Basic principles of wear protection technology
for bulk materials (Part 2)

12 Comparison of two-body (a) and three-body (b) abrasive wear

13 Formation of a wear pocket, increasing operating time from (a) to (c)

14 Impact wear as a function of temperature

15 Sliding wear as a function of temperature, measurements taken in a pot tester, sliding velocity u_S = 2.8 m/s, corundum D_P = (3–5) mm

16 Sliding wear against “Creusabro 4000” wall material

17 Blast wear: dependency W_M = W_M(u_P,0)

18 Blast wear as a function of impact angle and wall material

19 Blast wear as a function of impact density

20 Lower and upper wear levels

21 Blast wear of different wall materials stressed by quartz sand, angle of incidence a_S,W = 90°

$22 Wear resistance as a function of fracture toughness and material hardness$

22 Wear resistance as a function of fracture toughness and material hardness

23 Imperfections in a pneumatic conveying pipe

24 Wear protection against a sliding load: (a) autogenous protection, (b) fluidization

25 Wear caused by wedging effects [25]

26 Blast wear: different configurations of 90° changes in direction

27 Fracture position/primary impact point in a 90° pipe bend

Nozzle for the gas inlet in a fluidised bed

Summary: In many industries the wear caused by handling bulk materials is a factor that limits the availability of plants and thus considerably increases operating and production costs. The following article aims to provide plant operators affected by this problem with a sound basis for assessing, classifying and solving their problems in relation to wear. After a brief overview of the relationships relating to contact and fracture mechanics there is a systematic analysis of the basic interdependencies that affect the wear process and the extent of wear. Part 2 presents corresponding mathematical methods and models. The report concludes with a practical example highlighting the systemic nature of the problem of wear.

4 Calculation approaches/models

The research published in 1995 [18] identified 182 equations for describing different types of wear. 28 of these equations deal exclusively with wear by particle erosion and impact. They are analysed in detail in [18]. One of the latest reports on the subject of blast wear [19] appeared in 11/2008. These equations are based either on theoretical models or on descriptive formulae based on measurements. In each case they only apply to limited areas of application and/or idealized material behaviour and have to be adapted to suit the real situation through...