China special bolt factory CURVED TUNNEL BOLTS ITEM: CURVED TUNNEL BOLTS FOR SUBWAY AND METRO MATERIAL: BOTH LOW CARBON AND MEDIUM CARBON STEEL DIMENSION: ANSI/ASME B18.2.1 HEX BOLTS AND SCREWS FINISHING: BLACK ZINC PLATED YELLOW ZINC PLATED HOT DIP GALVANIZED Material Carbon steel,alloy steel etcners bolts for highway fence SizeM24-M48 or as requiredstud rail track bolts with nuts and washer FinishZinc plated( White, Blue),Black Oxide, Dacroment, etc Grade4.8/6.8/8.8/10.9/12.9 StandardDIN,GB,ISO etc AdvantagesOne-stop shopping; Competitive price; Timely delivery; NoticeWe support standard part and also welcome customized.Please inform the exact specification of inquiry such as Material, Grade, size etc. if it is special and non-standard products, please supply the drawing or the sample to us.China special bolt factory website:http://www.hualongfasteners.com/special-bolts/