... 3521,ASTM A227 Best quality and price steel wire/ spring wire/ high carbon steel wire/mattress spring wirewidely use for making compression ... EN10270-1, JIS G 3521 , ASTM A227 , GB4357-89Tensile strength : B,C grade Surface : smooth, phosphated and lead patent ... order quantity: 1 ton.Quality inspection of each coil : tensile strength, tolerance, surface smooth, torsion,bending,winding, ellipse , etc. ...