The paper describes the behavior of welded joints of NN-70 steel in the presence of a cracking error when bending with impact force. The experiment was performed with three groups of test tubes, depending on the cut-off point of the test tube notch with the tip of the crack in BM, in WM and in HAZ. The test method used was conducted on the instrume...

By NERMIN BIŠĆEVIĆ

The basic characteristics of the chemical composition of steel with improved machinability (X8CrNiS18-9) are the increased content of sulphur (0.15-0.45%), phosphorus (0.07-0.11%) and manganese (0.5-1.5%). Sulphur by creating sulphide inclusions reduces friction and cutting resistance, and increases the brittleness of the chip.Considering its harmf...

By DERVIŠ MUJAGIĆ, AIDA IMAMOVIĆ, MUSTAFA HADŽALIĆ

 In modern times, the science of materials cannot be imagined without metallography. The history of metallographic testing in Bosnia and Herzegovina is primarily related to Zenica. Today, most of the research related to the metal industry in BiH is conducted in laboratories at the Kemal Kapetanović Institute in Zenica. The Institute's Metallog...

By BELMA FAKIĆ, ADISA BURIĆ, EDIB HOROZ

The HK30Nb steel pipe casting was obtained by centrifugal casting. This steel is austenitic stainless steel grade AISI HK 30 and is standardized according to ASME SA-351 in as cast condition. HK 30 Nb steels not standardized i.e. it is HK 30 steel modified with niobium. In addition to the required mechanical properties, this steel is also tested fo...

By MIRSADA ORUČ, ALEN DELIĆ, ALMAIDA GIGOVIC-GEKIC, RAZA SUNULAHPAŠIĆ

Metallurgical coke as a fuel, reducing agent and permeable material in high-pressure processes must have pronounced strength and granulation properties due to expected changes in high temperature conditions. The best quality of metallurgical coke is achieved when coal mixtures satisfy a certain range of rheological parameters. The characterization ...

By SULEJMAN MUHAMEDAGIĆ, AMINA KURTOVIĆ, AZRA HALILOVIĆ

The ore consolidation process is a thermal process and it happens at the temperatures of the ore melting beginning, allowing the ore grains, additives and fluxes to be connected into a solid piece of sinter. The amount of carbon in the sinter mixture and the FeO content of the produced sinter affect the mechanical resistance of the sinter. Indicato...

By SULEJMAN MUHAMEDAGIĆ, MIRSADA ORUČ, AMNA KARIĆ

Metallic materials thanks to the excellent combination of data on material properties are obtained by standardized and agreed testing of samples made from semi-finished or finished products. Metallic materials can be tested by different testing techniques. One of them is metallographic testing, for which a light microscope is used as a basic device...

By ADISA BURIĆ, BELMA FAKIĆ, EDIB HOROZ, MIRSADA ORUČ

Some specific aspects in positioning of the re-heating furnaces at a layout of different rolling mills, for a period of about last hundred years in rolling mills practice are presented in this paper. Practical solutions in the above mentioned (a.m.) field are presented for the different rolling mills. Some of the a.m. aspects are explained, confirm...

By OMER BEGANOVIĆ, FAIK UZUNOVIĆ

Some specific aspects in positioning of the re/heating furnaces at a layout of the modern rolling mills are presented in this paper. Theoretical and practical solutions in the above mentioned (further a.m.) field are presented for both, wire rod and light section bar mills. Some of the a.m. aspects are explained, confirming that even unexpected sol...

By OMER BEGANOVIĆ, FAIK UZUNOVIĆ

Proper calibration of the device is important to prevent potential sources of error, which ensures that the test results most effectively represent the value of the sample being tested. In microhardness testing, the loading force does not exceed 1.96 N. The test surface requires a more complex metallographic preparation, and the smaller the injecti...

By EDIB HOROZ, BELMA FAKIĆ, ADISA BURIĆ, MIRSADA ORUČ

Dual phase steels are low carbon steels which are thermo-mechanically processed to getting better formability and toughness than ferrite-perlite steels with similar tensile strength. The microstructure of these steels consisting of a ferrite matrix with hard martensitic/ bainitic second phase. The concept of representative volume element (RVE) is c...

By EMINA VARDO, AIDA IMAMOVIĆ, JESSICA GOLA

Many researches are done for finding various ways of improving steel properties, since it's the most used material in the world. Instead of using high-alloyed steels, which are expensive, microalloying of carbon steels that will retain equal properties is an efficient replacement. For this research it was tested melts of low-carbon steel grade SAE ...

By AIDA IMAMOVIĆ, ADNA PULJIĆ, OMER KABLAR

This work aims at the development of low-carbon steel SAE 1006 through the microalloying addition of boron. Boron as alloying element is added in small amount, but it has significant effect on changes of properties of this kind of steel. The research is based on mechanical and microstructural testing of final product (wire) from the aspect of the i...

By AIDA IMAMOVIĆ, ALMA PULJIĆ, OMER KABLAR

The chemical composition of casting is an important factor affecting the shape of graphite and the mechanical properties and microstructure of the metal base. Different elements have different influence to casting properties. All elements that affect the microstructure development during casting solidification have significant influence on mechanic...

By AIDA IMAMOVIĆ, HASAN AVDUŠINOVIĆ, ANIDA HENJAKOVIĆ

Steel 67SiCr5 is a alloyed carbon steel usually used for production of springs. It is used for load bearing springs, ring-shape springs, spiral springs, anti vibration springs etc. Springs steels are usually distribute in annealed or hardened and tempered state. Heat treating could be performed before or after springs forming. In this article, the ...

By ALMAIDA GIGOVIĆ-GEKIĆ, JUSUF DURAKOVIĆ, HASAN AVDUŠINOVIĆ

The precipitation of sigma (σ) phase in austenitic stainless steels is a significant subject of many investigations. Exposure of these steels to elevated temperatures (from 600 °C to 900 °C) results in precipitation of σ phase (transformation product from delta (δ) ferrite) which is one of the main reasons for the deterior...

By AMNA HODŽIĆ, ALMAIDA GIGOVIC-GEKIC, RAZA SUNULAHPAŠIĆ

Thermal properties and microstructure of the Sn-10% Ag and Sn-20% Ag alloys were experimentally investigated in this study. Melting behavior of the alloys were studied using differential scanning calorimetry (DSC). Microstructure of the alloys was analyzed by optical microscopy. The xenon-flash method was used for the measurements of thermal diffus...

By DRAGAN MANASIJEVIĆ, LJUBIŠA BALANOVIĆ, IVANA MARKOVIĆ, DUŠKO MINIĆ, ALEKSADAR ĐORĐEVIĆ

Mine development imposes very high technical requirements of the mine hoisting equipment in terms of speed of transport. To meet these requirements it is necessary to properly design the structural elements of mine hoisting equipment which means that they must have the proper characteristics of the materials from which they are made such as mechani...

By MUSTAFA HADŽALIĆ, MIRSADA ORUČ, RAZA SUNULAHPAŠIĆ

Surface roughness is the totality of microgeometric irregularities on the surface of an object and it is caused by various factors, from which the most important are machining and processing techniques. This characteristic of the material is very important, especially in the case of high-quality materials designed for the demanding conditions of ex...

By RAZA SUNULAHPAŠIĆ, MIRSADA ORUČ, EDINA KARIĆ

In this paper were investigated the effect of hydrochloric acid concentration and addition of oxidizing agents on the rate of general corrosion of copper.For comparison, the corrosion rate in distilled water was also tested.Taffel extrapolation method was used for investigation of general corrosion of copper. Taffel extrapolation method implies sca...

By FARZET BIKIĆ, DEJANA KASAPOVIĆ

The presented investigation work investigates thermal properties of the ultra-high hardness (UHH) armour steel. Steel is distinguished with high hardness and strength. It is sold in the quenched or tempered state, because achieving planned hardness which has to be between 590 HB and 640 HB. In the frame of the investigation work the analysis of the...

By BORUT KOSEC, TJAŠA KRANJEC, BLAŽ KARPE, ALEŠ NAGODE, MILAN BIZJAK, JURE BERNETIČ, MIRKO GOJIĆ, ZIJAH BURZIĆ, MILAN RIMAC, GORAZD KOSEC

Some specific aspects in the improvement processes related to I-beams production, especially related to the conversion of classical to the universal rolling mills stands are presented in this paper. One of practical solutions in the a.m. conversion is described in some more details, as well as some of better designs in the variety of I-beams, conce...

By FAIK UZUNOVIĆ, OMER BEGANOVIĆ, LAMIJA SUŠIĆ

In this paper, we have introduced new contemporary materials for heat harvesting, based on thermoelectric effect (or Seebeck effect): rear earth mono-pnictides and graphene. Measure of effectiveness for transformation of heat to electricity is represented with zT factor, which measure heat harvesting potential. zT factor is related with heat and el...

By SINIŠA M. VUČENOVIĆ, JOVAN P. ŠETRAJČIĆ, STEVA K. JAĆIMOVSKI

This paper presents an experimental study to evaluate the possibility of CEM IV 42,5N producing by increasing the specific cement surface from 3180 to 3850 cm2 /g. In this paper, fly ash is used as a cement admixture because fly ash possesses both hydraulic and pozzolanic properties. If one part of the clinker, as a major cement admixture, is repla...

By NEVZET MERDIĆ, NEDŽAD HARAČIĆ, ILHAN BUŠATLIĆ, NADIRA BUŠATLIĆ, AMNA KARIĆ

The paper examined the changes in properties of conventional castables composed of a mixture of calcium-aluminate cement and chamotte caused by changes in the particle size distribution. Properties of castable with 20 % cement and „as received“ chamotte were compared with castableofparticle size distribution adapted to the calculated di...

By MARINA JOVANOVIĆ, ADNAN MUJKANOVIC

Particle size distribution measurements were performed on ground granulated blastfurnace slag by laser diffraction with the powder dispersed in distilled water with sodium hexametaphosphate used as dispersing agent, as well as in pure distilled water and propan-2-ol. Two samples of slag with Blaine fineness 4700 cm2 /g and5500 cm2 /g were tested.Th...

By ADNAN MUJKANOVIC, MARINA JOVANOVIĆ, AMEL ZAHIROVIĆ, MUSTAFA HADŽALIĆ, NEVZET MERDIĆ

This paper presents an experimental investigation into the effect of nanosilica addition to porosity and capillary absorption of concrete. Three concrete mixtures 0%, 2%, and 4% nanosilicaby weight of cementweretested.The procedure described in ASTM C642-06 was used to determine the total volume of permeable voids.Water absorption and the rate of w...

By ADNAN MUJKANOVIC, ANESA KLJUČANIN, MARINA JOVANOVIĆ, AMEL ZAHIROVIĆ, AMNA KARIĆ, NEVZET MERDIĆ

In this paper, the influence of Na2SiO3 /NaOH ratio on the compressive strength of fly ash - based geopolymers was tested. The fly ash from thermal power plant Stanari near Doboj, BiH is used.The ratio of alkali activator to fly ash (AA / FA ratio) was constant in all samples and it was 0.8. A 12M NaOH solution was used. The heat treatment temperat...

By NADIRA BUŠATLIĆ, ILHAN BUŠATLIĆ, NEVZET MERDIĆ, DŽENANA SMAJIĆ-TERZIĆ

In order to reduce the harmful effects of exhaust gases on the environment, as of January 1, 2017, at all stations for technical inspection of vehicles, during the regular technical inspection of vehicles, the contents of motor vehicle exhausts are also carried out - EKO test. According to the Rulebook on Exhaust Gas Testing of Motor Vehicles (ECO ...

By DRAGANA AGIĆ, FUAD KLISURA

In this paper, the results of changes in pH and conductivity values of the solutions during the rinsing of the adsorbent, as well as during the adsorption of copper ions were presented. Prior to the adsorption experiments, the sunflower heads were rinsed with 200 cm3 of distilled water in ten equal portions (20 cm3 each). After each water volume pa...

By MILAN GORGIEVSKI, NADA ŠTRBAC, VELIZAR STANKOVIĆ, VESNA GREKULOVIĆ, MILJAN MARKOVIĆ, DRAGANA BOŽIĆ

Mostly used food packing are: paper, cartoon, plastics, glass, metals and multilayer materials. The plastics and paper/cartoon make about 70% of all food packing. These two have the biggest migration potential. The use of plastics is regulated by specific EU rules, but it is not yet the same about the use of paper packing. In order to ensure health...

By BENJAMIN MUHAMEDBEGOVIĆ, MIDHAT JAŠIĆ, MARIZELA ŠABANOVIĆ, FAIK UZUNOVIĆ

The process of the pulp washing is very important both economically and environmentally, since the quality of cellulose washing is directly related to the efficiency of chemical regeneration and the quality of the wastewater generated. The purpose of the cellulose fiber washing process is to economically remove the maximum of soluble organic and so...

By AZRA HALILOVIĆ, ILHAN BUŠATLIĆ, ŠEFKIJA BOTONJIĆ, AMNA KARIĆ