Mieczysław Kuder

MECHANICAL PROPERTIES OF HIGH-ALLOYED, DISPERSION-HARDENED, MARTENSITIC CAST STEEL AFTER MULTI-STAGE HEAT TREATMENT

Abstract

High-alloyed Cr-Ni-Cu cast steel with additions of Mo and Nb and high nitrogen content was melted. The cast test ingots were subjected to a heat treatment. Metallographic examinations were made under an optical microscope and mechanical properties were determined. The most effective heat treatment cycles applied to the examined cast steel have proved to be the following ones: to obtain maximum hardness - solution heat treatment from 1060°C and tempering at 500°C, to obtain maximum strength - solution heat treatment and double tempering at 600°C. To obtain maximum elongation and impact resistance - quenching from 950°C followed by tempering at 600°C.

Keywords: martensitic cast steel, nitrogen, heat treatment, strength, impact resistance,

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Mieczysław Kuder

AN ASSESSMENT OF NITROGEN CONTENT EFFECT ON THE MECHANICAL PROPERTIES OF MARTENSITIC CAST STEEL

Abstract

The GX5CrNiCu16-4 martensitic cast steel with graded nitrogen content comprised in a range of 0,064-0,12% was melted; the chemical composition, including oxygen and nitrogen content, was determined. Test bars were subjected to two variants of the heat treatment. Metallographic examinations of the structure were made, impact fractures were examined, the chemical composition of some non-metallic inclusions was determined, and the mechanical properties as well as the erosive wear resistance were tested. It has been stated that increased nitrogen content raises the hardness and tensile strength (Rm) of cast steel after both variants of the heat treatment; the erosive wear resistance increases only after tempering at 500°C. The impact resistance of cast steel after both variants of the heat treatment has its maximum at a content of about 0,09% N.

Keywords: martensitic cast steel, nitrogen, tensile strength, impact resistance, erosive wear,

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Jacek Krokosz, Rafał Pabiś, Ewa Wiłkojć, Jan Kostecki, Andrzej Fudal

CHEMICAL COMPOSITION OF THE 16th – 18th CENTURY GUN BARRELS AND CANNON BALLS FROM AN ARMOURY OF THE ROYAL WAWEL CASTLE IN CRACOW EXAMINED BY X-RAY MICROFLUORESCENCE ANALYSIS

Abstract

The principles of operation of a portable X-ray microfluorescence analyser of the chemical composition were described. A short characteristic of the Niton device was also given. Examples of chemical compositions of the gun barrels from past centuries examined in different countries were specified and compared with the results of the chemical composition measurements made on the gun barrels kept in an Armoury of the Royal Wawel Caste in Cracow.

Keywords: analyser of chemical composition, X-ray microfluorescence,

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Robert Żuczek, Stanisław Pysz, Aleksander Karwiński

FROM FORGING TO CASTING – A CONVERSION IN BOTH MATERIAL AND DESIGN

Abstract

The study presents an analysis of the possibilities to change the fabrication technology of a rocker for automotive applications, changing also the type of material used for this element. The application of high-strength ductile iron enabled this element to be redesigned, resulting finally in the production of a grille-type, thin-walled, casting. The proposed modifications reduced the weight of the element without any harm to its mechanical properties.

Keywords: numerical simulation, ductile iron, conversion into casting,

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