The ability to produce high quality and consistant carburised parts requires precise control of the carbursing atmosphere. The use of mass flow controllers (MFCs) is described as a means to regulate the furnace atmosphere composition as well as to improve quality of the heat treated parts by the use of a consistent atmosphere. Furthermore, the increasing productivity by the use of accelerated carburising (ACP) and MFCs is reported.

The thermal decompositions of 3-ethyl-3-methyloxetan and 3,3-diethyloxetan have been followed in the gas phase. Both decompositions are homogeneous, kinetically first order and probably unimolecular. In the temperature range 407 to 448°C the 3-ethyl-3-methyl compound yields 2methylbut-1-ene and formaldehyde and the rate constants fit the Arrhenius equation log kl/s-' = 15.357kO.151-(251 230f2020) J mol-l/RTInlO. Similarly it was found that 3,3-diethyloxetan gave 2-ethylbut-1-ene and formaldehyde and in the temperature range 402 to 463°C the rate constants fitted the Arrhenius equation log kz/s-l = 15.297 2 0.063 -(249 8502 840) J mol-l/RTlnlO. The decompositions probably proceed by a biradical mechanism.

No abstract

No abstract