内六角花形半沉头螺钉(摘自GB 2674-86)
螺纹规格为M6~20的内六角花形半沉头螺钉。
标记示例:
螺纹规格d=M6、公称长度l=20mm、性能等级为4.8级、不经表面处理的内六角花形半沉头螺钉的标记:
螺钉 GB 2674 M6×20
螺纹规格为M6~20的内六角花形半沉头螺钉:
螺纹规格
d
|
P
|
a
max
|
b
min
|
dk
|
f≈
|
K
max
|
r
max
|
rf ≈
|
六角花形
|
X
max
|
l
|
理论值
max
|
实际值
|
代号
|
t
|
B
|
max
|
min
|
max
|
min
|
M6
|
1
|
2
|
38
|
12.6
|
11.3
|
10.9
|
1.4
|
3.3
|
1.5
|
12
|
T30
|
1.8
|
1.4
|
4.15
|
2.5
|
8~60
|
M8
|
1.25
|
2.5
|
38
|
17.3
|
15.8
|
15.4
|
2
|
4.65
|
2
|
16.5
|
T40
|
2.5
|
2.1
|
5
|
3.2
|
10~80
|
M10
|
1.5
|
3
|
38
|
20
|
18.3
|
17.8
|
2.3
|
5
|
2.5
|
19.5
|
T50
|
2.7
|
2.3
|
6.62
|
3.8
|
12~80
|
M12
|
1.75
|
3.5
|
48
|
24
|
22
|
21.5
|
3
|
6
|
2.5
|
21.2
|
T55
|
3.5
|
3.02
|
8.2
|
4.3
|
20~80
|
(M14)
|
2
|
4
|
48
|
28
|
25.5
|
25
|
3.5
|
7
|
2.5
|
25.43
|
T55
|
3.7
|
3.22
|
8.2
|
5
|
25~80
|
M16
|
2
|
4
|
48
|
32
|
29
|
28.5
|
4
|
8
|
3
|
27.83
|
T60
|
4.1
|
3.62
|
9.8
|
5
|
25~80
|
M20
|
2.5
|
5
|
48
|
40
|
36
|
35.4
|
5
|
10
|
3
|
34.36
|
T80
|
6
|
5.42
|
13
|
6.3
|
35~80
|
注:1)尽可能不采用括号内的规格。
2)P—螺距。
3)dk的理论值按GB 5279规定。
l的范围:
公称
|
8
|
10
|
12
|
(14)
|
16
|
20
|
25
|
30
|
35
|
40
|
45
|
50
|
(55)
|
60
|
70
|
80
|
min
|
7.71
|
9.71
|
11.65
|
13.65
|
15.65
|
19.58
|
24.58
|
29.58
|
34.50
|
39.50
|
44.50
|
49.50
|
54.05
|
59.05
|
69.4
|
79.4
|
max
|
8.29
|
10.29
|
12.35
|
14.35
|
16.35
|
20.42
|
25.42
|
30.42
|
35.50
|
40.50
|
45.50
|
50.50
|
55.95
|
60.95
|
70.6
|
80.6
|