Many wire products (e.g. nets) are made from galvanized material. The hot dip galvanizing process gives the possibility of applying in a respectively thick coat of zinc (also depending on the time of staying wires in the bath) which provides the protection of the product against corrosion. In the available literature there were no research concerned with the influence of hot dip galvanizing process on the mechanical properties TRIP structure steel wires. Therefore, an experiment was carried out in laboratory conditions allowing the determination of the influence of hot dip galvanizing process parameters on the mechanical properties (tensile strength UST and yield strength YS) of TRIP steel wires as well as on the amount of retained austenite in their structure. It has been stated that the hot galvanizing process of TRIP steel wires influences, proportionally to the time of staying wires in zinc bath, on their plastic properties (the increase in yield strength YS) as well as the decrease in the amount of retained austenite in their structure. Such a phenomenon can be caused by stresses responsible for rapid heating of the wire put in the zinc bath in temperature of 450°C and by the strengthening of the materials resulting from the transformation of retained austenite.
In this paper, an attempt was made to explain the causes of surface delamination in high carbon steel wires during the torsion test. For end wires with 1.7 mm diameter drawn at speeds of 5, 10, 15, 20, 25 m/s, technological tests were carried out. Then the susceptibility of the wire to plastic strain was determined. The microstructure analysis complemented the research. Analysis of the fracture torsion test showed that the wires drawn at speeds exceeding 15 m/s are delamination, which disqualify it as a material for a rope and a spring. The source of delamination in high carbon steel wires is their stronger strengthening, especially of the surface layer, which leads to a decrease in the orientation of the cementite laminaes and an increase in the degree of their fragmentation.
The effects of the miniature channel-shaped scratches not detectable by the present inline electromagnetic defect detection system employed for wires’ surface defect detection on the fracture behaviour of the wires for civil engineering applications were investigated numerically. Finite element analysis revealed that both miniature channel-shaped across-the-thickness and across-the-width scratches change the fracture behaviour of the wires in terms of the fracture initiation locations and fracture process sequence. However, miniature across-the-thickness scratches does not affect the fracture shape of the wire while miniature across-the-width scratches changed the wires’ cup and cone fracture to a fracture shape with a predominantly flat fracture. These results provide an understanding of the fracture behaviour of wires with miniature scratches and serve as an alternative or a complimentary tools to experimental or fractographic failure analysis of wires with miniatures scratches which are difficult to carry out in the laboratory due to the sizes of the scratches.
One of the most important parameters, crucial to applications of superconductors in cryo-electrotechnique, is power loss. Measurements of losses in superconducting long sample wires require AC magnetic fields of a special geometry and appropriate high homogeneity. In the paper part of the theoretical basis for calculations and a simple design method for a race-track coil set are presented. An example of such home-made coils, with a magnetic field uniformity of about 0.2 % over the range of about 8 cm, is given. Also a simple electronic measurement system for the determination of AC magnetization loss in samples of superconducting tapes is presented.
The results of studies on the use of modern two cored wires injection method for production of ferritic nodular cast iron (ductile iron) with use of unique implementation of drum ladle as a treatment / transport and casting ladle instead vertical treatment ladle was described. The injection of length of Ø 9mm wires, cored: in FeSi + Mg nodulariser mixture and inoculant master alloy is a treatment method which can be used to produce iron melted in coreless induction furnace. This paper describes the results and analysis of using this method for optimal production of ductile iron under specific industrial conditions. It means, that length of nodulariser wire plus treatment and pouring temperatures were optimized. In this case, was taken ductile iron with material designation: EN-GJS-SiMo40-6 Grade according EN 16124:2010 E. Microstructure of great number of trials was controlled on internally used sample which has been correlated with standard sample before. The paper presents typical ferritic metallic matrix and nodular graphite. Additionally, mechanical properties were checked in some experiments. Mean values of magnesium recovery and cost of this new method from optimized process parameters were calculated as well.