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1.渗碳阶段排气结束后,由于钢表面含碳量极低,需要大量的活性碳原子供给,因此,要最大限度地提高碳势,使炉气碳势远远超过预定表层碳浓度,在此高碳势下让钢的表面强烈增碳,造成很高的碳浓度梯度,增加碳原子活性和扩散速度,从而加速渗碳过程的进行。具体作法是:强渗期滴注大量煤油,不滴甲醇。煤油滴量以排气管火焰呈黄亮色,而不产生跳动火星为极限。如以75KW渗碳炉为例,大致为250～300滴/分,炉压保持在40mm水柱,时间为70～80分钟。 2.扩散阶段渗碳阶段结束后,由于表层具有超出预定的碳含量,低的渗层深度和高的碳浓度梯度,所以这一阶段要减少煤油滴量(约120～150滴/分)。加滴甲醇(100～120滴/分)据经验分析按此滴量,炉内碳势在0.9～1.0,和预定碳浓度相近,此时介质的碳势对表层碳浓度是脱碳气氛,表层碳原子一方面由表面向里
1. Carburizing stage After the end of the exhaust, due to the extremely low carbon content of the steel surface, requiring a large supply of activated carbon atoms, therefore, to maximize carbon potential, the carbon potential of the furnace far exceeds the scheduled surface carbon concentration, Under this high carbon potential, the surface of steel is strongly carbonated, resulting in a high carbon concentration gradient, increasing carbon atom activity and diffusion rate, thereby accelerating the carburization process. Specific approach is: strong infiltration of large drops of kerosene, do not drop methanol. Kerosene volume to the exhaust pipe flame was bright yellow, without pulsating Mars limit. Such as 75KW carburizing furnace, for example, roughly 250 to 300 drops / min, furnace pressure maintained at 40mm water column, the time was 70 to 80 minutes. 2. Diffusion Phase At the end of the carburization phase, the amount of kerosene is reduced (about 120-150 drops / min) at this stage due to the superficial overburden of carbon content, low depth of permeation and high carbon concentration gradient. Add drops of methanol (100 to 120 drops / min) According to empirical analysis, according to this volume, the carbon potential in the furnace 0.9 to 1.0, and the predetermined carbon concentration similar to the carbon potential of the medium on the surface carbon concentration decarburization atmosphere, the surface Carbon atoms on the one hand from the surface inward