开槽半沉头自攻螺钉 （摘自GB 5284-85）
螺纹规格为ST2.2～ST9.5的开槽半沉头自攻螺钉。
标记示例：
螺纹规格ST3.5、公称长度l=16mm、表面镀锌钝化的C型开槽半沉头自攻螺钉的标记：
自攻螺钉 GB 5284 ST3.5×16
螺纹规格为ST2.2～ST9.5的开槽半沉头自攻螺钉：
|
螺纹规格
d
|
P
|
a
max
|
dk
|
f≈
|
K
max
|
n
|
r
max
|
rf ≈
|
t
|
y参考
|
l
|
|
理论值
max
|
实际值
|
|
max
|
min
|
公称
|
min
|
max
|
min
|
max
|
C型
|
F型
|
|
ST2.2
|
0.8
|
0.8
|
4.4
|
3.8
|
3.5
|
0.5
|
1.1
|
0.5
|
0.56
|
0.7
|
0.8
|
4
|
1
|
1
|
2
|
1.6
|
4.5～16
|
|
ST2.9
|
1.1
|
1.1
|
6.3
|
5.5
|
5.2
|
0.7
|
1.7
|
0.8
|
0.86
|
1
|
1.2
|
6
|
1.45
|
1.45
|
2.6
|
2.1
|
6.5～19
|
|
ST3.5
|
1.3
|
1.3
|
8.2
|
7.3
|
6.9
|
0.8
|
2.35
|
1
|
1.06
|
1.2
|
1.4
|
8.5
|
1.7
|
1.7
|
3.2
|
2.5
|
6.5～22
|
|
ST4.2
|
1.4
|
1.4
|
9.4
|
8.4
|
8
|
1
|
2.6
|
1.2
|
1.26
|
1.51
|
1.6
|
9.5
|
1.9
|
1.9
|
3.7
|
2.8
|
9.5～25
|
|
ST4.8
|
1.6
|
1.6
|
10.4
|
9.3
|
8.9
|
1.2
|
2.8
|
1.2
|
1.26
|
1.51
|
2
|
9.5
|
2.4
|
2.4
|
4.3
|
3.2
|
9.5～32
|
|
ST5.5
|
1.8
|
1.8
|
11.5
|
10.3
|
9.9
|
1.3
|
3
|
1.6
|
1.66
|
1.91
|
2.2
|
11
|
2.6
|
2.6
|
5
|
3.6
|
13～32
|
|
ST6.3
|
1.8
|
1.8
|
12.6
|
11.3
|
10.9
|
1.4
|
3.15
|
1.6
|
1.66
|
1.91
|
2.4
|
12
|
2.8
|
2.8
|
6
|
3.6
|
13～38
|
|
ST8
|
2.1
|
2.1
|
17.3
|
15.8
|
15.4
|
2
|
4.65
|
2
|
2.06
|
2.31
|
3.2
|
16.5
|
3.7
|
3.7
|
7.5
|
4.2
|
16～50
|
|
ST9.5
|
2.1
|
2.1
|
20
|
18.3
|
17.8
|
2.3
|
5.25
|
2.5
|
2.56
|
2.81
|
4
|
19.5
|
4.4
|
4.4
|
8
|
4.2
|
16～50
|
注：P—螺距。
l的范围：
|
公称
|
4.5
|
6.5
|
9.5
|
13
|
16
|
19
|
22
|
25
|
32
|
38
|
45
|
50
|
|
C型
|
min
|
3.7
|
5.7
|
8.7
|
12.2
|
15.2
|
18.2
|
21.2
|
24.2
|
30.7
|
36.7
|
43.7
|
48.7
|
|
max
|
5.3
|
7.3
|
10.3
|
13.8
|
16.8
|
19.8
|
22.8
|
25.8
|
33.3
|
39.3
|
46.3
|
51.3
|
|
F型
|
min
|
3.7
|
5.7
|
8.7
|
12.2
|
15.2
|
18.2
|
20.7
|
23.7
|
30.7
|
36.7
|
43.5
|
48.5
|
|
max
|
4.5
|
6.5
|
9.5
|
13
|
16
|
19
|
22
|
25
|
32
|
38
|
45
|
50
|
