方钢的规格型号尺寸包括以下几种：
1. 实心方钢：
15mm x 15mm
20mm x 20mm
25mm x 25mm
30mm x 30mm
35mm x 35mm
40mm x 40mm
45mm x 45mm
50mm x 50mm
55mm x 55mm （0.5-6mm）
60mm x 60mm
65mm x 65mm
70mm x 70mm
75mm x 75mm
80mm x 80mm
85mm x 85mm
90mm x 90mm
95mm x 95mm
100mm x 100mm
105mm x 105mm
110mm x 110mm
115mm x 115mm
120mm x 120mm
125mm x 125mm
2. 空心方钢（方管）：
500mm x 500mm x 8-25mm
450mm x 450mm x 8-25mm
400mm x 400mm
300mm x 300mm x 4-12mm
200mm x 200mm x 4-12mm
150mm x 150mm x 4-12mm
100mm x 100mm x 4-12mm
50mm x 50mm x 0.8-1mm
建议根据具体应用需求选择合适的方钢型号，以确保结构的安全性和稳定性。