AUTOMOTIVE AND
LARGE BORE ENGINE APPLICATIONS A
Issue date: 03.01
Piston Rings and Piston Ring Elements
Cast Iron Materials
Desig- Reference Grade Hardness
nation
KS MED AE DIN
unalloyed, non
GOE 12 K1 47 A 210 6621-3 heat-treated grey 94-106 HRB
cast iron
unalloyed, non
GOE 13 K 25 47 T 6621-3 heat-treated grey 97-108 HRB
cast iron
alloyed, heat-treated
GOE 32 K 11 47 Z 6621-3 grey cast iron 109-116 HRB
with carbides
malleable
GOE 44 222 6621-3 102-111 HRB
cast iron
spheroidal graphite
GOE 52 K9 47 J 227 6621-3 104-112 HRB
cast iron
spheroidal graphite
GOE 56 K 22 130 A 232 6621-3 40-46 HRC
cast iron
Material Specification
Piston Rings
GOE 12 A
Reference: K1, MED 47 A, MC 13, AE 210 Issue date: 06.00
Material:
Non heat-treated grey cast iron,
according to ISO 6621-3, subclass 12
Chemical composition (%):
C: 3.4 - 3.9 Si: 2.2 - 3.2 Mn: 0.5 - 1.0
P: 0.3 - 0.6 S: max 0.13 Cr: 0.1 - 0.4
V: max 0.15 Cu: 0.1 - 0.7
unetched 100 : 1
Other elements may be present as impurities.
Microstructure:
Graphite: predominantly flaky and
uniformly distributed
Matrix: pearlite, ferrite not exceeding 5 %
Phosphide eutectic: evenly distributed
Mechanical properties:
Hardness: 94 - 106 HRB
200 - 290 HB
etched with HNO 3 500 : 1 Bending strength: min 350 MPa
Modulus of elasticity: 100000 MPa typical
85000 - 115000 MPa
strongly etched 20 : 1
Note: The analysis ranges are designed to allow for different cross sections. Variations are admissible on condition
that the structure and mechanical properties are not adversely affected. The hardness data are averages of three
measurements on a single ring: 1st measurement at the gap, 2nd measurement 90° from the gap,
3rd measurement diametrically opposite the gap.
Hardness testing to DIN EN 10109-1 and DIN EN 10003-1. However, the minimum distance between the middle of the
impression and the edge of the specimen must be 1.5 mm. For specimens with narrower test surfaces or with cross
sections having an insufficiently high bearing capacity for test loads, the hardness can be measured to DIN 50133.
In this case the limit values must be appropriately adjusted by means of comparative measurements.
The modulus of elasticity is determined at a bending stress of 200 MPa.
Material Specification
Piston Rings
GOE 13 A
Reference: K25, MED 47T Issue date: 10.97
Material:
Unalloyed non heat-treated
flake graphite cast iron,
according to ISO 6621-3, subclass 13*
Chemical composition (%):
C: 2.8 - 3.8 Si: 2.0 - 3.0 Mn: 0.5 - 0.9
P: 0.3 - 0.7 S: max 0.15 Cr: 0.15 - 0.6
V: max 0.2 Cu: 0.2 - 0.8
unetched 100 : 1
Other elements may be present as impurities.
Microstructure:
Graphite: predominantly flaky and
uniformly distributed
Matrix: pearlite, ferrite not exceeding 5 %
Phosphide eutectic: predominantly non-continuous
network
Mechanical properties:
etched with HNO 3 500 : 1 Hardness: 97 - 108 HRB
200 - 320 HB
Bending strength: min 420 MPa
Modulus of elasticity: 95000 - 125000 MPa
strongly etched 20 : 1
* ISO 6621-3 / Draft Sept. 1997
Note: The composition ranges are designed to allow for different cross sections. Variations are admissible on
condition that the structure and mechanical properties are not affected.
The hardness figures are averages from three measurements on a single ring: 1st measurement at the gap;
2nd measurement 90° to the gap; 3rd measurement diametrically opposite the gap.
Hardness testing to DIN EN 10109-1 and DIN EN 10003-1. The minimum permissible distance between the middle of
the impression and the edge of the specimen is 1.5 mm. For specimens with narrower test surfaces or with cross
sections having an insufficiently high bearing capacity for the test loads (e.g. slotted oil rings), the hardness can be
measured in HV5 to DIN 50 133, the applicable range being 230 - 340 HV5.
The modulus of elasticity is determined at a bending stress of 200 MPa.
Material Specification
Piston Rings
GOE 32 A
Reference: K11 (F14), MED 47Z Issue date: 10.97
Material:
Carbidic cast iron,
according to ISO 6621-3, subclass 32*
Chemical composition (%):
C: 2.5 - 3.3 Si: 3.6 - 4.6 Mn: 0.8 - 1.2
P: max 0.35 S: max 0.15 Cr: 0.2 - 0.6
V: 0.3 - 0.7 Mo: 0.5 - 1.0 Ni: 0.5 - 1.0
Cu: 0.5 - 1.0 Ti: max 0.3 W: 0.8 - 1.2
unetched 100 : 1
Nb: 0.1 - 0.4
Other elements may be present as impurities.
Microstructure:
Graphite: fine-flaked, punctiform
Matrix: tempered martensite with
uniformly distributed
Phosphide eutectic: punctiform tending to
non-continuous network
etched with HNO 3 500 : 1 Mechanical properties:
Hardness: 109 - 116 HRB
35 - 49 HRC
Bending strength: min 650 MPa
Bending strength: 130000 - 160000 MPa
* ISO 6621-3 /Draft Sept. 1997
Note: The composition ranges are designed to allow for different cross sections. Variations are admissible on
condition that the structure and mechanical properties are not affected.
The hardness figures are averages from three measurements on a single ring: 1st measurement at the gap;
2nd measurement 90° to the gap; 3rd measurement diametrically opposite the gap.
Hardness testing to DIN EN 10109-1 and DIN EN 10003-1. The minimum permissible distance between the middle of
the impression and the edge of the specimen is 1.5 mm. For specimens with narrower test surfaces or with cross
sections having an insufficiently high bearing capacity for the test loads, the hardness can be measured in HV5 to
DIN 50133, whereby the limit values are to be ascertained based on comparative measurements.
The modulus of elasticity is determined at a bending stress of 250 MPa.
Material Specification
Piston Rings
GOE 44 A
Reference: AE 222 Issue date: 10.99
Material:
Malleable cast iron,
according to ISO 6621-3, subclass 44 *
Chemical composition (%):
C: 2.7 - 3.3 Si: 1.5 - 2.5 Mn: 0.4 - 0.9
P: max 0.5 S: max 0.1 Cr: 0.3 - 0.85
V: 0.1 - 0.4
unetched 100 : 1
Other elements may be present as impurities.
Microstructure:
Graphite: uniformly distributed temper graphite aggregates
Matrix: pearlite containing 2-10 % (by area) of small well
distributed complex alloy carbides.
Some spheroidisation may be present.
Mechanical properties:
Hardness: 102 - 111 HRB
27 - 36 HRC
etched with HNO 3 500 : 1 Bending strength**: min 800 MPa
Modulus of elasticity: min 150000 MPa
* ISO 6621-3 / Draft Aug. 1998
** An exact determination of the bending strength as per material specification B 14 is not possible owing to the
high ductility of the material.
Note: The composition ranges are designed to allow for different cross sections. Variations are admissible on
condition that the structure and mechanical properties are not affected.
The hardness figures are averages from three measurements on a single ring: 1st measurement at the gap;
2nd measurement 90° from the gap; 3rd measurement diametrically opposite the gap.
Hardness testing to DIN EN ISO 6508-1. The minimum permissible distance between the middle of the impression and
the edge of the specimen is 1.5 mm. For specimens with narrower test surfaces or with cross sections having an
insufficiently high bearing capacity for the test loads, the hardness can be measured in HV5 to DIN 50 133, whereby
the limit values are to be ascertained based on comparative measurements.
Material Specification
Piston Rings
GOE 52 A
Reference: K9 (KV1), MED 47J, AE 227 Issue date: 10.97
Material:
Spheroidal graphite cast iron,
according to ISO 6621-3, subclass 52*
Chemical composition (%):
C: 3.5 - 4.0 Si: 2.4 - 3.2 Mn: max 0.5
P: max 0.3 S: max 0.05 Cr: max 0.2
Cu: max 1.0 Mg: max 0.1
unetched 100 : 1
Other elements may be present as impurities.
Microstructure:
Graphite: roughly spheroidal
Matrix: tempered martensite,
isolated carbide particles are acceptable
Mechanical properties:
Hardness: 104 - 112 HRB
25 - 42 HRC
Bending strength**: min 1300 MPa
etched with HNO 3 500 : 1 Modulus of elasticity: min 150000 MPa
Coefficient of thermal expansion 10-6/K:
20 - 100°C: 10.0
Density:
7.3 g/cm3
* ISO 6621-3 / Draft Sept. 1997
** An exact determination of the bending strength as per material specification B 14 is not possible owing to the
high ductility of the material.
Note: The composition ranges are designed to allow for different cross sections. Variations are admissible on
condition that the structure and mechanical properties are not affected.
The hardness figures are averages from three measurements on a single ring: 1st measurement at the gap;
2nd measurement 90° to the gap; 3rd measurement diametrically opposite the gap.
Hardness testing to DIN EN 10109-1 and DIN EN 10003-1. The minimum permissible distance between the middle of
the impression and the edge of the specimen is 1.5 mm. For specimens with narrower test surfaces or with cross
sections having an insufficiently high bearing capacity for the test loads, the hardness can be measured in HV5 to
DIN 50 133, whereby the limit values are to be ascertained based on comparative measurements.
Material Specification
Piston Rings
GOE 56 A
Reference: K 22 (KV4), MED 130 A, AE 232 Issue date: 10.97
Material:
Spheroidal graphite cast iron,
according to ISO 6621-3, subclass 56*
Chemical composition (%):
C: 3.5 - 4.0 Si: 2.4 - 3.2 Mn: max 0.5
P: max 0.3 S: max 0.05 Cr: max 0.2
Cu: max 1.0 Mg: max 0.1
unetched 100 : 1
Other elements may be present as impurities.
Microstructure:
Graphite: roughly spheroidal
Matrix: tempered martensite, isolated
carbide particles are acceptable
Mechanical properties:
Hardness: 40 - 46 HRC
390 - 470 HB
Bending strength**: min 1300 MPa
etched with HNO 3 500 : 1 Modulus of elasticity: min 150000 MPa
Coefficient of thermal expansion 10-6/K:
20 - 100°C: 10.0
Density:
7.3 g/cm3
* ISO 6621-3 / Draft Sept. 1997
** An exact determination of the bending strength as per material specification B 14 is not possible owing to the
high ductility of the material.
Note: The composition ranges are designed to allow for different cross sections. Variations are admissible on
condition that the structure and mechanical properties are not affected.
The hardness figures are averages from three measurements on a single ring: 1st measurement at the gap;
2nd measurement 90° to the gap; 3rd measurement diametrically opposite the gap.
Hardness testing to DIN EN 10109-1 and DIN EN 10008-1. The minimum permissible distance between the middle of
the impression and the edge of the specimen is 1.5 mm. For specimens with narrower test surfaces or with cross
sections having an insufficiently high bearing capacity for the test loads, the hardness can be measured in HV5 to
DIN 50133, whereby the limit values are to be ascertained based on comparative measurements.
