*The type of stainless steel were 316L, the diameter of the fiber were 12 micron.

Transcription

1 Advanced Materials Research Submitted: ISSN: , Vol. 1053, pp Accepted: doi: / Online: Trans Tech Publications, Switzerland Property Analysis of Stainless Steel Fiber (yarn) and its Effect on Knitting Process SUN Yuchai 1, 2, a 1, 2, b and CHENG Zhong 1 College of Textile & Clothing Engineering, Soochow University, Suzhou , China; 2 Nantong Soochow University Textile Research Institute, Nantong , China a sunyuchai@suda.edu.cn, b czhcheng@suda.edu.cn Keywords: stainless-steel, strength, elongation, friction, hairiness, knitting Abstract. In this paper the frictional and tensile properties of stainless-steel fiber, cotton fiber, polyester fiber and rayon fiber, as well as the tensile and surface hairy properties of stainless-steel yarn, cotton yarn and wool yarn were tested and compared. Experimental results shown that the stainless-steel fiber has greater density, friction coefficient and tensile breakage strength but smaller breaking elongation. On the basis of summarizing the differences between stainless-steel fiber (yarn) and conventional textile fibers (yarns), difficulties occurred during knitting process were analyzed and the corresponding solutions were proposed. Introduction Metal fibers have advantages of the inherent properties of metal material. Presented by stainless-steel fiber and Fe-Cr-Al (iron-chrome-alumina) fiber, metal textiles are now becoming more and more popular in the many fields as anti-static, anti-radiation, shape memory, filter, sound absorbing materials and so on. With the advance of material science, the equivalent diameter of stainless-steel fiber could be processed as fine as 1-2µm[2] which made the textile manufacturing processing possible. But the differences of spinning feasibility and fabrication feasibility between stainless steel and conventional textile materials are the main reason that caused difficulties during manufacturing process of knitting of pure stainless steel fiber. Loop construction and curved three-dimensional structure made knitting fabric more elastic, and more effective than woven and non-woven fabric in many fields. When used as separated cloth between glass (such as windshield and headlights of an automotive vehicle) and mould during high-temperature processing, knitting fabric did not left marks on the glass surface. Knitted fabric could cover mould better because the fabric could be draped better on mould surface and less or no folds would be created when bending the fabric, especially on three-dimensionally shaped surface. Besides, in many fields such as high-temperature smoke filter and dust removal, knitted stainless-steel fabric has advantages which other materials and fabrics could not provide. In this paper, stainless-steel fiber and yarn were selected as subjects of the study while cotton, wool, polyester, viscose fibers and cotton, wool yarns as the comparative objects. The tensile and frictional properties of selected fibers, tensile and hairy property of the selected yarns were tested. In the analysis, on the bases of comparing the differences between stainless-steel and conventional textile materials, difficulties during knitting of stainless-steel yarn were analyzed, and corresponding solution and countermeasures were suggested. Performance characteristics of stainless-steel fiber and yarn Mass density, tensile properties and frictional properties of stainless-steel fiber and yarn were obviously different from traditional textile material. Mass density. Mass density of pure stainless steel fibers was far greater than conventional textile fibers. Result of the comparison between stainless-steel fiber and conventional textile fibers were shown in Table 1. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-04/03/16,20:58:56)

2 94 Current Research on Functional Materials Table1 Comparison of mass density between stainless-steel and conventional textile fibers [1,4] Fiber Mass density[g/cm 3] Fiber Mass density[g/cm 3] Polyester Acrylic 1.17 Silk Polyamide Flax 1.49 Viscose 1.50 Cotton 1.54 Stainless-steel[5] 7.98* *The type of stainless steel were 316L, the diameter of the fiber were 12 micron. Data in table 1 indicated that the mass density of the stainless steel fibers was 5-8 times that of conventional textile fibers. Frictional properties. During knitting, yarn mainly friction with three kinds of material: friction with steel when yarn friction with steel machine components; friction with rubber when yarn friction with rubber yarn feeding strips and friction with yarn itself during yarn unwinding form bobbins and when the forming loop pass through the pre-formed loop during loop formation. Fiction properties of stainless-steel fiber with these three kinds of material were tested. During the simulated exam, stainless-steel fiber and the comparative conventional textile fibers fractioned with steel roller, rubber roller, fiber roller winded by the tested fiber respectively. Frictional properties were tested using Y151 fibers friction coefficient tester. Results were shown in table2. Table2 Comparison of friction coefficient between stainless-steel and conventional textile fibers Stainless-steel against-scale along-scale Polyester Cotton viscose S* D* S D S D S D S D S D Steel roller Rubber roller Fiber roller *S represents static friction coefficient; D represents dynamic friction coefficient Data in table 2 indicated that: 1) Friction with steel roller, static friction coefficient of stainless-steel fiber was about 7-37% higher than textile fibers while the dynamic friction coefficient about 6%-30% higher. 2) Friction with rubber roller, static friction coefficient of stainless-steel fiber was about 8-37 % higher than the textile fibers while the dynamic friction coefficient about 20-39% higher. 3) Friction with fiber roller, static friction coefficient of stainless-steel fiber was about 23-49% higher than the conventional textile fibers while the dynamic friction coefficient about 29-63% higher. The minimum friction coefficient differences occurred in dynamic friction when fiber friction with steel roller and maximum differences occurred in dynamic friction when fiber friction with rubber roller. Tensile properties. Tensile properties of fibers were analyzed. Breaking strength and breaking elongation of stainless-steel fiber and the comparative conventional textile fibers, cotton, viscose, polyester, were tested by using electronic single fiber strength and elongation tester YG001. Results were shown in table 3.

3 Advanced Materials Research Vol Table 3 Comparison of tensile properties between stainless-steel and conventional textile fibers Stainless-steel Cotton Viscose Polyester Breaking force(cn) Breaking elongation(%) Data in table 2 indicated that the breaking strength of stainless-steel fiber was about 2-4 times of the conventional textile fibers while the breaking elongation about 1/3-1/8 times of the conventional textiles fibers. Tensile properties of yarns were also analyzed. Breaking strength and breaking elongation of both stainless-steel yarn and the comparative conventional textile yarns, cotton and wool, were tested by using yarn strength and elongation tester XL -1. Results were shown in table 4. Table 4 Comparison of tensile properties between stainless-steel and conventional textile yarns Stainless-steel 11Nm/2 Stainless-steel 16 Nm/2 Cotton 21Ne 56Nm 32Nm Breaking force (CN) Breaking elongation (%) Data in Table 3 and Table 4 showed that Stainless steel yarn exhibit similar tendency as the fiber. The difference was that yarn showed greater difference of breaking strength, the strength of stainless-steel was about 6-9 times of the conventional textile fibers. But the breaking elongation of stainless-steel was improved and the difference between stainless-steel and conventional textile yarns reduced to 1/3--1/5 times. Hairiness on the yarn. Hairiness is the fiber ends or ring sticking out from the surface of yarn. It was defined by the cumulative number of hairiness which is longer than a certain length on one side of the yarn. Hairiness has negative effect on textile processing. Hairiness of both stainless-steel yarn and the comparative conventional textile yarns, cotton and wool, were tested by using hairiness tester YG172. Results were shown in table 5. Table 5 Comparison of hairiness between stainless-steel yarn and conventional textile yarns Hairiness(mm) Nm/2 Stainless-steel Ne Cotton Nm Nm Data in table 5 showed that hairiness, especially longer hairiness, of stainless-steel yarn was much more than conventional textile yarns. Hairiness longer than 5mm was about 3-30 times, longer than 2mm was times, longer than 1 mm was times of conventional textile yarns. Influence on knitting process and suggested corresponding countermeasures Performance differences between stainless steel and traditional textile material were the main influential factors that caused difficulties during the knitting of stainless steel fiber. The problems were mainly reflected in the following three aspects.

4 96 Current Research on Functional Materials Effect of fiber mass density. Mass density of pure stainless steel fibers was 5-8 times that of conventional textile fibers. The significant impact on knitting process caused by excessive density of stainless-steel was mainly in: 1) Would cause poor bobbin forming, so the thickness of yarn on bobbin could not be too thick; 2) Would cause yarn drooping during knitting, so special attention should be paid to shorten the length of free yarn during knitting. Effect of surface properties. The experimental results showed that surface properties of stainless-steel characterized by: 1) Biggest friction coefficient of stainless-steel fiber occurred during the static friction with rubber. Special attention should be given to positive yarn feeding process. If necessary, think about replace the rubber strip by steel strip during positive yarn feeding; 2)Higher friction coefficient occurred when stainless-steel yarn rubbed with the yarn itself which happened during yarn unwinding and loop formation; 3) More hairiness, especially longer hairiness, of yarn than conventional textile yarns would cause difficulties during yarn unwinding and loop formation. In order to improve the above problems, special attention should to be paid to improve the unwinding condition during yarn feeding process. Suggestion about the effective method to solve the problems caused by higher friction coefficient and longer hairiness during loop formation was to reduce the number of needle work simultaneously. Effect of tensile properties. The experimental results showed that both stainless-steel fiber and yarn have higher breaking strength and lower breaking elongation. Poor extensibility was the main reasons that created difficulties during knitting process. Corresponding measures to solve these problems was integrated design of production process and fabric structure. Summary Through comparative analysis it was concluded that significant performance differences between stainless-steel fiber (yarn) and conventional textile material characterized in greater mass density, higher friction coefficient, lower breaking elongation and more long hairiness. For a smoothly knitting process, special attention should be paid to the yarn unwinding process, positive yarn feeding process and loop formation process. Acknowledgment This work was supported by Nantong Science & Technology Bureau(BK ); Priority Academic Program of Jiangsu Higher Education Institutions. References [1] Xi Zhengpin, Research on Properties of Textile Stainless Steel Fiber, Rare Metal Materials and Engineering, 31(2002) [2] Zhou Juan, Xiao Yude, Development Research of Metal Fiber Industry, Hunan Nonferrous Metals, 24(2008) [3] Knitted stainless steel, Advances in Textiles Technology, 4(2002). [4] Yan Mu, Textile Materials, China Textile & Apparel Press, Beijing, (2009). [5] Information on

5 Current Research on Functional Materials / Property Analysis of Stainless Steel Fiber (Yarn) and its Effect on Knitting Process /