Study of the Formation of the Alloyed Surface Layer During Plasma Heating of Mixtures of Cu-Sn/CrXCY Alloys

Abstract

In this work, to assess the possibility of obtaining an alloyed layer by plasma heating of the mixture of the PRV-BrO10 alloy and the coating of the welding electrode OK 84.78. The study of the structure is given using the optical microscope MET-2 and the measurement of microhardness -hardness testers of the HMV-G series. It is established that with a thin layer of pre-coating, the coatings are completely saturated, and with a thick layer -the formed zones are different in microstructure and microhardness. In the case of 0.25 mm precoating thickness, the addition of chromium carbide leads the strong increasing of the hardness compared to tin-bronze alone. In the case of 0.50 mm pre-coating thickness, for the upper soft zone rich in copper, the average microhardness value is below 250 HV, and for hard particles in this zone in the range of 500-700 HV, the lower saturated zones have high hardness in a wide range . The slow scanning speed of the torch and a thick layer of pre-coating are the reason for incomplete saturation and the appearance of defects on the surface of St3 steel.

Study of Wear of an Alloyed Layer with Chromium Carbide Particles after Plasma Melting

“…The testing time for one sample with a fused layer was 3 h. During the first 90 min of the test process, the wear hole parameters were measured every 10 min. The wear volume V (cm 3 ) was calculated using the Formula (1) [12,16]:…”

“…However, in practice, the created alloys of the Fe-Cu system often have a number of disadvantages: layered and heterogeneous structure, limited hardness, a high probability of defects, and a tendency to pitting due to the formation of galvanic vapors between iron and copper [5][6][7][8]. Successful results of steel-bronze pseudo-alloys and surface alloying of cast iron with copper indicate the possibility of creating Fe-Cu-Sn system coatings with improved hardening properties on the surface of parts and tools [9][10][11][12][13][14][15].…”

“…Most works study the alloying factors of bronze [10][11][12][19][20][21][22]. In [12,22], plasma melting of a bronze-chromium alloy was used.…”

“…Most works study the alloying factors of bronze [10][11][12][19][20][21][22]. In [12,22], plasma melting of a bronze-chromium alloy was used. An increase in the hardness of the composition and an increase in wear resistance when tested for abrasive wear on a fixed abrasive was shown.…”

“…In terms of energy and technical and economic indicators, one of the effective methods of surface hardening of metals using highly concentrated sources is plasma alloying [8,[12][13][14][15][16][17][18][23][24][25][26][27][28][29][30][31][32][33][34]. Plasma treatment has a number of advantages: short processing time; high efficiency factor (efficiency); sequential heat treatment is not always required; low requirements for surface preparation before processing; and low cost of equipment [23,24,26,[35][36][37][38][39][40].…”