本帖最后由 leomet 于 2016-6-13 07:27 编辑
shenfuhai 发表于 2014-9-22 10:01
谢谢吴老师指导。
420不锈钢，我曾经加热到1100度，碳化物完全固溶；然后淬火，晶粒大的出奇。
好像只有你認同我的"双晶"說.........
我的照片中 有的Twin 形貌 還不包括在這四個形貌呢.
本帖最后由 leomet 于 2016-8-21 16:09 编辑
leomet 发表于 2015-8-8 16:19
More photos at high mag 高倍率. Go to:
http://www.rclbbs.com/forum.php?mod=viewthread&tid=16576&p ...
Twin boundary Carbide. Scroll up the 2nd photo to see the thickness of the twin carbide.
TAZ company , Germany
X46Cr13Martensitic stainless steel
本帖最后由 leomet 于 2016-8-21 16:53 编辑
偏析非常嚴重...................擴散退火未做(好)?
最下面照片中 白色網線是 鍛塊遺留下來的晶界.
三個黑"點"是嚴重偏析處.
Good carbide: well-dispersed carbide particles.
Bad carbide: continuous carbide particles.
本帖最后由 leomet 于 2016-8-26 10:08 编辑
SEM photos of this steel......................
Very flat fracture grain surfaces are twins.
本帖最后由 leomet 于 2016-8-21 17:40 编辑
This pellet-making tooling fractured in one day, and one day only !
Tooling was sent back from North America.
Grains flaked off the surface like this in one day.
Toughness of the Q/T steel must be very, very BAD !
本帖最后由 leomet 于 2016-8-21 15:59 编辑
Fracture surface taken with USB microscope.
Note those very flat and reflective twin surfaces.
Do you get the whole picture?You young and promising engineers.
本帖最后由 leomet 于 2016-8-24 18:00 编辑
OM Microstructure.....................
Carbide tinted in 2nd and 3rd photo.
本帖最后由 leomet 于 2016-8-21 19:09 编辑
Color etching.........................
See the last photo, 1 aa 4.jpg,you can see that density of twin carbide is very high, indeed.
I hope you young metallurgists enjoy reading these beautiful and instructive metallographic photos presented by the old man from Central Taiwan.
本帖最后由 leomet 于 2016-8-21 17:50 编辑
These photos of secondary cracking also show evidence
that twin carbides are the weakest sites of the steel.
No doubt about it.
leomet 发表于 2014-9-22 19:17
那2張影印的照片來自一份台灣權威單位(MIDRC, 金屬中心)的分析報告. 不知哪個經驗太稚嫩的小朋友分析的 ...
吴先生，我今日偶然看到此贴。
本人非常认同吴先生的看法。原两粗晶的金相图片，主要是锻造过程未细化晶粒所致。
本帖最后由 leomet 于 2016-8-26 10:06 编辑
leomet 发表于 2016-8-21 15:57
Fracture surface taken with USB microscope.
Note those very flat and reflective twin surfaces.
SEM photos of this cracked surface.
You never see fracture surface with so many twin boundary carbide like this.
本帖最后由 leomet 于 2016-8-26 10:04 编辑
shenfuhai 发表于 2014-9-21 22:11
吴老师好。这个粗大的晶界是原材的遗留的；晶界非常清晰，估计于在1030度保温时间过短有关系，从晶界碳化物 ...
這些平行線是魏先生碳化物, 與双晶碳化物有別.........
不是搞高Cr鑄造的, 難得見到它. 我只看過這一次. 所以用SEM把它記錄起來.
大佬聊天，新手学习！