1. Material:Q235,35#,etc 2.Certificate:ISO9001:2008 3.Application:railway fastening system 4.Also manufacture by requirement. WasherTypeflat washerspring washerlock washerMaterialQ235,35#,etc.65Mn,60Si2Mn,etc.60Si2Mn,65Mn,etc.SizeM1.6-M64M2.1-M48.5M1.6-M64Hardness100HV,200HV,300HVHRC42-45HRC41-46Finish codePlain,Zine-plate,Dacromet,etc.Passivate,Zine-plated,Phosphate,etc.Antirust,etc.Flat washer ...