Assessment of the wear resistance of surfacing materials for hardening parts of crushing grinding equipment
Year: 2024
Type: article
Abstract: Introduction. Parts made from Hadfield steels are used in many important applications such as drilling, railways, crushers, etc. However, their replacement during service is costly. To extend the service life of such parts, welding and surfacing are used. For this purpose, a comparative assessment of the use of various surfacing materials in the process of surfacing steel 110G13L on a steel substrate was carried out to reduce wear of parts of crushing equipment. Materials and methods. For surfacing, flux-cored wires with a diameter of 1.6 mm were used: PP-NP80Kh20R3T; PP-NP30Kh4G2M, differing in the content of chromium, carbon and boron. Chemical composition of wires PP-NP80Х20Р3Т; PP-NP30Kh4G2M according to GOST 26101-84. Average hardness after surfacing according to certificate a for wire: PP-NP80Kh20R3T – HRC 57.25 HRC; PP-NP30Kh4G2M – HRC 48.6.To perform surfacing, a standard set of equipment for welding and surfacing in shielding gases was used. Surfacing was carried out using a gas mixture Ar/CO2 82/18. Gas supply volume is 10–15 liters. Current, 190–210 A. Voltage, 21–24 V. Welding speed, 8–11 mm/s. The microstructure was characterized using a Micro-med 2 optical microscope. Micro-hardness measurements along the top surface of the cladding layers towards the substrate were performed using a TMVS-1 microhardness tester with a load of 1.96 N and a holding time of 15 s for each. Wear tests were carried out using an MLD-10 abrasive testing device. Results. The microstructure of the two reinforcement layers consists of both a large number of dendrites and inter-crystalline connections, with the exception of some blocky or rod-like particles. The content of elements C, Cr and Fe in dendrites is slightly lower than in inter-crystalline compounds. It can be concluded that the microstructure of the two deposited metal layers consisted of a typical Fe–Cr–C hypoeutectic microstructure. Namely, the dendrites were austenite, and the inter-crystalline compounds were eutectic carbides γ-(Cr,Fe)7C3.Analysis of the microstructures of the deposited layer and base c also shows that the overlapped cladding layer consists of coarser austenite and less eutectic carbides than the point cladding layer. This indicates that the dilution rate of the overlapped cladding layer was higher than that of the dotted cladding layer. In the multi-track overlap process, the thermal input was higher and the thermal accumulation was stronger. This resulted in a longer molten pool lifetime and thus a longer austenite growth time and a higher dilution rate of the cladding layer. The average micro-hardness of the lap cladding layer and the spot cladding layer was about 650 and 840 HV0.2, respectively. The wear resistance of the deposited layers is 2–3 times higher than that of Hatfield steel. Conclusion. There were two clear differences between the two wires used. One was that the micro-hardness of the deposited coating layer for PP-NP80Kh20R3T wire was approximately 150 HV0.2 higher than that of the coating layer for PP-NP30Kh4G2M wire. Increasing the microhardness of the coating layer was useful for improving its resistance to gouging when exposed to abrasive. Resume. The use of surfacing wires to increase wear resistance for application to Hadfield steel parts used in ore grinding machines is a significant factor in increasing operational durability and reducing costs associated with replacement and repair.1. The microstructure of the strengthening layer on a steel substrate with 110G13L consists of a hypoeutectic Fe–Cr–C microstructure. The reinforced Fe–Cr–C layer can improve the impact abrasive wear resistance of Hadfield steel under wear conditions of various natural materials. 2. Analysis of the micro-hardness of the deposited layers with PP-NP80Kh20R3T and PP-NP30Kh4G2M wires showed values between 7800 and 860 HV, values much higher than those of the Hadfield substrate, about 250 HV. Suggestions for practical applications and directions for future research. This high hardness is due to the high content of chromium carbides dispersed throughout the martens tic matrix.3. Conducted industrial tests showed an increase in the service life of the welded blows by at least 2 times, which significantly reduces operating costs during rock crushing operations.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4408831385