The Increase in Wear Resistance of Low Carbon Steel by Flux-Cored Wire Surfacing Followed Be Electron Beam Processing

Abstract

Abstract. Structure-phase state and tribological properties of the coating deposited on Hardox 450 martensitic low-carbon steel by flux-cored wire Fe-C-Cr-Nb-W and modified by subsequent electron-beam processing were studied. It is shown that the electron beam processing of ~ 5 mm thick deposited layer leads to the formation of ~ 20 µm thick modified surface layer with the main phases of α-Fe and NbC, Fe3C and M6C(Fe3W3C) carbides. Wear resistance of the weld layer is 70 times higher than the one of the original steel. IntroductionThe production of coatings with high service properties making possible the increase in service durability of the articles in the extreme conditions of high wear, corrosion, mechanical loads and temperatures is the important fundamental problem. The thorough analysis of the relation «wear parameters -hardness -microstructure» is necessary in scientific and practical use of various kinds of surfacing in the critical articles. Only in this case it is possible to produce the articles with high service parameters [1 -8].The purpose of the research is the analysis of structure and tribological properties of the layer formed on Hardox 450 steel by electrocontact surfacing of powder wire of system Fe-C-Cr-Nb-W and modified by high intensity pulsed electron beam irradiation.Hardox 450 steel (weight %): (0.19-0.26 C; 0.70 Si; 1.6 Mn; 0.025 P; 0.010 S; 0.25 Cr; 0.25 Mo; 0.004 B; balance -Fe) was used as a test material. The surfaced electrode 1.6 mm in diameter had the following chemical composition (weight %): 1.3 C; 7.0 Cr; 8.5 Nb; 1.4 W; 0.9 Mn; 1.1 Si, balance -Fe.The testing techniques of the surfacing by methods of modern physical material science are presented in [1].

Surfacing – Technologies and Layer Properties (A Review)

“…The components added in the flux which leads to increasing of the hardening phases [2] results in similar effects on hardness and wear resistance. The core wire are widely used in another electric arc processes -TIG [11], [12] and [13] and MIG/MAG [3], [10], [15], [16], [17] 20]. The solid wires are applicable in the MIG / MAG process [4], [8], [9], [10], [18] too.…”

“…The solid wires are applicable in the MIG / MAG process [4], [8], [9], [10], [18] too. Additional impacts such as forced gas cooling [4], longitudinal electromagnetic field [10] and post-surfacing electron beam treatment [3] are also used to improve the characteristics of the applied layer. The heat output of the welding arc is also used for remelting of the pre-deposited layer [14].…”

“…When the aim is to obtain intermetallic compounds with the metal of the substrate in the coating, this can be achieved by adding the second metal in the form of a powder [23]. High cooling rates using heat sources with high energy concentration such as electron beam surfacing (EBS) [25], [26], [27], [28] and [29] or laser surfacing (LS) [30] - [39] creates conditions for modifying the surface layer even without the use of filler materials [25] or after a surfacing process has been performed [3], [26]. The electron beam process is also used for sintering [27] of powder mixture to form layers.…”

“…In the publications reviewed, the materials used as substrates can be divided into the following main groups: carbon steels [3], [6], [7], [12], [13], [15], [16] 17, 18, 21, 25, 26, 29, 36 and 37; alloyed steels [1], [4], [8], [9], [20], [22], [24], [30], [41] and [42]; highly alloyed steels [5] and [32]; aluminium and aluminium alloys [11], [28], [39], [43], [44] and [45]; titanium and titanium alloys [23], [31], [34] and [35]; ductile cast iron [33] and [40]. The SAS, MIG / MAG, TIG, PST, EBS and LS methods were used to apply the layers to carbon steels.…”

“…In MIG / MAG overlaying [3], [9], [14], [15] and [18], core wires are commonly used. Table 4 shows the chemical composition.…”