C45

General Information

C45 is a medium carbon steel for e.g. mechanical engineering and automotive components.

Variant SB8673 / SB-C45 is a variant with a narrowed chemical composition in order to reach a high hardenability and it is fine grain treated with Al

Variant SB1672 is a standard variant of C45 with medium Carbon for all purpose use

Variant SB1671 is a C45 with slightly lower alloy content and with an increased Sulphur content

Variant 5081 is a M-treated variant wich is offered under the name Imatra 4M

Variant 5155 is similar to 5081 but is a non M-steel with lower Sulphur content

Variant 047A is an ingot cast variant. High hardness and high strength can be achieved after hardening thanks to the relatively high carbon content. The steel is suitable for various type of applications where high strength is needed.

For additional Heat Treatment Data, please visit the Heat Treatment Guide.

M-Steel^®
The concept: Our M-Steel treatment can be applied to any steel grade. The basis for the concept is that non-metallic inclusions are modified and controlled with calcium treatment. These inclusions are modified in a way to maximize machinability and to improve transverse fatigue strength. In this way, a protective layer is formed on the cutting tool during machining that very significantly reduces the wear on the tool and increases the tool life. At every stage of the M-Steel production process the material is optimised to improve machinability, from raw material through melt, to casting, hot rolling and the final heat treatment. Individual delivery requirements can be met to supply your material in the best form for your machines in compliance with tight straightness and dimensional tolerances. M-Steel has a consistent machinability from cast to cast, meaning that machines can be run with fixed high cutting rates and predictable tool change intervals from one production run to another. Recent findings also show that the M-Steel effect is particularly pronounced in turning in very hard condition using Cubic Boron Nitride (CBN) inserts. Replacing traditional grinding of case- or induction-hardened surfaces with Hard Part Turning can mean very large cost savings, together with production lead time and quality improvements.

Similar designations

C43, C44, C45R - 1.1201, C45E - 1.1191, Ck45, St70-2, SAE 1045, 080A42, SS 1672, XC 48, C 45, S 45 C, GOST 45, AISI/SAE/ASTM 1045, 1.0503

Variant	Cast	Weldability		C %	Si %	Mn %	P %	S %	Cr %	Ni %	Mo %	V %	Ti %	Cu %	Al %	DI %
SB8673	CC	CEV 0.71_max	Min	0.46	0.15	0.70	-	0.020	0.25	0.10	-	-	-	-	0.020	1.70
Pcm 0.55_max	Max	0.49	0.35	0.80	0.020	0.035	0.30	0.20	-	-	-	0.25	0.040	2.00
SB1672	CC	CEV 0.72_max	Min	0.42	0.10	0.50	-	0.020	-	-	-	-	-	-	-	1.10
Pcm 0.55_max	Max	0.50	0.40	0.90	0.045	0.045	0.40	0.40	0.10	-	-	-	-	1.80
SB1671	CC	CEV 0.58_max	Min	0.42	0.15	0.50	-	0.035	-	-	-	-	-	-	-	1.20
Pcm 0.51_max	Max	0.50	0.40	0.80	0.045	0.050	-	-	-	-	-	-	-	1.60
5081, Imatra 4 M	CC	CEV 0.72_max	Min	0.42	0.10	0.50	-	0.020	-	-	-	-	-	-	-	1.10
Pcm 0.55_max	Max	0.50	0.40	0.90	0.030	0.035	0.40	0.40	0.10	-	-	-	-	1.80
5155	CC	CEV 0.72_max	Min	0.44	0.10	0.50	-	-	-	-	-	-	-	-	-	1.10
Pcm 0.55_max	Max	0.49	0.40	0.80	0.030	0.025	0.40	0.40	0.10	-	-	-	-	1.80
047A	IC	CEV 0.76_max	Min	0.46	0.15	0.50	-	0.020	-	-	-	-	-	-	0.015	-
Pcm 0.6_max	Max	0.50	0.40	0.80	0.030	0.030	0.25	0.25	0.10	0.100	0.005	0.25	0.030	-
C45 EN ISO 683-1	Std	CEV _max	Min	0.42	0.10	0.50	-	-	-	-	-	-	-	-	-	-
Pcm _max	Max	0.50	0.40	0.80	0.045	0.045	0.40	0.40	0.10	-	-	0.30	-	-

Variant

Cast

Weldability

C %

Si %

Mn %

P %

S %

Cr %

Ni %

Mo %

V %

Ti %

Cu %

Al %

DI %

SB8673

CEV 0.71_max

Min

0.46

0.15

0.70

0.020

0.25

0.10

0.020

1.70

Pcm 0.55_max

Max

0.49

0.35

0.80

0.020

0.035

0.30

0.20

0.25

0.040

2.00

SB1672

CEV 0.72_max

Min

0.42

0.10

0.50

0.020

1.10

Pcm 0.55_max

Max

0.50

0.40

0.90

0.045

0.40

0.10

1.80

SB1671

CEV 0.58_max

Min

0.42

0.15

0.50

0.035

1.20

Pcm 0.51_max

Max

0.50

0.40

0.80

0.045

0.050

1.60

5081, Imatra 4 M

CEV 0.72_max

Min

0.42

0.10

0.50

0.020

1.10

Pcm 0.55_max

Max

0.50

0.40

0.90

0.030

0.035

0.40

0.10

1.80

5155

CEV 0.72_max

Min

0.44

0.10

0.50

1.10

Pcm 0.55_max

Max

0.49

0.40

0.80

0.030

0.025

0.40

0.10

1.80

047A

CEV 0.76_max

Min

0.46

0.15

0.50

0.020

0.015

Pcm 0.6_max

Max

0.50

0.40

0.80

0.030

0.25

0.10

0.100

0.005

0.25

0.030

C45 EN ISO 683-1

Std

CEV _max

Min

0.42

0.10

0.50

Pcm _max

Max

0.50

0.40

0.80

0.045

0.40

0.10

0.30

Variant	Condition	Format	Dimension [mm]	Yield strength min [MPa]	Tensile strength [MPa]	Elongation A₅ [%]	Reduction of area Z_min [%]	Hardness	Impact (ISO-V) strength_min
Rp_0.2 * R_eh, ** R_el
SB1672			< 16	320**	590-740	14	-	165-220 HB	-
	16 < 40	310**	590-740	14	-	165-220 HB	-
	40 < 63	300**	590-740	14	-	165-220 HB	-
	63 < 120	280**	590-740	14	-	165-220 HB	-
5081, Imatra 4 M	+AR	Round bar	25 < 180	-	-	-	-	< 230 HB	-
+QT	Round bar	25 < 40	430**	650-800	16	40	190-240 HB	20 °C 25 J (long)
Round bar	40 < 100	370**	630-780	17	45	185-235 HB	20 °C 25 J (long)
5155	+AR	Round bar	25 < 180	-	-	-	-	< 230 HB	-
+QT	Round bar	25 < 40	430**	650-800	16	40	190-240 HB	20 °C 25 J (long)
Round bar	40 < 100	370**	630-780	17	45	185-235 HB	20 °C 25 J (long)
047A	+U	Tube,wall	10 < 36	320	650 typical	16	-	200 HB typical	-
Tube,wall	36 < 60	300	630 typical	16	-	200 HB typical	-
Tube,wall	> 60	280	600 typical	16	-	200 HB typical	-
Round bar	10 < 36	320	650 typical	16	-	200 HB typical	-
Round bar	36 < 60	300	630 typical	16	-	200 HB typical	-
Round bar	< 60	280	600 typical	16	-	200 HB typical	-
+N	Tube,wall	< 10	320	660 typical	16	-	190 HB typical	-
Tube,wall	10 < 50	300	630 typical	16	-	190 HB typical	-
Tube,wall	< 50	280	600 typical	16	-	190 HB typical	-
Round bar	< 10	320	660 typical	16	-	190 HB typical	-
Round bar	10 < 50	300	630 typical	16	-	190 HB typical	-
Round bar	< 50	280	600 typical	16	-	190 HB typical	-
+QT	Tube,wall	10 < 40	370	690-770	14	-	210-240 HB	-
Round bar	10 < 40	370	690-770	14	-	210-240 HB	-

Variant

Condition

Format

Dimension [mm]

Yield strength min [MPa]

Tensile strength [MPa]

Elongation A₅ [%]

Reduction of area Z_min [%]

Hardness

Impact (ISO-V) strength_min

Rp_0.2 * R_eh, ** R_el

SB1672

< 16

320**

590-740

165-220 HB

16 < 40

310**

590-740

165-220 HB

40 < 63

300**

590-740

165-220 HB

63 < 120

280**

590-740

165-220 HB

5081, Imatra 4 M

+AR

Round bar

25 < 180

< 230 HB

+QT

Round bar

25 < 40

430**

650-800

190-240 HB

20 °C 25 J (long)

Round bar

40 < 100

370**

630-780

185-235 HB

20 °C 25 J (long)

5155

+AR

Round bar

25 < 180

< 230 HB

+QT

Round bar

25 < 40

430**

650-800

190-240 HB

20 °C 25 J (long)

Round bar

40 < 100

370**

630-780

185-235 HB

20 °C 25 J (long)

047A

Tube,wall

10 < 36

320

650 typical

200 HB typical

Tube,wall

36 < 60

300

630 typical

200 HB typical

Tube,wall

> 60

280

600 typical

200 HB typical

Round bar

10 < 36

320

650 typical

200 HB typical

Round bar

36 < 60

300

630 typical

200 HB typical

Round bar

< 60

280

600 typical

200 HB typical

Tube,wall

< 10

320

660 typical

190 HB typical

Tube,wall

10 < 50

300

630 typical

190 HB typical

Tube,wall

< 50

280

600 typical

190 HB typical

Round bar

< 10

320

660 typical

190 HB typical

Round bar

10 < 50

300

630 typical

190 HB typical

Round bar

< 50

280

600 typical

190 HB typical

+QT

Tube,wall

10 < 40

370

690-770

210-240 HB

Round bar

10 < 40

370

690-770

210-240 HB

	Temperature °C
MS	305
AC1	725
AC3	760

Temperature °C

305

AC1

725

AC3

760

Treatment	Condition	Temperature cycle	Cooling/quenching
Hot forging	+U	800-1150°C	In still air
Normalizing	+N	840-870°C	In still air
Soft annealing	+SA	650-700°C	In still air
Stress relieve annealing	+SRA	550-650°C	In still air
Quench & Tempering	+QT	840-870°C	In oil Temper immediately
Quench & Tempering	+QT	820-850°C	In water Temper immediately
Induction or Flame hardening	I-F	870-900°C	In oil Temper immediately

Treatment

Condition

Temperature cycle

Cooling/quenching

Hot forging

800-1150°C

In still air

Normalizing

840-870°C

In still air

Soft annealing

+SA

650-700°C

In still air

Stress relieve annealing

+SRA

550-650°C

In still air

Quench & Tempering

+QT

840-870°C

In oil Temper immediately

Quench & Tempering

+QT

820-850°C

In water Temper immediately

Induction or Flame hardening

I-F

870-900°C

In oil Temper immediately

Youngs module (GPa)	Poisson´s ratio (-)	Shear module (GPa)	Density (kg/m3)
210	0.3	80	7800
Average CTE 20-300°C (µm/m°K)	Specific heat capacity 50/100°C (J/kg°K)	Thermal conductivity Ambient temperature (W/m°K)	Electrical resistivityAmbient temperature (µΩm)
12	460 - 480	40 - 45	0.20 - 0.25

Youngs module (GPa)

Poisson´s ratio (-)

Shear module (GPa)

Density (kg/m3)

210

0.3

7800

Average CTE 20-300°C (µm/m°K)

Specific heat capacity 50/100°C (J/kg°K)

Thermal conductivity Ambient temperature (W/m°K)

Electrical resistivityAmbient temperature (µΩm)

460 - 480

40 - 45

0.20 - 0.25

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Steel grade

C45

General Information

Similar designations

Chemical composition

Mechanical Properties

Transformation temperatures

Heat treatment recommendations

Heat Treatment Guide generated Graphs

Other properties (typical values)

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