2 2.3 2.5 2.7 3 3.2 3.5 3.7 4 15*15 0.808 0.908 0.971 20*20 1.119 1.266 1.36 1.452 25*25 1.43 1.623 1.749 1.872 2.052 30*30 1.741 1.98 2.137 2.291 2.518 2.666 2.883 40*40 2.363 2.695 2.914 3.131 3.451 3.661 3.971 4.175 4.476 50*50 2.984 3.41 3.691 3.97 40383 4.655 5.059 5.325 5.72 60*60 3.606 4.125 4.469 4.809 5.316 5.65 6.147 6.476 6.963 65*65 3.917 4.483 4.857 5.229 5.782 6.148 6.691 7.051 7.585
直径d (或边长 a)/mm 5.5 O.2375 0.3 0.186 0.237 6 0.2827 0.36 0.222 0.283 6.5 0.3318 0.42 0.26 0.332 7 0.3848 0.49 0.302 0.385 8 0.5077 0.64 0.395 0.502 9 0.6362 0.81 0.499 0.636 10 0.7854 1 0.617 0.785 1l 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 1.2l 1.54 15 1.767 2.25 1.39 1.77 16 2.011 2.56 1.58 2.01 17 2.27 2.89 1.78 2.27 18 2.545 3.24 2 2.54 19 2.835 3.6