零保温加热时间的计算方法及其应用

Calculation Method of Heating Time and Its Application for Zero Holding Time Technology

根据工件的体积(V)与表面积(F)之比(V/F)的物理意义提出“等效厚度(D)”和“等效系数(β)”的概念,并存在D′β=D(有效厚度)的关系,从而得到零保温加热时间的计算式τ=αD′。此法吸收了τ=αD法和τ=kW法各自的优点,克服其缺点,使之具有前法的简便性和后法的合理性。又通过工厂现场应用试验求得批量装炉生产时τ=RαD′法中的堆装系数R,使τ=RαD′法方便地应用在生产上,节电效果达25～30%,并减少了工时。

Based on the physical meaning of ratio V/F (V, F denote respectively the volume and the surface of work piece), this paper suggests the conceptions of equivalent thickness D' and equivalent coefficient β. There exists the relation βD'= D, where D is the effective thickness, thus acquiring the formula of heating time for zero holding time technology τ=αD'. This method adopts respective merits of τ=αD method and τ= KW method and also overcomes their shortcomings. It possesses the simplicity of method τ=αD and the reasonableness of method τ= KW. Through experimental applications in workshop, values of packing factor R of work piece in oven for lot production in the formula τ=RαD' have been found out, thus making method τ= RαD' more convenient to use in production. Electrical energy saving reaches 25～30% and labour saving is also achieved.