Abrasion wear

performance of quenched

wear resistant steels

Niko Ojala1)*, Kati Valtonen1), Marke Kallio2), Joonas Aaltonen2),

Pekka Siitonen2) and Veli-Tapani Kuokkala1)

1) Tampere University of Technology,

Department of Materials Science, Tampere Wear Center, Finland 2) Metso Minerals, Inc., Finland

*email: niko.ojala@tut.fi

WTC 2013

Torino, Italy

8th – 13th September 2013

Motivation

• Quenched wear resistant steels are widely

used in industrial applications.

• The Brinell hardness grades are considered

as standards.

• But the wear performance is not extensively

studied.

Overview to topics

1) Materials and methods

2) Results

3) Discussion

0.1

42

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58

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63

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65

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72

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76

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80

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86

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89

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92

0.1

99

0.2

02

0.2

08

0.2

16

0

100

200

300

400

500

600

700

800

900

1000

0.000

0.050

0.100

0.150

0.200

0.250

0 2 15 4 14 3 10 11 5 24 18 17 6 16 1

Su

rfa

ce h

ard

nes

s [H

V5

]

Ma

ss l

oss

[g

]15 commercially available

400 HB steels were tested

• Sheet thicknesses were 10 or 12 mm.

• Decarburization layers were removed before testing

• Five steels were selected to closer study.

A B C D E

Crushing pin-on-disk

• The equipment is based on the pin-on-disk

principle

• In the tests, the pin is repeatedly pressed against

the gravel bed and the disk with a pneumatic

cylinder

– The pin does not come into direct contact with the

disk at any time

• The loss of material of both the pin and the disk

are measured by weighting, and the size change of

the abrasive during the test can measure by sieving

Test parameters

• Disk speed: 20 rpm

• Disk material: S355 (200 HV)

• Pin pressure: 1.1 bar

– 235 N nominal crushing force

• Pretest: 15 minutes, 10 minutes contact time

– 500 grams of 2/4 mm granite

• Test: 30 minutes, 20 minutes contact time

– With granite gravel

according to the table

10

0%

11

6%

13

1%

13

5%

15

3%

430390

450

350400

0

100

200

300

400

500

600

700

800

0%

20%

40%

60%

80%

100%

120%

140%

160%

A B C D E

Su

rfa

ce h

ard

nes

s [H

V5

]

Ma

ss l

oss

co

mp

are

d t

o s

teel

A

Up to 50 % difference in abrasion

wear performance

Average mass

losses [mg] 142 165 186 192 216

Tempered martensite with

untempered white martensite

A

B

C

D

20 µm

E

High-stress abrasive wear

E A

In general, the

more scratches

on the wear

surface, the

larger the mass

loss.

Wear mechanism

for scracthes:

two-body

abrasion

Surface characterization with

optical profilometer

• Estimated

average thickness

of the removed

material was

between 20 and

30 µm

• Deepest

scratches were

about 50-60 µm

deep

Optical profilometer image of steel C

Differences in wear surface

deformations

C

B A

E

Chemical compositions

• Hardenability

– Carbon

– Molybdenum (+Nickel)

– Boron

• Martensite formation

– Total amount of alloying

elements

– Amount of aluminum

and nickel

Steel A B C E

C 0.16 0.15 0.15 0.14

Si 0.4 0.28 0.22 0.38

Cr 0.14 0.37 0.41 0.46

Ni 0.04 0.07 0.09 0.04

Mo 0.15 0.1 0.01 0

Al 0.034 0.031 0.1 0.025

N 0.005 0.006 0.005 0.007

B 0.003 0.001 0.002 0.002

∑ 2.349 2.013 2.4 2.519

Chemical composition (wt%)

Steel D is removed due to possible manufacturing

faults

Concluding remarks

• Marked differences between the 400 HB grade

quenched steels in the wear performance

• Chemical composition: hardenability,

martensite formation and self temperability

• Microstructure: grain size and amount of

tempered martensite and white martensite

• Wear process: abrasive cutting

• Surface deformation: hardenability and self

temperability (a localized ‘requench’ process)

Thank you for your attention!

Niko Ojala

Research Scientist, PhD student

Tampere University of Technology

Department of Materials Science, Tampere Wear Center

P.O.Box 589, FI-33101 Tampere, Finland

phone: +358 50 317 4516

email: niko.ojala@tut.fi

www.tut.fi/twc/en

Acknowledgements