Some Mechanical Properties of Small Specimens Cut from 1. 79-inch- Thick Southern Pine Dried for 6 Hours at 300 F or for 5 Days at 180 F-a Comparison
نویسندگان
چکیده
During the past decade the southern pine industry has adopted technology for kilndrying dimension lumber at temperatures above the boiling point of water. Does exposure to such temperatures diminish the mechanical properties of southern pine? Previous research (Koch 1971) has indicated that when dried 21 hours at 240 F (100 F wet-bulb temperature) with crosscirculation air velocity of 1,(XX) £pm, 2 by 4's cut from southern pine veneer cores and small logs suffered no significant ( 0.05 level) reductions in modulus of elasticity (MOE), modulus of rupture (MOR), or proportional limit ( PL ) when tested in 8-foot lengths in edgewise bending. Nei-
منابع مشابه
Power , and Lumber Dwell Time in Zones of a Continuous Tunnel Kiln for 1 - 3 / 4 - Inch - Thick Southern Pine Lumber
I:U+ Abstract Length-sorted lumber is surfaced on one side t() 1.75-inch thickness, mechanically stacked 5 feet wide and 10 feet high on 1-1/4-inch-thick sticks, and continuously transported through a zone-controlled tunnel kiln at 8 ft./hr. t() yield 500,000 tbm of lumber dried t() 9 percent average MC per 168hour week. In the tunnel, the lumber is dried for 8 (possibly 10) hours at 270°F, con...
متن کاملRelation between Stump Diameter and Length of Shear - Caused Splits in Planed
When logs of three 4iaineter classes and two specific gravity classes were sheared with a 3/8-inch-thick knife travelling at 2 inches per minute, shearing force and work averaged greatest for dense 13.6-inch logs cut with a knife having a 45" sharpness angle (73,517 pounds; 49,838 footpounds). Force and work averaged least for 5.1-inch bolts of low density when cut with a knife having 22-1/2" s...
متن کاملComparison of Carburizing and Boronizing Processes on Mechanical and Wear Properties of PM Parts
In this study carburizing and boronizing processes were applied to powder metallurgy steel specimens and the mechanical and tribological properties of the substrate and coatings were evaluated under various process conditions.
The specimens, made from industrial test pieces, were carburized in a powder pack for a duration of 2-5 hrs at 850-950 ˚C. Similar specimens were pack boronized for 4 ...
متن کاملComparison of Carburizing and Boronizing Processes on Mechanical and Wear Properties of PM Parts
In this study carburizing and boronizing processes were applied to powder metallurgy steel specimens and the mechanical and tribological properties of the substrate and coatings were evaluated under various process conditions. The specimens, made from industrial test pieces, were carburized in a powder pack for a duration of 2-5 hrs at 850-950 ˚C. Similar specimens were pack boronized for 4 hr...
متن کاملMoisture Content of Southern Pine as Related
Holes 3-1/2 inches deep were bored with a I-inch spur machine bit in southern pine having specific gravity of 0.53 (ovendry weight and volume at 10.4 percent moisture). The bit was rotated at 2,400 rpm and removed chips 0.020 inch thick. For wood moisture contents ranging from ovendry to saturation, thrust was lower when boring along the grain (average 98 pounds) than across the grain (average ...
متن کامل