Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in... more Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in power plants. Increased requirements for quality and safety of welded joints in certain service conditions require achieving a series of mechanical and structural properties of welded joints. This paper presents the results of microstructure, grain size, hardness and impact test in the HAZ in the welded samples of thickness 10 mm are welded MMA and MAG. Hardness testing of welded joints according to standard BAS EN 1043-1 and microstructure examination in places where it tested the hardness of HAZ show some differences in the mechanical and metallographic properties of the applied welding processes.
Precipitation hardening at low temperature is a heat treatment in which
the material is hardened... more Precipitation hardening at low temperature is a heat treatment in which
the material is hardened by the precipitation of secondary phases from a solid solution. The first degree of hardening of steel 17-7PH is the transformation of austenite
into martensite. Cryogenic heat treatment of this material offers the possibility of
obtaining a suitable combination of martensite and austenite. The microstructural
constituents of martensite, austenite and delta ferrite were determined using an
optical light microscope and the Feritoscope. The mechanical properties were
determined at room and high temperature. Fire resistance testing of 17-7PH steel
with high chromium and nickel content to show that it retains its high strength at
high temperatures
M. Oruč, University of Zenica, Zenica, B and H; J. Duraković, S. Muhamedagić, University of Zenic... more M. Oruč, University of Zenica, Zenica, B and H; J. Duraković, S. Muhamedagić, University of Zenica, Faculty of Metallurgy and Materials Science, Zenica, B and H; B. Fakić, M. Rimac, University of Zenica, Metallurgical Institute „Kemal Kapetanović“, Zenica, B and H In this paper is given the research conducted at the specified quality screws which had different mechanical properties after completion of the same heat treatment. Results of chemical and metallographic analysis and hardness tests indicated the deficiencies that can be corrected in the course of production and thermal processing of finished products screws.
Precipitation hardening stainless steel 17-7PH with modified chemical composition was heat treate... more Precipitation hardening stainless steel 17-7PH with modified chemical composition was heat treated by modified RH950 condition. In this paper is presented the results of tests of microstructure and mechanical properties of precipitation hardened stainless steel 17-7PH with modified chemical composition, heat treated in modificated RH950 conditions. Regression analysis showed which variables are statistically significant in predicting the value of mechanical properties of the steel 17-7PH chemically modified composition.
Possibilities of the application of new materials in the automotive industry place challenges in ... more Possibilities of the application of new materials in the automotive industry place challenges in front of researchers of our times. Modification of the chemical composition and different variants of heat treatment allows achieving improved mechanical properties. Steel 17-7PH is austenitic-martensitic steel with high strength (750-1500 MPa) and hardness (34-49HRC), which is achieved by controlled phase transformation and complex heat treatment of precipitation strengthening. In this paper, through the results of tensile properties of steel 17-7PH for condition TH1050 and modified condition RH 950 obtained at room temperature, the influence of heat treatment will be presented. 1. INTRODUCTION Stainless steel are defined as iron based alloys containing at least 10,5% chromium and a maximum of 1,2 % carbon. Stainless steels may contain nickel as another major alloying element, with a content of up to 38%, plus other alloying elements and stabilisers. The chromium content renders stainle...
Metallic glasses are metastable amorphous structures produced by quenching-rapid cooling techniqu... more Metallic glasses are metastable amorphous structures produced by quenching-rapid cooling technique. Due to very high cooling rates during the production process, it is very difficult to produce homogeneous samples with identical chemical composition. In this paper we will present preliminary results of homogeneity and structure examinations of a CuZrAlY metallic glass ribbon. The ribbon, approximately 1.5 m long and 1 mm wide, was produced using melt spinning technique. Samples from the middle and the end of the ribbon were chosen for further examination. Surface was checked by metallographic and electron scanning microscopy. Chemical composition in different areas of each sample was checked by energy-dispersive X-ray spectroscopy. Electrical resistivity measurements in the temperature range from 80 K to 280 K were also conducted.
Additional strengthening of superalloy N07080 described in this work was achieved by warm rolling... more Additional strengthening of superalloy N07080 described in this work was achieved by warm rolling. Control of the ratio of strength and ductile properties of the superalloy is possible by appropriate selection of the amount of warm deformation and the appropriate selection of the partial recrystallization temperature. In addition, recrystallization annealing makes it possible to equalize the grain size across the cross section of the warm rolled bars, which before recrystallization differ significantly in size in the central and peripheral parts of the bars.
The material of journal end wall for cement mill is cast steel GS-20Mn5, WNo: 1.1120 according to... more The material of journal end wall for cement mill is cast steel GS-20Mn5, WNo: 1.1120 according to standard DIN 17182. The journal end wall is made from two separately cast part - the plate and the cylinder, which are joined by welding. Inhomogeneity in the rough cast microstructure of materials, inadequate heat treatment of normalization, large nonmetallic inclusions and porosity together with dynamic loading during exploitation adversely affected the work of the journal end wall and lead to cracking of the material.
This paper provides an overview of the development of research in the design of semi austenitic s... more This paper provides an overview of the development of research in the design of semi austenitic stainless steel 17-7PH, with a focus on research mechanism of precipitation hardening, assessment of the current situation in the field of development of the steel and new possibilities for research in this area.
ABSRACT Dry machining and near-dry machining were developed as an alternative to flood and intern... more ABSRACT Dry machining and near-dry machining were developed as an alternative to flood and internal high-pressure coolant supply to reduce metal working fluids consuption. In dry machining, compressed air introduces into the cutting zone, while near-dry machining supplies very small quantities of lubricant into the cutting zone. Both these techniques have been introduced with the aim to reduce the use traditional coolant and lubricant. One of the many dry machining techniques is the usage of cooled compressed air. SEM and metallographic analysis of the chip during dry machining are presented in this paper. Machining tests were performed by turning of three grade of workpiece materijal: alloyed steel, aluminium bronze, and pure aluminium. Three ways of dry machining are performed: machining without the use of coolant and lubricant, cold air dry machining and with a cooling of workpiece before machining. Analysis of produced chips shows some advantages of dry machining, mainly in the ...
Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in... more Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in power plants. Increased requirements for quality and safety of welded joints in certain service conditions require achieving a series of mechanical and structural properties of welded joints. This paper presents the results of microstructure, grain size, hardness and impact test in the HAZ in the welded samples of thickness 10 mm are welded MMA and MAG. Hardness testing of welded joints according to standard BAS EN 1043-1 and microstructure examination in places where it tested the hardness of HAZ show some differences in the mechanical and metallographic properties of the applied welding processes.
Modern trends in the development of automotive industry, constantly setting new requirements in t... more Modern trends in the development of automotive industry, constantly setting new requirements in terms of improving the work and performance of the engine. Research has mainly focused on increasing the mechanical and exploitation properties of materials used to operate at elevated temperatures. One possibility is a new procedure to modify the surface of ferrous super alloys A286, applying metallic coatings NiCrAlY, and using HVOF (High velocity oxyfuel) procedure Diamond Jet.
Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in... more Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in power plants. Increased requirements for quality and safety of welded joints in certain service conditions require achieving a series of mechanical and structural properties of welded joints. This paper presents the results of microstructure, grain size, hardness and impact test in the HAZ in the welded samples of thickness 10 mm are welded MMA and MAG. Hardness testing of welded joints according to standard BAS EN 1043-1 and microstructure examination in places where it tested the hardness of HAZ show some differences in the mechanical and metallographic properties of the applied welding processes.
Precipitation hardening at low temperature is a heat treatment in which
the material is hardened... more Precipitation hardening at low temperature is a heat treatment in which
the material is hardened by the precipitation of secondary phases from a solid solution. The first degree of hardening of steel 17-7PH is the transformation of austenite
into martensite. Cryogenic heat treatment of this material offers the possibility of
obtaining a suitable combination of martensite and austenite. The microstructural
constituents of martensite, austenite and delta ferrite were determined using an
optical light microscope and the Feritoscope. The mechanical properties were
determined at room and high temperature. Fire resistance testing of 17-7PH steel
with high chromium and nickel content to show that it retains its high strength at
high temperatures
M. Oruč, University of Zenica, Zenica, B and H; J. Duraković, S. Muhamedagić, University of Zenic... more M. Oruč, University of Zenica, Zenica, B and H; J. Duraković, S. Muhamedagić, University of Zenica, Faculty of Metallurgy and Materials Science, Zenica, B and H; B. Fakić, M. Rimac, University of Zenica, Metallurgical Institute „Kemal Kapetanović“, Zenica, B and H In this paper is given the research conducted at the specified quality screws which had different mechanical properties after completion of the same heat treatment. Results of chemical and metallographic analysis and hardness tests indicated the deficiencies that can be corrected in the course of production and thermal processing of finished products screws.
Precipitation hardening stainless steel 17-7PH with modified chemical composition was heat treate... more Precipitation hardening stainless steel 17-7PH with modified chemical composition was heat treated by modified RH950 condition. In this paper is presented the results of tests of microstructure and mechanical properties of precipitation hardened stainless steel 17-7PH with modified chemical composition, heat treated in modificated RH950 conditions. Regression analysis showed which variables are statistically significant in predicting the value of mechanical properties of the steel 17-7PH chemically modified composition.
Possibilities of the application of new materials in the automotive industry place challenges in ... more Possibilities of the application of new materials in the automotive industry place challenges in front of researchers of our times. Modification of the chemical composition and different variants of heat treatment allows achieving improved mechanical properties. Steel 17-7PH is austenitic-martensitic steel with high strength (750-1500 MPa) and hardness (34-49HRC), which is achieved by controlled phase transformation and complex heat treatment of precipitation strengthening. In this paper, through the results of tensile properties of steel 17-7PH for condition TH1050 and modified condition RH 950 obtained at room temperature, the influence of heat treatment will be presented. 1. INTRODUCTION Stainless steel are defined as iron based alloys containing at least 10,5% chromium and a maximum of 1,2 % carbon. Stainless steels may contain nickel as another major alloying element, with a content of up to 38%, plus other alloying elements and stabilisers. The chromium content renders stainle...
Metallic glasses are metastable amorphous structures produced by quenching-rapid cooling techniqu... more Metallic glasses are metastable amorphous structures produced by quenching-rapid cooling technique. Due to very high cooling rates during the production process, it is very difficult to produce homogeneous samples with identical chemical composition. In this paper we will present preliminary results of homogeneity and structure examinations of a CuZrAlY metallic glass ribbon. The ribbon, approximately 1.5 m long and 1 mm wide, was produced using melt spinning technique. Samples from the middle and the end of the ribbon were chosen for further examination. Surface was checked by metallographic and electron scanning microscopy. Chemical composition in different areas of each sample was checked by energy-dispersive X-ray spectroscopy. Electrical resistivity measurements in the temperature range from 80 K to 280 K were also conducted.
Additional strengthening of superalloy N07080 described in this work was achieved by warm rolling... more Additional strengthening of superalloy N07080 described in this work was achieved by warm rolling. Control of the ratio of strength and ductile properties of the superalloy is possible by appropriate selection of the amount of warm deformation and the appropriate selection of the partial recrystallization temperature. In addition, recrystallization annealing makes it possible to equalize the grain size across the cross section of the warm rolled bars, which before recrystallization differ significantly in size in the central and peripheral parts of the bars.
The material of journal end wall for cement mill is cast steel GS-20Mn5, WNo: 1.1120 according to... more The material of journal end wall for cement mill is cast steel GS-20Mn5, WNo: 1.1120 according to standard DIN 17182. The journal end wall is made from two separately cast part - the plate and the cylinder, which are joined by welding. Inhomogeneity in the rough cast microstructure of materials, inadequate heat treatment of normalization, large nonmetallic inclusions and porosity together with dynamic loading during exploitation adversely affected the work of the journal end wall and lead to cracking of the material.
This paper provides an overview of the development of research in the design of semi austenitic s... more This paper provides an overview of the development of research in the design of semi austenitic stainless steel 17-7PH, with a focus on research mechanism of precipitation hardening, assessment of the current situation in the field of development of the steel and new possibilities for research in this area.
ABSRACT Dry machining and near-dry machining were developed as an alternative to flood and intern... more ABSRACT Dry machining and near-dry machining were developed as an alternative to flood and internal high-pressure coolant supply to reduce metal working fluids consuption. In dry machining, compressed air introduces into the cutting zone, while near-dry machining supplies very small quantities of lubricant into the cutting zone. Both these techniques have been introduced with the aim to reduce the use traditional coolant and lubricant. One of the many dry machining techniques is the usage of cooled compressed air. SEM and metallographic analysis of the chip during dry machining are presented in this paper. Machining tests were performed by turning of three grade of workpiece materijal: alloyed steel, aluminium bronze, and pure aluminium. Three ways of dry machining are performed: machining without the use of coolant and lubricant, cold air dry machining and with a cooling of workpiece before machining. Analysis of produced chips shows some advantages of dry machining, mainly in the ...
Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in... more Low alloy steel 16Mo3 designed to operate at elevated temperatures has a very wide application in power plants. Increased requirements for quality and safety of welded joints in certain service conditions require achieving a series of mechanical and structural properties of welded joints. This paper presents the results of microstructure, grain size, hardness and impact test in the HAZ in the welded samples of thickness 10 mm are welded MMA and MAG. Hardness testing of welded joints according to standard BAS EN 1043-1 and microstructure examination in places where it tested the hardness of HAZ show some differences in the mechanical and metallographic properties of the applied welding processes.
Modern trends in the development of automotive industry, constantly setting new requirements in t... more Modern trends in the development of automotive industry, constantly setting new requirements in terms of improving the work and performance of the engine. Research has mainly focused on increasing the mechanical and exploitation properties of materials used to operate at elevated temperatures. One possibility is a new procedure to modify the surface of ferrous super alloys A286, applying metallic coatings NiCrAlY, and using HVOF (High velocity oxyfuel) procedure Diamond Jet.
Steel 17-7PH is austenitic-martensitic steel with high strength (750-1500 MPa) and hardness (34-4... more Steel 17-7PH is austenitic-martensitic steel with high strength (750-1500 MPa) and hardness (34-49HRC), which is achieved by controlled phase transformation and complex heat treatment of precipitation strengthening. In this paper, the influence of heat treatment will be presented through the results of microstructure of steel 17-7PH for condition TH1050 and modified condition RH 950 obtained at room temperature,. Microhardness in white zones (austenite) shows difference between martensite and austenite hardness value.
Rezime
Metali su polikristalni materijali i sastoje se od velikog broja zrna, odnosno kristala. ... more Rezime
Metali su polikristalni materijali i sastoje se od velikog broja zrna, odnosno kristala. Veličina zrna ima veliki utjecaj na svojstva metala i to na: tvrdoću, zateznu čvrstoću, izduženje, udarnu žilavost, dinamičku čvrstoću, proces ojačavanja, mašinsku obradu... Obzirom da se postupcima livenja, deformacijom na toplo i hladno te žarenjem može utjecati na veličinu zrna, određeni standardi za proizvode propisuju granične vrijednosti veličine zrna. Mjerenjem veličine zrna može se utvrditi da li je određeni proces dobro proveden. U ovom radu su date uporedne metode određivanja veličine primarnog austenitnog zrna kod niskolegiranog čelika 100CrMn6, dobivenog postupkom oksidacije – prema tački A3.2.1.5. standarda ASTM E 112. Uporedne metode koje su korištene za određivanje veličine zrna su metoda poređenja, planimetrijska metoda i metoda intersepta.
SAŽETAK:
Tvrdoća je važno svojstvo metalnih ma... more SAŽETAK:
Tvrdoća je važno svojstvo metalnih materijala, koje daje dosta informacija o materijalu, na osnovu kojih se mogu odrediti ostala mehanička svojstva. U ovom radu su predstavljeni rezultati ispitivanja tvrdoće precipitaciono ojačanog nehrđajućeg čelika 17-7PH sa modifikovanim hemijskim sastavom u stanju nakon termičkih tretmana TH1050 i RH950. Regresiona analiza je pokazala koje su varijable statistički značajne za predviđanje vrijednosti tvrdoće HV10 u čeliku 17-7PH sa modifikovanim hemijskim sastavom.
Hardness is an important property of metallic materials, which gives a lot of information about the material on the basis of which to define other mechanical properties. In this paper is presented the results of tests of hardness of precipitation hardened stainless steel 17-7PH with modified chemical composition, heat treated in conditions TH1050 and RH950. Regression analysis showed which variables are statistically significant in predicting the value of the hardness HV10 of the steel 17-7PH chemically modified composition.
Uploads
Papers by Belma Fakić
the material is hardened by the precipitation of secondary phases from a solid solution. The first degree of hardening of steel 17-7PH is the transformation of austenite
into martensite. Cryogenic heat treatment of this material offers the possibility of
obtaining a suitable combination of martensite and austenite. The microstructural
constituents of martensite, austenite and delta ferrite were determined using an
optical light microscope and the Feritoscope. The mechanical properties were
determined at room and high temperature. Fire resistance testing of 17-7PH steel
with high chromium and nickel content to show that it retains its high strength at
high temperatures
the material is hardened by the precipitation of secondary phases from a solid solution. The first degree of hardening of steel 17-7PH is the transformation of austenite
into martensite. Cryogenic heat treatment of this material offers the possibility of
obtaining a suitable combination of martensite and austenite. The microstructural
constituents of martensite, austenite and delta ferrite were determined using an
optical light microscope and the Feritoscope. The mechanical properties were
determined at room and high temperature. Fire resistance testing of 17-7PH steel
with high chromium and nickel content to show that it retains its high strength at
high temperatures
Metali su polikristalni materijali i sastoje se od velikog broja zrna, odnosno kristala. Veličina zrna ima veliki utjecaj na svojstva metala i to na: tvrdoću, zateznu čvrstoću, izduženje, udarnu žilavost, dinamičku čvrstoću, proces ojačavanja, mašinsku obradu...
Obzirom da se postupcima livenja, deformacijom na toplo i hladno te žarenjem može utjecati na veličinu zrna, određeni standardi za proizvode propisuju granične vrijednosti veličine zrna. Mjerenjem veličine zrna može se utvrditi da li je određeni proces dobro proveden.
U ovom radu su date uporedne metode određivanja veličine primarnog austenitnog zrna kod niskolegiranog čelika 100CrMn6, dobivenog postupkom oksidacije – prema tački A3.2.1.5. standarda ASTM E 112. Uporedne metode koje su korištene za određivanje veličine zrna su metoda poređenja, planimetrijska metoda i metoda intersepta.
Tvrdoća je važno svojstvo metalnih materijala, koje daje dosta informacija o materijalu, na osnovu kojih se mogu odrediti ostala mehanička svojstva. U ovom radu su predstavljeni rezultati ispitivanja tvrdoće precipitaciono ojačanog nehrđajućeg čelika 17-7PH sa modifikovanim hemijskim sastavom u stanju nakon termičkih tretmana TH1050 i RH950. Regresiona analiza je pokazala koje su varijable statistički značajne za predviđanje vrijednosti tvrdoće HV10 u čeliku 17-7PH sa modifikovanim hemijskim sastavom.
Ključne riječi: čelik 17-7PH, tvrdoća, regresija, precipitaciono ojačavanje
ABSTRACT:
Hardness is an important property of metallic materials, which gives a lot of information about the material on the basis of which to define other mechanical properties. In this paper is presented the results of tests of hardness of precipitation hardened stainless steel 17-7PH with modified chemical composition, heat treated in conditions TH1050 and RH950. Regression analysis showed which variables are statistically significant in predicting the value of the hardness HV10 of the steel 17-7PH chemically modified composition.
Keywords: steel 17-7PH, hardness, regession, precipitation hardening