Coworkers of researching program together with the investor of the research Acroni d.o.o. and foreign institutions of knowledge have been designing and developing a high quality of new generation of HSLA steel PROTAC 500 in the form of plate for the armour prevention. PROTAC 500 is a lowcarbon (0,27 m. %) steel with conditional weldability. The steel is alloyed with Si (1.01 m. %), Cr (0,69 m. %), Mo (0,33 m. %) and microalloyed with Ti (0.027 m. %) for the crystal grain size control as well as with B (0,002 m. %) for better hardenability. Ms temperature of PROTAC 500 steel is relatively high which allows self tempering. The PROTAC 500 steel exhibit the following mechanical properties: hardness from 480 to 535 HB, Proof strength Rp0.2 from 1150 to 1250 N mm2, tensile strength Rm from 1500 to 1700 N mm2, Rp0.2/Rm ratio from 0,56 to 0,75, elongation A5 min. 9 %, Charpy impact toughness ( T = 40 °C, V notch) min. 20 J. Official ballistic testing and the Certificates giving ceremony of the ballistic testing has been carried out in NATO accredited Beschussamt Institute in Ulm. After ballistic testing of PROTAC 500 steel the Acroni d.o.o. company has been awarded with 5 certificates from the level 5 to level 11 according to European standard VPAM APR 2006 as well as with 5 certificates i.e. three for the level 1, one for level 2 and one for level 3 according to NATO AEP55 STANAG 4569 standard.
F.06 Development of a new product
COBISS.SI-ID: 1218655Innovative idea, concept and construction was carried out and controlled by members of the program group in cooperation with Slovenian companies. Since the electrical resistance is one of the most structurally sensitive properties of the materials, we used its measurement to detect microstructural changes caused by phase transformations or chemical reactions. Until now, we analyzed the phase transitions in rapidly solidified alloys of copper and aluminum, nickel and nickel alloys, and several types of steel made by Slovenian steel producers.
F.13 Development of new production methods and tools or processes
COBISS.SI-ID: 1175135This paper describes the superplastic behaviour of the Al4.5Mg0.46Mn0.44Sc alloy. The investigated alloy was produced by casting and conventionally processed to form a sheet with a thickness of 1.9 mm and an average grain size of 11 micrometer, The superplastic properties of the alloy were investigated using a uniaxial tensile test with a constant crosshead speed and a constant strain rate in the range 1x104s-1 to 5x102s-1 at temperatures from 390°C to 550°C. The investigations included determinations of the truestress, truestrain characteristics, the maximum elongations to failure, the strainrate sensitivity indexes m and the microstructure of the alloy. The mvalues determined with the strain rate jump test varied from 0.35 to 0.70 in the temperature interval 390 - 550° C and strain rates up to 2x102s-1. The m values decreased with increased strain during pulling under constant test conditions. The elongations to failure were in accordance with the mvalues. They increased with the temperature and were over 1000%, up to 1x103s-1 at 480°C and up to 1x102s-1 at 550°C. A maximum elongation of 1969% was achieved at an initial strain rate of 5x103s-1 and 550°C. The results show that the addition of about 0.4wt.% of scandium to the standard AlMgMn alloy, fabricated by a conventional manufacturing route, including hot and cold rolling with subsequent recrystallization annealing, results in good superplastic ductility.
F.06 Development of a new product
COBISS.SI-ID: 1004639Presented work discusses a complex process of inductive heating and quenching of carbon steel CK 45 planetary shafts for diesel engine starters. Planetary shafts assembled in starters are subjected to high thermal and mechanical loads during their exploitation. Surface temperature measurements during the inductive heating process were realized in the industrial environment. The intensity and homogeneity of temperature fields on the surface of the planetary shafts were measured by thermographic camera. On the measurements base and theoretical knowledge, a mathematical model for temperature conditions determination in the shaft during the entire process of heating and quenching was carried out. On the basis of developed mathematical model a computer program was developed, and used for analyses and induction hardening process optimization of planetary shaft.
F.14 Improvements to existing production methods and tools or processes
COBISS.SI-ID: 1144415Single roll melt spinning is the most commonly used process for the production of rapidly solidified thin metal ribbons. Microstructure development over the ribbon thickness mostly depend on the ribbon thickness itself, contact resistance between the melt and chilling wheel, heat transfer in the melt and the wheel, and nucleation and crystal growth characteristics of the particular casting material. The calculations show that contact resistance between metal melt and chilling wheel has a great influence on melt cooling and wheel heating rate, and must not be neglected in heat transfer calculations, even if its value is very low. New method for determining contact resistance through variable heat transfer coefficient is introduced which takes into account physical properties of the casting material, process parameters and contact time/length between metal melt and chilling wheel. It can be concluded from the results that process parameters which determine the thickness of the melt puddle in the downstream have major influence on cooling and solidifying rate of the ribbon. For the propose of industrial continuous casting of larger material quantities, heat balance of the wheel is calculated and influence of the chill wheel cooling mode on cooling rate of metallic ribbon is analyzed.
F.09 Development of a new technological process or technology
COBISS.SI-ID: 1084255