... service life is more than ten years.3.SPECIFICATIONS Model MA categoryspecificationheight(mm)column pile center distancematerials ... STANDARDS Raw materials standard NO.PERFORMED STANDARD NAME OF RAW MATERIALS1GB700-88CARBON STRUCTURAL STEEL2GB704-88HOT ROLLED FLAT ... , without obvious uneven,density impurity , no toughness feeling of hand touch, steel exposure ,buuble, pin hole, obvious trace are ...