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1

The Effect of Si and Mn on Microstructure and Selected Properties of Cr-Ni Stainless Steels

Kalandyk B., Zapała R., Starowicz M.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

192--196

EN

Cast stainless steel of the Cr-Ni duplex type is used, among others, for the cast parts of pumps and valves handling various chemically aggressive media. Therefore, the main problem discussed in this article is the problem of abrasion wear resistance in a mixture of SiC and water and resistance to electrochemical corrosion in a 3% NaCl- H2O solution of selected cast steel grades, i.e. typical duplex cast steel, high silicon and manganese duplex cast steel, and Cr-Ni austenitic cast steel (type AISI 316L). The study shows that the best abrasion wear resistance comparable to Ni-Hart cast iron was obtained in the cast duplex steel, where Ni was partially replaced with Mn and N. This cast steel was also characterized by the highest hardness and matrix microhardness among all the tested cast steel grades. The best resistance to electrochemical corrosion in 3% NaCl- H2O solution showed the cast duplex steel with high content of Cr, Mo and N. The addition of Ni plays rather insignificant role in the improvement of corrosion resistance of the materials tested.

2

Effects of Rare Earth Metal Addition on Wear Resistance of Chromium-Molybdenum Cast Steel

Kasińska J., Kalandyk B.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

63--68

EN

This paper discusses changes in the microstructure and abrasive wear resistance of G17CrMo5-5 cast steel modified with rare earth metals (REM). The changes were assessed using scanning microscopy. The wear response was determined in the Miller test to ASTM G75. Abrasion tests were supplemented with the surface profile measurements of non-modified and modified cast steel using a Talysurf CCI optical profilometer. It was demonstrated that the modification substantially affected the microstructure of the alloy, leading to grain size reduction and changed morphology of non-metallic inclusions. The observed changes in the microstructure resulted in a three times higher impact strength (from 33 to 99 kJ/cm2) and more than two times higher resistance to cracking (from 116 to 250 MPa). The following surface parameters were computed: Sa: Arithmetic mean deviation of the surface, Sq: Root-mean-square deviation of the surface, Sp: Maximum height of the peak, Sv: Maximum depth of the valley, Sz: Ten Point Average, Ssk: Asymmetry of the surface, Sku: Kurtosis of the surface. The findings also indicated that the addition of rare earth metals had a positive effect on the abrasion behaviour of G17CrMo5-5 cast steel.

3

The influence of residual stress in selected non-oxide ceramics composites on their wear resistance in different environments

Pędzich Z., Grabowski G., Saferna I., Ziąbka M., Gubernat A., Kot M.

Composites Theory and Practice

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2015

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R. 15, nr 4

203--208

EN

The application of structural non-oxide ceramics is at present a common trend in machines and the construction of mechanical devices. Dense ceramic sinters made of silicon carbide or silicon nitride very often replace metallic parts. The advantages of ceramics are especially evident when they work as parts of machinery exposed to the action of loose and hard particles. The paper compares the abrasive wear susceptibility of both the mentioned phases and two particulate composites made on SiC and Si3N4 matrices. Two types of tests were performed. The Dry Sand Test, which indicates the wear susceptibility of the material to wear during the abrasive action of hard particles without any lubricant, was the first one. The Miller Test was the second. This test examined the wear of materials during the action of hard particles in a wet environment (pulp). In both tests the same abrasive, silicon carbide powder, was used.

PL

Zastosowanie ceramiki nietlenkowej jest obecnie powszechnym trendem w konstruowaniu części maszyn i urządzeń. Gęste spieki z węglika krzemu i azotku krzemu bardzo często zastępują części metaliczne. Zalety materiałów ceramicznych są wyraźnie widoczne wówczas, gdy części maszyn są narażone na działanie luźnych, twardych cząstek. Prezentowany artykuł porównuje podatność na zużycie ścierne obu wymienionych faz, a także kompozytów na ich osnowach. Wykonano dwa rodzaje testów zużycia. Pierwszy to tzw. Dry Sand Test, który mierzy podatność na zużycie ścierne luźnym ścierniwem, w warunkach suchych, bez smarowania. Drugim testem był tzw. test Millera, który pozwala uzyskać informacje na temat zużywania się materiałów podczas działania luźnych, twardych cząstek w środowisku mokrej pulpy, tj. gęstej zawiesiny. W obu testach użyto tych samych ziaren ściernych, gruboziarnistego węglika krzemu.

4

Wear resistance of 18%Cr-9%Ni steel used for cast parts of pumps operating in corrosive – erosive environments

Kalandyk B.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 3

841--844

EN

This paper presents the results of experimental studies, the main aim of which has been to demonstrate that changes in the microstructure of austenitic 18%Cr-9%Ni cast steel provoked by the addition of 1.4% boron, and boron with titanium, give increased wear resistance. After melting the high-alloyed 18%Cr-9%Ni cast steel with an addition of boron, and boron with titanium, metallographic examinations were conducted using light microscopy and SEM. These examinations revealed in the austenitic structure of the 18%Cr-9%Ni cast steel, the presence of a eutectic rich in boron and chromium, and characterised by a microhardness of 1838-1890 μ HV20 . Additionally, in the cast steel inoculated with boron and titanium, the presence of titanium nitride precipitates was observed. Changes that have occurred in the microstructure as a result of introducing the additions of boron, and boron with titanium, also caused an increase of the cast steel hardness from 212 HV30 to 290-320 HV30 and 320-350 HV30, respectively. To determine the abrasive wear resistance, 16-hour Miller test was performed (ASTM G 75-07), wherein the abrasive medium was a mixture of SiC and water. Obtaining the hard, rich in boron and chromium, eutectic and titanium nitride precipitates in the structure of 18%Cr-9%Ni cast steel increased the abrasive wear resistance by approximately 21%, according to the data recorded in the sixteenth hour of the test cycle. As an additional benchmark point for the results obtained served the wear resistant, structural, L35GSM steel used for castings working in difficult conditions. Comparing the values of abrasive wear resistance obtained for the 18%Cr-9%Ni cast steel and cast L35GSM steel, an increase in the wear resistance of the 18%Cr-9%Ni cast steel by about 35% has been proved.

PL

W artykule przedstawiono wyniki badań eksperymentalnych, których celem było wykazanie, że zmiany w mikrostrukturze austenitycznego staliwa 18%Cr-9%Ni na skutek wprowadzenie dodatku 1,4% boru oraz boru i tytanu skutkują zwiększeniem odporności na zużycie. Po wytopieniu wysokostopowego staliwa 18%Cr-9%Ni z borem oraz z dodatkiem boru i tytanu przeprowadzono badania metalograficzne z wykorzystaniem mikroskopu świetlnego i skaningowego. Badania te wykazały obecność w austenitycznej strukturze staliwa 18%Cr-9%Ni eutektyki bogatej w bor i chrom, o mikrotwardosci 1838-1890 μHV20: W staliwie modyfikowanym borem i tytanem dodatkowo stwierdzono obecność wydzieleń azotków tytanu. Zmiany jakie zaszły w mikrostrukturze po wprowadzeniu dodatków boru oraz boru i tytanu spowodowały również wzrost twardości staliwa z 212 HV30 odpowiednio do 290-320 HV30 oraz do 320-350 HV30 . Do określenia odporności na zużycie ścierne wykonano 16-godzinny test Millera (ASTM G 75-07), w którym medium ścierającym była mieszanina SiC i wody. Uzyskanie twardej eutektyki bogatej w bor i chrom oraz wydzieleń azotków tytanu w strukturze staliwa 18%Cr-9%Ni doprowadziło do zwiększenia odporności na ścieranie o około 21% w 16 godzinie cyklu badań. Dodatkowym punktem odniesienia uzyskanych wyników było odporne za zużycie, konstrukcyjne staliwo L35GSM stosowane na odlewy pracujące w trudnych warunkach. Porównując otrzymane wyniki odporności na zużycie ścierne staliwa 18Cr-9%Ni oraz staliwa L35GSM wykazano, wzrost odporności na zużycie staliwa 18%Cr-9%Ni o około 35%.

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Zastosowanie matematycznego modelu kinetyki zużycia skumulowanego w warunkach testu Millera

Kalandyk B.

Archiwum Odlewnictwa

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2002

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R. 2, nr 4

376--383

PL

W pracy porównano wyniki skumulowanych ubytków masy otrzymane w próbie Millera z danymi obliczonymi wg matematycznego modelu kinetyki zużycia [1]. Weryfikację modelu przeprowadzono w środowisku mieszaniny SiC-woda, na wybranych gatunkach staliwa węglowego i stopowego. Na podstawie przeprowadzonych badań stwierdzono dużą zgodność wyników obliczeń z danymi eksperymentalnymi w całym zakresie trwania testu.

EN

The results of measurement by Miller test and calculated by theoretical equations of cast steel weight losses are compared. The mathematical model of weight losses have been verified for ten grades cast steels. All grades were tested in SiC – water slury. Total test duration was 16 hours and mass loses were recorded in each 4 hours of test. The results of wear losses predicted by mathematical model [1] are more close with experimental data obtained by Miller test, than calculations based on equation (3).