66SiMnCrMo6-6-4*

General Information

Ovako 677L & 677Q is an air-hardening bearing steel with high mechanical strength and fatigue properties. By using gas cooling or air-hardening it is possible to reduce the amount of distortion. Additionally the use of quenching medias such as oil and salt can be avoided, which improves both safety and environment.

Through hardenability corresponding to a bar with approx. ∅40 mm (cooling in still air)
Can be induction or flame hardened
Good machinability in soft annealed condition
Machinable in hardened condition using hard-turning techniques
Good dimensional stability
Corresponds to BQ and IQ specifications
Delivered in soft annealed condition

Ovako 677L - BQ ( Bearing Quality) - Standard

Ovako 677Q - IQ (Isotropic Quality) - Due to a reduced sulphide inclusion content and a finer oxide inclusion distribution, Ovako 677Q is a steel with isotropic properties with excellent fatigue strength in both transverse and longitudinal directions.

IQ-Steel®

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

BQ-Steel®
BQ-Steel® is a bearing quality clean steel optimized for fatigue strength and is also ideal for new design solutions outside the bearing industry.

Similar designations

66SiMnCrMo6-6-4

Variant	Cast		C %	Si %	Mn %	P %	S %	Cr %	Ni %	Mo %
677Q	IC	Min	0.63	1.40	1.35	-	-	1.00	-	0.23
Max	0.70	1.60	1.55	0.025	0.001	1.20	0.25	0.27
677L	IC	Min	0.65	1.45	1.35	-	0.004	1.00	-	0.23
Max	0.70	1.55	1.55	0.025	0.015	1.10	0.25	0.27

Variant

Cast

C %

Si %

Mn %

P %

S %

Cr %

Ni %

Mo %

677Q

Min

0.63

1.40

1.35

1.00

0.23

Max

0.70

1.60

1.55

0.025

0.001

1.20

0.25

0.27

677L

Min

0.65

1.45

1.35

0.004

1.00

0.23

Max

0.70

1.55

0.025

0.015

1.10

0.25

0.27

Variant	Condition	Format	Yield strength min [MPa]	Tensile strength [MPa]	Elongation A₅ [%]	Hardness
Rp_0.2 * R_eh, ** R_el
677Q	+SA	Round bar	-	-	-	220 HB typical
+Q	Round bar	1700	2300 typical	2	61 HRC typical
677L	+SA	Round bar	-	-	-	220 HB typical
+Q	Round bar	1700	2300 typical	2	61 HRC typical

Variant

Condition

Format

Yield strength min [MPa]

Tensile strength [MPa]

Elongation A₅ [%]

Hardness

Rp_0.2 * R_eh, ** R_el

677Q

+SA

Round bar

220 HB typical

Round bar

1700

2300 typical

61 HRC typical

677L

+SA

Round bar

220 HB typical

Round bar

1700

2300 typical

61 HRC typical

	Temperature °C
MS	193
AC1	768
AC3	792

Temperature °C

193

AC1

768

AC3

792

Treatment	Condition	Temperature cycle	Cooling/quenching
Hot forging	+AR	900-1200°C	Slowly or in air
Soft annealing	+SA	775°C / 1h	Slowly to 650^oC in 8h
Hardening	+QT	880-1000°C	Directly hardened in air or by gas quenching
Tempering	+QT	150-710°C	In air

Treatment

Condition

Temperature cycle

Cooling/quenching

Hot forging

+AR

900-1200°C

Slowly or in air

Soft annealing

+SA

775°C / 1h

Slowly to 650^oC in 8h

Hardening

+QT

880-1000°C

Directly hardened in air or by gas quenching

Tempering

+QT

150-710°C

In air

Micro inclusions - BQ		Macro inclusions - BQ
Applied standard	ASTM 45		Applied standard	ISO 3763 (Blue fracture) Statistical testing on billets
Sampling	ASTM A295		Sampling
Maximum average limits	A	B	C	D		Limits	< 2,5 mm/dm²
Th	He	Th	He	Th	He	Th	He
2.0	1.5	0.8	0.1	0	0	0.5	0.3

Micro inclusions - IQ		Macro inclusions - IQ
Applied standard	DIN 50602 K1		Applied standard	ISO 3763 (Blue fracture)	10 M Hz UST (Ovako internal procedure)
Sampling	Six random samples from final product dimension		Sampling	Statistical testing on billets
Limits	The limit is dimension dependent. The average rating of six samples should not exceed the limits given in the graph		Limits	< 1mm /dm²	<18 defects /dm³ > 0.2 mm FBH

Micro inclusions - BQ

Macro inclusions - BQ

Applied standard

ASTM 45

Applied standard

ISO 3763 (Blue fracture)

Statistical testing on billets

Sampling

ASTM A295

Sampling

Maximum average limits

Limits

< 2,5 mm/dm²

2.0

1.5

0.8

0.1

0.5

0.3

Micro inclusions - IQ

Macro inclusions - IQ

Applied standard

DIN 50602 K1

Applied standard

ISO 3763

(Blue fracture)

10 M Hz UST

(Ovako internal procedure)

Sampling

Six random samples from final product dimension

Sampling

Statistical testing on billets

Limits

The limit is dimension dependent. The average rating of six samples should not exceed the limits given in the graph

Limits

< 1mm

/dm²

<18 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)
677	Round bar	+AR	636	251
677	Tube,wall	+AR	680	280

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)

677

Round bar

+AR

636

251

677

Tube,wall

+AR

680

280

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

66SiMnCrMo6-6-4*

General Information

Similar designations

Chemical composition

Mechanical Properties

Transformation temperatures

Heat treatment recommendations

Heat Treatment Guide generated Graphs

Steel cleanliness

IQ

Tempering response Ovako 677

Transformation diagrams

Hardenability

SUSTAINABILITY-ENVIRONMENTAL IMPACT DATA

Other properties (typical values)

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