically where a
water phase is condensing
78
Sulfuric acid promotes ___________ corrosion of carbon steel and other alloys. Carbon steel heat affected zones may experience severe corrosion.
General and localized
79
Carbon steel corrosion rates increase significantly if the flow velocity exceeds about 2 to 3 fps (0.6 to 0.9 m/s) or at acid concentrations below ___________.
65%
80
Sulfuric acid alkylation units and waste water treatment plants are affected. Appearance of the damage can be __________.
Mostly general in nature, but attacks carbon steel weld heat affected zones rapidly.

API 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry (1 decks)

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