Laser cladding of NiCrBSiFe−WC coating with multichannel laser

Abstract

A metalloceramic NiCrBSiFe−WC coating on structural steel 40Kh was prepared by the method of laser cladding. The cladding was performed using a multichannel continuous СО 2 laser radiation using the complex of ALTKU3 model produced by LLC "Centre of laser technologies", the city of Vladimir. The complex includes a multichannel (40 rays) СО 2 laser with the output power of 3 kW and a technological stand with five coordinates for ray manipulation and with two ones for manipulation of the piece under processing. The prepared samples were examined metallographically. It is shown that at optimal modes a practically pore-free coating is formed with a minimal penetration into the base ensuring metallurgical fusion. According to the X-ray spectral microanalysis data the chemical composition is practically the same as that of the raw powder. In particular, the content of iron in the granules and in the matrix is nearly the same (about 4…5 %). Due to the automatization of the processing by crossed rollers the sample surface after cladding is nearly flat and only requires a slight machining. The thickness of the cladding layer is about 700 μm in one pass. No cracks in the plane of the sample were observed. The weld junction demonstrates the same structure lengthwise thus indicating a high uniformity of the heat input during the cladding. The size of the thermal effect zone in the substrate is about 450 μm. The laser cladding of the highly alloyed powder of the system NiCrBSiFe−WC onto the structural steel by means of the multichannel СО 2 laser makes it possible to obtain a high-quality wear-proof coating since, in contrast to single ray lasers, it provides a high uniformity of integral heat input in the processing zone.

Features of eddy-current testing of the fatigue degradation of laser clad cobalt-nickel-chromium coating under contact loading

“…Показано, что контроль вихретоковым методом усталостной деградации при контактном нагружении покрытия ПГ-10К-01 возможен, однако имеет определенные ограничения вследствие немонотонного изменения показаний вихретокового прибора α от числа циклов нагружения. При этом с одной стороны, возможен контроль резкого роста размера контактных повреждений, который при данных условиях нагружения происходит при 5 ×10 4 и 5 ×10 5 циклов, и обусловлен образованием большого количества периферийных кольцевых трещин в зоне разрушения и соответствующим снижением величины α вследствие роста удельного электросопротивления покрытия. С другой стороны, возможен контроль достижения определенного числа циклов нагружения в диапазоне 8 ×10 5 -1×10 6 , когда показания вихретокового прибора превысят исходные значения.…”

“…Сплавы на основе кобальта часто используются как износо-и коррозионностойкие материалы для бессмазочных систем или для работы при повышенных температурах [1][2][3][4]. Покрытия из сплавов, содержащих кобальт, по сравнению с безкобальтовыми покрытиями [5], обладают повышенной жаростойкостью, более высокой пластичностью [3] и износостойкостью [4]. При этом кобальт несколько снижает коррозионную стойкость покрытий при обычных температурах, поскольку является более активным металлом, чем никель [3,4].…”

Features of frictional treatment of the composite NiCrBSi-Cr3C2 laser clad coating

“…The formation of coatings with high-performance properties on the surface of machine parts and tools is an effective method for increasing their durability [1]. The deposition of NiCrBSi coatings is widely used for parts exposed to wear or corrosion [1][2][3].…”

“…The formation of coatings with high-performance properties on the surface of machine parts and tools is an effective method for increasing their durability [1]. The deposition of NiCrBSi coatings is widely used for parts exposed to wear or corrosion [1][2][3]. The addition of hard particles during cladding / spraying further improves the performance of NiCrBSi coatings by creating metal-matrix composite coatings based on NiCrBSi with undissolved particles during the formation of coatings [1,4,5].…”

“…The deposition of NiCrBSi coatings is widely used for parts exposed to wear or corrosion [1][2][3]. The addition of hard particles during cladding / spraying further improves the performance of NiCrBSi coatings by creating metal-matrix composite coatings based on NiCrBSi with undissolved particles during the formation of coatings [1,4,5]. Additives WC / W 2 C, SiC, TaC, VC, TiC can be used as strengthening carbide particles when creating composite coatings based on NiCrBSi [6 -8].…”