Question 1

What is EN8 / 080M40 / C45 steel used for?

Accepted Answer

EN8 (080M40, C45) is one of the most widely stocked medium carbon steels globally, used wherever moderate strength, good machinability, and cost-effectiveness must be combined. Key applications in UAE and GCC include: general engineering shafts, axles, and spindles for manufacturing plant and conveyor systems; keys, couplings, and power transmission components; bright drawn bar for precision guide rods, dowel pins, and close-tolerance machined parts; automotive components including connecting rods and camshafts in moderate-duty applications; structural frames, brackets, and supports in plant fabrication; pump shafts for water and process service; agricultural and construction equipment components; and tooling fixtures and jig bodies. EN8 is the default choice when carbon steel properties are sufficient and alloy steel (4140, 4340) cost is not justified.

Question 2

What is the EN / DIN equivalent of EN8 and 080M40?

Accepted Answer

The European DIN equivalent of EN8 / 080M40 is C45 (Werkstoff-Nr. 1.0503) per BS EN 10083-2. The ISO designation is C45 (ISO 683-1). The nearest North American equivalent is AISI 1045 (UNS G10450), though the composition is not identical - always verify against the MTC rather than assuming full interchangeability. The JIS equivalent is S45C per JIS G4051. EN8 and 080M40 are both British Standard (BS 970) designations for the same grade - EN8 is the legacy designation, 080M40 is the formal BS 970 Part 1 designation. 080M46 is a slightly higher-carbon BS 970 variant sometimes supplied under the EN8 designation.

Question 3

What is the difference between EN8 and EN9?

Accepted Answer

EN8 (080M40, C45) contains 0.36-0.44% carbon while EN9 (080M50) contains 0.45-0.55% carbon. The higher carbon in EN9 gives greater hardness and wear resistance after hardening (EN9 achieves approximately 58-62 HRC surface hardness vs 55-58 HRC for EN8) but at the cost of lower toughness and more challenging weldability. EN8 is the general-purpose choice for engineering shafts, keys, and machined components; EN9 is specified where higher surface hardness from induction or flame hardening is required, such as gears, camshafts, and wear-resistant surfaces in heavy machinery. Both grades have similar machinability in the normalised condition.

Question 4

What condition is EN8 / C45 normally supplied in?

Accepted Answer

EN8 / 080M40 is most commonly supplied in the normalised condition (hot-rolled bar, air-cooled after rolling). This gives a uniform pearlitic-ferritic microstructure with typical hardness of 152-207 HB and UTS of 540-700 MPa. Bright drawn condition (cold drawn after normalising) provides improved dimensional tolerance and surface finish for precision applications. Annealed condition (170-207 HB) is available for maximum machinability when the customer will perform heat treatment. Q&T condition (201-255 HB) is available for applications requiring higher strength - specify target hardness at order stage. Note: EN8 has limited hardenability in large sections.

Question 5

Is EN8 / C45 suitable for welding?

Accepted Answer

Yes, EN8 is weldable but requires preheat for sections above 13 mm due to its medium carbon content (carbon equivalent approximately 0.45-0.55). Preheat to 100-200 degrees C for sections 13-50 mm, and 200-300 degrees C for sections above 50 mm. Use low-hydrogen consumables: ER70S-6 for MIG/TIG, E7018 for stick welding. Post-weld stress relief at 550-650 degrees C is recommended for critical or heavily constrained joints. EN8 is significantly easier to weld than alloy steels (4140, 4340) due to the absence of chromium and molybdenum, but requires more preheat precaution than mild steel (EN3, S275) due to the higher carbon content.

Question 6

What is the difference between EN8 and AISI 1045?

Accepted Answer

EN8 (080M40) and AISI 1045 are closely related medium carbon steels but are not identical. The main differences are in their chemical composition tolerances - particularly the sulphur and phosphorus limits, which are tighter in BS EN 10083-2 (C45) than in ASTM A29 (1045). The manganese range also differs slightly. In practice, for most general engineering applications the two grades are functionally interchangeable, but they should not be specified as equivalent for critical applications without verifying the actual composition on the MTC. For export projects requiring ASTM compliance, specify ASTM A29 Grade 1045 specifically.

Question 7

What sizes of EN8 / C45 are available in UAE?

Accepted Answer

Nifty Alloys stocks EN8 / 080M40 / C45 in the following forms from our Dubai warehouse: Round Bar: 10-500 mm diameter (normalised standard). Flat Bar: 5-100 mm thickness, width 20-300 mm. Square Bar: 10-100 mm cross-section. Hexagonal Bar: 10-100 mm across flats. Plate / Sheet: 3-100 mm thickness. Bright Drawn Round Bar: 5-100 mm diameter (h9/h11 tolerance). Standard normalised and bright drawn stock held across a wide range. For Q&T and annealed conditions, contact our team for availability.

Question 8

What certifications are supplied with EN8 from Nifty Alloys?

Accepted Answer

All EN8 / 080M40 / C45 supplied by Nifty Alloys is accompanied by EN 10204 3.1 Mill Test Certificates as standard, confirming chemical composition, mechanical properties per condition (normalised, bright drawn, etc.), and full traceability to mill source and heat number. EN 10204 3.2 third-party inspection is available on request. For Q&T supply, the MTC confirms achieved hardness and mechanical test results. No AMS or MIL-SPEC certifications are applicable to EN8 / C45.

Question 9

Can EN8 be induction hardened or surface hardened?

Accepted Answer

Yes - EN8 / C45 responds well to both induction hardening and flame hardening, which are the most common ways to achieve a hard wear-resistant surface on this grade. Induction hardening at 870-950 degrees C followed by water or polymer quench achieves surface hardness of 55-60 HRC with case depth of 1-5 mm, while the core remains in the normalised condition (tough and ductile). This combination makes EN8 suitable for gear teeth, cams, journal surfaces, and sprockets. Induction-hardened EN8 is widely used in automotive and industrial machinery applications in UAE. The advantage of surface hardening vs through-hardening is that distortion is minimised and the tough core is retained.

Question 10

What is the difference between EN8 and EN8D (free-cutting variant)?

Accepted Answer

EN8D (080M40 with sulphur addition) is a free-machining variant of EN8 where sulphur is deliberately added (typically 0.08-0.13% S) to improve chip-breaking and surface finish during automatic and CNC machining. EN8D achieves machinability ratings approximately 50% better than standard EN8, at the cost of reduced transverse ductility, impact strength, and fatigue life due to the manganese sulphide inclusions acting as stress concentrators. Specify EN8D for high-volume turned parts on automatic lathes where surface finish and tool life are the priorities; specify standard EN8 for components subject to bending, impact, or fatigue loading.

Standard	Status	Notes
EN 10204 3.1	Suitable	Mill Test Certificate from manufacturer's authorised inspector. Standard with all Nifty Alloys supply.
EN 10204 3.2	Conditional	Independent third-party MTC. Available on request. NACE MR0175 may be applicable in specific conditions - verify hardness at order stage. No AMS or MIL standards apply to EN8 / C45.

Property	EN8 / 080M40 / C45 — BS 970 Part 1 — NormalisedDefault	EN8 / 080M40 / C45 — BS 970 Part 1 — Bright Drawn	EN8 / 080M40 / C45 — EN ISO 683-2 — Annealed	EN8 / 080M40 / C45 — EN ISO 683-2 — Quenched & Tempered
Tensile Strength (UTS)range	540–700 MPaTypical: 620 MPaCondition: Room temp, longitudinalNotes: Per BS 970 Part 1 normalised. Values for sections up to 63 mm. Larger sections: lower values.	620–750 MPaTypical: 685 MPaCondition: Room temp, longitudinalNotes: Cold work increases UTS vs normalised condition.	510–650 MPaTypical: 580 MPaCondition: Room tempNotes: Annealed condition.	700–850 MPaTypical: 775 MPaCondition: Room temp, longitudinalNotes: Per BS EN 10083-2 / EN ISO 683-2 for sections to 63 mm. Larger sections significantly lower.
Yield Strength (0.2% Proof Stress)range	330–465 MPaTypical: 400 MPaCondition: Room tempNotes: 0.2% offset.	465–600 MPaTypical: 530 MPaCondition: Room tempNotes: Higher yield vs normalised due to cold work.	290–380 MPaTypical: 335 MPaCondition: Room temp	530–680 MPaTypical: 600 MPaCondition: Room temp
Elongationmin	16 %Typical: 20 %Condition: 50 mm gauge length	10 %Typical: 14 %Condition: 50 mm gauge lengthNotes: Lower than normalised due to cold work.	18 %Typical: 24 %Condition: 50 mm gauge length	13 %Typical: 16 %Condition: 50 mm gauge length
Reduction of Areamin	40 %Typical: 50 %Condition: Longitudinal	30 %Typical: 40 %Condition: Longitudinal	45 %Typical: 55 %Condition: Longitudinal	40 %Typical: 50 %Condition: Longitudinal
Hardnessrange	152–207 HBTypical: 180 HBCondition: Surface, BrinellNotes: Normalised range. Section-dependent.	179–229 HBTypical: 204 HBCondition: Surface, BrinellNotes: Higher than normalised due to cold work.	207 HBTypical: 185 HBCondition: Surface, BrinellNotes: Max 207 HB per BS EN 10083-2 annealed.	201–255 HBTypical: 228 HBCondition: Surface, BrinellNotes: Approximate 21-27 HRC equivalent. Section-dependent.
Impact Energy (Charpy)max	34 JCondition: Room temp, V-notchNotes: [VERIFY]	20 JCondition: Room tempNotes: Lower toughness than normalised. [VERIFY]	40 JCondition: Room tempNotes: [VERIFY]	35 JCondition: Room temp, V-notchNotes: Lower than alloy steels (4140, 4340) at equivalent hardness. [VERIFY]

Property	EN8 / 080M40 / C45 — BS 970 Part 1 — NormalisedDefault	EN8 / 080M40 / C45 — BS 970 Part 1 — Bright Drawn	EN8 / 080M40 / C45 — EN ISO 683-2 — Annealed	EN8 / 080M40 / C45 — EN ISO 683-2 — Quenched & Tempered
Density20 degrees C	7.85 g/cm3	7.85 g/cm3	7.85 g/cm3	7.85 g/cm3
Modulus of Elasticity25 degrees C	210 GPa	210 GPa	210 GPa	210 GPa
Thermal Conductivity100 degrees C	51 W/m·K	51 W/m·K	51 W/m·K	51 W/m·K
Coefficient of Thermal Expansion20-100 degrees C	11.7 um/m·°C	11.7 um/m·°C	11.7 um/m·°C	11.7 um/m·°C
Specific Heat Capacity20 degrees C	490 J/kg·K	490 J/kg·K	490 J/kg·K	490 J/kg·K
Melting Point / RangeSolidus	1425 degrees C	1425 degrees C	1425 degrees C	1425 degrees C

EN8 / 080M40 / C45 / 1.0503

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Standard

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Overview

Frequently Asked Questions

What is EN8 / 080M40 / C45 steel used for?

What is the EN / DIN equivalent of EN8 and 080M40?

What is the difference between EN8 and EN9?

What condition is EN8 / C45 normally supplied in?

Is EN8 / C45 suitable for welding?

What is the difference between EN8 and AISI 1045?

What sizes of EN8 / C45 are available in UAE?

What certifications are supplied with EN8 from Nifty Alloys?

Can EN8 be induction hardened or surface hardened?

What is the difference between EN8 and EN8D (free-cutting variant)?

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Standard	Designation	Notes
BS	EN8	BS 970 legacy EN designation. EN8 and 080M40 are interchangeable.
BS	080M40	BS 970 Part 1 formal designation.
BS	080M46	BS 970 Part 1 variant - slightly higher-carbon variant sometimes supplied as EN8; verify on MTC.
EN Name	C45	EN 10083-2 / DIN designation.
EN / Werkstoff	1.0503	Werkstoff-Nr. (DIN).
AISI / SAE	AISI 1045	Nearest North American equivalent; not a direct match - always confirm composition on MTC.
UNS	G10450	Nearest equivalent.
JIS	S45C	Nearest equivalent (JIS G4051).
ASTM	A29 Grade 1045	Nearest equivalent.
ISO	C45	ISO 683-1.