EN9/070M55 steel,called ’55’ Carbon steel, is a common unalloyed medium steel as per British standard BS 970.It has carbon content with 0.50-0.60% which gives it tensile strength between 500-800Mpa when supplied in untreated condition or normalized condition.EN9 is also suitable in the hardened and tempered condition for tensile ranges of R(700-850Mpa),S(775-925Mpa),and T(850-1000Mpa). For further process,it can be flame or induction hardened to produce a high surface hardness with excellent wear resistance .This material has poor weldability, pre-heat treatment before welding is recommended to prevent cracking.Annealing after welding is also suggested to minimize the risk of breaking.
1.Supply Form & Size & Tolerance
Hot Forged Round bar:Φ80-Φ1000mm
Hot Forged Square bar: Max Thickness:500mm
Flat bar/Blcoks:Thickness :120-800mm ,Width:120-1500mm
|Surface Finish||Black-Forged||Black-Rolled||Turned||Grinding||Polished||Peeled||Cold Drawn|
|Tolerance||(0，+5mm)||(0，+1mm)||(0，+3mm)||Best h9||Best h11||Best H11||Best H11|
EN9 Series For Speical Applications:EN9K
3. Equivalent Grade
- BS 970-1991:070M55
- AISI/ :1050,1055
- DIN Werkstoff No.: 1.0535,1.1209
- BS & DIN European:C50,C55,CK55
4. Mechanical Property
|Normalized||Hardened & Tempered
|Ruling Section,inch||4||2||1 1/8||1 1/8|
EN9 Round steel Lab Tesing Data with Normalizing condition
|Diameter,mm||Tensile Strength MPa||Yield Strength MPa||Elongation %||Hardness,HB|
5.Forging EN9/070M55 steel
Recommended Forging temperature:800℃- 1200℃,and final forging temperature should not below 800℃,EN9 steel should be cooled as slowly as possible in still air(may get fine grain) or in sand after forged.
Heat the steel to the temperaure 810-840ºC with several steps,keep proper holding time depend on the steel size, then followed by cooling in still air.
EN9/070M55 Normalizing Diagram
Heat the steel to the temperaure 770-810ºC,and enough soaking time for the steel heating, Cool slowly in the furnace.
Hardening temperature is carried out from an austenitizing temperature of 810-840ºC, followed by oil quenching.
Temperaure between 550°C to 660°C is recommended for tempering,and one hour per inch for holding time of heating.
EN9 steel is widely used in engineering applications which require higher strength and wear resistance.