• Journal of the Korea Furniture Society
• /
• v.11 no.1
• /
• pp.85-89
• /
• 2000

This study investigated the effect of steaming on fixation of compression set and the effect of these treatments on mechanical properties of heat-compressed wood specimens. To determine the effect of steaming after compression set, wood specimens were compressed for 100min at 180f and then steamed for 20-100min at $120^{\circ}C$. Swelling tests were used to evaluate recovery of compression set. Bending, compression, and Brinell hardness tests were carried out for evaluating mechanical properties. Compressed wood steamed for 100 min at $120^{\circ}C$ showed 1.9% recovery of set, increases in bending and compressive properties, and no hardness change. We concluded that almost complete fixation of compression set in wood can be achieved by steaming compressed wood.

• Journal of the Korea Furniture Society
• /
• v.23 no.4
• /
• pp.460-466
• /
• 2012

This study was conducted to investigate the surface hardness of thermally-compressed larch wood by compression set and temperature. The surface hardness of thermally-compressed larch wood increased with increasing compression set and temperature. For compression set 60%, the specific gravity was increased as 0.93. However, the surface hardness was lower value as 31.1 N/$mm^2$ compared with a similar specific gravity of the tropical timber. For density profile, less than compression set 40%, compression was observed mainly surface area. On the other hand, more than 50%, density profile variation was reduced by compression of central part. Results of this study indicate that thermally-compressed larch wood can be replace some imported hardwoods such as oak or cherry. However, thermally-compressed larch wood was difficult to replace the tropical timber being imported in terms of surface hardness.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.4
• /
• pp.470-477
• /
• 2015

This study was carried out to investigate the change of dimensional stability of thermally compressed Korean pine (Pinus koraiensis Sieb. et Zucc.) wood by post heat treatment. Specific gravity of compressed wood was notably increased with thermal compression. In the compression set 50%, compressed Korean pine showed a specific gravity of 0.84. The amount of water absorption and swelling of thermally compressed Korean pine decreased with increasing temperature and time of the heat treatment. Set recovery also decreased with increasing temperature and time of heat treatment. Thermally compressed Korean pine that heat-treated in $120^{\circ}C$ for 24 hours showed a set recovery of 3.8%, whereas non-treated group showed 11.5%. Therefore, it was confirmed that the thermal treatment was a very effective method for the dimensional stability of the heat compressed wood.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.4
• /
• pp.303-310
• /
• 2011

The mechanical properties of heat-compressed Radiata pine (Pinus radiata D.Don) by compression temperature and time were investigated. The compressive strength and bending strength of heat-compressed wood increased with increasing compression temperature and time. But the compressive strength and bending strength decreased with press temperature $220^{\circ}C$. It was considered due to thermal degradation during high temperature conditions. The surface hardness of heat-compressed wood increased with increasing compression temperature. However, the effect of compression time was negligible. The nail holding power was not affected by compression temperature and time.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.4
• /
• pp.311-317
• /
• 2011

The mechanical properties of heat-compressed Radiata pine (Pinus radiata D.Don) by compression set were investigated. Heat-compression condition was temperature at $180^{\circ}C$ and press time for 60 minutes. The mechanical properties of heat-compressed wood increased with increasing compression set. Increase of the specific gravity has led to increase in mechanical properties. The maximum compression set of Radiata pine was investigated approximately 65%. It was almost same result with porosity 68% of Radiata pine in specific gravity 0.48.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.2
• /
• pp.162-170
• /
• 2011

As the result of implementing a treated material test and durability test after quickly drying S.P.F. species, a type of softwood structural material, within a short period time, soaking it in liquid phosphate flame proof agent for an hour, microwave heating it, and compressing it from 3.8cm to 1cm, when setting the appropriate heating time of microwave heating at 7 minutes at 5kW, it is observed that it satisfies the target water content (4~5%). It is shown that in a water content measurement of the wood that is compressed after being softened by soaking in the flame proof agent, drying and heating at 3kW for 9 minutes, all specimens satisfied 12~14%, the appropriate water content for exterior wood. Also, it is shown that in terms of the flame performance obtained through a flame resistance treatment of the compressed wood and a treated material test, the specimen soaked in flame proof agent for 30 minutes was the most excellent, and that the performance test result of the compressed wood in all areas, such as nail withdrawal resistance, compression, bending strength, and shearing strength, were all improved in their mechanical features to twice to three times better performances.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.5
• /
• pp.471-485
• /
• 2018

Post-heat treatment experiments were carried out for complete dimensional stabilization of thermally compressed wood (Pinus koraiensis). An absorption test was carried out to evaluate the dimensional stability. The specific gravity increased from 0.43 to 0.79 by thermal compression at a compression ratio of 50% thickness. Through the post-heat treatment of compressed wood, the water absorption and thickness swelling decreased with increasing the heat treatment temperature and time. In the case of the thickness recovery rate, when the heat treatment was performed for 24 hours at $120^{\circ}C$, $140^{\circ}C$ and $160^{\circ}C$, the thickness recovery was less than 1%. Therefore, it can be confirmed that the method of dimensional stabilization method of the thermal compression wood can be carried out very effectively through post heat treatment process.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.3
• /
• pp.206-212
• /
• 2011

It was investigated the hardness and dimensional stability of heat-compressed wood by compression temperature and time. The surface hardness of heat-compressed wood increased with increasing compression temperature. The lowest hardness value (5.0 N/$mm^2$) was observed in the temperature $70^{\circ}C$ while the highest value (15.6 N/$mm^2$) was obtained in compression temperature $220^{\circ}C$. Dimensional recovery test results showed that fixation of compression set improved with increasing compression temperature. However, the fixation effects were negligible by press time. Contact angle increased with increasing press temperature and time.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.1
• /
• pp.68-75
• /
• 2015

We conducted a thermal compression of domestic Korean pinewood for a use in flooring. For the evaluation of flooring material, we measured dimensional stability and surface hardness of thermally compressed wood. It is possible to make high-specific gravity woods with a range of 0.82-0.92 after the thermal compression with 50% compression set. The surface hardness increased with an increase in the pressing temperature. The highest value of surface hardness was $23.6N/mm^2$, which was obtained from the thermal compressed wood with pressing temperature of $160^{\circ}C$ and 30 minutes of pressing time. However, the surface hardness of woods treated at high temperature of $180^{\circ}C$ or greater decreased. The recovery of thickness decreased with increasing the pressing temperature. For dimensional stability, compression temperature was more dominant than compression time.

• Journal of the Korea Furniture Society
• /
• v.11 no.2
• /
• pp.1-6
• /
• 2000

This study was carried out to investigate the effect of steaming on mechanical properties of heat-compressed wood specimens. The specimens for this mechanical strength tests were prepared to super-heated steam treatment after compression to the radial direction of sonamu (Pinus densiflora). The specimen's size is $50(L)mm{\times}20(R)mm{\times}17(T)mm$. Steaming temperature and treatment time is $120^{\circ}C$ and 20, 40, 60, 80, 100 minutes, respectively. Modulus of elasticity(MOE) in compressive test is directly proportional to steaming time. On the other hand, modulus of elasticity in bending test between steaming and not steaming after heat-compressed wood is similar irrespective of steaming time. The reason for this phenomenon is not clear yet.