Dimensional Stability of Poplar Wood after Densification Combined with Heat Treatment

2012 ◽  
Vol 152-154 ◽  
pp. 112-116 ◽  
Author(s):  
Jia Bin Cai ◽  
Tao Ding ◽  
Liu Yang
Keyword(s):  
Heat Treatment ◽  
Dimensional Stability ◽  
Hybrid Poplar ◽  
Treatment Temperature ◽  
Thermal Modification ◽  
Holding Time ◽  
Poplar Wood ◽  
Compression Set ◽  
Densification Temperature

Hybrid poplar boards were subjected to thermo-mechanical densification combined with heat treatment. Hydroscopicity and hygroscopicity of the treated samples were measured. The results showed that dimensional stability of the samples was influenced by compression set significantly. The higher the compression set, the greater the swelling of the samples. On the contrary, the influence of densification temperature and duration was not significant. Thermal modification significantly reduced hydroscopicity and hygroscopicity of the samples. Both higher treatment temperature and longer holding time resulted in better dimensional stability.

A thermal modification technique combining bulk densification and heat treatment for poplar wood with low moisture content

2021 ◽  
Vol 291 ◽  
pp. 123395
Author(s):  
Xianju Wang ◽  
Dengyun Tu ◽  
Chuanfu Chen ◽  
Qiaofang Zhou ◽  
Huixian Huang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Thermal Modification ◽  
Poplar Wood ◽  
Modification Technique

Microstructure of Semi-Solid Extruded Copper Alloy after Heat Treatment

2019 ◽  
Vol 285 ◽  
pp. 146-152
Author(s):  
Nai Yong Li ◽  
Han Xiao ◽  
Chi Xiong ◽  
De Hong Lu ◽  
Rong Feng Zhou
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Copper Alloy ◽  
Treatment Time ◽  
Solid Phase ◽  
Treatment Temperature ◽  
Primary Phase ◽  
Holding Time ◽  
Average Grain Size ◽  
Semi Solid

The semi-solid extruded ZCuSn10P1 copper alloy were annealed at different temperatures and time. The influences of heat treatment temperature and holding time on the microstructure of semi-solid ZCuSn10P1 copper alloy were investigated. The results show that with the increase of heat treatment temperature, the morphology of the semi-solid microstructure was improved, the sharp angle around the primary phase α-Cu and the liquid droplets were reduced. With the increase of heat treatment time, the solid-liquid segregation of the semi-solid structure was improved. The average grain size of the solid phase increased with the increasing of the holding time. After heat treatment, the solid solubility of the primary phase α-Cu increased, and the Sn and P elements in the liquid phase continued to diffuse to the primary phase α-Cu. The microstructure of semi-solid copper alloy was the most uniform after heat treatment at 350°C for 120 min.

scholarly journals Influence of Site Conditions and Quality of Birch Wood on Its Properties and Utilization after Heat Treatment. Part I—Elastic and Strength Properties, Relationship to Water and Dimensional Stability

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 189 ◽  
Author(s):  
Vlastimil Borůvka ◽  
Roman Dudík ◽  
Aleš Zeidler ◽  
Tomáš Holeček
Keyword(s):  
Heat Treatment ◽  
Dimensional Stability ◽  
Bending Strength ◽  
Color Change ◽  
Untreated Wood ◽  
Strength Properties ◽  
Treatment Temperature ◽  
Impact Bending ◽  
The Impact

This work deals with the quality of birch (Betula pendula) wood from different sites and the impact of heat treatment on it. Two degrees of heat treatment were used, 170 °C and 190 °C. The resulting property values were compared with reference to untreated wood samples. These values were wood density, compressive strength, modulus of elasticity (MOE), bending strength (MOR), impact bending strength (toughness), hardness, swelling, limit of hygroscopicity, moisture content and color change. It was supposed that an increase in heat-treatment temperature could reduce strength properties and, adversely, lead to better shape and dimensional stability, which was confirmed by experiments. It was also shown that the properties of the wood before treatment affected their condition after heat treatment, and that the characteristic values and variability of birch properties from 4 sites, 8 stems totally, were reflected in the properties of the heat-treated wood. Values of static MOR were the exception, where the quality of the input wood was less significant at a higher temperature, and this was even more significant in impact bending strength, where it manifested at a lower temperature degree. Impact bending strength also proved to be significantly negatively affected by heat treatment, about 48% at 170 °C, and up to 67% at 190 °C. On the contrary, the most positive results were the MOE and hardness increases at 170 °C by about 30% and about 21%, respectively, with a decrease in swelling at 190 °C by about 31%. On the basis of color change and other ascertained properties, there is a possibility that, after suitable heat treatment, birch could replace other woods (e.g., beech) for certain specific purposes, particularly in the furniture industry.

scholarly journals Effects of heat and steam on the mechanical properties and dimensional stability of thermo-hygromechanically-densified sugar maple wood

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 9212-9226
Author(s):  
Qilan Fu ◽  
Alain Cloutier ◽  
Aziz Laghdir
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Dimensional Stability ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Bending Strength ◽  
Bending Stiffness ◽  
Treatment Temperature ◽  
Densification Process ◽  
Compression Set

Effects of heat and steam were investigated relative to the mechanical properties and dimensional stability of thermo-hygromechanically-densified sugar maple wood (Acer saccharum Marsh.). The densification process was performed at four temperatures (180 °C, 190 °C, 200 °C, and 210 °C) with and without steam. The hardness, bending strength, bending stiffness, and compression set recovery of the control and densified samples were determined. The effects of heat and steam on the density profile of the samples across thickness were also investigated. The results suggested that the effects of steam on the mechanical properties and dimensional stability of sugar maple wood were more important than that of heat’s influence. Compared to the samples densified without steam, the samples densified with steam showed higher values for hardness, bending strength, bending stiffness, compression set, and density, but much lower compression set recovery when treatment temperature was below 200 °C. High temperature combined with steam contributed to decreased compression set recovery. The lowest compression set recovery was obtained after the first swelling/drying cycle for all of the treatments. A higher weight loss occurred at 210 °C, which resulted in a noticeable decrease of wood density.

scholarly journals Dimensional stability, fungal resistance and mechanical properties of radiata pine after combined thermo-mechanical compression and oil heat-treatment

Holzforschung ◽  
2016 ◽  
Vol 70 (8) ◽  
pp. 793-800 ◽  
Author(s):  
Manoj Kumar Dubey ◽  
Shusheng Pang ◽  
Shakti Chauhan ◽  
John Walker
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Dimensional Stability ◽  
Linseed Oil ◽  
Treated Wood ◽  
Untreated Wood ◽  
Radiata Pine ◽  
Fungal Resistance ◽  
Compression Set ◽  
Decay Test

Abstract The dimensional stability and mechanical properties of radiata pine (Pinus radiata) has been investigated after thermo-mechanically compression (TMC) followed by oil heat-treatment (OHT). Wood specimens were first compressed in the radial direction then heat-treated in a linseed oil bath at 160–210°C. Spring-back percentage, water repellence efficiencies, and compression set recovery percentage were determined as indicators of dimensional stability. The resistance of treated wood against a brown rot fungi was assessed based on an accelerated laboratory fungal decay test. Strength, stiffness and hardness were determined as a function of different treatment parameters. After TMC, high compression set (39%) was achieved without any surface checks and cracks. Specimens undergoing TMC followed by OHT showed relatively less swelling and low compression set recovery under high moisture conditions. The fungal resistance of wood after TMC+OHT slightly increased compared to untreated wood and TMC wood. The mechanical properties of TMC+OHT wood were inferior to those of TMC wood.

scholarly journals Evaluation of the Dimensional Stability of Black Poplar Wood Modified Thermally in Nitrogen Atmosphere

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1491
Author(s):  
Olga Bytner ◽  
Agnieszka Laskowska ◽  
Michał Drożdżek ◽  
Paweł Kozakiewicz ◽  
Janusz Zawadzki
Keyword(s):  
Dimensional Stability ◽  
Nitrogen Atmosphere ◽  
Thermal Modification ◽  
Poplar Wood ◽  
Dimensional Changes ◽  
Processing Times ◽  
Modification Process ◽  
Black Poplar ◽  
Tangential Directions ◽  
Modified Wood

Black poplar (Populus nigra L.) was thermally modified in nitrogen atmosphere. The effects of the modification process on poplar wood were evaluated for temperatures: 160 °C, 190 °C, and 220 °C applied for 2 h; and 160 °C and 190 °C for 6 h. The percentual impact of temperature and time of modification on the properties of modified wood was analysed. The study permitted the identification correlations between the chemical composition and selected physical properties of thermally modified poplar wood. The dimensional stability of poplar wood was improved after thermal modification in nitrogen. The higher the temperature of modification, the lower the equilibrium moisture content (EMC) of black poplar. At the temperature of 220 °C, EMC was two times lower than the EMC of non-modified black poplar. It is also possible to reduce the dimensional changes of wood two-fold (at the modification temperature of 220 °C), both in radial and tangential directions, independently of the acclimatization conditions (from 34% to 98% relative humidity, RH). Similar correlations have been found for wood that has been soaked in water. Higher modification temperatures and longer processing times contributed to a lower swelling anisotropy (SA).

Effect of High Temperature on the Change in Color, Dimensional Stability and Mechanical Properties of Spruce Wood

Holzforschung ◽  
2003 ◽  
Vol 57 (5) ◽  
pp. 539-546 ◽  
Author(s):  
P. Bekhta ◽  
P. Niemz
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Dimensional Stability ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Treatment Time ◽  
Color Difference ◽  
Treatment Temperature ◽  
Color Changes

Summary In this study the effect of high temperature on mechanical properties, dimensional stability and color of spruce was investigated. Wood specimens conditioned at different relative humidities (50, 65, 80 and 95%) were subjected to heat treatment at 200°C for 2, 4, 8, 10 and 24 h and at 100, 150 and 200°C for 24 h. Color changes were measured in the Minolta Croma-Meter CR-300 color system. Bending strength and modulus of elasticity were determined according to DIN 52186. The results show that heat treatment mainly resulted in a darkening of wood tissues, improvement of the dimensional stability of wood and reduction of its mechanical properties. The darkening accelerated generally when treatment temperature exceeded approximately 200°C. Most of the darkening occurred within the first 4 h of exposure. For the specimens heated to high temperatures, the average decrease in bending strength was about 44–50%, while modulus of elasticity was reduced by only 4–9%. We found that treatment time and temperature were more important than relative humidity regarding the color responses. Strong correlations between total color difference and both modulus of elasticity and bending strength were found. Thus, the color parameters can be estimated quantitatively and used as a prediction of wood strength.

scholarly journals Effects of Heat Treatment on the Color Change and Dimensional Stability ofGmelina arboreaandMelia azedarachWoods

2018 ◽  
Vol 68 ◽  
pp. 03010
Author(s):  
Wahyu Hidayat ◽  
Fauzi Febrianto ◽  
Byantara Darsan Purusatama ◽  
Nam Hun Kim
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Water Absorption ◽  
Equilibrium Moisture Content ◽  
Dimensional Stability ◽  
Color Change ◽  
Value Added ◽  
Treatment Temperature ◽  
Melia Azedarach ◽  
Color Properties

This study aimed to improve the color properties and dimensional stability of gmelina (Gmelina arborea) and mindi (Melia azedarach) woods via heat treatment. Heat treatment was conducted using an electric furnace at 180°C and 210°C for 3 h, with a heating rate of 2°C/min. Wood samples were stacked with and without metal clamp. The effectsof temperature and clamping during heat treatment on the color change and dimensional stability were evaluated. The evaluation of color change was performed using the CIE-Lab color system and the evaluation of dimensional stability was conducted by measuring the equilibrium moisture content and water absorption. The results showed that the overall color changes(ΔE*) in gmelina and mindi woods were mainly affected by the reduction in lightness (L*) due to heat treatment. TheΔE*increased with increasing treatment temperature, with a higher degree obtained in gmelina wood. Application of metal clamp during treatment limited the exposure of wood surface to the heated air, resulting in lower value ofΔE*than the samples without metal clamp. Dimensional stability of gmelina and mindiwoods improved by heat treatment, showing lower equilibrium moisture content and water absorption than the untreated woods. Furthermore, heat treated mindi absorbed less water than gmelina. The results suggested that heat treatment could enhance the color properties and dimensional stability of gmelina and mindi woods for value added products.

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