Influence of the modes of laser cladding on bond strength and wear resistance of coatings

Transcription

1 Journal of Physics: Conference Series PAPER OPEN ACCESS Influence of the modes of laser cladding on bond strength and wear resistance of coatings To cite this article: V P Birukov et al 2017 J. Phys.: Conf. Ser View the article online for updates and enhancements. This content was downloaded from IP address on 22/09/2018 at 19:43

2 Influence of the modes of laser cladding on bond strength and wear resistance of coatings V P Birukov 1, *, D Yu Tatarkin 2, E V Chriptovish 2 and A A Fichkov 1 1 Federal budget-funded research Institute for machine science named after A. A. Blagonravov of the Russian Academy of Sciences (IMASH RAN), Maly Kharitonievskiy Pereulok 4, Moscow101990, Russia 2 IPG IRE-Polus, Vvedenskogo Sq. 1, Fryazino, Moscow141190, Russia * laser-52@yandex.ru Abstract. The paper presents the results of metallographic studies and laboratory comparative tests on the adhesion strength of the coating to the substrate and abrasion on the scheme Brinell-Haworth cladding powder coatings on Nickel-based and samples of steel 40X. Strength of adhesion of the first coating layer with a hardness of HRC was MPa. It is shown that when the hardness of the deposited layer HRC wear resistance of the coatings is higher than 40X steel in the normalized and improved in 10 and 4.6 times, respectively. 1. Introduction In industry there are different methods for cladding of metals: electric arc, plasma, laser, gas, high frequency cladding and others. Each of existing methods has its advantages and disadvantages, which are characterized by specific technical and economic indicators in determining the effective areas of their application. For arc cladding in conditions of hydro-abrasive wear should be preferred deposited coating carbide phase having a higher wear resistance compared to martensite-austenitic structures [1]. After electric arc cladding the allowance on subsequent machining can reach 2 mm, which increases the complexity of manufacturing products. Modern plasma and gas-dynamic methods allow obtain coatings with porosity 1 10% [2, 3]. The allowance on machining after laser cladding should not exceed mm. In the deposited layer do not contain defects like pores, cavities and cracks. Methods of feeding the filler materials can be divided into two main groups: pre-location of the powder materials on the surface and flow directly into the treatment area simultaneously with the laser radiation [4]. A method for pre-coating by using the slip coating is characterized by high utilization of powder material. However, a more common method of feeding the powder material is forced feed directly into the molten bath of base material. Investigations of the coatings based on Nickel with a hardness of HRC, obtained by laser cladding with a gas and fiber lasers show improved wear resistance of friction sliding 2 times as much in comparison with steel 38CrNi3Mo [5, 6]. The aim of this work was to increase the utilization rate of the powder material, the determination of the strength of adhesion coatings which uses as intermediate layer and optimization laser cladding for increase abrasive wear resistance, the deposited layers. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by Ltd 1

3 2. Materials and equipment In the experiments used the universal equipment: IPG IRE-Polus with fiber laser LS-5, the robot of the company KUKA, optical head company PRECITEC. As a finishing material was chosen powders are Nickel-based firm Höganäs, Sweden and OJSC "POLEMA", Tula. The size of particle the powder was 40 to 150 µm. The laser power was varied in the range of W. The speed is of movement of the optical head abaut m/s in the transverse direction and from 1 to 15 mm/s in the longitudinal direction. In laser cladding of pre-poured the powder layer thickness 3 10 mm. The samples were cut from steel plate with dimensions of mm with electric-spark method with dimensions mm. Metallographic studies were performed with use of hardness testing of the PHT-3M, metallographic microscope Altami met-1c. The abrasion testing was carried out on the machine friction of BH-4 upgraded to IMASH RAN scheme Brinell-Haworth [7]. Samples for testing the strength of adhesion of the coating to the substrate was carried out on the testing machine "Instron" 1115 in accordance with GМ "Determination of the adhesion strength of thermal spray coating with the base metal. Guidance materials ", revised taking into account the specifics of laser cladding [8]. 3. Results and experiment Sample of the investigated material deposited on it a coating with a hardness of HRC 38 42, symmetrically on both sides mechanically processed to the width of the deposited layer in the direction of compression is 2 mm. Then the sample was mounted in a fixture and pressed through a die. Thus, under the action of shearing stresses was the cut of the deposited layer, and the shear stress determined the adhesion strength of the deposited layer to the substrate. The sample made of the base metal in the form of a plate thickness of 10 mm, a width and a length of 25 mm. Thickness of the deposited layer was mm. The results of the tests obtained values of the strength adhesion of coatings in the range of 400 to 480 MPa, depending from the processing mode. For testing technological regimes used powder firms Höganäs brand 1360 (claimed hardness HRC 58) with different thickness of the poured layer of mm. Obtained deposited layers of thickness 3 9 mm, width mm in one pass of hand robot. Figure 1 is the metallographic of a single claddings tracks. By change power, speed and diameter of the laser beam on the cladding surface had been bring to light conformity to natural laws of change micro-hardness in the deposited layer. The overlapping cladding paths is shown in figure 2. In it there are no defects like pores, cracks and cavities, as and track cladding under optimum processing conditions. Figure 1. Metallographic of a cladding a single track in a single pass 7. Figure 2. Metallographic of the overlap area of the deposited layers 10. When change mode cladding surfacing micro-hardness in the deposited layer varies widely MPa. At high energy density laser beam of alloying elements and carbon burn and microhardness in the deposited layer decreases, defects appear in the form of pores. At low values of the energy density of the laser radiation is not a complete fusion in the powder material, and reduced micro-hardness. 2

4 Table 1 shows the results of testing abrasion wear according to the scheme Brinell-Haworth. Rotating rubber disk pressed on flat sample with the deposited coating. In the friction zone was fed silica sand with a size of particle µm. The test duration was 10 minutes. By results the tests of three samples was determined average value of the mass loss of the deposited coating at each mode of processing. Table 1. Results of the Brinell-Havorth abrasion test. Powder grade Micro-hardness, MPa Loss of mass, g As a result of the carry out studies on abrasive wear of the first batch of samples were found, optimal regimes of laser cladding of powder coatings. The second batch of samples was melted with powders of different hardness and both manufacturers of powder materials. Figure 3 shows the dependence of Brinell-Havort's abrasive wear from the hardness of the deposited layer and abrasive wear of the samples 40X steel. From the given data, it follows that the cladding layers with a hardness of HRC (powders of the company Höganäs-1 and OJSC POLEMA-2) are 10 times as much than wear resistance the normalized steel 40X (HB180) and 4.6 times as much higher, than the improved steel 40Х (НВ ). Figure 3. Dependence of abrasive wear from the hardness of the deposited layer powder materials and a sample of steel 40X: 1 Höganäs, HRC 58 61; 2 OJSC POLEMA, HRC 58 61; 3 Höganäs, HRC 38 42; 4 OJSC POLEMA, HRC 38 42; 5 steel 40Х, НВ ; 6 steel 40X, HB Conclusion The technology was developed of laser cladding of powder materials on the basis of nickel with a width of the deposited layer of mm and a roller height of 3 9 mm at one pass hand of robot. The carried out tests for abrasive wear according to the Brinell-Havorth scheme showed an increase in 3

5 wear resistance of the cladding coatings by 10 times as much in comparison with the normalized steel 40X. The adhesion strength of a coating powder based on nickel with hardness of HRC was MPa. References [1] Pogodaev L I and Ezhov Y E 2014 J. of Machinery Manufacture and Reliability [2] Zabelin A M, Shiganov I and Chirkov A M 2007 Hybrid Laser Surfacing Technology (Moscow: MGOU) in Russian [3] da Costa Alves Borges B M F 2008 Laser Cladding Using Filler Powder and Wire. Productivity and Quality Ph.D. thesis Technical University of Lisbon [4] Grigoryants A G and Misyurov A I 2005 Tekhnologiya Mashinostroeniya [5] Biryukov V P and Dozorov A V 2006 J. of Machinery Manufacture and Reliability 1 60 [6] Biryukov V P, Lapteva V G and Khrennikova I A 2013 Problems of mechanical engineering and reliability of machines 5 1 [7] Khrushchov M M and Babichev M M 1970 Abrasion wear (Moscow: Nauka) in Russian [8] Biryukov V P 2014 Proc. of GOSNITI