With focus on the welding process the state of the art is presented. Among other aspects, cladding is used to produce a hard, wear-resistant and corrosion-resistant layer, to repair and improve used components and to optimise new components [
4]. For this purpose, different processes such as laser metal deposition by wire [
2,
5], metal inert gas welding, laser metal deposition by powder [
5] and plasma powder welding are used. The main materials used for cladding are ceramics, their alloys or a composite of different ceramics [
6]. According to [
6], pure metals or alloys are used less frequently. Based on a previous work within the Collaborative Research Center 1153 called tailored forming [
7], the plasma transferred arc welding is chosen as the welding process. It is characterised by its cladding material, which is applied in powder form. Further benefits are a high degree of automation and reproducibility [
8]. The chosen cladding material AISI 52100 is considered non-weldable because of its carbon equivalent of CEV > 1 according to [
9,
10]. Compared to other welding processes, the transfer arc welding process allows a high heat input and high cladding rate. Due to these characteristics, the AISI 52100 can be welded and forms a strong bond with the base material. Another important factor is the availability of the cladding material. Materials in powder form, especially steels with a high carbon content for the application in a bearing, are widely available and can be used with high flexibility in the welding process. Experience in the cladding of steels, especially of non-weldable steels, is rather limited to this day. Kilicay et al. added a protective layer of FeCrC powder to AISI 5115 steel by plasma transferred arc welding. FeCrC has a weight percentage of 6.64% C, which means it is considered difficult to weld. Nevertheless the cladding forms a strong bonding with the base material and reduces the coefficient of friction and wear [
11]. Ferozhkhan et al. used plasma transferred arc welding to weld 6 mm of Stellite 6 alloys on stainless steel to increase the resistance against abrasive wear in high temperature valve applications achieving good results. The cladding layer formed a strong bond with the base material. However, the samples were not specially inspected for defects below the surface [
12]. In [
13] a WCP/NiBSi-multi-material was manufactured by plasma transferred arc welding with an overall hardness of HRC 65 ± 1. The bonding between the applied layer and the base material was strong, but intrinsic defects, such as pores and cracks, were formed. Due to the application as a wear protection layer in [
14], these defects could be neglected. But this is not permissible for a rolling bearing and the number of defects must be reduced significantly in order to achieve a service lifetime comparable to that of conventional rolling bearings. Pores in the loaded zone cause local stress peaks and can be the starting points for further crack initiation. Studies in [
15] show this effect and the increase in the load on the material through pores. However, due to the poor weldability of AISI 52100, defects occur in the cladding and intermediate layer, such as gas inclusions, pores or cracks, which could be reduced by a subsequent forming process. The procedure and results are explained in the following sections.