直径d
(或边长a)
/mm
精度组别
截面面积/cm²
理论质量(kg/m)
1组
2组
3组
圆 钢
方 钢
允许偏差/mm
5.5
±0.20
±0.30
±0.40
..2375
0.30
0.186
0.237
6
0.2827
0.36
0.222
0.283
6.5
0.3318
0.42
0.260
0.332
7
0.3848
0.49
0.302
0.385
8
±0.25
±0.35
0.5077
0.64
0.395
0.502
9
0.6362
0.81
0.499
0.636
10
0.7854
1.0
0.617
0.785
*11
0.9503
1.21
0.746
0.95
12
1.131
1.44
0.888
1.13
13
1.327
1.69
1.04
1.33
14
1.539
1.96
1.54
15
1.767
2.25
1.39
1.77
16
2.011
2.56
1.58
2.01
17
2.270
2.89
1.78
2.27
18
2.545
3.24
2.00
2.54
19
2.835
3.61
2.23
2.83
20
3.142
4.00
2.47
3.14
21
±. 30
±. 40
±. 50
3.464
4.41
2.72
3.46
22
3.801
4.84
2.98
3.80
*23
4.155
5.29
3.26
4.15
24
4.524
5.76
3.55
4.52
25
4.909
6.25
3.85
4.91
26
5.309
6.76
4.17
5.31
*27
5.726
7.29
4.49
5.72
28
6.158
7.84
4.83
6.15
*29
6.605
8.41
5.18
6.60
30
7.069
9.00
5.55
7.06
*31
±0.50
±0.60
7.548
9.61
5.93
7.54
32
8.042
10.24
6.31
8.04
*33
8.553
10.89
6.71
8.55
34
9.097
11.56
7.13
9.07
*35
9.621
12.25
7.55
9.62
36
10.18
12.96
7.99
10.2
38
11.34
14.44
8.90
11.3
40
12.57
16.00
9.86
12.6
42
13.85
17.64
10.9
13.8
45
15.90
20.25
12.5
15.9
48
18.10
23.04
14.2
18.1
50
19.64
25.00
15.4
19.6
53
±. 70
±0.80
22.06
28.09
17.3
22..
*55
23.76
30.25
18.6
23.7
56
24.63
31.36
19.3
24.6
*58
26.42
33.64
20.7
26.4
60
±. 60
28.27
36.00
22.2
28.3
63
31.17
39.69
24.5
31.2
*65
33.18
42.25
26..
33.2
*68
36.32
46.24
28.5
36.3
70
38.48
49.00
30.2
38.5
75
44.18
56.25
34.7
44.2
80
50.27
64.00
39.5
50.2
85
±. 9
±1.0
±1.1
56.75
72.25
44.5
56.7
90
63.62
81.00
49.9
63.6
95
70.88
90.25
55.6
70.8
100
78.54
100.00
61.7
78.5
105
86.59
110.25
68.0
86.5
110
95.03
121.00
74.6
95.0
115
±1.2
±1.3
±1.4
103.82
132.26
81.5
104
120
113.10
144.00
88.8
113
125
122.72
156.25
96.3
123
130
132.73
169.00
133
140
153.94
196.00
121
154
150
176.72
225.00
139
177
160
-
±2.0
201.06
256.00
158
201
170
226.98
289.00
178
227
180
254.47
324.00
200
254
190
283.53
361.00
223
283
±2.5
314.16
400.00
247
314
220
380.13
298
250
490.88
385
注:1.表中的理论质量是按钢的密度为7.85g/crn3计算的。