708M40 - BS 970-1-1983

Grade	708M40
Corresponding Standard	BS 970-1-1983 British Standard Specification for Wrough steels for mechanical and allied engineering purposes Part 1. General inspection and testing procedures and specific requirements for carbon,carbon manganese,alloy and stainless steels
Classification	Alloy Steel

708M40 Chemical Element Composition Content (%)

Component	C	Mn	P	S	Cr	Ni	Mo
Minimum Value	0.36	0.7	-	0.025	0.9	-	0.15
Maximum Value	0.44	1	0.035	0.05	1.2	0.4	0.25

• For older grades of stainless steel, see Table 2 of standard BS 970-4-1970

708M40 Mechanical Properties

diameter or across flats d mm	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %	Hardness HBW	Impact Energy Absorption KV2 J
Bright bars; 150＜d≤250	Quenching and Tempering + Turning or Grinding R	700~850	Re: ≥495 Rp0.2: ≥480	≥15	201~255	Izod: ≥25ft.lb KCV: ≥28
Bright bars; 63＜d≤150	Quenching and Tempering + Turning or Grinding R	700~850	Re: ≥525 Rp0.2: ≥510	≥17	201~255	Izod: ≥40ft.lb KCV: ≥50
Bright bar; 29<d≤100	Quenching and tempering + turning or grinding S	775~925	Re: ≥585 Rp0.2: ≥570	≥15	223~277	Izod: ≥40ft.lb KCV: ≥50
Bright bar; 6 ≤ d ≤ 63	Quenched and Tempered + Turning or Grinding T	850~1000	Re: ≥680 Rp0.2: ≥665	≥13	248~302	Izod: ≥40ft.lb KCV: ≥50
Bright bars; 6≤d≤29	Quenched and Tempered + Turning or Grinding U	925~1075	Re: ≥755 Rp0.2: ≥740	≥12	269~331	Izod: ≥35ft.lb KCV: ≥42
Bright bars; 6≤d≤19	Quenching and Tempering + Turning or Grinding V	1000~1150	Re: ≥850 Rp0.2: ≥835	≥12	293~352	Izod: ≥35ft.lb KCV: ≥42
Bright bars; 6≤d≤13	Quenching and tempering + turning or grinding W℗®	1075~1225	Re: ≥940 Rp0.2: ≥925	≥12	311~375	Izod: ≥30ft.lb KCV: ≥35
Bright bars; 63＜d≤150	Quenching and tempering + cold drawing or Quenching and tempering + cold drawing + grinding R	700~850	Re: ≥540 Rp0.2: ≥525	≥12	© 201~255	Izod: ≥40ft.lb
Bright bar; 29<d≤100	Quenched and Tempered + Cold Drawing or Quenched and Tempered + Cold Drawing + Grinding S	775~925	Re: ≥600 Rp0.2: ≥585	≥11	© 223~277	Izod: ≥40ft.lb
Bright bar; 6 ≤ d ≤ 63	Quenching and Tempering + Cold Drawing or Quenching and Tempering + Cold Drawing + Grinding T	850~1000	Re: ≥700 Rp0.2: ≥680	≥9	© 248~302	Izod: ≥40ft.lb
Bright bars; 6≤d≤29	Quenching and Tempering + Cold Drawing or Quenching and Tempering + Cold Drawing + Grinding U	925~1075	Re: ≥770 Rp0.2: ≥755	≥9	© 269~331	Izod: ≥35ft.lb
Bright bars; 6≤d≤19	Quenching and tempering + cold drawing or Quenching and tempering + cold drawing + grinding V	1000~1150	Re: ≥865 Rp0.2: ≥850	≥9	© 293~352	Izod: ≥35ft.lb
Bright bars; 6≤d≤13	Quenching and tempering + cold drawing or Quenching and tempering + cold drawing + grinding W℗®	1075~1225	Re: ≥955 Rp0.2: ≥940	≥8	© 311~375	Izod: ≥30ft.lb
Bright Bar	Turning, Grinding or Cold Drawing and Softening				≤248

• Re-yield strength；Rp0.2-Stress at 0.2% proof plastic elongation (0.2% proof strength).
• Not specified, σs in the table refers to Re
• ft.lb=1.3558J

1 Approximate Comparison Table Structural Alloy Steel

China

Taiwan, China

Japan

South Korea

United States

International Organization for Standardization

Germany

France

European Standard

Sweden

United Kingdom

ISC

CNS

JIS

ASTM/AISI

UNS

ISO

DIN EN/DIN

W-Nr.

NF EN/NF

Numerical Grade

SS₁₄

BS EN/BS

42CrMo

A30422

SCM440

SCM440
SCM440H

SCM440

4140
4142

G41400
G41420

42CrMo4

1.7225

42CD4

42CrMo4

1.7225

2244

708M40

2 Approximate Comparison Table Structural Alloy Steel

China	Japan	United States	International Organization for Standardization	Germany		European Standard		United Kingdom
GB	JIS	ASTM	ISO	W-Nr.	L-Nr.	EN	Numerical Grade	BS EN/BS
50CrMo	SCM445	4150	50CrMo4	50CrMo4	1.7228	50CrMo4	1.7228	708M40 708M50

3 Approximate Comparison Table Structural Alloy Steel

China	Japan	United States	International Organization for Standardization	Germany	France	European Standard		Russia	Sweden	United Kingdom
GB	JIS	ASTM	ISO	DIN EN/DIN	NF EN/NF	EN	Numerical Grade	GOST	SS	BS EN/BS
42CrMo	SCM440H	4140 4142	42CrMo4	42CrMo4	42CD4	42CrMo4	1.7225	35KHM 38KHM	2244	708M40 CFS11

4 Approximate Comparison Table Structural Alloy Steel

Japan	United States		Germany		France	European Standard	Russia	United Kingdom
JIS	ASTM/AISI	UNS	DIN EN/DIN	W-Nr.	NF EN/NF	EN	GOST	BS EN/BS
SCM440	4140 4142 6135	G41400	41CrMo4	1.7223	42CD4TS	41CrMo	40ХФА 40KHFA	3111-5/1 42CrMo4 708M40

708M40 Corresponding Standards(Same grade name, different standards)

1	BS 970-3-1991
	708M40
2	BS 970-1-1983
	708M40

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