From the User’s point of view when doing regeneration we consider the following points to be essential:

- As far as wear is concerned the choice of the best welding material.

- Choice of the best welding technology and welding procedure that influences alloy formation.

- Cost reasons for the mechanical execution of the welding process aimed at obtaining higher and consistent performance with reproducible quality.

Before coating the basic material of the worn parts undergoes controls with penetrant liquids

Coating can be carried out only in the absence of cracking and/or tearing. The fusion pores can be left alone.
The biggest defects such as the shrink cavity must be eliminated prior to sandblasting. The presence of cracking and/or deep defects cannot be tolerated.
The alloys used as welding material against abrasion due to minerals belong to a group of special eutectic steel.

Carbon is mainly linked in the form of carbides (M7C3, MC) and as a hard material in a more or less hard matrix stored thanks to austenitic super saturation.
Wear Resistance is defined by the volume, hardness and size of the carbide and by the hardness of the matrix.
The choice of the eutectic alloys is made among a wide range of alloys that are available in flux cored-wire welding and that have been especially developed for hard coat welding, for coal pulverising and/or cement plants.

Elettromeccanica Viotto in collaboration with Corodur has dealt with these problems by studying

and analysing each single problem through research aimed at improving the analysis and mechanical characteristics of the material used for coating by choosing the most appropriate alloys to be used in line with resistance to wear.
The Open-Arc welding procedure, in other words with flux cored-wire is chosen on the basis of guaranteeing homogeneity throughout the entire coating surface. Such homogeneity is guaranteed as regards both chemical, mechanical and hardness characteristics thanks to our achievements in research and development.

As far as the homogeneity of the repaired surface is concerned the use of finalised materials is indispensable, in other words materials that have chemical-mechanical characteristics that are as much in line as possible with the needs of the plant indicated only for the melting part of the welding material both as a stabilisation moment of the welding arc as well as with elements that can ideally be incorporated on the bath in a stable and homogenous form.

By using alloys in conformity with the customer’s needs, one can make structures that present bigger chromium carbides than those present in the melted material. For this reason the life of equipment armoured with these alloys is longer than that of non-armoured equipment.

Whether a welding alloy will completely or only in part be wear resistant mainly depends on the welding technology used.

This is especially true when coat welding is carried out at high speed and with thin run welding.
The welding technology that is chosen fixes the degree of dilution with the base material and with it the alloy’s content, the formation of the structure and the resistance to wear following coat welding. As one can see from the photos the coating surface of the rollers and/or the crushing area are quite big.