**Abstract**

Blasting modifies the surface state of materials in terms of surface irregularities too. Bearing in mind that the roughness characteristics affect the components functionality, it is essential to study and evaluation the surface state of pretreated materials. The chapter deals with evaluation of relation between individual surface roughness parameters of the blasted surfaces based on the measured values on the surfaces, which were blasted by various types of blasting materials. Based on the analysis of the results were also proposed sets of surface roughness parameters, which can be used in the assessment of the blasted surfaces. These allow you to effectively distinguish differences in roughness of blasted surfaces from the point of view of other follow-up technologies. It also lists the main factors that affect surface roughness.

**Keywords:** blasting, surface, roughness, blasting abrasive, surface roughness parameters, technological parameters

### **1. Introduction**

The blasting process involves several simultaneously occurring processes. From the point of view of blasting effect on the base material, it is necessary to understand blasting process as the process of surface deformation or elastic-plastic deformation of metal in its full volume.

The quality of blasted surface is characterized by the following features, namely:


From the point of view of a component function, geometrical properties of a surface are very important in many cases (e.g., in conditions of friction and wear). Therefore it is necessary to put a sufficient emphasis on evaluation of surfaces geometry and the determination of profile deviations from the defined plain [1–4]. From the micro-geometry point of view, surfaces can be divide into:


On the basis of the stated facts, it is possible to classify the blasted surface like non-oriented (isotropic) surface, while its creation is mainly conditioned by abrasive particle shape used, **Figure 1**. The selection of a type, size, and shape of blasting material depends on a purpose of newly created surface usage. This selection is the basic issue for the process of blasting.

Juvenile surface, obtained by a blasting process, has a specific character. The micro-geometry of a blasted surface depends on:


**Figure 1.** *The classification of surfaces in terms of microgeometry.*

**Figure 2.** *The surface of metallic substrate blasted by polydispersed (a) shot, and (b) grit.*

size of a blasting material. The ratio of hardness of blasting material to a hardness of blasted metal is important from the point of view of surface qualitative affection as well as in terms of removal of base material;

• blasting parameters. In selection of blasting material type, blasting parameters are also important. The same blasting material creates various surface roughnesses in the different blasting parameters (an abrasive speed, an impact angle, etc.) [5–7].

Blasting abrasives are loose materials of granular nature consisting of different large particles (polydispersion). There are mainly two types of blasting media used—metallic and nonmetallic ones. Metal blasting abrasives can be in three different forms:


The shape of particle of blasting abrasives used determines the resulting surface relief [4, 8, 9]. Surface has rounded small peaks after the blasting with grit or sharp notches after grit, **Figure 2**.
