Classification of pressure equipment according to directive 2014/68/EU and regulation no 1272/2008/EU

For the first time after 17 years the Directive 97/23/EC of the European Council and the Council on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment has been changed and gets a new number - Directive 2014/68/EU. In addition to changes in the names of modules required for manufacturers and notified bodies, the declaration of conformity and others, one of the changes is the classification of pressure equipment. Regulation No. 1272/2008 has relied on Directive 67/548/EEC, and introduced changes in PED 97/23. Now, the new PED 2014/68 is in line with that Regulation. The paper presents a new classification of fluids and shows the most important parts of PED 2014/68 and Regulation No 1272/2008 concerning the new classification of the fluid by nature and hazard level

Classification of pressure equipment according to directive 2014/68/EU and regulation no 1272/2008/EU

For the first time after 17 years the Directive 97/23/EC of the European Council and the Council on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment has been changed and gets a new number - Directive 2014/68/EU. In addition to changes in the names of modules required for manufacturers and notified bodies, the declaration of conformity and others, one of the changes is the classification of pressure equipment. Regulation No. 1272/2008 has relied on Directive 67/548/EEC, and introduced changes in PED 97/23. Now, the new PED 2014/68 is in line with that Regulation. The paper presents a new classification of fluids and shows the most important parts of PED 2014/68 and Regulation No 1272/2008 concerning the new classification of the fluid by nature and hazard level

Microstructure and fracture mode of unalloyed dual-phase austempered ductile iron

Dual-phase ADI material microstructure consists of different amounts and morphologies of ausferrite and free ferrite, obtained by subjecting ductile iron to specific heat treatment. Its strength is lower compared to comparable ADI materials but exhibits a higher ductility, the major disadvantage of ADI. In the current study, an unalloyed ductile iron was intercritical austenitized in two-phase regions (??+??) at four temperatures from 840 to 780 ??C for 2 h and austempered at 400 ??C for 1 h to obtain dual-phase ADI with different percentages of free ferrite and ausferrite. Light and scanning electron microscopy was performed for the metallographic and fracture studies, respectively. Microscopy results were correlated to tensile testing results. The results indicated that, as the amount of ausferrite present in the matrix increases, higher values of strength and lower ductility are obtained. The fracture surfaces of dual-phase ADI microstructures with 22.8% of ausferrite in their matrix have regions of quasi-cleavage fracture around last-to-freeze zones, related to the presence of ausferrite in those areas. The specimens with the highest values of ausferrite of 86.8% among the dual-phase microstructure have a dominant quasi-cleavage type of fracture

Definition of welding parameters by cooling time in temperature range 800-500ºC

Vreme hlađenja u temperaturnom intervalu 800 - 500ºC (t8/5) ima veliki uticaj na strukture koje nastaju u zoni uticaja toplote zavarenih spojeva čelika. Podaci o optimalnim vremenima hlađenja t8/5 za pojedine čelike se mogu naći u literaturi. Na veličinu vremena hlađenja t8/5, pri zavarivanju konkretnog spoja, pored debljine i fizičkih osobina zavarivanog čelika imaju uticaj i oblik spoja, postupak zavarivanja i parametri, kao što su temperatura predgrevanja, struja, napon i brzina zavarivanja. U ovom radu je prikazan postupak za izbor parametara zavarivanja za jedan sučeoni spoj zavaren na mikrolegiranom čeliku P 460 NL1. Prikazane su mikrostrukture u zoni uticaja toplote i rezultati merenja njihovih tvrdoća. Zaključeno je da parametri zavarivanja odabrani uz pomoć vremena hlađenja t8/5 daju spoj sa zadovoljavajućim strukturama i tvrdoćama.Cooling time in the temperature range 800 - 500°C has a great effect on the structures that arrise in the heat affected zone of welds steel. Data on optimal cooling time t8/5 for the certain steels can be found in the literature. The period of the cooling time t8/5, during the welding of the particular joints, in addition to the thickness and physical properties of welded steel, depends on shape of the weld, the welding process and welding parameters as well. In this work, the procedure for the selection of welding parameters for a butt joint welded to the microalloyed steel P 460 NL1 is presented. The microstructure in the heat affected zone and the results of measurement of their hardness are showed and analysed. It is concluded that the welding parameters selected with the help of cooling time t8/5 provide the satisfactory structure and hardness of welds

Ballistic Behaviour of Austempered Compacted Graphite Iron Perforated Plates

In this study, the performance of austempered compacted graphite iron was evaluated to find its suitability as perforated plates used in add-on armour. Perforated compacted graphite plates were subjected to austenitisation at 900 degrees C for 2 h followed by austempering at 275 and 400 degrees C for 1 h. The basic plate was fixed at 400 mm away from the perforated plate and armour and then piercing incendiary projectile was shot from a distance of 100 m. It was observed that both 7 mm and 9 mm perforated plates austempered at lower temperature of 275 degrees C producing higher hardness and lower ductility were effective in fracturing the penetrating core, thereby significantly decreasing the chances of penetrating the basic plate

Mikrostrukturni razvoj i degradacija mehaničkih svojstava legure HPNB posle jedanaest godina eksploatacije

In this work, the heat-resistant cast steel HP40Nb alloy, produced in the form of a centrifugally cast tube, which failed after 11.4 years service is investigated. The microstructure is examined using a scanning electron microscope (SEM), while the phases observed are analysed using an energy dispersive X-ray analyser system (EDS). Additionally, fractography is performed on the fractured surface of failed specimens. Mechanical properties of the tube are evaluated by using tensile and Charpy impact testing at room temperature (298 K). Main results indicate that the failed tube microstructure consists of an austenitic matrix and a continuous network of primary eutectic carbides of two types: one rich in Nb (bright particles), and one rich in Cr (dark particles). These carbides are NbC and complex M7C3 (M = Cr, Ni, Fe) type. The brittle intergranular fracture mode is explained by the presence of massive precipitation and coarsening of intergranular carbides at grain boundaries. Lower tensile properties of the in-service exposed tube might be correlated to the morphological, chemical, and distribution changes of precipitates during service at high temperature. Decreased values of hardness can be attributed to increase in grain size, as well as due to the decomposition of Cr-carbide during the heat treatment at temperatures above 1073 K.U ovom radu је ispitivana legura od livenog čelika HP40Nb otpornog na toplotu, proizvedena u obliku centrifugalno livene cevi, koja je otkazala posle 11,4 godina eksploatacije. Mikrostruktura je ispitivana primenom skenirajućeg elektronskog mikroskopa SEM, dok su uočene faze analizirane korišćenjem sistema energetski disperzivnog rendgenskog analizatora (EDS). Dodatno, fraktografija je urađena na površini loma oštećenih uzoraka. Mehanička svojstva su procenjena ispitivanjem na zatezanje i ispitivanjem energije udara po Šarpiju na sobnoj temperaturi (298 K). Glavni rezultati su pokazali da se mikrostruktura oštećene cevi sastoji od austenitne osnove i neprekidne mreže primarnih eutektičkih karbida dva tipa: jednog bogatog Nb (svetle čestice) i jednog bogatog Cr (tamne čestice). Oba karbida su tipa NbC i složeni M7C3 (M = Cr, Ni, Fe). Mehanizam krtog intergranularnog loma objašnjen je prisustvom masivnog taloženja grubih intergranularnih karbida na granicama zrna. Niža zatezna svojstva cevi izložene eksploataciji mogu biti u korelaciji sa morfološkim, hemijskim i distributivnim promenama taloga tokom eksploatacije na visokoj temperaturi. Smanjenje vrednosti tvrdoće može se pripisati povećanju veličine zrna kao i razlaganju Cr-karbida tokom termičke obrade na temperaturama iznad 1073 K

Ballistic Behaviour of Austempered Compacted Graphite Iron Perforated Plates

In this study, the performance of austempered compacted graphite iron was evaluated to find its suitability as perforated plates used in add-on armour. Perforated compacted graphite plates were subjected to austenitisation at 900 °C for 2 h followed by austempering at 275 and 400 °C for 1 h. The basic plate was fixed at 400 mm away from the perforated plate and armour and then piercing incendiary projectile was shot from a distance of 100 m. It was observed that both 7 mm and 9 mm perforated plates austempered at lower temperature of 275 °C producing higher hardness and lower ductility were effective in fracturing the penetrating core, thereby significantly decreasing the chances of penetrating the basic plate

Laser treatments of Nimonic 263 nickel-based superalloy

U ovom radu, proučavan je uticaj parametara određenih procesa laserske tehnike obrade materijala superlegure Nimonic 263 - bušenje, rezanje, zavarivanje i mehanička obrada laserom. Bušenje i zavarivanje su vršeni na laseru Nd:YAG laserom model HTS Mobile LS-P160. Prilikom bušenja rupa varirani su parametri frekvencije impulsa (5 Hz, 7Hz i 9 Hz) i dužine trajanja impulsa (1,8 ms do 3,6 ms). Ispitivana je mikrostruktura i određene su geometrijske i metalurške karakteristike rupa dobijenih ovim parametrima, na osnovu čega je izvršena optimizacija parametara obrade. Rezanje je izvedeno na laseru tipa Bistronic laser, (2000), BISTAR 3015. Varirani su parametri srednje snage lasera, brzina lasera, pritisak gasa i položaj fokusa. Na osnovu dobijenih geometrijskih karakteristika rezova i površinske morfologije diskutovani su i određeni optimalni parametri. Laserom zavareni spojevi limova legure Nimonik 263 su, osim mikroskopskih i profilometrijskih ispitivanja površina, ispitivani i metodom sa razaranjem. Prilikom laserskog deformacionog ojačavanja uzorci su bili izloženi laserskom svetlu na talasnoj dužini od 1064 nm i 532 nm, sa brojem akumuliranih impulsa: 50, 100 i 200. U svim delovima eksperimenta strukturna analiza superlegure Nimonic 263 izvedena je pomoću svetlosne mikroskopije (SM), skenirajuće elektronske mikroskopije (SEM) i EDS-analize. Merenja mikrotvrdoće vršena su pomoću metode Vikersa pod opterećenjem od 9,81N. Profilometrija je izvedena na beskontaktnom profilometru Zygo NewView 7100.In this paper, the influence of parameters of laser processing (drilling, cutting, welding and laser shock peening) on microstructure of superalloy Nimonic 263 are investigated. Drilling and welding process are carried out on the Nd: YAG laser model LS-HTS Mobile P160. When drilling the holes, the parameters of pulse frequency (5 Hz, 7 Hz and 9 Hz) and the pulses duration (1.8 ms to 3.6 ms) are varied. The microstructure is investigated and geometrical and metallurgical characteristics of the holes are determined.Cutting is carried out on the laser BISTRONIC, (2000), BISTAR 3015. The parameters that were varied are as follows: the average laser power, laser velocity, the pressure of the assisting gas and the focus position. Based on the geometrical characteristics of the cuts and surface morphology the optimal parameters are discussed and defined. The laser welded joints of Nimonic 263, in addition to microscopic examination and surface profilometry, were subjected to the destructive testing. During the laser shock peening, the samples were exposed to laser light at a wavelength of 1064 nm and 532 nm, with the number of accumulated pulses 50, 100 and 200. The operating laser was Nd: YAG EKSPLO, SL212P model. Structural analysis of Nimonic 263 was carried out using light microscopy, scanning electron microscopy and EDS analysis. Microhardness measurements were carried out using the Vickers method under load of 9,81N. Profilometry was performed on a contactless profilometer Zygo Newview 7100

Impact of austenitic steels' mechanical properties on allowed stress and wall thickness of pressure equipment

The Pressure Equipment Directive (PED) and Regulations on Technical Requirements for Designing, Manufacturing and Conformity Assessment of Pressure Equipment bring a number of changes to the design of pressure equipment in relation to the Technical Regulations for Stable Pressure Vessels, 1983. Among the most important changes are the essential safety requirements for pressure equipment. The changes in the formula, for all materials, for calculating the allowable stresses, as well as the change in the value of the test pressure, the new Regulations use the 1.0% proof strength as the relevant value for calculating the permissible membrane stress and thickness of pressure equipment walls. In this paper, the differences in the allowable stresses, the required wall thicknesses, and the approximate savings in the material in the case of a milk reservoir, calculated according to the requirements of the Directive and the new Regulations on one hand, and the old Regulations on the other, are presented

Impact of austenitic steels’ mechanical properties on allowed stress and wall thickness of pressure equipment

The Pressure Equipment Directive (PED) and Regulations on Technical Requirements for Designing, Manufacturing and Conformity Assessment of Pressure Equipment bring a number of changes to the design of pressure equipment in relation to the Technical Regulations for Stable Pressure Vessels, 1983. Among the most important changes are the essential safety requirements for pressure equipment. The changes in the formula, for all materials, for calculating the allowable stresses, as well as the change in the value of the test pressure, the new Regulations use the 1.0% proof strength as the relevant value for calculating the permissible membrane stress and thickness of pressure equipment walls. In this paper, the differences in the allowable stresses, the required wall thicknesses, and the approximate savings in the material in the case of a milk reservoir, calculated according to the requirements of the Directive and the new Regulations on one hand, and the old Regulations on the other, are presented. © 2018 The Author