12# I-Beam can be used for mine tram road size:9#,11#,12#,20# Materials:Q235 Length:8,9, ... 10 standard:ISO9001:2000 12# I-Beam can be used for mine tram road ... size:9#,11#,12#,20# Materials:Q235Length:8,9,10standard:ISO9001:2000 ... of QU70QU80QU100 & QU120, I-beam of the mine usage steel of 9#11# & 12#, U-Beam for the ... from now on more than ten years. 12# I-Beam