Slurry and dry erosion of

wear resistant steels

Niko Ojala

Hard Rock Tribology Course and Seminar

Tampere University of Technology

November 4th – 5th 2014

Motivation

• In mining and mineral

processes particle sizes

can be up to several

centimeters

• But the erosion wear

research have been

often done with

under 1 mm particles

Objectives

• New versatile and application oriented test

method

• Powerful wear tester

• Possibility to test many material types

Overview to topics

1) The wear tester

2) Slurry and dry erosion testing

3) Wear results

High speed slurry-pot tester

• Samples in the pin mill configuration

– Four sample levels

– Different sample shapes and sizes

– Up to 20 m/s sample speed

– Up to 10 mm particle size

– Sample rotation test method

time [min]

0-5 L1 L2 L3 L4

5-10 L4 L1 L2 L3

10-15 L3 L4 L1 L2

15-20 L2 L3 L4 L1

One or two samples on one level

Sample levels

Versatile sample size & shape

Sample types and dimensions

Round profile Ø 18.5 & 26 mm

Square profile 15 x 15 mm

Plate sample 64 x 40 x 6-10 mm

Plate w/ edge

protection35 x 35 x 1-10 mm

Other profiles height <40 mm

Rotating

radius, max95 mm

• New high speed slurry-pot tester enables testing

– With high speeds, up to 20 m/s

– With large particle sizes, up to 10 mm

– In slurry and dry environments

– Of different materials with various sample profiles

– Of erosiveness (abrasivity) of different abrasives

10 mm

Summary

2) Slurry and dry erosion testing

3) Wear results

Slurry and dry erosion testing

• High speed slurry-pot can be used for testing:

– Slurry pumping/transportation

– Wear protection and liner materials in mineral

processes

– Drilling and excavation

– Different materials:

• Steels, cast irons, rubbers, polymers, composites,

thin and thick coatings, surface treated materials,

hard weld overlays…

Slurry and dry erosion testing

Slurry-pot Dry-pot

Wear mechanisms slurry-erosion, abrasive

erosion

erosion, grinding

abrasion

Particle concentration 0-50 wt.% 100 wt.%

Sample angle (currently) ±45°, 90° 0°

Sample tip speed up to 20 m/s up to 10 m/s

Test time (typical) 4 x 5-20 minutes with

sample rotation

4 x 2-5 minutes

One tester, many applications…

3) Wear results

A structural steel vs a wear resistant steel after the tests with 9 wt% 8/10 mm granite slurry.

Wear surface of a wear resistant steel

Wear surfaces

Dry grinding abrasion

• Wear resistant steels tested with oversized

granite (12/14 mm).

• Short samples (45 mm), 5 m/s, 2 minutes

Upper surface Lower surface

Dry grinding abrasion

• Both methods can yield high wear rates

• For comparison the wear rates below are

calculated for nominal wear areas

0

500

1000

1500

2000

2500

3000

3500

250 rpm2 minutes

500 rpm2 minutes

1000 rpm2 minutes

We

ar

rate

[g

/h m

2]

Dry-pot

S355 400HB 500HB

0

500

1000

1500

2000

2500

Sample level 1 Sample level 2

We

ar

rate

[g

/h m

2]

5 minutes at 1500 rpm

Slurry-pot

S355 400HB 500HB

Slurry and dry erosion

Conclusions

• The high speed slurry-pot is application

oriented erosion wear tester.

• Sample shape and size can be adjusted for

the needs of the real life application.

• Both slurry and dry erosion testing is

possible.

• Wear environment can be chosen from mild

erosion to severe abrasive erosion or

grinding abrasion.

Thank you for your attention!

Niko Ojala

Research Scientist, Doctoral 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