The article discusses the morphology, microstructure and chemical composition of the boundary layer in explosive welding of low-carbon steel and tantalum plates. Pools of melt composed of both metals ...and having a heterogeneous chemical composition appear on the boundary layer. This phenomenon is the result of incomplete mixing of both: molten metals due to rapid cooling and solidification. Within the pools of alloy, a large number of non-metallic oxide inclusions, products of deoxidation of molten alloys, can be found. The non-metal inclusions arc round (0,1 to 2 *mm in diameter) and vary in both: size and chemical composition. The main component of the non-metal inclusions is Ta2O5, which also contains iron, manganese, and aluminium oxides. The number of non-metal inclusions is unusually high for low-carbon steel and comparable to the number of non-metal inclusions in welds. Oxygen which causes the large number of deoxidised products does not originate in the low-carbon steel, as this steel is relatively clean. The most probable source of oxygen is the oxide scale from the surface of the low-carbon steel, which was poorly cleaned prior to welding.
MMDS group TV signal transmitter Polyakov, S.V.; Sviridenko, V.I.; Sologub, V.V. ...
2004 14th International Crimean Conference "Microwave and Telecommunication Technology" (IEEE Cat. No.04EX843),
2004
Conference Proceeding
The possibility of MMDS group TV signal transmitter creation is considered. The system of transmitting a group TV signal (up to 25 channels) in the MMDS range using one transmitter is known. The use ...of several one-channel transmitters instead of one group signal transmitter allows an increase in system reliability and repairability, lowers its cost and enables its introduction into operation in stages. The proposed method of using MMDS transmitters demands five antenna-feeders. That is the system's weak point. On the other hand, if one channel transmitter fails, it does not affect the others. Block construction allows the failed block to be changed quickly without switching off the others.
An investigation conducted on two steel ploughs found at Saint Sveti Ahac above Ilirska Bistrica dating from the fourth and the sixth centuries AD are presented. The ploughs were made by ...forge-welding many layers of steel extracted directly from the furnace melt containing mainly slag inclusions. The ploughs were made by placing steels of higher strength and hardness were the load was greatest. Metallographic examination, chemical and microchemical analysis and hardness measurements contributed significantly to the information regarding the manufacturing process of the archeological ploughs. Possible reactions during melting and steel production are also presented.
Namjena istraživanja je izraditi termodinamički proračun svih mogućih reakcija u sustavu Cu-Se-O i obrazložiti mehanizme oksidacije u različitim uvjetima. Za takovo izučavanje izrađen je model bakra ...sa samo jednim uključkom i legura sa 1,65 mas. % Se. U ovisnosti od vremena, oksidacija se odvijala kod različitih temperatura i kod dviju različitih djelomičnih tlakova kisika. Oksidirani uzorci su bili ispitivani metodom DTA, optičkom i elektronskom mikroskopijom (SEM).
Legure srebra s telurom, selenom i sumporom ispunjavaju uvjete za unutarnju oksidaciju. Mirkostruktura ovih legura sastoji se od osnove (razrijeđena kruta otopina) i čestica intermetalnih spojeva. ...Unutarnja oksidacija ternarnih legura veoma je slična onoj za binarne legure, ali postoje i razlike u termodinamičkim svojstvima legirajućih elemenata. Kod izravne oksidacije čestica intermetalnog spoja zapažena je pojava selektivne oksidacije. Koncentracija reaktivnijih elemenata raste u oksidiranom dijelu čestica intermentalnog spoja (Te u AgTeSe leguri). Prema tome precipitirani oksidi nastali difuzijskom unutarnjom oksidacijom su bogati s manje reaktivnim legirajućim elementom (Se u AgTeSe leguri). U percipitiranim oksidnim česticama koncentracija selena je dvostruko veća nego telura.
LFM-700 device is considered here, it was designed and prepared for producing by "Beta TV com" enterprise, which is the future design of 500 and 600 series. In this device frequency windows in which ...signal analyses were not carried out are removed (862...950 MHz, 2150...2400 MHz), frequency range was enlarged from 2700 MHz (LFM 500 series) to 6000 MHz (LFM 700). There is a tendency to have generator HF, ALC meter, and spectrum analyzer in one device
Članak raspravlja o morfologiji, mikrostrukturi i kemijskom sastavu pograničnog sloja pri eksplozivnom zavarivanju traka niskougljičnog čelika i tantala. Područje zone taljenja sastavljeno je od oba ...metala i na graničnom sloju pojavljuje se heterogeni kemijski sastav. Ova pojava je posljedica nepotpunog miješanja oba rastaljena metala, zbog naglog hlađenja i očvršćivanja. Unutar područja spajanja legure može se utvrditi veliki broj nemetalnih oksidnih uključaka, produkata dezoksidacije rastaljenih legura. Nemetalni uključci su okrugli (0.1 do 2 µm) i variraju u veličini i kemijskom sastavu. Glavna komponenta nemetalnih uključaka je Ta2O5, koji također sadrži željezne, manganove i aluminijeve okside. Broj nemetalnih uključaka je neouobičajeno velik za niskougljični čelik i usporediv je s brojem nemetalnih uključaka u zavarima. Kisik koji dovodi do nastanka velikog broja produkata dezoksidacije ne potiče iz niskougljičnog čelika jer je čelik relativno čist. Najvjerojatniji izvor kisika je površinski oksidni sloj niskougljičnog čelika koji je slabo očišćen prije procesa zavarivanja.
