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Analiza porównawcza własności dwóch niekonwencjonalnych superwytrzymałych stali typu maraging do zaawansowanych zastosowań konstrukcyjnych

Pawlak Stanisław Jerzy

Stal, Metale & Nowe Technologie

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2021

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nr 1-2

32--36

PL

W artykule analizowano własności i mikrostrukturę dwóch wytapianych próżniowo niekonwencjonalnych stali typu maraging: wysokokobaltowej (0,23C-11,5Ni-13,4Co-1,5Mo) i bezkobaltowej (19Ni-4Mo-1Ti). Obie stale miały granicę plastyczności wynoszącą powyżej 1600 MPa i odporność na pękanie (K1C) wyższą od 70 MPa·m1/2. Bardzo wysokie wartości wytrzymałości i odporności na pękanie uzyskane dla badanych stali umożliwiają wykorzystywanie ich do wielu zaawansowanych zastosowań konstrukcyjnych.

EN

The article analyses the properties and microstructure of two unconventional vacuum melted maraging steels: high-cobalt (0.23C-11.5Ni- -13.4Co-1.5Mo) and cobalt-free (19Ni-4Mo-1Ti). Both steels had the yield strength of above 1600 MPa and the fracture toughness (K1C) of over 70 MPa·m1/2. The very high strength and fracture toughness values obtained for the tested steels make them suitable for many advanced structural applications.

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Microstructure, properties and hot deformability of the new maraging steels

Pawlak S. J., Zalecki W.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 29, nr 1

31-38

EN

Purpose: The effects of relevant metallurgical factors on the structure, fracture mode and properties of the high cobalt and cobalt free maraging steel has been studied. The aim was to better understand structure-property relations and enhance mechanical properties of the steels. To provide data needed for production and manufacturing technology, the high temperature deformability using physical simulation method was used. Design/methodology/approach: To study structure-property relation, broad range of the experimental techniques was used: quantitative metallography, X-ray diffraction phase analysis, transmission electron microscopy and SEM fractography. The flow properties in the range of hot working processes were determined by physical simulation approach, using Gleeble 3800 system. Findings: The cobalt-free maraging steel proved to be a valuable structural steel. At much higher fracture toughness it had only about 100 MPa lower yield stress, compared to that of high cobalt steel. Fracture surface morphologies were highly dependent on the steel grade and type of the mechanical test. The hot stress-strain characteristics were established for cobalt free maraging steel and compared to that of a stainless steel. Research limitations/implications: To fully evaluate potential field of applications, deeper comparative studies of the high cobalt and cobalt-free maraging steels are needed, particularly fracture modes and service properties of some parts. Practical implications: Very high mechanical properties and fracture toughness values obtained for the steels studied, make them suitable for advanced structural applications. The studies on the hot deformation behaviour of the steels are of practical value for the hot working process development. Originality/value: Detailed evaluation of the metallurgical purity, microstructure and fracture modes, allowed for better understanding of the microstructure-property relationships in selected high strength steels. The results obtained are of practical value for the development, production and manufacture of the high strength maraging steels with improved properties.

3

Microstructure and properties of vacuum melted high cobalt and cobalt-free maraging steels

Pawlak S. J.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 27, nr 1

31-34

EN

Purpose: Steel cleanliness, microstructure and fracture mode have been studied, with the aim of enhancing mechanical properties and toughness of the high cobalt and cobalt-free maraging steels. Design/methodology/approach: To fully evaluate all relevant metallurgical factors affecting steel mechanical properties and toughness, broad range of the experimental techniques was used: quantitative metallography, X-ray diffraction, TEM and SEM fractography. Findings: Purity of the laboratory vacuum melted steels was similar to that of foreign industrial steels of the aircraft quality. It was showed that cobalt-free maraging steel could achieve properties comparable to the steel with very high cobalt content. Fracture surface morphologies were highly dependent on the steel grade and type of the mechanical test. In higher strength, the high cobalt steel fractures were generally more flat and more ductile than in the Co-free steel, particularly in the impact test. Research limitations/implications: Further comparative studies of the high cobalt and cobalt-free maraging steels are required on the properties, fracture modes and service properties of a selected parts. Practical implications: Very high mechanical properties and fracture toughness values obtained for the steels studied, are suitable for advanced structural applications. Originality/value: Detailed evaluation of the metallurgical purity, microstructure and fracture modes, allowed for better understanding of the microstructure-property relationships in selected high strength steels. The results obtained are of practical value for the development and production of the high strength steels with improved properties.