Type Analysis
| Description | Selection | Corrosion Resistance | Elevated Temperature Use |
|
Element |
Min |
Max |
|
Carbon |
-- |
0.05 |
|
Manganese |
-- |
2.00 |
|
Silicon |
-- |
0.50 |
|
Phosphorus |
-- |
0.040 |
|
Sulfur |
-- |
0.030 |
|
Chromium |
11.00 |
12.50 |
|
Nickel |
7.50 |
9.50 |
|
Molybdenum |
-- |
0.50 |
|
Copper |
1.50 |
2.50 |
|
Columbium+Tantalum |
0.10 |
0.50 |
Recognizing the need for high-strength alloys with good corrosion resistance to atmospheric environments, and a martensitic age-hardenable stainless steel. This alloy is relatively soft and formable in the annealed condition. Asingle-step aging treatment develops exception-alloy high yield strength with good ductility and toughness.
This stainless can be machined in the annealed condition , and welded in much the same manner as other precipitation hardenable stainless steels. Because of its low work-hardening rate, it can be extensively cold formed. The dimensional change during hardening is only about -0.001 in/in, which permits close-tolerance finish machining in the annealed state.
Custom 455 stainless represents a significant advancement in the area of precipitation hardening stainless steels. It should be considered where simplicity of heat treatment, ease of fabrication, high strength and corrosion resistance are required in combination.
Because of the unique combination of high strength and corrosion resistance of Custom 455 stainless there are few other alloys available for consideration. PH13-8 Mo* can be considered where good transverse toughness and ductility are necessary in large sections. *PH13-8 Mo is registered trademark of ARMCO, Inc.
Custome 455 stainless resists staining in normal air atmospheres, and shows no corrosion in fresh water. Test in 5% salt spray at 95 °F(35 °C) and in 5% ferric chloride at room temperature have demonstrated good resistance to pitting and rusting. Laboratory test s in a variety of mild chemical environments have shown that the level of general corrosion resistance is superior to that of the 12% chromium steels (Type 430). In most tests there was no significant effect of aging temperature on corrosion resistance. Hydrogen embrittlement tests in 5% acetic acid saturated with sulfuric hydrogen at room temperature show the same degree of susceptibility as other high-strength martensitic stainless steels. All high-strength steels are subject to stress corrosion under certain stress conditions and in certain environments. Numerous severe tests have been conducted to evaluate the behavior of Custom 455 stainless in different environments, and to determine the effect of aging temperature on resistance to stress -corrosion cracking. These tests include U-bend specimens, direct tension specimens, C-rings and precracked cantilever beam specimens. Environments have included marine atmospheres, 20% salt spray, and 3-1/2% sodium chloride solutions. All tests have shown that Custom 455 stainless has inherently good resistance to stress-corrosion cracking, and that this resistance improves markedly as aging temperature is increased. For optimum corrosion resistance, surfaces must be free of scale and foreign particles and finished parts should be passivated.
Custom 455 stainless has displayed excellent resistance to oxidation up to approximately 1100 °F. Long-term exposure to temperatures between about 600-900 °F can result in reduced toughness in precipitaiton hardenable stainless steels. The reduction in toughness can be minimized in some cases by using higher aging temperatures. Short exposures to elevated temperatures can be considered, provided the maximum temperature is at least 50 °F less than the aging temperature.
|
(Condition H 950) |
Modulus of Rigidity (G) |
Mean Coefficient fo thermal expansion
|
Temperature |
10(-6)/°F |
10(-6)/K |
|
|
72 °F to |
22 °C to |
||
|
200 |
93 |
5.90 |
10.6 |
|
300 |
149 |
6.03 |
10.9 |
|
500 |
260 |
6.20 |
11.20 |
|
700 |
371 |
6.45 |
11.6 |
|
900 |
482 |
6.68 |
12.0 |
Thermal Conductivity
|
Test |
Btu-in/ft²-h-°F |
W/m-K |
|
|
°F |
°C |
||
|
212 |
100 |
125 |
18.0 |
|
392 |
200 |
137 |
19.7 |
|
572 |
300 |
148 |
21.3 |
|
752 |
400 |
162 |
23.4 |
|
932 |
500 |
172 |
24.7 |
Electrical Resistivity
|
Condition |
Ohm-cir-mil/ft |
Microhm/mm |
|
A |
545 |
906 |
|
H 950 |
456 |
758 |
Condition A
(Solution
Treated or Annealed): Heat to 1500/1550 °F, and cool rapidly.
Water quenching is preferred for small sections. Custom 455 stainless
will normally be supplied from the mill in the annealed condition,
ready for the one-step hardening treatment.
Condition H 900, H
950, H 1000, H 1050
(Precipitation or Age Hardened): The high
strength levels of Custom 455 are derived from a single
precipitation-hardening treatment consisting of heating to a selected
temperature between 900/1050 °F, holding for 4 hours and air
cooling
Average Longitudinal
Size Change (Contracting)
Solution-treated to aged condition
|
Condition |
Contraction |
|
H 900 |
0.0007 |
|
H 950 |
0.0009 |
|
H 1000 |
0.0012 |
Cleaning
Descaling
following forging and annealing can be accomplished by acid cleaning
or grit blasting. The acic treatment consists of 2 minutes in 50% by
volume muriatic acid at 180 °F, followed by 4 minutes in a
mixture of 15% by volume nitric acid, plus 3% by volume hydrofluoric
acid at room temperature. Repeat cleaning procedure as neccessary but
decrease the times by 50% (i.e., 1 and 2 minutes, respectively). The
heat tint from aging can be removed by polishing, vapor blasting or
pickling 4 to 6 minutes in a mixture of 15% by volume nitric acid,
followed by a water rinse. Repeat the acid cleaning procedure if
necessary, but decrease the time by 2 to 3 minutes. Desmut in 20% by
volume nitric acid at room temperature. After acid cleaning, bake 1
to 3 hours at 300/350 °F to remover hydrogen.
Hot working
Custome
455 stainless is easily forged within the temperature range fo
1650/2300 °F. For optimum mechanical properties, material to be
forged should be heated uniformly to 1900/2100 °F and soaked at
heat; fnishing temperature should be within the range of 1500/1700 °F
to obtain an optimum grain size and properties after heat treating.
Cool forging in air to rom temperature and anneal.
Cold working
Cold
working is readily performed despite the fact that Custom 455
stainless is martensitic in the annealed condition, and has a
hardness of Rockwell C 30/35. Deep drawing or sketching operations
will required intermediate anneals because the elongation tends to be
localized. For other cold-forming operations such as cold drawing and
cold rolling, the work-hardening rate in the annealed condition is
extremely low allowing considearble cold working without intermediate
annealing. Cold-heading and warm-heading operations are also easily
performed. Cold working prior to aging results in even higher tensile
and yield strengths in the hardened condition.
Spring Properties
Wire in the annealed or lightly drawn condition and annealed strip can be aged for 2 to 4 hours at 900°F (482°C) to achieve a tensile strength in excess of 250 ksi (1742 MPa). As such, Custom 455 stainless can be used in relatively large diameters and thicknesses and still have good spring characteristics. This greatly expands the range of sizes of corrosion-resistant springs available to designers.
Custom 455 stainless can also be extensively cold worked prior to aging to achieve even higher levels of strength. Extensive cold working reduces the aging time required to reach maximum mechanical properties. Therefore, cold-drawn spring wire and cold-rolled strip in Condition C need only be aged for 1/2 hour at 850°F (454°C).
|
Diameter |
Nominal |
Age-Hardened Tensile |
|||||
|
inches |
mm |
ksi |
MPa |
MIN |
MAX |
MIN |
MAX |
Machining
Custom
455 stainless have been machined successfully using the same
practices required for other high-strength alloys; i.e., rigid tool
and work supports, slower speeds, positive cuts and adequate amounts
of coolant. The machining characteristics of Custom 455 stainless are
similar to those of the nickel maraging steeels. When using carbide
tools , surface speed feet/minute can be increased between 2 to 3
times over the high speed suggestions. Feeds can be increased between
50 and 100%.
|
High Speed Tool |
||||
|
Turning- |
Cut-Off |
1/16" |
SFPM |
60 |
|
1/8" |
SFPM |
60 |
||
|
1/4" |
SFPM |
60 |
||
|
1/2" |
SFPM |
60 |
||
|
Form |
1" |
SFPM |
60 |
|
|
1-1/2" |
SFPM |
60 |
||
|
Drilling |
Drill |
1/4" |
SFPM |
50 |
|
3/4" |
SFPM |
50 |
||
|
Reaming |
Under 1/2" |
SFPM |
60 |
|
|
Over 1/2" |
SFPM |
60 |
||
|
Die |
T.P.I |
3-7½ |
SFPM |
5-12 |
|
8-15 |
SFPM |
8-15 |
||
|
Over 16 |
SFPM |
10-20 |
||
Welding
Custom
455 stainless can be satisfactorily welded by the shielded fusion and
resistance welding processes. Oxyacetylene welding is not
recommended, since carbon pickup in the weld may occur. Preheating is
not required to prevent cracking during the welding of this alloy.
Normally, welding in the solution-annealed condition is satisfactory;
however, where high welding stresses are anticipated, it may be
advantageous to weld in the overaged (aged at 1150 °F) condition.
If welded in the solution-annealed condition, the alloy can be
directly aged to the desired strength level after welding. However,
the optimum combination of strength, ductitlity and corrosion
resistance is obtained by solution annealing the welded part before
aging. If welded in the overaged condition, the part should be
solution annealed before aging.
Typical Room
Temperature Mechanical Properties
Bar, 1"(25.4mm) section
|
Condition |
0.2% |
Ultimate |
Notch |
% |
% |
Rockwell |
Charpy |
||||
|
ksi |
MPa |
ksi |
MPa |
ksi |
MPa |
ft-lb |
J |
||||
|
A |
115 |
793 |
140 |
965 |
-- |
-- |
12 |
50 |
31 |
-- |
-- |
|
H 900 |
220 |
1516 |
230 |
1585 |
250 |
1723 |
10 |
45 |
48 |
8 |
11 |
|
H 1000 |
195 |
1344 |
205 |
1413 |
250 |
1723 |
12 |
45 |
45 |
12 |
16 |
|
H 1050 |
175 |
1206 |
190 |
1309 |
250 |
1723 |
14 |
50 |
40 |
25 |
34 |
Typical Elevated
Temperature
Tensile properties, condition H950
|
Test |
0.2% |
Ultimate |
% |
% |
Room
Temp. |
|||
|
°F |
°C |
ksi |
MPa |
ksi |
MPa |
|||
|
Room |
220 |
1517 |
230 |
1586 |
12 |
50 |
48 |
|
|
600 |
316 |
185 |
1276 |
195 |
1345 |
12 |
50 |
48 |
|
800 |
427 |
163 |
1124 |
175 |
1207 |
14 |
60 |
48 |
|
1000 |
538 |
110 |
758 |
130 |
896 |
18 |
70 |
48 |
Typical Elevated
Temperature
Tensile properties, condition H1000
|
Test |
0.2% |
Ultimate |
% |
% |
Room
Temp. |
|||
|
°F |
°C |
ksi |
MPa |
ksi |
MPa |
|||
|
Room |
195 |
1345 |
205 |
1413 |
14 |
55 |
44 |
|
|
600 |
316 |
165 |
1138 |
174 |
1200 |
14 |
60 |
44 |
|
800 |
427 |
163 |
1020 |
154 |
1062 |
15 |
65 |
44 |
|
1000 |
538 |
110 |
758 |
118 |
814 |
20 |
75 |
44 |
Typical Stress Rupture Strength
|
Test Temperature |
Condition |
Stress for rupture in |
||||||
|
°F |
°C |
ksi |
MPa |
ksi |
MPa |
ksi |
MPa |
|
|
800 |
427 |
H 950 |
142 |
979 |
117 |
807 |
91 |
627 |
|
900 |
482 |
H 950 |
109 |
752 |
82 |
565 |
54 |
372 |
Type Analysis
| Description | Selection | Corrosion Resistance | Elevated Temperature Use |
|
Element |
Min |
Max |
|
Carbon |
-- |
0.05 |
|
Manganese |
-- |
2.00 |
|
Silicon |
-- |
0.50 |
|
Phosphorus |
-- |
0.040 |
|
Sulfur |
-- |
0.030 |
|
Chromium |
11.00 |
12.50 |
|
Nickel |
7.50 |
9.50 |
|
Molybdenum |
-- |
0.50 |
|
Copper |
1.50 |
2.50 |
|
Columbium+Tantalum |
0.10 |
0.50 |
Recognizing the need for high-strength alloys with good corrosion resistance to atmospheric environments, and a martensitic age-hardenable stainless steel. This alloy is relatively soft and formable in the annealed condition. Asingle-step aging treatment develops exception-alloy high yield strength with good ductility and toughness.
This stainless can be machined in the annealed condition , and welded in much the same manner as other precipitation hardenable stainless steels. Because of its low work-hardening rate, it can be extensively cold formed. The dimensional change during hardening is only about -0.001 in/in, which permits close-tolerance finish machining in the annealed state.
Custom 455 stainless represents a significant advancement in the area of precipitation hardening stainless steels. It should be considered where simplicity of heat treatment, ease of fabrication, high strength and corrosion resistance are required in combination.
Because of the unique combination of high strength and corrosion resistance of Custom 455 stainless there are few other alloys available for consideration. PH13-8 Mo* can be considered where good transverse toughness and ductility are necessary in large sections. *PH13-8 Mo is registered trademark of ARMCO, Inc.
Custome 455 stainless resists staining in normal air atmospheres, and shows no corrosion in fresh water. Test in 5% salt spray at 95 °F(35 °C) and in 5% ferric chloride at room temperature have demonstrated good resistance to pitting and rusting. Laboratory test s in a variety of mild chemical environments have shown that the level of general corrosion resistance is superior to that of the 12% chromium steels (Type 430). In most tests there was no significant effect of aging temperature on corrosion resistance. Hydrogen embrittlement tests in 5% acetic acid saturated with sulfuric hydrogen at room temperature show the same degree of susceptibility as other high-strength martensitic stainless steels. All high-strength steels are subject to stress corrosion under certain stress conditions and in certain environments. Numerous severe tests have been conducted to evaluate the behavior of Custom 455 stainless in different environments, and to determine the effect of aging temperature on resistance to stress -corrosion cracking. These tests include U-bend specimens, direct tension specimens, C-rings and precracked cantilever beam specimens. Environments have included marine atmospheres, 20% salt spray, and 3-1/2% sodium chloride solutions. All tests have shown that Custom 455 stainless has inherently good resistance to stress-corrosion cracking, and that this resistance improves markedly as aging temperature is increased. For optimum corrosion resistance, surfaces must be free of scale and foreign particles and finished parts should be passivated.
Custom 455 stainless has displayed excellent resistance to oxidation up to approximately 1100 °F. Long-term exposure to temperatures between about 600-900 °F can result in reduced toughness in precipitaiton hardenable stainless steels. The reduction in toughness can be minimized in some cases by using higher aging temperatures. Short exposures to elevated temperatures can be considered, provided the maximum temperature is at least 50 °F less than the aging temperature.
|
(Condition H 950) |
Modulus of Rigidity (G) |
Mean Coefficient fo thermal expansion
|
Temperature |
10(-6)/°F |
10(-6)/K |
|
|
72 °F to |
22 °C to |
||
|
200 |
93 |
5.90 |
10.6 |
|
300 |
149 |
6.03 |
10.9 |
|
500 |
260 |
6.20 |
11.20 |
|
700 |
371 |
6.45 |
11.6 |
|
900 |
482 |
6.68 |
12.0 |
Thermal Conductivity
|
Test |
Btu-in/ft²-h-°F |
W/m-K |
|
|
°F |
°C |
||
|
212 |
100 |
125 |
18.0 |
|
392 |
200 |
137 |
19.7 |
|
572 |
300 |
148 |
21.3 |
|
752 |
400 |
162 |
23.4 |
|
932 |
500 |
172 |
24.7 |
Electrical Resistivity
|
Condition |
Ohm-cir-mil/ft |
Microhm/mm |
|
A |
545 |
906 |
|
H 950 |
456 |
758 |
Condition A
(Solution
Treated or Annealed): Heat to 1500/1550 °F, and cool rapidly.
Water quenching is preferred for small sections. Custom 455 stainless
will normally be supplied from the mill in the annealed condition,
ready for the one-step hardening treatment.
Condition H 900, H
950, H 1000, H 1050
(Precipitation or Age Hardened): The high
strength levels of Custom 455 are derived from a single
precipitation-hardening treatment consisting of heating to a selected
temperature between 900/1050 °F, holding for 4 hours and air
cooling
Average Longitudinal
Size Change (Contracting)
Solution-treated to aged condition
|
Condition |
Contraction |
|
H 900 |
0.0007 |
|
H 950 |
0.0009 |
|
H 1000 |
0.0012 |
Cleaning
Descaling
following forging and annealing can be accomplished by acid cleaning
or grit blasting. The acic treatment consists of 2 minutes in 50% by
volume muriatic acid at 180 °F, followed by 4 minutes in a
mixture of 15% by volume nitric acid, plus 3% by volume hydrofluoric
acid at room temperature. Repeat cleaning procedure as neccessary but
decrease the times by 50% (i.e., 1 and 2 minutes, respectively). The
heat tint from aging can be removed by polishing, vapor blasting or
pickling 4 to 6 minutes in a mixture of 15% by volume nitric acid,
followed by a water rinse. Repeat the acid cleaning procedure if
necessary, but decrease the time by 2 to 3 minutes. Desmut in 20% by
volume nitric acid at room temperature. After acid cleaning, bake 1
to 3 hours at 300/350 °F to remover hydrogen.
Hot working
Custome
455 stainless is easily forged within the temperature range fo
1650/2300 °F. For optimum mechanical properties, material to be
forged should be heated uniformly to 1900/2100 °F and soaked at
heat; fnishing temperature should be within the range of 1500/1700 °F
to obtain an optimum grain size and properties after heat treating.
Cool forging in air to rom temperature and anneal.
Cold working
Cold
working is readily performed despite the fact that Custom 455
stainless is martensitic in the annealed condition, and has a
hardness of Rockwell C 30/35. Deep drawing or sketching operations
will required intermediate anneals because the elongation tends to be
localized. For other cold-forming operations such as cold drawing and
cold rolling, the work-hardening rate in the annealed condition is
extremely low allowing considearble cold working without intermediate
annealing. Cold-heading and warm-heading operations are also easily
performed. Cold working prior to aging results in even higher tensile
and yield strengths in the hardened condition.
Spring Properties
Wire in the annealed or lightly drawn condition and annealed strip can be aged for 2 to 4 hours at 900°F (482°C) to achieve a tensile strength in excess of 250 ksi (1742 MPa). As such, Custom 455 stainless can be used in relatively large diameters and thicknesses and still have good spring characteristics. This greatly expands the range of sizes of corrosion-resistant springs available to designers.
Custom 455 stainless can also be extensively cold worked prior to aging to achieve even higher levels of strength. Extensive cold working reduces the aging time required to reach maximum mechanical properties. Therefore, cold-drawn spring wire and cold-rolled strip in Condition C need only be aged for 1/2 hour at 850°F (454°C).
|
Diameter |
Nominal |
Age-Hardened Tensile |
|||||
|
inches |
mm |
ksi |
MPa |
MIN |
MAX |
MIN |
MAX |
Machining
Custom
455 stainless have been machined successfully using the same
practices required for other high-strength alloys; i.e., rigid tool
and work supports, slower speeds, positive cuts and adequate amounts
of coolant. The machining characteristics of Custom 455 stainless are
similar to those of the nickel maraging steeels. When using carbide
tools , surface speed feet/minute can be increased between 2 to 3
times over the high speed suggestions. Feeds can be increased between
50 and 100%.
|
High Speed Tool |
||||
|
Turning- |
Cut-Off |
1/16" |
SFPM |
60 |
|
1/8" |
SFPM |
60 |
||
|
1/4" |
SFPM |
60 |
||
|
1/2" |
SFPM |
60 |
||
|
Form |
1" |
SFPM |
60 |
|
|
1-1/2" |
SFPM |
60 |
||
|
Drilling |
Drill |
1/4" |
SFPM |
50 |
|
3/4" |
SFPM |
50 |
||
|
Reaming |
Under 1/2" |
SFPM |
60 |
|
|
Over 1/2" |
SFPM |
60 |
||
|
Die |
T.P.I |
3-7½ |
SFPM |
5-12 |
|
8-15 |
SFPM |
8-15 |
||
|
Over 16 |
SFPM |
10-20 |
||
Welding
Custom
455 stainless can be satisfactorily welded by the shielded fusion and
resistance welding processes. Oxyacetylene welding is not
recommended, since carbon pickup in the weld may occur. Preheating is
not required to prevent cracking during the welding of this alloy.
Normally, welding in the solution-annealed condition is satisfactory;
however, where high welding stresses are anticipated, it may be
advantageous to weld in the overaged (aged at 1150 °F) condition.
If welded in the solution-annealed condition, the alloy can be
directly aged to the desired strength level after welding. However,
the optimum combination of strength, ductitlity and corrosion
resistance is obtained by solution annealing the welded part before
aging. If welded in the overaged condition, the part should be
solution annealed before aging.
Typical Room
Temperature Mechanical Properties
Bar, 1"(25.4mm) section
|
Condition |
0.2% |
Ultimate |
Notch |
% |
% |
Rockwell |
Charpy |
||||
|
ksi |
MPa |
ksi |
MPa |
ksi |
MPa |
ft-lb |
J |
||||
|
A |
115 |
793 |
140 |
965 |
-- |
-- |
12 |
50 |
31 |
-- |
-- |
|
H 900 |
220 |
1516 |
230 |
1585 |
250 |
1723 |
10 |
45 |
48 |
8 |
11 |
|
H 1000 |
195 |
1344 |
205 |
1413 |
250 |
1723 |
12 |
45 |
45 |
12 |
16 |
|
H 1050 |
175 |
1206 |
190 |
1309 |
250 |
1723 |
14 |
50 |
40 |
25 |
34 |
Typical Elevated
Temperature
Tensile properties, condition H950
|
Test |
0.2% |
Ultimate |
% |
% |
Room
Temp. |
|||
|
°F |
°C |
ksi |
MPa |
ksi |
MPa |
|||
|
Room |
220 |
1517 |
230 |
1586 |
12 |
50 |
48 |
|
|
600 |
316 |
185 |
1276 |
195 |
1345 |
12 |
50 |
48 |
|
800 |
427 |
163 |
1124 |
175 |
1207 |
14 |
60 |
48 |
|
1000 |
538 |
110 |
758 |
130 |
896 |
18 |
70 |
48 |
Typical Elevated
Temperature
Tensile properties, condition H1000
|
Test |
0.2% |
Ultimate |
% |
% |
Room
Temp. |
|||
|
°F |
°C |
ksi |
MPa |
ksi |
MPa |
|||
|
Room |
195 |
1345 |
205 |
1413 |
14 |
55 |
44 |
|
|
600 |
316 |
165 |
1138 |
174 |
1200 |
14 |
60 |
44 |
|
800 |
427 |
163 |
1020 |
154 |
1062 |
15 |
65 |
44 |
|
1000 |
538 |
110 |
758 |
118 |
814 |
20 |
75 |
44 |
Typical Stress Rupture Strength
|
Test Temperature |
Condition |
Stress for rupture in |
||||||
|
°F |
°C |
ksi |
MPa |
ksi |
MPa |
ksi |
MPa |
|
|
800 |
427 |
H 950 |
142 |
979 |
117 |
807 |
91 |
627 |
|
900 |
482 |
H 950 |
109 |
752 |
82 |
565 |
54 |
372 |