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Development the High-Carbon Wire for Cutting Hard-Brittle Material and Research on the Organization and Performance of the Wire

Author: CaiWei
Tutor: JiangLiQiang
School: Zhejiang University of Technology
Course: Materials Science
Keywords: high carbon steel wire sorbite pearlite drawing strengthen
CLC: TG356.46
Type: Master's thesis
Year: 2011
Downloads: 80
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Abstract

Cutting is the key process of hard-brittle material processing, the cost of cutting processing accounted for nearly half the cost. Diamond wire saw is the main form of solar wafer cutting. Therefore, the wire for cutting as the most critical supplies is of concern. Deformed by cold drawing to obtain high-strength steel has become the main form of preparation of cutting wire. With decreasing the thickness of silicon wafer, wire diameter is getting smaller, but the corresponding strength is increasing. In recent years, The researchers attached importance to the preparation of high strength steel wire, and they had breakthrough in production of steel wire rod. However, Currently in finished wire for solar wafer cutting (line diameter less than 0.12 mm) research is still relatively lack. In addition, domestic steel wire exist problems such as unstable. Therefore, in order to meet the market demand, this paper is devoted to the development production quality stable, tiny diameter, high strength wire.This paper summarizes domestic production of high-strength steel wires, especially in-depth research high strength steel wire for cutting solar wafer. The main studies are as follow: analyze the structure of the wire before cold drawing, through the optical microscope and scanning electron microscopy to observe the organization during the process, build organizational evolution model, research steel wire strengthen process, probe into strengthening mechanisms, and get the best production technology at last.The results of the study show that SWRH82A high-carbon wire that the sorbite content is as high as 99% was used as raw materials, which was drawn fromΦ0.893mm toΦ0.12mm, percent reduction in area reached 98.2%. And the tensile strength was improved form 1000MPa nearly to 4000Mpa. During process of deep plastic deformation, the sorbite tend to be consistent with the direction of the drawing axis by distorting, bending and fracture. Grains were refined and fibrous shaped, interlamellar spacing of sorbite decreased correspondingly from the initial 70-120nm into 10-50nm. For parallel to the orientation of drawing axial or lamellar already tended to the direction of the drawing axis, interlamellar spacing of sorbite and Wire Diameter exist relationship dε= (d0 / D0)×Dε=d0 exp(-ε/2) With the increasing of drawing strain, tensile strength of wire was improved. The process of Strengthen included four steps and the effect of each steps was different. When ture strainεwas between 1 20 and 2 32, there were linear relationship (ln? ? ?) between tensile strength and strain. Through the study of aging temperature and aging time, the production process was determined. The area reduction was less than 30% before the lamellae aligned along the drawing axis. And the area reduction was less than 20% at the last two steps. Wire strength is nearly improved 5.4% after being tempered at 200℃for 30min. The strength of wire was close to 3800MPa finally.

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