The EN range of steel specifications was first introduced in 1941 as the War Emergency, British Standard Schedule BS970. With the assistance of the Technical Advisory Committee of the Special & Alloy Steels Committee the British Standards Institute published 58 specifications (EN1 to EN58). These steels covered a variety of types including carbon steels, alloy steels, case hardening steels, spring steels and stainless steels. The grades were arranged sequentially according to the chemical composition, starting with low carbon grades EN1, EN2 and EN3 working up to stainless steel grades EN56, EN57 and EN58. IN 1955 the BS970 EN range of steel specifications was revised to add further steel grades.
No allowance had been made in the 1941 edition for a possible insertion of further steel grades and the British Standards Institution considered that to have applied a high EN number would have divorced the grades completely from steels of similar types. Therefore with numerous grades suffix letters were added (for example EN19 became EN19A, EN19B and EN19C). The BS970 1955 revision of the standard increased the number of specifications to nearly 200.
| STEEL TYPE | VEW | CHEMICAL ANALYSIS % | |||||||
| C% | Si% | Mn% | Cr% | Mo% | W% | V% | Co% | ||
| EN SERIES STEEL | EN-1A | 0.007 TO 0.15 | 0.10 | 0.80 TO 1.00 | S | P | - | - | - |
| 0.20 TO 0.30 | 0.70 MAX | ||||||||
| EN-8 | 0.35 TO 0.45 | 0.05 TO 0.30 | 0.60 TO 1.00 | S | P | - | - | - | |
| 0.06 MAX | 0.06 MAX | ||||||||
| EN-9 | 0.50 TO 0.60 | 0.05 TO 0.30 | 0.5 TO 0.80 | - | - | - | - | - | |
| EN-19(V 320) | 0.35 TO 0.45 | 0.10 TO 0.30 | 0.5 TO 0.80 | 0.90 TO 1.40 | 0.20 TO 0.40 | - | - | ||
| EN-24(V 130) | 0.35 TO 0.45 | 0.10 TO 0.35 | 0.45 TO 0.70 | 0.90 TO 1.40 | 0.20 TO 0.35 | NI | - | - | |
| 1.3 TO 1.8 | |||||||||
| EN-31 R-100 | 0.90 TO 1.20 | 0.10 TO 0.35 | 0.30 TO 0.75 | 1.00 TO 1.60 | - | - | - | - | |
| EN-36C E-200 | 0.12 TO 0.18 | 0.10 TO 0.35 | 0.30 TO 0.60 | 0.60 TO 1.10 | - | NI | - | - | |
| 3.0 TO 3.75 | |||||||||
| EN-42 | 0.70 TO 0.85 | 0.10 TO 0.40 | 0.55 TO 0.75 | - | - | - | - | - | |
| EN-44 | 0.90 TO 1.20 | 0.30 | 0.45 TO 0.70 | - | - | - | - | - | |
| EN-45 F-110 | 50 TO 0.60 | 1.5 TO 2.0 | 0.70 TO 1.00 | - | - | - | - | - | |
| EN-351 | 0.10 TO 0.20 | 0.35 | 0.60 TO 1.00 | 0.40 to 0.80 | 0.08 to 0.10 | NI | - | - | |
| 0.60 TO 1.00 | |||||||||
| EN-353 | 0.10 TO 0.20 | 0.35 | 0.50 TO 1.00 | 0.75 TO 1.25 | 0.08 to o.15 | NI | - | - | |
| 1.00 TO 1.50 | |||||||||
| STEEL TYPE | VEW | HEAT TREATMENT | CORRESPONDING SPECIFICATION | |||||
| Hardening Temperature | Quenching Medium | Tempering Temperature | Brinell Rock well hardness | JAPAN JIS | AISI | POLDI THREAD | ||
| EN SERIES STEEL | EN-1A | - | - | - | - | - | - | - |
| EN-8 | 750-900 | OIL | 150-200 | |||||
| EN-9 | 850-900 | OIL | 200-250 | 55-60 | ||||
| EN-19 (V 320) | 900-950 | OIL | 200-225 | 45-55 | SCM 4 | 4140 | ||
| EN-24 (V 130) | 830-860 | OIL | 540-680 | 45-55 | SNCM 8 | 4340 | ||
| EN-31 R-100 | 820-860 | OIL | 180-225 | 59-65 | ||||
| EN-36C E-200 |
780-860 | OIL | 170-210 | 61-63 | SNC 22 | 3415 | ||
| EN-42 | 600-700 | DIRECT HARDENING | 40-45 | |||||
| EN-44 | 650-750 | OIL | 150 | 45-50 | ||||
| EN-45 | 830-860 | OIL | 470-520 | 50-55 | 9255 | |||
| EN-351 | 850-860 | OIL | 175-200 | 62-64 | ||||
| EN-353 | 840-870 | OIL | 150-200 | 62-64 | ||||
| STEEL TYPE | VEW | TYPICAL APPLICATION | |||||||
| EN SERIES STEEL | EN-1A | Auto Parts, Tools & Production Machine. | |||||||
| EN-8 | Components of small cross section, requiring low tensile strength, as well as heavy forging in the normalised condition for automative & general engineering such as axles, clutch, shafts, presses & Punches Parts, Piston rods & gear rods. | ||||||||
| EN-9 | Bolts, M/C Tool, Axial shaft | ||||||||
| EN-19 (V 320) | Components of mediums & large cross section, requiring high tensile strength & toughness for automatic engineering and gear & engine construction such as Crane Shafts Steering Knocking Connecting. | ||||||||
| EN-24 (V 130) | Highly stressed components of large cross section for aircraft, automotive & general enginery application such as Properller Shafts Connecting Rods Gear Shafts Craneshafts & Landing Gear Components, Heavy Forging such as Rotar Shafts & Discs. | ||||||||
| EN-31 R-100 |
For roller bearing components such as Baks, Cylinderical, Conical & Needle Rollers. | ||||||||
| EN-36C E-200 |
Components with large cross section requiring high toughness & score strength such as Gears, Crane Shafts & Heavy Duty Gearshafts in Aircrafts & Truck Construction & Mechanical Engineering. | ||||||||
| EN-42 | Special gear case Hardening Tensile Tools | ||||||||
| EN-44 | Spring action parts. | ||||||||
| EN-45 F-110 |
Leaf & Truncated Conical Springs for Automate & General Engineering | ||||||||
| EN-351 | M/C Spring Parts | ||||||||
| EN-353 | M/C Components | ||||||||