Keranji


INTRODUCTION

The Standard Malaysian Name for the timber of Dialium spp. (Leguminosae). Vernacular names applied include keranji (Peninsular Malaysia, Sabah and Sarawak) with various epithets. Major species include D. indum, D. platysepalum, D. procerum and D. kunstleri. The sapwood is white to yellowish white, becomes light brown on exposure and is very distinct from the heartwood, which is golden brown or red-brown and darkens on exposure.

Also known as Keranji (Brunei); Kralanh and Kralanh lomie (Cambodia); Kedjongong, Kerandji, Kerandji asap, Keranji and Nyamut (Indonesia); Kheng and Mai kheem pheep (Laos); Taung-kaye (Myanmar); Kayi-khao, Khleng and Yi-thongbung (Thailand); and Xoay (Vietnam).


DENSITY

The timber is a Heavy Hardwood with a density of 755-1250 kg/m3 air dry.


NATURAL DURABILITY

Keranji is classified as moderately durable under the typical Malaysian conditions.


PRESERVATIVE TREATMENT

The timber is difficult to treat and the heartwood is resistant to preservative treatment.


TEXTURE

Texture is fine to moderately coarse and even, with deeply interlocked and sometimes wavy grain.


STRENGTH PROPERTIES

The timber falls into Strength Group A (Engku, 1988) or SG 3 (MS 544:Part 2:2001).


Strength Properties of Keranji 

Species

Test Condition

Modulus of Elasticity(MPa)

Modulus of Rupture(MPa)

Compression parallel to grain (MPa)

Compression perpendicular to grain (MPa)

Shear strength(MPa)

D. platysepalum

Green

18,800

109

54.5

-

10.9

Air dry

20,100

134

72.0

-

16.0

D. wallichii

Green

21,000

129

68.8

9.24

10.9

D. patens

Green

19,200

156

88.7

19.72

17.0


MACHINING PROPERTIES

It is easy to very difficult to resaw and easy to difficult to cross-cut, depending on the species. Planing is easy to slightly difficult and the planed surface is smooth, moderately smooth or rough in some radial boards due to picking-up of the grain.


Machining Properties of Keranji 

Species

Test Condition

Sawing

Planing

Boring

Turning

Re-sawing

Cross Cutting

Ease of planing

Quality of finish

Ease of boring

Quality of finish

Ease of turning

Quality of finish

D. laurinum

Green

slightly difficult

slightly easy

moderately easy

smooth

moderately easy

smooth

-

-

Air dry

-

-

-

-

-

-

-

-

D. patens

Green

difficult

slightly difficult

slightly difficult

tangential: smooth, radial: rough due to grain pick up

easy

moderately smooth

-

-

Air dry

very difficult

difficult

slightly difficult

moderately smooth

fairly easy

moderately smooth

easy

smooth

D. platysepalum

Green

easy

easy

easy

smooth

easy

smooth

-

-

Air dry

difficult

slightly difficult

easy

smooth

easy

smooth

easy

smooth

D. wallichii

Green

difficult

difficult

slightly difficult

moderately smooth

-

-

-

-

Air dry

very difficult

difficult

slightly difficult

moderately smooth

-

-

-

-


NAILING PROPERTY

Nailing property is rated as good.


AIR DRYING

The timber seasons fairly slowly with slight degrade, like cupping, bowing, twisting, splitting, surface-checking as well as insect and fungal attacks on the sapwood. The timber is also moderately prone to end-checking. 13 mm thick boards take approximately 2 months to air dry, while 38 mm thick boards take 6 months.


KILN-DRYING

Kiln Schedule E is recommended. The timber is prone to surface-checking and end-splitting. 25 mm thick boards take approximately 10 days to kiln-dry from 50 to 10% moisture content.


Kiln Schedule E

Moisture Content (%)

Temperature (Dry-bulb)

Temperature (Wet-bulb)

Relative Humidity (%) (approx.)

F

C

F

C

Green

120

48.5

115

46.0

85

60

120

48.5

113

45.0

80

40

125

51.5

116

46.5

75

30

130

54.5

117

47.0

65

25

140

60.0

120

49.0

55

20

155

68.0

127

53.0

45

15

170

76.5

136

58.0

40


SHRINKAGE

Shrinkage is variable, depending on species. D. platysepalum shows high shrinkage with radial shrinkage averages 2.3% and tangential shrinkage averages 3.7%. D. wallichii shows rather low shrinkage in that radial shrinkage averages only 1% and tangential shrinkage averages 1.7%.


MOVEMENT IN SERVICE

The movement of seasoned timber is classified under Type II.


USES

The timber is suitable for heavy construction, gymnasium equipment, railway sleepers, tool handles (impact), vehicle bodies (framework and floor boards), mallets, poles, telegraphic and power transmission posts and cross arms, bridges, pallets (permanent and heavy duty type), laboratory benches, heavy duty furniture, flooring (heavy traffic), piling, door and window frames and sills, posts, beams, joists, rafters, fender supports, columns (heavy duty), staircase (balustrade, carriage, newel, riser, stringer, tread, bullnose, round end and winder), interior finishing, panelling, mouldings, joinery and cabinet making.


REFERENCES

  1. Ani Sulaiman & Lim, S. C. 1990. Malaysian Timbers - Keranji. Timber Trade Leaflet No. 112. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 7 pp.
  2. Engku Abdul Rahman Chik. 1998b. Basic and Grade Stresses for Strength Groups of Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 38. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 13 pp.
  3. Menon, P. K. B. 1986. Uses of Some Malaysian Timbers. Revised by Lim, S. C. Timber Trade Leaflet No. 31. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 48 pp.
  4. MS 544:Part 2:2001. Code of Practice for the Structural Use of Timber: Permissible Stress Design of Solid Timber.
  5. Wong, T. M. 1982. A Dictionary of Malaysian Timbers. Revised by Lim, S. C. & Chung, R. C. K. Malayan Forest Records No. 30. Forest Research Institute Malaysia, Kuala Lumpur. 201 pp.