18CrNiMo7-6

General Information

18CrNiMo7-6 is a case hardening steel with high toughness. There are a number of variants with high cleanliness requirements. All variants possess tighter composition ranges compared to the standard. One variant is produced with the quality class IQ (isotropic quality). This ensures a very low number of elongated sulphide inclusions which will give more isotropic properties. The high oxidic cleanliness will enable the steel to meet the same high cleanliness demands as for re-melted qualities.

Grade 159A - Variant with low sulphur content and high cleanliness demands

Grade 159B - Variant with controlled sulphur content for consistent machinability and +H hardenability

Grade 159Q - Isotropic properties (IQ) and better fatigue strength due to higher cleanliness levels, and a finer size and distribution of non-metallic inclusions

Grade 159X - Variant with controlled sulphur content for consistent machinability and +H hardenability

Grade 159S - Variant with increased sulphur content.

Grade 4761(MoCN216) - Low sulphur variant of Imatra

IQ-Steel®

IQ-Steel® is an isotropic quality ultra clean steel optimized for high fatigue strength under multi axial loading.

Similar designations

1.6587, AISI4820, DIN17CrNiMo6, 18CND6, EN ISO 683-17

Variant	Cast	Weldability		C %	Si %	Mn %	P %	S %	Cr %	Ni %	Mo %	Cu %
159A	IC	CEV 0.91_max	Min	0.15	0.10	0.50	-	-	1.60	1.50	0.25	-
Pcm 0.4_max	Max	0.19	0.30	0.95	0.015	0.005	1.80	1.70	0.35	-
159B	IC	CEV 0.85_max	Min	0.15	0.20	0.50	-	0.008	1.50	1.50	0.25	-
Pcm 0.38_max	Max	0.18	0.35	0.60	0.015	0.015	1.80	1.70	0.35	0.25
159Q	IC	CEV 0.86_max	Min	0.16	0.20	0.50	-	-	1.60	1.50	0.25	-
Pcm 0.39_max	Max	0.19	0.35	0.60	0.015	0.002	1.80	1.70	0.35	0.25
159X	IC	CEV 0.86_max	Min	0.16	0.25	0.50	-	0.008	1.60	1.50	0.25	-
Pcm 0.39_max	Max	0.19	0.35	0.60	0.015	0.013	1.80	1.70	0.35	0.25
159S	IC	CEV 0.87_max	Min	0.15	0.25	0.40	-	0.015	1.50	1.40	0.25	0.10
Pcm 0.4_max	Max	0.19	0.40	0.60	0.020	0.020	1.80	1.70	0.35	0.25
4761, MoCN 216	CC	CEV 0.79_max	Min	0.15	0.10	0.50	0.000	-	1.50	1.40	0.25	0.00
Pcm 0.36_max	Max	0.21	0.40	0.90	0.015	0.015	1.80	1.70	0.35	0.30
18CrNiMo7-6 EN ISO 683-3	Std	CEV _max	Min	0.15	0.15	0.50	-	-	1.50	1.40	0.25	-
Pcm _max	Max	0.21	0.40	0.90	0.025	0.035	1.80	1.70	0.35	0.40

Variant

Cast

Weldability

C %

Si %

Mn %

P %

S %

Cr %

Ni %

Mo %

Cu %

159A

CEV 0.91_max

Min

0.15

0.10

0.50

1.60

1.50

0.25

Pcm 0.4_max

Max

0.19

0.30

0.95

0.015

0.005

1.80

1.70

0.35

159B

CEV 0.85_max

Min

0.15

0.20

0.50

0.008

1.50

0.25

Pcm 0.38_max

Max

0.18

0.35

0.60

0.015

1.80

1.70

0.35

0.25

159Q

CEV 0.86_max

Min

0.16

0.20

0.50

1.60

1.50

0.25

Pcm 0.39_max

Max

0.19

0.35

0.60

0.015

0.002

1.80

1.70

0.35

0.25

159X

CEV 0.86_max

Min

0.16

0.25

0.50

0.008

1.60

1.50

0.25

Pcm 0.39_max

Max

0.19

0.35

0.60

0.015

0.013

1.80

1.70

0.35

0.25

159S

CEV 0.87_max

Min

0.15

0.25

0.40

0.015

1.50

1.40

0.25

0.10

Pcm 0.4_max

Max

0.19

0.40

0.60

0.020

1.80

1.70

0.35

0.25

4761, MoCN 216

CEV 0.79_max

Min

0.15

0.10

0.50

0.000

1.50

1.40

0.25

0.00

Pcm 0.36_max

Max

0.21

0.40

0.90

0.015

1.80

1.70

0.35

0.30

18CrNiMo7-6 EN ISO 683-3

Std

CEV _max

Min

0.15

0.50

1.50

1.40

0.25

Pcm _max

Max

0.21

0.40

0.90

0.025

0.035

1.80

1.70

0.35

0.40

Variant	Condition	Format	Dimension [mm]	Yield strength min [MPa]	Tensile strength [MPa]	Elongation A₅ [%]	Reduction of area Z_min [%]	Hardness
Rp_0.2 * R_eh, ** R_el
159A	+QT	Round bar	30 typical	780	1080-1320	8	-	-
Round bar	63 typical	690	980-1270	8	-	-
159B	+QT	Round bar	30 typical	780	1080-1320	8	-	-
Round bar	63 typical	690	980-1270	8	-	-
159Q	+QT	Round bar	30 typical	780	1080-1320	8	-	-
Round bar	63 typical	690	980-1270	8	-	-
159X	+QT	Round bar	30 typical	780	1080-1320	8	-	-
Round bar	63 typical	690	980-1270	8	-	-
159S	+QT	Round bar	30 typical	780	1080-1320	8	-	-
Round bar	63 typical	690	980-1270	8	0	-
4761, MoCN 216	+AR	Round bar	25 < 160	-	-	-	-	< 320 HB
+A	Round bar	25 < 160	-	-	-	-	< 229 HB

Variant

Condition

Format

Dimension [mm]

Yield strength min [MPa]

Tensile strength [MPa]

Elongation A₅ [%]

Reduction of area Z_min [%]

Hardness

Rp_0.2 * R_eh, ** R_el

159A

+QT

Round bar

30 typical

780

1080-1320

Round bar

63 typical

690

980-1270

159B

+QT

Round bar

30 typical

780

1080-1320

Round bar

63 typical

690

980-1270

159Q

+QT

Round bar

30 typical

780

1080-1320

Round bar

63 typical

690

980-1270

159X

+QT

Round bar

30 typical

780

1080-1320

Round bar

63 typical

690

980-1270

159S

+QT

Round bar

30 typical

780

1080-1320

Round bar

63 typical

690

980-1270

4761, MoCN 216

+AR

Round bar

25 < 160

< 320 HB

Round bar

25 < 160

< 229 HB

	Temperature °C
MS	410
AC1	726
AC3	833

Temperature °C

410

AC1

726

AC3

833

Treatment	Condition	Temperature cycle	Cooling/quenching
Hot forging	+U	800-1200°C	In air
Normalizing	+N	860-890°C	In air
Carburizing	+C	850-930°C Carbon potential see diagram
Hardening	+QT	840-870°C	In oil
Hardening	+QT	780-830°C Hardening of as-carburized components	In oil

Treatment

Condition

Temperature cycle

Cooling/quenching

Hot forging

800-1200°C

In air

Normalizing

860-890°C

In air

Carburizing

850-930°C Carbon potential see diagram

Hardening

+QT

840-870°C

In oil

Hardening

+QT

780-830°C Hardening of as-carburized components

In oil

Micro inclusions - steel grade 159X		Macro inclusions - 159X
Applied standard	ASTM E45		Applied standard	ISO 3763 (Blue fracture)
Sampling	ASTM A295		Sampling	Statistical sampling on billets
Maximum average limits	A	B	C	D		Limits	<2,5 mm/dm²
Th	He	Th	He	Th	He	Th	He
2.0	1.5	1.5	0.5	0.0	0.0	1.0	1.0

Micro inclusions - IQ - steel grade 159Q		Macro inclusions - IQ - 159Q
Applied standard	DIN 50602 K1		Applied standard	10 MHz UST (Ovako internal procedure)
Sampling	Six random sample from final product		Sampling	Statistical sampling on billets
Limits	The limits is dimension dependent. The average rating of six samples should not exeed the limits given in the graph.		Limits	<10 defects/dm3 >0,2 mm FBH

Micro inclusions - steel grade 159X

Macro inclusions - 159X

Applied standard

ASTM E45

Applied standard

ISO 3763

(Blue fracture)

Sampling

ASTM A295

Sampling

Statistical sampling on billets

Maximum

average limits

Limits

<2,5 mm/dm²

2.0

1.5

0.5

0.0

1.0

Micro inclusions - IQ - steel grade 159Q

Macro inclusions - IQ - 159Q

Applied standard

DIN 50602 K1

Applied standard

10 MHz UST (Ovako internal

procedure)

Sampling

Six random sample from final product

Sampling

Statistical sampling on billets

Limits

The limits is dimension dependent. The average rating of six samples should not exeed

the limits given in the graph.

Limits

<10 defects/dm3 >0,2 mm

FBH

Steel works	Hofors	Smedjebacken	Imatra
CO2e/kg	120	62	76

Steel works

Hofors

Smedjebacken

Imatra

CO2e/kg

120

Steel Grade	Format	Condition	Scope 1-3 (CO2e kg /1000 kg steel)	Climate compensated Net emission = Scope 3 (CO2e kg /1000 kg steel) Scope 1 - 2 = 0 (compensated)
159	Round bar	+AR	855	462
159	Round bar	+SA	861	464
159	Tube,wall	+AR	904	503
159	Tube,wall	+SA	905	503
4761, MoCN 216	Round bar	+AR	792	489

Steel Grade

Format

Condition

Scope 1-3 (CO2e kg /1000 kg steel)

Climate compensated Net emission = Scope 3 (CO2e kg /1000 kg steel) Scope 1 - 2 = 0 (compensated)

159

Round bar

+AR

855

462

159

Round bar

+SA

861

464

159

Tube,wall

+AR

904

503

159

Tube,wall

+SA

905

503

4761, MoCN 216

Round bar

+AR

792

489

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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Material data sheet

Steel grade

18CrNiMo7-6

General Information

Similar designations

Chemical composition

Mechanical Properties

Transformation temperatures

Heat treatment recommendations

Heat Treatment Guide generated Graphs

Hardenability

Carburizing response - Ovako 159

Steel cleanliness

IQ

SUSTAINABILITY-ENVIRONMENTAL IMPACT DATA

Other properties (typical values)

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