Low Temperature Plasma Nitriding of Inner Surfaces in Stainless Steel Mini-/Micro-Pipes and Nozzles

Aizawa, Tatsuhiko; Wasa, Kiyotaka

doi:10.3390/mi8050157

Cited by 14 publications

(14 citation statements)

References 11 publications

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“…As demonstrated in [9][10][11], the corrosion toughness was also improved in these nitrogen supersaturated stainless steels. Furthermore, inner surfaces and small holes in the dies and punches are efficiently nitrided and hardened with more ease than coatings [12,13]. These intrinsic features of low-temperature plasma nitriding were accommodated to miniature tools, and even parts, by scaling down the chamber size [14,15]; e.g., the hollow cathode device assisted the high-density plasma nitriding process in the smaller chamber systems.…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Plasma Nitriding of Mini-/Micro-Tools and Parts by Table-Top System

Aizawa

Morita²,

Wasa

2019

Applied Sciences

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Miniature products and components must be surface treated to improve their wear resistance and corrosion toughness. Among various processes, low-temperature plasma nitriding was employed to harden the outer and inner surfaces of micro-nozzles and to strengthen the micro-springs. A table-top nitriding system was developed even for simultaneous treatment of nozzles and springs. A single AISI316 micro-nozzle was nitrided at 673 K for 7.2 ks to have a surface hardness of 2000 HV0.02 and nitrogen solute content up to 10 mass%. In particular, the inner and outer surfaces of a micro-nozzle outlet were uniformly nitrided. In addition, the surface contact angle increased from 40° for bare stainless steels to 104° only by low-temperature plasma nitriding. A stack of micro-nozzles was simultaneously nitrided for mass production. Micro-springs were also nitrided to improve their stiffness for medical application.

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Section: Introductionmentioning

confidence: 99%

Low-Temperature Plasma Nitriding of Mini-/Micro-Tools and Parts by Table-Top System

Aizawa

Morita²,

Wasa

2019

Applied Sciences

Self Cite

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“…This prevents plastic and elastic deformations of the tool surface as well as brittle rupture of the deposited coating [8][9][10]. The combined strengthening of cutting tools based on the vacuum arc, which includes pre-nitriding and deposition of the wear-resistant coating, can be carried out in the same vacuum chamber [11,12]. The tools are immersed in nitrogen plasma and heated up to an effective temperature of thermodiffusion 500-800 • C by ions accelerated from the plasma by a negative bias voltage applied to the tools.…”

Section: Introductionmentioning

confidence: 99%

Equipment and Technology for Combined Ion–Plasma Strengthening of Cutting Tools

et al. 2018

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Y.A.M.); m.volosova@stankin.ru (M.A.V.)Abstract: A combined strengthening of cutting tools for finishing has been carried out in glow discharge plasma filling a process vacuum chamber. At the first stage, reamers rotating around the axis distanced from the magnetron targets at 8 cm were bombarded by fast argon atoms produced due to charge exchange collisions of ions accelerated in space charge sheathes between the plasma and a negatively biased to 3 kV grid with a 25 cm radius of its concave surface curvature. The reamer bombardment by fast neutral atoms led to a reduction of its cutting-edge radius from~7 µm to~2 µm. At the second stage, the reamer surface was nitrided within 1 h at a temperature of 500 • C stabilized by regulation of the negative bias voltage accelerating the nitrogen ions. At the third stage, a 3 µm thick TiN coating has been synthesized on the reamer bombarded by pulsed beams of 3 keV neutral atoms at a 50 Hz repetition rate of 50 µs wide pulses. After the combined strengthening, the cutting edge radius of the coated reamer amounted to~5 µm and the roughness of the area machined by the reamer holes in blanks made of structural steel reduced by about 1.5 times.

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“…A review of foreign [1][2][3][4][5][6][7][8] and Russian [9][10][11][12] studies shows that heating parameters for concentrated sources with a high energy density are chosen on the basis of deep penetration welding procedures [2][3][4] or determined empirically [5]. After a part is hardened, a hardness profile of the hardened layer is measured using a destructive method.…”

Section: Introductionmentioning

confidence: 99%

“…This requires considerable time and money. The most common techniques include low-temperature plasma nitriding [2,3] and plasma heat treatment [4,11]. The key factors influencing hardening of steel parts, however, have not yet been established.…”

Section: Introductionmentioning

confidence: 99%

Calculation of hardening process parameters for locomotive parts

et al. 2018

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The existing theoretical models of heating by concentrated sources with a high energy density generally describe processes with deep penetration welding of part surfaces. The purpose of this study is to identify the factors that have a major effect on hardening of parts through heat treatment with a high-speed or pulsed scanning stationary heat source, which creates a uniform temperature field. Using methods of regression analysis, the authors derived equations for calculating the hardening depth in the proposed hardening process, the rate and time of steel cooling in a critical temperature range. The paper presents the calculated parameters of the hardening process in which parts, including wheel flanges of locomotives, are heated by a plasma arc in nitrogen. The findings can be used to reduce costs of complex experiments aimed at selecting surface heat hardening parameters to increase the service life of locomotive mechanical parts.

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Low Temperature Plasma Nitriding of Inner Surfaces in Stainless Steel Mini-/Micro-Pipes and Nozzles

Cited by 14 publications

References 11 publications

Low-Temperature Plasma Nitriding of Mini-/Micro-Tools and Parts by Table-Top System

Low-Temperature Plasma Nitriding of Mini-/Micro-Tools and Parts by Table-Top System

Equipment and Technology for Combined Ion–Plasma Strengthening of Cutting Tools

Calculation of hardening process parameters for locomotive parts

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