回复 6# leomet 的帖子
我认为不是蚀孔而是材料本身含有夹杂物，经过抛光出现的，我以前也见过有类似的！40CrMo 感應淬裂
40CrMo 感應淬裂, 肇因於初始組織不良.初始組織是假調質(軋延態, as-rolled)[ 本帖最后由 leomet 于 2009-7-21 07:41 编辑 ]
H13 原材料缺陷
本帖最后由 leomet 于 2010-6-6 07:34 编辑原材料缺陷
undissolved interdendritic carbide film segments that formed
after ingot forging and left after austenizing, prior to quenching.
These carbides are very minute and are difficult to be detected with low price OM.
They aretoughness killers, therefore, Most of the toolings with
this kind of carbide film will fail prematurely, for sure.
Note: 固析者殺傷力較液析者大.
[ 本帖最后由 leomet 于 2009-8-12 23:45 编辑 ] 本帖最后由 leomet 于 2009-11-29 06:53 编辑 感應淬火時的熔融層淬油時增碳?
We see this once in a blue moon. 本帖最后由 leomet 于 2009-11-29 06:50 编辑
189# leomet
专家能否谈谈浸蚀剂的应用情况？ 190# 风来疏竹
FeCl, Nothing special.
試樣以高週波感應燒熔後入油槽. 無意中發現此層. 本帖最后由 leomet 于 2009-9-16 06:24 编辑
H13 原材料缺陷
A stressed part failed prematurely because of these cubic carbide particles.
Cracks were found to originate from sharp corners ofcubic "vanadium carbide(?)" particles.
Photo ~467, looks like sugar cube, does'nt it? 本帖最后由 leomet 于 2009-12-10 07:16 编辑
氫裂 caused by 過度酸洗
磷酸膜處理的齒輪未使用, 發現裂紋.
.........這些碳化物所處的晶界, 也是氫原子聚集的位置. 原子氫(H)一旦聚集成了分子氫(H2), 晶界上就有氣体壓力, 氣体壓力累積夠大時, 就會把晶界撐裂開來. 金屬科學上稱為”氫引發的破裂”(hydrogen-induced cracking). 高強度(淬回火)的鋼零件, 表面處理後都需實施去氫處理就是要避免此悲劇發生. 本帖最后由 leomet 于 2009-10-23 17:11 编辑
本帖最后由 leomet 于 2015-5-27 08:46 编辑
A hard lesson learned.
Faulty parts are being recalled in theU.S.
A ball stud casing, supposed to have an induction-hardened case depth of 1 mm and 3~4 mm ductile core material to backup the brittle hardened layer.
This failed part was found to have a case that was induction-hardened all the way through, from inside out (>4 mm thick).And the hardened-layer was not even tempered! Therefore the thru-hardened case is too brittle and was not able to withstand any slightest impact load.Now, recall is the only way to reduce the future loss of money. There are over 12000 pieces out there in the USA market. Should a human life is lost, lawsuit will follow and money lost will be astronomical.
I was told that in the process of getting quotation for induction hardening a year ago, one very good induction heattreater quoted 0.8 RMB per piece. Butthey turned to a cheaper offer of 0.5 RMB per piece from a heattreater which is less-experienced and has poor quality management. This tragedy doomed.
Penny wise and pound foolish is what I would describe this auto parts export company. This event will cost the owner of this company "an arm and a leg", but he will survive. I do hope that he would get back on his feet soon and do some overhaul to the management in his company.i 本帖最后由 leomet 于 2009-11-30 09:30 编辑
後記: 這老闆怕被國外求償, 趕快改了公司名.
本帖最后由 leomet 于 2010-7-31 06:42 编辑
194# leomet
A failed stress ring. Crack was found to originated from top of thread.
Very detrimental dendrite arm boundary carbide(arrowed) was found in its microstructure. 本帖最后由 leomet 于 2009-10-23 18:48 编辑
破裂面照明:頂光 與 側光 本帖最后由 leomet 于 2013-8-9 14:55 编辑
195# leomet
JIS SCM 440, As-rolled. 假調質. Shown to you are very detrimental carbide "blades"
that will lead you to hell if you use this steel to make parts.
Color eteched to high-light carbide particles from matrix of ferrite.
Otherwise, findingcarbide in white ferrite would be like finding a white rabbit in a snow field.
white spots in photos 744, 746 are retained austenite? 本帖最后由 leomet 于 2009-12-9 07:15 编辑
本帖最后由 leomet 于 2011-2-3 21:20 编辑
Another 假調質. Most of thecarbide particles retained in white streaks after hot rolling.
Note:Not all the white spots are carbide. Most of them are retained austenite, accompanied by carbide. 本帖最后由 leomet 于 2009-12-31 09:22 编辑
These white spots are named MA islands because they are highly alloyed.M+A+K are what you find here.. 本帖最后由 leomet 于 2015-5-27 08:48 编辑
Same steel as above. Normal etching, without tinting.
本帖最后由 leomet 于 2009-10-30 09:23 编辑
枝晶間的空隙 interdendritic voids 铸铝109进行固溶与时效时的金相照片
固溶：
时效：
可观察到合金相的析出与形态变化 非常好的资料
但是建议楼主每张照片标注放大比例 简直太精美了 从未看见过如此多的、精美的金相图片，收藏学习了，谢谢 本帖最后由 leomet 于 2010-1-30 21:43 编辑
Faulty H13 in annealed condition. Its Q / T tooling for forging Al car wheel
failed prematurely because of its Giant grains.
Each view was taken as a pair---- of bright and dark fields.
MicrostructureTHIS BAD does not come by often, you see this only once in a blue moon.