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1

Structure and properties of forming austenitic X5CrNi18-9 stainless steel in a cold working

100%

Ozgowicz W. , Kurc A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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tom Vol. 33, nr 1

19-26

EN

Purpose: The aim of the paper is to analyze the influence of the degree of rolling reduction on the structure forming and changes of mechanical properties in cold-rolled sheet-metals of austenitic X5CrNi18-9 stainless steel. Design/methodology/approach: The examinations contained metallographic observations of the structure on a light microscope and on the scanning electron microscope (SEM), researches of mechanical properties in a static tensile test and microhardness measurements made by Vickers’s method. The analysis of the phase composition was carried out on the basis of X-ray researches. In the qualitative X-ray analysis the comparative method was applied. Fractographic tests of the fracture after the decohesion of samples in a static tensile test at room temperature were executed in a SEM. Findings: It has been found that plastic deformation in a cold working of austenitic stainless steel type X5CrNi18-9 induced in its structure martensitic transformation . › .’. The occurrence of martensite phases .’ in the investigated steel structure has an essential meaning in manufacturing process of forming sheet-metals from austenitic steel. Research limitations/implications: The X-ray phase analysis in particular permitted to disclose and identify the main phases on the structure of the investigated steel after its deformation within the range from 10% to 70%. Moreover, the results of the X-ray quantitative analysis allowed to determine the proportional part of martensite phases .` in the structure of investigated steel in the examined range of cold plastic deformation. Practical implications: The analysis of the obtained results permits to state that the amount of martensite phases .` in the investigated steel structure increases with the degree of deformation in the cold rolling. Besides, a good correlation was found between changes of the structure and the effects of investigations of the mechanical properties. Originality/value: Good correlation between changes of the structure and the effects of investigations of the mechanical properties in the austenitic X5CrNi18-9 stainless steel was found.

2

Influence of cold rolling on the corrosion resistance of austenitic steel

80%

Kurc A. , Kciuk M. , Basiaga M.

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tom Vol. 38, nr 2

154-162

EN

Purpose: The paper analyzes the effects of plastic deformation in cold working process on the corrosion resistance, micro-hardness and mechanical properties of austenitic stainless steel X5CrNi18-10. Design/methodology/approach: Corrosion resistance of X5CrNi18-10 steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 87 days. The evaluation of the corrosion behaviour of investigated steel in the potentiodynamic method was realized by registering of anodic polarization curves. The VoltaLabŽ PGP 201 system for electrochemical tests was applied. The tests were carried out at room temperature in electrolyte simulating artificial sea water (3.5% NaCl). Registering of anodic polarization curves was conducted at the potential rate equal to 1 mV/s. As the reference electrode the saturated calomel electrode (SCE) was applied, the auxiliary electrode was platinum electrode. Mechanical properties were evaluated on the basis of the static tensile and Vickers micro-hardness test. The observations of the surface morphology after corrosive tests were carried out using Scanning Electron Microscope SUPRA™25. Findings: According to the results of potentiodynamic analyses it was found that plastic deformation in a cold working of austenitic steel grade X5CrNi18-10 affected to lower its corrosion resistance in 3.5% NaCl solution, what has an essential meaning in industrial applications of this group of materials. Research limitations/implications: The microscope observations of the surface samples subjected to corrosion resistance test in 3.5% NaCl solution permitted to evaluate types and the rate of corrosion damages. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of a special group of steels. Originality/value: The corrosion behaviour in chloride solution of a Cr-Ni austenitic stainless steel was investigated.

3

Structure and corrosion resistance of aluminium AlMg2.5; AlMg5Mn and AlZn5Mg1 alloys

80%

Kciuk M. , Kurc A. , Szewczenko J.

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tom Vol. 41, nr 1-2

74-81

EN

Purpose: The aim of the work was the evaluation of corrosion resistance and structure of aluminium AlMg2.5; AlMg5Mn and AlZn5Mg1 alloys. Design/methodology/approach: The corrosion resistance tests of investigated alloys were carried out by means of potentiodynamic method registering anodic polarization curves in 3.5% NaCl solution at room temperature. Registering anodic polarization curves was conducted at the potential rate equal to 1mV/s. As the reference electrode was used saturated calomel electrode (SCE) and the auxiliary electrode was platinum electrode. Mechanical properties were evaluated on the basis of Vickers hardness test. The test was realized with the use of Hauser hardness tester. The observations of the surface morphology after corrosive tests were carried out using Digital Scanning Electron Microscope DSM 940 OPTON. Findings: The investigations of corrosion resistance of examined aluminium alloys shows that the highest corrosion resistance in 3.5% NaCl solution was observed for AlZn5Mg1 aluminium alloy. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of analysed alloys because better corrosion resistance, lightweight of aluminium and its alloys makes them as most attractive for the steel replacement in shipbuilding. Originality/value: The corrosion behaviour in chloride solution of AlMg2.5; AlMg5Mn and AlZn5Mg1 alloys was investigated.