18Ni鋼的化學成分�
化學成分見表1�
�1 18Ni鋼[18Ni(250)�18Ni(300)�18Ni(350)]化學成分（質(zhì)量分�(shù)�%�
|
鋼號 |
C |
Si |
Mn |
Mo |
Ni |
Co |
Ti |
Al |
P |
S |
|
18Ni(250) |
≤0.03 |
≤0.10 |
≤0.10 |
4.25~5.25 |
17.50~18.50 |
7.00~8.00 |
0.30~0.50 |
0.05~0.15 |
≤0.01 |
≤0.01 |
|
18Ni(300) |
≤0.03 |
≤0.10 |
≤0.10 |
4.60~5.20 |
18.00~19.00 |
8.50~9.50 |
0.50~0.80 |
0.05~0.15 |
≤0.01 |
≤0.01 |
|
18Ni(350) |
≤0.03 |
≤0.10 |
≤0.10 |
4.00~5.00 |
17.00~19.00 |
11.00~12.75 |
1.20~1.45 |
0.05~0.15 |
≤0.01 |
≤0.01 |
18Ni鋼的熱處理：
固溶溫度�815~830�，油冷或空冷（加熱時�、鹽� 1min/mm，空氣爐2~2.5min/mm�，固溶硬度為28HRC。時效溫度為480℃[18Ni(250)]、[18Ni(300)]，時�3h，硬度為43HRC；時�6h，硬度為52HRC。時效溫度為510℃[18Ni(350)]，時效時�6h，硬度為57~60HRC�
18Ni鋼的滲氮處理�
18Ni(300)鋼氣體滲氮工藝：滲氮溫度�(455±10)�，時�24~28h�
18Ni鋼的力學性能�
18Ni類鋼力學性能見表2�
�2 18Ni類鋼[18Ni(250)�18Ni(300)�18Ni(350)]力學性能
|
鋼號 |
固溶溫度/� |
時效溫度/� |
時效硬度/HRC |
σb/MPa |
σs/MPa |
δ(%) |
ψ(%) |
|
18Ni(250) |
815~830 |
480±5 |
50~52 |
1850 |
1800 |
10~12 |
48~58 |
|
18Ni(300) |
815~830 |
480±5 |
53~54 |
2060 |
2010 |
12 |
60 |
|
18Ni(350) |
815~830 |
510±5 |
57~60 |
2490 |
- |
- |
- |
注：固溶時效�