Abstract:

By study the drying characteristics of Eucalyptus grandis × E. urophylla wood and make its drying schedule, provided a reasonable theoretical basis when made the drying process on the actual production. The experimental method was the 100℃ test, on the basis of drying defects of initial check, internal check, and collapse of E. grandis × E. urophylla wood were investigated based on the (100±2)℃ constant temperature, then made the drying schedule. The level of initial check, internal check, collapse , warp distortion and drying speed of Eucalyptus grandis × E. urophylla were 1,2,3,2 and 2, respectively; and its volume shrinkage degrees was 19.04%, tangential shrinkage degrees was 9.60%, radial shrinkage degrees was 6.65%, longitudinal shrinkage degrees was 0.33%. The initial and final drying temperature of E. grandis × E. urophylla lumber were 60 and 75℃, and the temperature difference of dry-wet ball in initial drying stage was 3-5℃. After the Eucalyptus grandis × E. urophylla panel with thickness of 25 mm was dried in forced circulation drying oven for 10 (8) days (in parentheses for hard benchmark conditions), its water content was decreased to 10%. The main defects of Eucalyptus grandis × E. urophylla wood were internal check and collapse, tried to use the soft drying schedule in the actual production process, timely adjusted wet process in drying metaphase and later period.