 |
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| 21-4 N valve steel | 21-12 N valve steel | X45CrSi93 valve steel | SUH3 / SUH11 Heat resisting steel bars |
| |
| Typical Analysis : |
| Carbon |
0.20% |
Manganese |
1.75% |
Silicon |
0.80% |
| Chromium |
21.00% |
Nickel |
11.50% |
Nitrogen |
0.20% |
|
| |
| Applications :
|
| This alloy has been used as the head material in two-piece
exhaust valves for both diesel and gasoline engines. It offers excellent high
temperature strength and hardness as well as corrosion resistance to combustion
products. |
| |
| Workability :
|
Forging : 21-12 N can be readily forged by both
upset and extrusion methods at temperatures in the range of 2050 / 2150 °F (1121 / 1177 °C). Do not forge at temperatures above 2200 °F
(1204 °F) nor below 1800 °F (982 °C). Forgings can be
rapidly cooled.
Machinability : Machinability properties are comparable to the standard 18-8 stainless alloys. |
| |
| Heat Treatment : |
Annealing : Heat approximately 1 hour at 1900 °F (1028 °C) and cool rapidly. This will result in a hardness of 241 BHN.
Stress Relieve Anneal : When required, parts can be stress relieved by holding at 1400 °F ( 760 °C) for 4 to 8 hours, followed by air cooling.
Solution Heat Treatment : For critical applications requiring maximum high temperature strength, forgings can be solution heat treatment at 2050 / 2150 °F (1121 / 1177 °C) and water quenched. |
| |
| Typical Mechanical Properties : |
| Elevated Temperature Mechanical Properties |
| Specimens treated 1900 °F (1038 °C) water quenched |
| Test Temperature |
0.2 % Yield Strength |
Ultimate Tensile Strength |
% Elongation In 4 D |
% Reduction Of Area |
Brinell Hardness |
V-Notch Charpy Impact |
| °F |
°C |
Ksi |
MPa |
Ksi |
MPa |
Ft-Ib |
J |
| 77 |
25 |
75.0 |
17 |
123.5 |
852 |
42.0 |
60.0 |
241 |
74 |
100.0 |
| 1200 |
649 |
34.0 |
234 |
73.0 |
503 |
32.5 |
37.5 |
131 |
72 |
98.0 |
| 1350 |
732 |
29.5 |
203 |
52.2 |
360 |
33.0 |
53.0 |
120 |
70 |
95.1 |
| 1400 |
760 |
28.5 |
197 |
50.5 |
348 |
24.5 |
28.0 |
113 |
67 |
91.1 |
| 1500 |
816 |
27.0 |
186 |
40.5 |
279 |
22.0 |
30.0 |
72 |
73 |
99.0 |
|
| |
| Stress Rupture Properties at 1350 °F (732 °C) |
| Specimens treated 1900 °F (1038 °C), water quenched |
| |
Time to Rupture |
| 10 Hrs. |
100 Hrs. |
500 Hrs. |
Stress to produce rupture,
psi (Mpa)% Elongation, 1'' (25.4 mm)
% Reduction of Area |
29.000 (196) |
18.000 (127) |
13.000 (88) |
| 26.0 |
27.0 |
41.0 |
| 35.0 |
28.0 |
40.0 |
|
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