Naslov
INFLUENCE OF ARTILLERY WEAPON BARREL SUPERHEAT ON EROSION WEAR RESISTANCE OF MATERIAL

Autori
Jakopčić, Mirko ; Grilec, Krešimir

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
MATRIB 2008 / Grilec, Krešimir ; Marić, Gojko ; Jakovljević, Suzana - Zagreb : Hrvatsko društvo za materijale i tribologiju (HDMT), 2008, 115-121

ISBN
978-953-7040-14-7

Skup
MATRIB 2008

Mjesto i datum
Vela Luka, Hrvatska, 26.06.2008. - 28.06.2008

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
weapon barrel; fire rate; superheat; erosion

Sažetak
This paper researches the influence of the artillery weapon barrel superheat on the change of erosion wear resistance of material. A great quantity of the powder gasses evolves by the weapon firing in the weapon barrel. The temperature of these gasses reaches up to 3800 K, and their maximum pressure is up to 6000 bar. The powder gasses have a compound chemical composition, so they make a very aggressive atmosphere in relation to the barrel material. At the same time, the powder gasses contain the solid particles too: the soot particles and the unburned powder grains. These particles are moving by great speed in the strong turbulent streaming of the powder gasses. In this way, the erosive wear of the barrel material appears on the bore surface. This is the erosive wear of material by the solid particles. At the same time, the contact pressure on the rotating band and the barrel bore surfaces appears. It results with normal force effect on the contact surfaces, so a strong sliding friction force is generated on those surfaces. The sliding friction energy transforms to the heat energy too, so the barrel material heating is very intensive in such firing conditions. Therefore, the rate of fire is determined for every artillery weapon to keep the barrel heating on the allowed level. The test samples production was based on the previous analysis of some weapon barrel materials. So, the erosion test samples are made of heat treated steel 42CrMo4. This steel has the similar chemical, metallographic and mechanical properties as the analysed weapon barrel steel. The test samples were tempered at 600 °C, 700 °C, 800 °C and 900 °C, over a period of one hour, and then air cooled. It’ s the similar way of heating and cooling as the superheating and cooling of the barrel by intensive firing. The wear resistance is represented by the sample mass loss after 15, 30, 45 and 60 minutes of erosion wear time. The test results represent that unheated samples have got the best wear resistance in comparison with the heated samples. The wear resistance increases as many as 3, 9 times if material was previously heated at 600 °C. The heating of material at 700 °C and 800 °C causes more intensive material wear. The significant material wear increase is shown in the samples which were heated at the 900 °C. The samples heated in this way represent as many as 17, 5 times bigger material loss than unheated samples. The test results show that adhering to the determined fire rate is very important: the exceeded fire causes the weapon barrel superheat, as well as the significant decrease of the material wear resistance.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

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