EN8 Steel Properties BS970 080M40 Equivalent Material Tensile Yield Strength

EN8 Steel (BS970 080M40 Material)

En8 steel was renamed 080M40 in 1970. It is a commonly used medium carbon engineering steel with good mechanical properties and is widely used in the manufacture of mechanical parts, such as general axles and shafts, gears, bolts and stud bolts. The standard for this steel is BS970, first published in 1941.

EN8 Steel Properties & Specifications

The following tables summarize En8 steel properties, and specifications including chemical composition, mechanical properties, welding, hardness, heat treatment, etc.

Chemical Composition

EN8 steel and BS970 080M40 material chemical composition is listed in the following table.

Chemical Composition (Cast Analyses ), %
Country (Region)	Standard	Steel	C	Si	Mn	P, ≤	S, ≤
Britain (UK)	BS 970-1955	En8	0.35-0.45	0.05-0.35	0.60-1.00	0.06	0.06
	BS 970-1991	080M40	0.36-0.44	0.10-0.40	0.60-1.00	0.05	0.05

Mechanical Properties

En8 and 080M40 steel mechanical properties are listed in the following tables including yield strength (yield stress), ultimate tensile strength, shear strength, modulus of elasticity, young’s modulus, etc.

Notes:

• 1 MPa = 1 N/mm2
• 1 GPa = 1 kN/mm2

BS970 080M40, En8 Steel Mechanical Properties
Standard	Steel	Tensile strength, Mpa (ksi), ≥	Yield strength, Mpa (ksi), ≥	0,2 % proof strength	Elongation after fracture, 5,65 S0 , ≥	Impact, Izod (Charpy V-notch impac) in J, ≥	Hardness, HB	Diameter across flats or thickness (t), mm	Condition
BS 970-1991	080M40 (En8)	550 (80)	280 (40)	–	16	20 (16)	152-207	6≤t≤ 150	Normalized + turned or ground
		510 (74)	245 (35)	–	17	–	146-197	150<t≤ 250
		660 (95.7)	530 (77)	495 (71)	7	–		6<t≤ 13	Hot rolled + cold drawn or hot rolled + cold drawn + ground
		650 (94)	510 (74)	485 (70)	8	–		13<t≤ 16
		620 (90)	480 (70)	435 (63)	9	–		16 <t≤ 40
		600 (87)	465 (67)	370 (53)	10	–		40 <t≤ 63
		570 (82.6)	430 (62)	350 (50)	10	–		63 <t≤ 76
		625-775 (90-110)	385 (55)	355 (51)	16	34 (28)	179-229	6≤ t≤ 63	Hardened and tempered + turned or ground
		700-850 (100-123)	465 (67)	450 (65)	16	34 (28)	201-255	6≤ t≤ 19
		625-775 (90-110)	435 (63)	380 (55)	12	34 (28)	179-229	6≤ t≤ 63	Hardened and tempered + cold drawn or hardened and tempered + cold drawn + ground
		700-850 (100-123)	490 (71)	460 (66)	12	34 (28)	201-255	6≤ t≤ 19

En8 Heat Treatment

En8 material heat treatment are listed below, including normalizing, hardening and termpering.

• Normalizing temperature: 830 to 860 °C (1525-1580 °F)
• Hardening: 830 to 860 °C (1525-1580 °F), oil quench,
• Tempering temperature: 550 to 660 °C (1020-1220 °F)

En8 Steel Equivalent Grade

BS970 080M40 material or En8 steel equivalent to European EN (German DIN EN, French NF EN), ISO, Japanese JIS and Chinese GB standard (for reference).

En8 and 080M40 Steel Equivalent Grade
Britain		European Union		US		China		Japan		ISO
Standard	Steel name	Standard	Steel name (Steel number)	Standard	Grade (UNS)	Standard	Grade	Standard	Grade	Standard	Grade
BS970-1955; BS970-1991	En8; 080M40	EN 10083-2	C40 (1.0511); C40E (1.1186); C45 (1.0503)	AISI SAE; ASTM A29/A29M	1040 (G10400) 1045 (G10450)	GB/T 699	40; 45 steel	JIS G4051	S40C	ISO 683-18	C40; C40E; C45

Related material: 1.4404 (X2CrNiMo17-12-2), AISI 1018, AISI 1095, SAE 1020, AISI 1080