100CrMo7

General Information

Ovako 824 is a through hardening bearing steels intended for rolling contact and other high fatigued applications. In the hardened condition the high hardness, high strength and high cleanliness provides the steel with the right properties to withstand high cycle, high stress fatigue. Ovako 824 is mainly used for small and medium sized bearing components. It is also regularly used for other machine components that require high tensile strength and high hardness. The hardenability approximately corresponds to a ring with maximum 20 mm wall thickness. It is suitable for both martensitic and bainitic hardening. Ovako 824 comes in two variants. One Bearing Quality (BQ) variant that fulfills tough Ovako internal quality demands and consequently also the ISO 683-17 demands. One Isotropic Quality (IQ) with higher demands regarding micro inclusion cleanliness and improved isotropic properties. Additionally this variant has a slightly reduced carbon content to reduce the carbide segregation tendency. The IQ variant is especially suited for applications subjected to a complex loading mode.

824B - Bearing quality (BQ) variant

824P - Bearing quality (BQ) variant with low sulphur content

824Q - Isotropic quality (IQ) variant

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

100CD7, ASTM A485 grade 3, 1.3537

Variant	Cast		C %	Si %	Mn %	P %	S %	Cr %	Ni %	Mo %
824B	IC	Min	0.93	0.25	0.25	-	0.003	1.65	-	0.15
Max	1.02	0.35	0.40	0.025	0.015	1.95	0.25	0.25
824P	IC	Min	0.93	0.25	0.30	-	0.003	1.80	-	0.15
Max	0.98	0.35	0.40	0.025	0.008	1.95	0.25	0.25
824Q	IC	Min	0.92	0.25	0.25	-	-	1.80	-	0.15
Max	1.00	0.35	0.40	0.020	0.001	1.95	0.25	0.25
EN ISO 683-17	Std	Min	0.93	0.15	0.25	-	-	1.65	-	0.15
Max	1.05	0.45	0.45	0.025	0.015	1.95	-	0.30

Variant

Cast

C %

Si %

Mn %

P %

S %

Cr %

Ni %

Mo %

824B

Min

0.93

0.25

0.003

1.65

0.15

Max

1.02

0.35

0.40

0.025

0.015

1.95

0.25

824P

Min

0.93

0.25

0.30

0.003

1.80

0.15

Max

0.98

0.35

0.40

0.025

0.008

1.95

0.25

824Q

Min

0.92

0.25

1.80

0.15

Max

1.00

0.35

0.40

0.020

0.001

1.95

0.25

EN ISO 683-17

Std

Min

0.93

0.15

0.25

1.65

0.15

Max

1.05

0.45

0.025

0.015

1.95

0.30

Variant	Condition	Format	Dimension [mm]	Yield strength min [MPa]	Tensile strength [MPa]	Elongation A₅ [%]	Hardness
Rp_0.2 * R_eh, ** R_el
824B	+SA	All formats	24 < 190	420	< 700	27	< 200 HB
+Q/T(m)	Ring, wall	< 20	1700	< 2300	2	< 61 HRC
+Q/T(b)	Ring, wall	< 20	2000	< 2200	7	< 59 HRC

Variant

Condition

Format

Dimension [mm]

Yield strength min [MPa]

Tensile strength [MPa]

Elongation A₅ [%]

Hardness

Rp_0.2 * R_eh, ** R_el

824B

+SA

All formats

24 < 190

420

< 700

< 200 HB

+Q/T(m)

Ring, wall

< 20

1700

< 2300

< 61 HRC

+Q/T(b)

Ring, wall

< 20

2000

< 2200

< 59 HRC

	Temperature °C
MS	186
AC1	750
AC3	750

Temperature °C

186

AC1

750

AC3

750

Treatment	Condition	Temperature cycle	Cooling/quenching
Hot forging	+U	800-1100C	In air
Soft annealing	+SA	RT-820C 1h 820C 2h 820-740C 1h 740-690C 12h	In air
Stress relieve annealing	+SRA	550-650C 1h	In air
Q/T (martensite)	+Q/T(m)	830-870C 10-60 min	In oil. Temper within 2h
Q/T (bainite)	+Q/T(b)	850-875C 10-60 min	Salt bath 220-250C 3-8h
Tempering	+T	160-500C	In air

Treatment

Condition

Temperature cycle

Cooling/quenching

Hot forging

800-1100C

In air

Soft annealing

+SA

RT-820C 1h 820C 2h 820-740C 1h 740-690C 12h

In air

Stress relieve annealing

+SRA

550-650C 1h

In air

Q/T (martensite)

+Q/T(m)

830-870C 10-60 min

In oil. Temper within 2h

Q/T (bainite)

+Q/T(b)

850-875C 10-60 min

Salt bath 220-250C 3-8h

Tempering

160-500C

In air

Micro inclusions - Ovako 824B + 824P		Macro inclusions - 824B + 824P
Applied standard	ASTM E45	Applied standard	ISO 3763 (Blue fracture)
Sampling	ASTM A295	Sampling	Statistical testing 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	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	< 1 mm/dm²	< 5 defects/dm³ > 0,2 mm FBH

Micro inclusions - Ovako 824B + 824P

Macro inclusions - 824B + 824P

Applied standard

ASTM E45

Applied standard

ISO 3763

(Blue fracture)

Sampling

ASTM A295

Sampling

Statistical testing on billets.

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

< 1 mm/dm²

< 5 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)
824	Round bar	+SA	608	212
824	Tube,wall	+SA	632	230

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)

824

Round bar

+SA

608

212

824

Tube,wall

+SA

632

230

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

100CrMo7

General Information

Similar designations

Chemical composition

Mechanical Properties

Transformation temperatures

Heat treatment recommendations

Heat Treatment Guide generated Graphs

CCT

Steel cleanliness

IQ

SUSTAINABILITY-ENVIRONMENTAL IMPACT DATA

Other properties (typical values)

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