120301a Flashcards
(195 cards)
1
Q
What is stainless steel?
A
Stainless steel is an iron-chromium alloy that is highly resistant to corrosion and oxidation.
2
Q
When was stainless steel discovered?
A
The discovery of stainless steel dates back to the early 1900s.
3
Q
List some applications of stainless steel.
A
- Cooking utensils
- Cutlery
- Fasteners
- Welding
- Industrial fields
- Processing plants
- Health and sanitation applications
- Pulp and paper industry
- Petrochemical refineries
- Decorative architectural elements
4
Q
What is the minimum percentage of chromium required to create stainless steel?
A
10%
5
Q
What happens when chromium is added to iron in stainless steel?
A
A silvery, tightly adherent film of chromium oxide forms spontaneously on exposed surfaces.
6
Q
What is the role of the chromium oxide film in stainless steel?
A
It provides resistance to corrosion and oxidation.
7
Q
What occurs if the chromium oxide film is broken?
A
Oxygen immediately combines with the chromium, and the film re-forms.
8
Q
What additional elements may be found in some stainless steels to enhance properties?
A
- Nickel
- Manganese
- Molybdenum
9
Q
What is the typical carbon content range in most stainless steels?
A
0.03% to 0.10%
10
Q
True or False: Stainless steel is resistant to hydrochloric acid.
A
False
11
Q
Fill in the blank: Stainless steels are highly resistant to most types of _____ and _____ from hot gases.
A
corrosion, oxidation
12
Q
What characteristic allows stainless steel to maintain high strengths at elevated temperatures?
A
Its composition and structural integrity.
13
Q
Describe a practical application of stainless steel mentioned in the text.
A
A temperature sensor made of stainless steel with a flexible lead wire.
14
Q
What percentage of chromium do many stainless steel alloys contain?
A
More than 10% chromium.
15
Q
What does chromium improve in stainless steel?
A
Corrosion resistance and resistance to oxidation at high temperatures.
16
Q
What is the effect of chromium on strength at high temperatures?
A
There is little loss of strength in chromium steels at temperatures up to 482°C (900°F).
17
Q
What is creep in metals?
A
The gradual plastic deformation of metals that leads to their ultimate failure.
18
Q
What effect does nickel have when used as an alloying element?
A
In excess of about 6%, it increases corrosion resistance slightly and greatly improves mechanical properties.
19
Q
How does nickel affect strength at low temperatures?
A
It increases strength at very low temperatures without decreasing toughness.
20
Q
What is the role of molybdenum in stainless steel?
A
It increases resistance to pitting type corrosion and improves high temperature strength.
21
Q
What effect does carbon have in stainless steel?
A
Increases strength in amounts less than 0.04%; amounts above that cause chromium carbide precipitation.
22
Q
What does silicon do in stainless steel?
A
Increases oxidation resistance at high temperatures.
23
Q
How does thermal conductivity of stainless steel compare to low carbon steels?
A
Thermal conductivity is lower, making it susceptible to overheating and distortion during welding.
24
Q
What is the effect of higher thermal expansion in stainless steel?
A
Leads to increased distortion and higher residual stresses on the welds.
25
Why can't stainless steels be cut using conventional oxyfuel equipment?
They resist oxidation.
26
What is the weldability of stainless steel affected by?
The weldability of stainless steel is affected by the reactions of chromium with carbon and oxygen at elevated temperatures.
27
What are some common welding processes for stainless steel?
Common welding processes for stainless steel include:
1. Gas Metal Arc Welding (GMAW)
2. Gas Tungsten Arc Welding (GTAW)
3. Flux Core Arc Welding (FCAW)
4. Shielded Metal Arc Welding (SMAW)
5. Submerged Arc Welding (SAW)
6. Plasma Arc Welding (PAW)
28
What should be considered when choosing filler metals for welding stainless steel?
The filler metal should match or exceed the chemistry of the base metal in specific alloying elements.
29
Can you arc weld stainless steels containing aluminum or titanium?
Yes, you can arc weld stainless steels that contain aluminum or titanium with similar filler metals using gas shielded processes or the electric resistance welding process.
30
What should you do when you need specific information about a type of stainless steel?
Consult the manufacturer for technical data to develop a proper welding procedure.
31
What are the three major types of stainless steel?
The three major types of stainless steel are austenitic, ferritic, and martensitic.
32
What are some additional types of stainless steel?
Additional types of stainless steel include duplex and precipitation hardening.
33
What is the chromium content in austenitic stainless steel?
Austenitic stainless steel contains 16% to 26% chromium.
34
What are the major alloying elements of austenitic stainless steels?
The major alloying elements range from 6% to 22% nickel and 0.03% to 0.25% carbon.
35
What is a key characteristic of austenitic stainless steels?
Austenitic stainless steels are non-magnetic and exhibit good resistance to corrosion and oxidation.
36
What is the temperature resistance of austenitic stainless steels?
They can withstand temperatures up to 649°C (1200°F) or higher.
37
What is the original chromium-nickel alloy composition?
The original chromium-nickel alloy (18-8 stainless) contained 18% chromium and 8% nickel.
38
What does the suffix 'N' indicate in stainless steel types?
The suffix 'N' indicates the addition of nitrogen, which increases strength and stability of austenite.
39
What does the suffix 'H' indicate in stainless steel types?
The suffix 'H' indicates high carbon content added to increase high-temperature strength.
40
What does the suffix 'L' indicate in stainless steel types?
The suffix 'L' indicates low carbon content, which helps eliminate carbide precipitation.
41
What is the atomic structure of austenitic stainless steel?
Austenitic stainless steel has a face-centred cubic (fcc) structure with an atom at each corner and an atom in the center of each face, totaling 14 atoms.
42
What happens to the atomic structure of low alloy steels at temperatures above 910°C (1670°F)?
Low alloy steels revert to a body-centred cubic (bcc) structure.
43
What is the effect of nickel on the structure of austenitic stainless steel?
The presence of nickel keeps austenitic stainless steel in a face-centred cubic structure at all temperatures.
44
What are the advantages of the fcc structure in austenitic stainless steels?
Austenitic stainless steels have better ductility and toughness than carbon and low alloy steels, making them suitable for forming and deep drawing operations.
45
How does the bcc structure behave at low temperatures?
The bcc structure becomes brittle at low temperatures.
46
Can austenitic steels be hardened using heat treatment?
No, heat treatment cannot be used to harden austenitic steels.
47
What method can be used to harden austenitic steels?
Cold working can rapidly work-harden austenitic steels.
48
What are the major alloying elements in ferritic stainless steels?
The major alloying elements are 10.5% to 30% chromium, little or no nickel, and small amounts of carbon (0.07% to 0.259%) and nitrogen (0.15% to 2.5%).
49
What is the microstructure of ferritic stainless steels at room temperature?
At room temperature, ferritic stainless steels have a bcc microstructure.
50
What is the main advantage of ferritic stainless steel?
Ferritic stainless steel provides good resistance to chloride stress corrosion cracking, atmospheric corrosion, and oxidation at a relatively low cost.
51
What is the general use of low-chromium ferritic stainless steels?
Low-chromium alloys (approximately 11%) have fair corrosion and oxidation resistance and are extensively used in automotive exhaust systems.
52
What is the use of intermediate-chromium ferritic stainless steels?
Intermediate-chromium alloys (16% to 18%) are used for automotive trim components and cooking utensils, but they cannot be fabricated as readily due to poor toughness and weldability.
53
What applications require high-chromium ferritic stainless steels?
High-chromium alloys (19% to 30%) are used for applications requiring a high level of corrosion and oxidation resistance.
54
What additional elements may high-chromium alloys contain?
High-chromium alloys often contain small amounts of either aluminum or molybdenum and have a very low carbon content.
55
What happens to ferritic stainless steels at temperatures above approximately 816°C (1500°F)?
They can lead to the formation of austenite, which consists of ultra-hard, needle-like crystals that give the steel high strength and hardness.
56
What effect does cooling in air have on austenite in ferritic stainless steels?
Cooling in air can cause austenite to transform to martensite.
57
What is the recommended temperature for annealing ferritic stainless steels?
Annealing should be done at temperatures about 760°C (1400°F).
58
What is the purpose of annealing ferritic stainless steels?
It transforms martensite back to ferrite and helps restore ductility and optimize corrosion resistance.
59
What are the major alloying elements in martensitic stainless steel?
They range from 11.5% to 18% chromium and 0.15% to 1.20% carbon.
60
Why are martensitic stainless steels often called straight chrome stainless steels?
Because they contain little or no nickel.
61
What is the microstructure of martensitic stainless steels in the hardened condition?
They possess a body-centered cubic (bcc) microstructure.
62
What are the welding characteristics of martensitic stainless steels?
They can be welded but usually require preheat and post-weld tempering to prevent cracking.
63
What are martensitic stainless steels in the annealed condition?
They are ferritic (BCC) in the annealed condition.
## Footnote
They can be heat treated to form martensite.
64
How are martensitic stainless steels hardened?
They are hardened using heat treatment.
## Footnote
The high-temperature austenitic phase transforms to the hard martensitic phase during quenching.
65
What is the response of martensitic stainless steels to hardening and tempering?
Their response is similar to that of hardenable carbon and low alloy steels.
66
What elements can be added to martensitic stainless steels to improve properties at elevated temperatures?
Molybdenum, vanadium, niobium, and tungsten.
67
What are the corrosion resistance characteristics of martensitic stainless steels?
They have moderate corrosion resistance and are not as corrosion-resistant as austenitic and ferritic types.
68
What are the applications of martensitic stainless steels?
They are used in steam and gas turbine components, cutlery, and bearings.
69
What are the two groups of martensitic stainless steels?
12% chromium, low carbon, engineering grades and higher chromium, high carbon, cutlery grades.
70
What advantages do duplex stainless steel (DSS) alloys combine?
They combine advantages of ferritic and austenitic stainless steels.
71
What is a disadvantage of duplex stainless steels?
They can experience embrittlement.
72
What are the advantages of duplex alloys over austenitic alloys?
They have resistance to stress corrosion cracking and pitting, and yield strengths that are twice that of austenitic alloys.
73
What are the steps in the precipitation heat treatment process?
1. Heat the metal to put the alloys into solution. 2. Quench the metal to trap the alloys in solution. 3. Reheat the metal to harden it.
74
What alloying elements promote precipitation hardening?
Copper, titanium, niobium, or aluminum.
75
What does the AISI numbering system classify?
The AISI numbering system classifies stainless steels.
76
What does the first digit in the AISI classification represent?
The first digit represents the type of stainless steel.
77
What do the second and third digits in the AISI classification identify?
The second and third digits identify the specific alloys.
78
What is added to the grade to identify modifications?
A letter suffix is added to identify modifications to the original grade.
79
What are the major alloying elements in Austenitic stainless steels?
Chromium, nickel, manganese.
80
What is the basic grade of Austenitic stainless steel?
The basic grade (type 302) is 18-8 (18% Cr, 8% Ni).
81
What characterizes AISI 200 and 300 series stainless steels?
All AISI 200 and 300 series are austenitic stainless steels.
82
What does the suffix 'L' indicate in stainless steel grades?
The suffix 'L' indicates low carbon versions.
83
What does the suffix 'N' denote in stainless steel grades?
The suffix 'N' denotes the addition of nitrogen.
84
What does the suffix 'H' indicate in stainless steel grades?
The suffix 'H' denotes high carbon content.
85
What does the suffix 'B' indicate in stainless steel grades?
The suffix 'B' denotes additional silicon.
86
What is the main alloying element in the 200 series?
Manganese is used as a main alloying element in addition to chromium and nickel.
87
What is the characteristic of the 5xx series stainless steels?
The 5xx series are not true stainless steels as they contain less than 10% chromium.
88
What is the highest tonnage of weldable stainless steels produced?
The highest tonnage produced is austenitic stainless steels.
89
What improves heat resistance in stainless steels?
Increasing the silicon content improves heat resistance.
90
What series do ferritic stainless steels belong to?
Ferritic stainless steels are part of the AISI 400 series.
91
Are ferritic stainless steels magnetic?
Yes, ferritic stainless steels are magnetic.
92
What series do martensitic stainless steels belong to?
Martensitic stainless steels are also part of the AISI 400 series.
93
Are martensitic stainless steels magnetic?
Yes, martensitic stainless steels are magnetic.
94
What is the base alloy for martensitic stainless steels?
The base alloy for the group is type 410.
95
What are other types of martensitic stainless steels?
Other types are 403, 416, 418, 422, and 429.
96
What is carbide precipitation?
Carbide precipitation is a chemical reaction where chromium in the grain boundaries combines with carbon to form chromium carbides during welding of austenitic stainless steels.
97
At what temperature range does carbide precipitation occur?
Carbide precipitation occurs in the temperature range of 427°C to 816°C (800°F to 1500°F).
98
What is the effect of carbide precipitation on corrosion resistance?
Carbide precipitation depletes chromium available for forming chromium oxides, leading to a loss of corrosion resistance.
99
Where does carbide precipitation primarily occur?
Carbide precipitation primarily occurs near the grain boundaries of the metal.
100
What is the heat-affected zone (HAZ)?
The heat-affected zone (HAZ) is the area adjacent to the fusion line in welding that reaches temperatures where carbide precipitation can occur.
101
What is sensitization in stainless steels?
Sensitization is a phenomenon where stainless steels not stabilized with titanium or niobium form chromium carbides along the austenite grain boundaries when subjected to sustained temperatures of 427°C to 816°C (800°F to 1500°F).
102
What can contribute to carbide precipitation during welding?
Severe over welding, indicated by the number of stringer beads, can contribute to carbide precipitation.
103
What is the consequence of sensitization?
Sensitization can lead to inter-granular corrosion due to the formation of chromium carbides.
104
What are the four ways to prevent carbide precipitation?
1. Limit the carbon level, 2. Add stabilizers, 3. Control heating and cooling, 4. Use welding procedures
105
What is the maximum carbon content for ELC stainless steels?
0.03% in the base metal
106
What are ELC and L types of stainless steel?
Stainless steels with a maximum carbon content of 0.03% are commonly called ELC (extra low carbon) or L (low carbon) types.
107
Why do ELC stainless steels resist carbide precipitation?
They have less carbon to unite with the chromium.
108
What is the service temperature limit for ELC types?
427°C (800°F)
109
What is the most common way to prevent carbide precipitation?
Using stainless steels that contain added stabilizers.
110
How do stabilizers prevent carbide precipitation?
They combine more readily with carbon than chromium does, forming harmless carbides.
111
What do stabilizers ensure in stainless steel?
They leave chromium free to combine with oxygen, ensuring good corrosion resistance.
112
What are common stabilizers in stainless steel?
Common stabilizers include columbium (niobium), titanium, and tantalum.
113
Which types of stainless steel are considered unstabilized?
Stainless steels with a maximum carbon content of 0.159% (301, 302, 303, 304, and 308) are unstabilized steels.
114
What is the maximum carbon content in grades 304 and 308 stainless steels?
The maximum carbon content in grades 304 and 308 is lower, at 0.08%.
115
What temperature range is associated with carbide precipitation?
Carbide precipitation is likely to occur in the temperature range of 427°C to 816°C (800°F to 1500°F).
116
How can carbide precipitation be prevented?
Carbide precipitation can be prevented by solution heat-treating the stainless steel.
117
What does solution heat treatment involve?
Solution heat treatment involves heating stainless steel to 1150°C (2102°F) to dissolve carbides, followed by rapid cooling.
118
What is the purpose of rapid cooling in solution heat treatment?
Rapid cooling prevents the re-formation of carbides and restores carbon into solution in the austenite.
119
What welding processes can be used with stainless steel?
SMAW, GTAW, GMAW, and MCAW.
120
What is the AWS Specification Number for stainless steel welding electrodes for Shielded Metal Arc Welding?
A5.4
121
What is the AWS Specification Number for Bare Stainless Steel Welding Electrodes and Rods?
A5.9
122
What is the AWS Specification Number for Stainless Steel Flux Cored and Metal Cored Electrodes and Rods?
A5.22
123
What is the AWS Specification Number for Consumable Inserts?
A5.30
124
What does CSA W48 cover?
Filler metals and allied materials for metal arc welding.
125
What is the importance of protecting stainless steel SMAW electrodes?
They must be protected from moisture pickup, which can cause porosity in the weld metal and cracking in martensitic chromium steels.
126
What do AWS specifications and CSA standards specify?
They specify the identification and packaging requirements for most filler metals.
127
How long can electrodes in hermetically sealed containers be stored without deterioration?
They can be stored for several months without deteriorating.
128
What should you do before using electrodes that have been rebaked?
Be careful when using electrodes that have been rebaked because the coating may come loose.
129
What temperature and duration is recommended for rebaking electrodes?
Rebake at 260°C (500°F) for one hour to restore the electrode to its original condition.
130
What should you do with electrodes exposed to humid conditions?
Re-bake them at high temperatures according to the manufacturer's specifications.
131
How should stainless steel electrodes be stored?
Store stainless steel separately, supported on wood or similar non-contaminating materials.
132
What should be used to protect stainless steels during rolling or forming?
Use paper or other means to protect stainless steels from contamination.
133
What can cause crevice corrosion in stainless steel?
Iron contamination can cause crevice corrosion.
134
How should carbon steel lifting devices be handled?
Coat or cover carbon steel slings, clamps, or other lifting devices to protect stainless steel.
135
What is the recommended storage temperature for unused electrodes?
Store them in holding ovens at about 93°C to 121°C (200°F to 250°F) until just before they are needed for welding.
136
What happens if stainless steel comes in contact with carbon steel?
Carbon steel residue on stainless steel may cause it to rust in service, leading to a serious loss of corrosion resistance.
137
What are the precautions for handling and storing stainless steel?
Working with stainless steel requires special procedures to avoid contamination.
138
What is the purpose of gas shielding when welding a butt joint?
To protect the other side from contamination during the welding process.
139
What should be done to clean the material before welding?
Use a suitable solvent to remove all hydrocarbons, grease, oil, and chloride-free cutting fluid if machining or grinding.
140
How should oxide film be removed prior to welding?
Remove any oxide film from plasma arc cutting, carbon arc gouging, or aluminum oxide grinding disc used for stainless steel only.
141
What is recommended for removing moisture from a weldment?
Moisture can be removed by heat or by blowing with dry air.
142
What can cause stress cracking in stainless steel during welding?
The presence of contaminants such as chlorine and fluorine can contribute to stress cracking.
143
What should be done to determine the kind and amount of contamination on the surface?
Wiping down the surface helps identify the contamination that needs to be removed.
144
What are some methods for cleaning stainless steel prior to welding?
Methods include power brushing, degreasing, pickling, and grinding.
145
What is the difference in electrode current ranges for stainless steel compared to carbon steel?
Electrode currents for stainless steel are 10% to 15% lower than for the same size of carbon steel SMAW electrode.
146
What controls are necessary due to stainless steel's low thermal conductivity?
Stricter control over heat input is required to avoid overheating the electrode and weld zone.
147
What can moisture in electrode coatings and shielding gases cause?
Moisture can cause porosity in the weld metal.
148
What is the general weldability of austenitic stainless steels?
Most austenitic stainless steels have excellent weldability, and preheat and post-heat treatments are not normally necessary.
149
What electrode should be used for the first layer in a surfacing operation on carbon steel?
Use E309 for the first layer and subsequent layers with E.
## Footnote
Sufficient alloy content is needed to handle dilution.
150
What electrode is recommended when welding stainless steel to carbon steel?
Use an electrode with 308.
## Footnote
This ensures compatibility.
151
What electrode is suitable for welding molybdenum-containing stainless steel?
Use an electrode with a matching content, such as E316.
## Footnote
A stabilized type (E347) may also be suitable.
152
What electrode should be used for low carbon grade stainless steel (304L)?
Use either a low carbon electrode (E308L) or E308.
## Footnote
E308 has a higher content of nickel and chromium.
153
What is a key consideration when welding ferritic stainless steels?
Minimize joint restraint and pre-setting.
## Footnote
This is important to control distortion.
154
What happens to ferritic stainless steels during welding?
They do not undergo any microstructure phase change and are not hardenable by heat treatment.
## Footnote
Instead, they may experience grain growth.
155
How can distortion be controlled when welding stainless steel?
Use more tack welds, jigs, or an alternative method.
## Footnote
Stainless steel expands more than carbon steel when heated.
156
What is the effect of grain growth in stainless steel welding?
Large grains can have a detrimental effect on toughness and ductility.
## Footnote
This is particularly problematic when welding thin sections.
157
What should be done to overcome warping in stainless steel welding?
Implement controls for thermal expansion.
## Footnote
This is necessary to prevent issues during the welding process.
158
What factors influence grain growth in welding?
The extent of grain growth depends on the heat input of the welding process and careful control of interpass temperatures.
159
How can smaller cracking and reduced toughness be controlled in welding?
Through preheating to temperatures of about 150°C (302°F), which also removes hydrogen and relieves metal stress.
160
What is the recommended electrode for welding ferritic stainless steels?
The only ferritic stainless steel electrode for shielded metal arc welding in AWS is E430.
161
What should be matched when welding ferritic stainless steels?
Match the filler metals to join ferritic stainless steels, particularly when using SMAW.
162
What is a common challenge when welding martensitic stainless steels?
Preventing cracking in the heat-affected zone and weld metal as the weld cools.
163
What causes cracking in martensitic stainless steels during welding?
Cracking results from the high hardness of these steels, which increases with carbon content.
164
What is the recommended preheating temperature range for welding martensitic stainless steels?
The preheating temperature should be in the range of 204°C to 316°C (400°F to 600°F).
165
What should be eliminated to prevent hydrogen-related cracking during welding?
Eliminate all sources of hydrogen contamination, including dirt, moisture, and grease.
166
What are the preheat minimum temperatures based on carbon content for martensitic stainless steels?
Less than 0.05%: 121°C (250°F), 0.05% to 0.15%: 204°C (400°F), More than 0.15%: 316°C (600°F).
167
What is the post-weld heat treatment requirement for martensitic stainless steels with high carbon content?
High carbon types 420 and 440 martensitic stainless steel weldments usually require heat treatment to achieve high hardness.
168
What types of electrodes can be used for welding martensitic stainless steels?
Matching electrodes that produce a martensitic weld deposit or austenitic electrodes can be used.
169
When should martensitic weld metal be used?
When the weld metal must match the base metal in hardness and wear resistance.
170
When can austenitic electrodes be used in welding?
When hardness is not a consideration and only corrosion resistance is a factor.
171
What does chromium do in alloys?
Chromium acts as a protective layer against oxidation and corrosion.
172
What is the effect of chromium on corrosion resistance?
Chromium improves corrosion resistance due to its ability to form a protective oxide layer.
173
What is the minimum percentage of chromium needed for oxidation resistance?
A minimum of 10% chromium is required for effective oxidation resistance.
174
What role does silicon play in alloys?
Silicon serves as a lower-cost replacement for nickel in some alloys.
175
How does molybdenum affect high-temperature strength?
Molybdenum improves strength at high temperatures and enhances resistance to creep.
176
What is creep in metals?
Creep is the gradual plastic deformation of a material under constant stress over time.
177
How does carbon affect the strength of alloys?
Carbon increases strength in amounts less than 0.04%.
178
What is the relationship between temperature and strength in alloys?
Strength often decreases at elevated temperatures.
179
What is the significance of tough in material strength?
Tough refers to the ability of a material to withstand stress without breaking.
180
What is the primary metal used in stainless steel?
Filler metal should match or exceed the chemistry of the base metal
181
Austenitic
200-300 series
16%- 26% chromium
6%-22% nickel
0.03%-0.25% carbon
182
What is the magnetic property of stainless steel?
Non-magnetic
## Footnote
This is important for applications where magnetism is a concern.
183
What is the significance of 'H' in stainless steel?
H = High carbon (3% or more)
## Footnote
High carbon content can affect hardness and strength.
184
What does 'L' refer to in stainless steel?
L = Low carbon (0.03% or less)
## Footnote
Low carbon content helps in welding and reduces carbide precipitation.
185
Fcc?
Face-centered cubic (FCC) in all temperatures
This structure contributes to its ductility and toughness.
186
How does stainless steel compare to carbon steel?
Better ductility and toughness than carbon steel
## Footnote
This makes it more suitable for various applications.
187
What should be done to overcome warping during welding?
Use more tack/jigs or alternate weld sequence
## Footnote
These methods help control heat distribution.
188
What is crucial about the electrode used in welding stainless steel?
Electrode must match base or have higher nickel/chromium
## Footnote
This ensures compatibility and strength of the weld.
189
Ferritic
400 series (straight chrome)
10.5%- 30% chromium
Little to no nickel
Small amounts of carbon (0.07%-0.25%)
Small amounts of nitrogen
(0.15%- 2.5%)
Are magnetic
BBC
Low cost
190
Ferritic provides:
Resistance to chloride stress corrosion cracking
Resistance to atmospheric corrosion
Resistance to oxidation
191
What is martensite?
Martensite is a microstructure consisting of needle like crystals
192
What is the temperature to avoid unwanted ferritic martensite
From temps of 1400°f
193
Austentic transforms to martensite
When cooling in air
194
What are the properties of austentic materials?
Austentic materials are characterized by their face-centered cubic structure.
195
What is the role of carbon in steel?
Carbon content affects the hardness and strength of steel.
