AISI 420casting, Q & T.
This specimen was cut from center of a dia. 40 cast bar.
photo ~406: darker areas are dendrite arm boundaries---the last sites to freeze.
They are rich incarbidebecause of the solute-atom segregation
during solidificaton. Surface of casting does not have this segregation problem. 本帖最后由 leomet 于 2011-10-22 06:23 编辑
半分解的 Pearlite, partially dissolved.
Taken from a cast iron specimen. 本帖最后由 leomet 于 2011-10-22 06:26 编辑
Divorced carbide in a AISI 1008 low carbon steel. In sheet metal forming, cracking often
occur because of this kind of carbide films. 你好，感谢你为我们提供了这些难得的资源。
我想咨询一下，金相图片经过染色后在普通的显微镜上是不是也能看到呀，我们是奥林巴斯的GX41显微镜。 回复 353# xichuan5201
可以. 回复 305# leomet
谢谢！:victory:
粉末 鋼
本帖最后由 leomet 于 2011-7-10 12:32 编辑P/M HSS
OM / SEM photos I'm very grateful teacher Wu can share these precious metallographic photo with us.Thank you very much.
P/M gear from gkn
本帖最后由 leomet 于 2011-10-12 19:11 编辑Sintered Gear (carbon ~ 0.60%C, as I was told)
Microstructures of a sinterered steel : Ferrite + Carbide (both eutectoid and divorced).
Note that big bands of divorced carbide. A small portion of them will remain after hardening
because they just don't have enoughtime to fully dissolve into solution during Austenization.
Gear teeth induction hardened. Microstructures are very various because of the short heating time---only a few seconds.
In such a short time and with such a poor initial microstructures (i.e. big bands of carbides), you really don't expect to have a homogeneous Martensite structure. Therefore, present in the photos are retained Ferrite, retained carbide, Martensite with various carbon%.
Retained Austenite? Possible, but less likely. Why? Because heating time is so short that not all0.6C%
goes into Austenite matrix.
Bainite? Even less likely. Why? The phase transformation time is way too short for bainite formation.
LeoMet seeing MYG
The meeting of two old fellows. 老师的图片非常好，就是用的外语，文化程度太低了，有好多看不懂，最好标注一下，老师成心教我们请不要用外语表达，在此我代表看不懂的坛友万分感谢你，我们会常常关注你的成功佳作，带给我们很好的学习机会，由于文化有限，不对之处请老师原谅。 本帖最后由 leomet 于 2011-10-22 06:34 编辑
热处理老学徒 发表于 2011-9-28 15:49 static/image/common/back.gif
老师的图片非常好，就是用的外语，文化程度太低了，有好多看不懂，最好标注一下，老师成心教我们请不要用外 ...
1. 我並沒有要教任何人. 只是展示/分享漂亮的照片. 文章是自言自語, 練習寫作.英語能力夠的人可在此撿到一些知識---我也常在英文網站上撿知識.
2. 我英文輸入要遠比中文快. 會變成這樣是有其歷史淵源的:
我們讀大學的60年代, 只有國文/軍訓與國父(孫中山)思想三科是中文.
其餘物理/化學/所有專業科目都是盜版英文書----很沒民族自尊, 但接軌國際, 受益多多.
我的顧問工作上有時需用英文與外國客戶溝通. 用中文討論的機會卻是---無.
所以我腦子裡裝的術語,英文多於中文. 而且(台灣)與你所習用的名詞也大不相同.
仔細想了想, 其實在工程技術的養成訓練上, 我並未受過正統中文名詞訓練. 當年老師也鼓勵學生多用英文名詞.
80年代, 我们連聽個"粱祝小提琴協奏曲"(因為是大陸作品)都要偷偷的聽. 否則台灣當局要找你麻煩的.(現在你們也是不能看台灣網站---同樣意思.)所以過去60年, 不可能有大陸的書出現在台灣市場. 大陸使用的名詞, 我們都沒學過. 在這裡會的人很少, 請見諒!
leomet 发表于 2011-10-4 21:56 static/image/common/back.gif
1. 我並沒有要教任何人. 只是展示/分享漂亮的照片. 文章是自言自語, 練習寫作. 或與外國技師討論事情(# ...
前辈老师，理解你的人生历史后，感到惭愧之至，去年见过台湾的数控加工中心的专家，40岁左右，他对员工非常严格，管理非常到位，我们公司全体员工受益匪浅。 很精致的照片，学习了，有标出就更好了！ leomet 发表于 2011-10-4 21:56 static/image/common/back.gif
1. 我並沒有要教任何人. 只是展示/分享漂亮的照片. 文章是自言自語, 練習寫作.英語能力夠的人可在此撿 ...
请问leomet老师：您经常拣知识的英文网站有哪些呢？能共享不？ 无容置疑，这是本坛最华丽的篇章！:victory::victory::victory: phase transformation films:
惠德曼肥粒鉄,魏氏鉄素体: http://www.youtube.com/watch?v=hXUmqM_8yJ4
麻田散鉄 Martensite: http://www.youtube.com/watch?v=OQ5lVjYssko
晶粒成長: http://www.youtube.com/watch?v=J_2FdkRqmCA
www.msm.cam.ac.uk/phase-trans/abstracts/CP1b.html英國劍橋大學材料系
http://www.metallographic.com/Brochures/Met-Manual-2b.pdf
http://www.amazon.com/Metallography-Principles-George-Vander-Voort/dp/0871706725
本帖最后由 leomet 于 2012-1-21 04:56 编辑
夭壽的排氣閥,傘面上的疲勞裂紋. 材料:耐熱鋼, 氣閥鋼 valve steel: SUH 35, 1.4871, 21-4N, 21Cr-4Ni-N, Fatigue crack on the head of ex valve. 本帖最后由 leomet 于 2015-1-1 19:33 编辑
Below: fatigue cracks that got started from corrosion pits on the surface of head.
Fatigue crack surface was darkened by high temp oxidation.
Above: Newly opened crack surface (by me) is bright and shiny (green arrows).