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Acidic Corrosion Behaviour of Niobium-Added Welding Overlays Fabricated by Self-Shielded Metal-Cored Wires

Liu Dashuang, Wu Yucheng, Long Weimin, Wei Ping, Wang Rui, Zhou Wei

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

887--894

EN

Both corrosion and abrasion remove materials from some engineering components such as impact coal crusher hammers, pulverizer rings, chute liner, and rolls or molds. Intensive research has been done on improving the wear resistance of high chromium alloys, however, studies into corrosion resistance of high chromium alloys are insufficient. In order to determine the amount of ferroniobium addition in the wire to achieve the best corrosion resistance, and find out the mechanism of ferroniobium enhancing the corrosion resistance of the welding overlays, the high-Cr iron-based welding overlays with different niobium addition were fabricated by using self-made self-shielded metal-cored wires and their acidic corrosion resistance in 3.5 wt.% NaCl solution + 0.01 mol/L HCl solution were investigated by electrochemical corrosion test. The microstructure and corrosion morphology were characterized by OM, SEM, XRD and EDS. The polarization curves and values of Icorr, Ecorr and Rc indicate the corrosion resistance is at the highest with 3.6 wt.% niobium addition, and at the lowest when the niobium addition is 10.8 wt.%. The corrosion of welding overlay occurs in the matrix of microstructure. With the increase of niobium addition from 3.6 wt.% to 10.8 wt.%, the proportion of network eutectic structure in the welding overlay is increased. Up to 10.8 wt.%, the microstructure is transformed from hypereutectic structure into eutectic one, leading to a higher acceleration of corrosion rate. When niobium addition reaches 14.4 wt.%, the welding overlay is transformed into a hypoeutectic structure. The addition of niobium element consumes carbon element in the alloy, which makes the increase of chromium content in the final solidified matrix, leading to an improvement in corrosion resistance.

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Distribution of the Polymer Melt Velocity and Temperature in the Spinneret Channel of Bi-component Fibre Melt Spinning: a Mathematical Model

Feng Pei, Liu Dashuang, Zhang Ronggen, Yang Chongchang

Fibres & Textiles in Eastern Europe

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2021

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Vol. 29, no. 6 (150)

49--53

EN

For the stability of composite fibre spinning, the difference in and distribution of the polymer melt velocity during the spinning are among the factors of importance. Based on the basic equation for the control of composite spinning dynamics, boundary conditions are identified and reported in this paper. A mathematical model for the symmetric and asymmetric distribution of the melt flow velocity in the microhole of the spinneret of the composite spinning assembly was developed. The accuracy of the mathematical model was also ascertained. It gives a theoretical basis for the designing of a composite spinning assembly.

3

High Efficiency Covering Technology for Covered Yarn Production: Controlling the Spandex Yarn Draw Ratio

Feng Pei, Liu Dashuang, Yang Chongchang

Fibres & Textiles in Eastern Europe

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2020

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Vol. 28, no. 6 (144)

24--28

EN

This paper proposes a new covered yarn system in which the tension of spandex elastic yarn drawing is controlled. By analysing the relationship between the draw ratio and yarn tension, it was verified that the new tension controlled drawing system is feasible and results in yarns of superior quality and process stability.

PL

W pracy zaproponowano nowy system wytwarzania przędzy oplatanej, w którym kontrolowane jest naprężenie rozciągania przędzy elastycznej spandex. Analizując zależność między współczynnikiem rozciągania a naprężeniem przędzy, zweryfikowano, że zaproponowany system ciągnienia z kontrolowanym naprężeniem jest wykonalny i zapewnia wytworzenie przędzy o najwyższej jakości z zachowaniem stabilności procesu.