本帖最后由 leomet 于 2010-2-18 10:14 编辑
Near eutectic,white cast iron
rod-like eutectic mixture of carbide and iron (rods)
本帖最后由 leomet 于 2010-7-31 07:23 编辑
AISI 310, heat-resistant steel. 枝晶界碳化物
As-cast : carbide particles in dendrite arm boundaries.
solution treated at 1050 C and quenched in water.
本帖最后由 leomet 于 2010-10-24 06:55 编辑
Nowhere else but this forum can you find such a wealth of quality photos (metallographic micrographs).
A tooling was scrapped before shipping to customer because of dimensional change.
The swelling with time was caused by too much R.A. in the matrix.
This is an age-old problem but you still encounter it once in a long while.
Carbide phase is tinted pale blue to red-purple for sharper contrast--easier distinction of R. A.
which is now white and pale yellow in the matrix, mostly. Darker area in the matrix is T.M.
R.A. is brighter because those areas are flatter and more reflective to lncident light.
Two of these photos are in 800x600 format for your visual delight. 本帖最后由 leomet 于 2009-12-30 06:38 编辑
D-type graphite for glass molds, aiming to delay
formation of “heat checks” on glass-mold surfaces.
The proper coloring of carbide was obtained bya lot of hard-work (different times of etching+tinting),
------ anda bit of luck as well. 本帖最后由 leomet 于 2009-12-9 07:09 编辑
SKD 11锻前的共晶碳化物经锻打被击碎，都成带状组织分布
Two cold work tool steels. Annealed condition: colored carbide particles in the white matrix of ferrite.
Carbide tinted.Note the network of secondary carbide in the matrix. 本帖最后由 leomet 于 2009-12-20 09:37 编辑
本帖最后由 leomet 于 2011-5-4 06:15 编辑
189# leomet
A cold work tool steel, same as that shown in #185, quenched and deep-frozened and tempered.
Carbide particles in the matrix of tempered martensite.
Compare to #185, R.A. is now gone and nowhere to be found. 本帖最后由 leomet 于 2009-12-20 09:39 编辑
彩色金相就漂亮，我一直想做，就是每天太忙没时间呀！哈哈
191# tanggang3008
不難, 只是非常耗時, 有時 5, 6 次才會碰上一次滿意的色彩. 本帖最后由 leomet 于 2009-12-11 10:35 编辑
本帖最后由 leomet 于 2011-5-4 06:17 编辑
190# leomet
Same cold work tool steels as above (#189). Matrix is tinted while Carbide is unaffected.
Note the network of carbide particles in photo 195~225. These network of carbide, if not completely go into the solution of austenite before quenching. Traces of it will remain in the grainboundaries after quenching. Although it might not be seen under O.M., itput the toughness of the steel in harm's way. 本帖最后由 leomet 于 2009-12-13 09:06 编辑
193# leomet
Metallographic micrographes for a glass mold.
Ti is usually added to encourage formation of finely dispersed D-type graphite
which provide the mold with a longer thermal fatigue life.
Orange phase in the cell boundaries is Steadite. Sharp, pointed spikes of steadite
are very harmful to thermal fatigue life
because they are stress-risers and thus, initiation sites for microcracks. 本帖最后由 leomet 于 2009-12-13 08:18 编辑
194# leomet
A hot work tool steel (~ H11), Q/T. 本帖最后由 leomet 于 2009-12-14 13:23 编辑
195# leomet
FT 300grey cast iron with steadite tinted pink. 本帖最后由 leomet 于 2010-1-1 08:54 编辑
30# leomet
这是亚共析钢等温淬火后的相组织图吧？
Cold work steelhardened, subzero treated and tempered.
carbide phase is tinted pink and purple. 本帖最后由 leomet 于 2009-12-20 09:46 编辑
AISI 4340 casting, 550C x 2 hrtempered.
Focusing on the area near interdendritic shrinkage.
Note the carbide film in-between dendrite arms. 本帖最后由 leomet 于 2009-12-24 08:37 编辑
本帖最后由 leomet 于 2010-7-31 07:30 编辑
AISI 4340 casting, same as # 199
Showing dendritic segregation. Dark areas are rich
in C% and alloying elements.
So you will often find Hi C Martensite, R.A., inclusion, and even carbide in
these areas in as-cast condition, and also in continuous cast and rolled steel
rods without homogenization annealing or normalizing.
My footprints on the sand of time of my career as a metallurgist.
178# leomet
Solution treated (K in 310). Some of them were aged (Others). As-cast (The last one) 本帖最后由 leomet 于 2009-12-25 10:55 编辑
请教下各位专家在测量脱碳层深度时，有部分贫碳，同时过渡区不明显。按照什么样的标准测量？
199# leomet
Alloy grey cast iron. Annealed at 900C. Most of the pearlite is spheroidized. 本帖最后由 leomet 于 2009-12-31 10:05 编辑