大家帮我看看这个大沙的刀尖

jasonp

.............这把SLCC真不是退火了，我觉得是热处痕迹没有磨掉，也没地方退火去

nightsky

不可能是什么退火，普通碳钢的退火温度要在1400度（760摄氏度）以上，象S30这种合金钢还要高，普通沙带机打磨刀刃怎么可能在室温的情况下产生那么高的热量，使刀尖达到那么高的温度？热处理时，在炉子里加到那么高的温度也要一段时间，而且热处理的温度还要低于退火的温度。再说，象CR这种专业的刀具制造厂，不可能在工艺上有这么大的缺陷。刀尖开完刃就变软了？那样的话工艺早就改了，谁违反工艺干活，早就被开了。

gu

个人还是认为这绝对是开锋造成的。

nightsky

哈哈，可能我说的不对，对S30不了解，热处理也只是有点理论知识，也没干过几次。如果说的不错的话，回火（TEMPERING）是指热处理后消除应力的加热过程，温度较低，这不在本帖的讨论范围。淬火温度（HAEDENUING），是指热处理要达到的温度。那么如果活干错了，要重新做，退火（ANNEALING）使金属重新变软，需要的温度要高于淬火温度，而且要保持一段时间，采取合适的降温措施。至少对碳钢的处理是这样的。

nightsky

CPM® S30V®
Issue #4
Carbon 1.45%
Chromium 14.00%
Vanadium 4.00%
Molybdenum 2.00%

Thermal Treatments

Forging: 2100°F (1150°C) Do not forge below 1750°F (950°C).
Annealing: Heat to 1650°F (900°C), hold 2 hours, slow cool no faster than 25°F (15°C) per hour to 1100°F (595°C), then furnace cool or cool in still air to room temperature.
Annealed Hardness: About BHN 255

Stress Relieving
Annealed Parts: Heat to 1100-1300°F (595-705°C), hold 2 hours, then furnace cool or cool in still air. Hardened Parts: Heat to 25-50°F (15-30°C) below original tempering temperature, hold 2 hours, then furnace cool or cool in still air.
Straightening: Best done warm 400-800°F (200-430°C)
Hardening
Preheat: Heat to 1550-1600°F (845-870°C) Equalize.
Austenitize: 1900-2000°F (1035-1095°C), hold time at temperature 15-30 minutes.
Quench: Air or positive pressure quench (2 bar minimum) to below 125°F (50°C), or salt or interrupted oil quench to about 1000°F (540°C), then air cool to below 125°F (50°C).
Temper: Double temper at 400-750°F (200-400°C). Hold for 2 hours minimum each time. (See Table) A freezing treatment may be used between the first and second tempers. Freezing treatments help to attain maximum hardenability and must always be followed by at least one temper.
NOTE: For optimum stress relieving, CPM S30V may be tempered at 1000-1025°F (540-550°C). Tempering in this range may result in a slight decrease in corrosion resistance.

Size Change: +0.05 to +0.10% when fully martensitic. The presence of retained austenite may reduce the net growth. When tempering at 400-750°F (200-400°C), freezing treatments may be necessary to minimize retained austenite.

Recommended Heat Treatment:
Austenitize 1950°F (1065°C). Quench to below 125°F (50°C).
Double temper at 600°F (315°C) 2 hrs. minimum each temper. Cool to hand warm between tempers. A freezing treatment may be added between tempers.
Aim hardness: 58-61 HRC.

刀友是个好地方，和朋友们聊聊，自己也能学点东西，以上是网上找的S30热处理过程。
引自：http://www.knifekits.com/vcom/pr ... amp;products_id=940

nightsky

Annealing: Heat to 1650°F (900°C), hold 2 hours, slow cool no faster than 25°F (15°C) per hour to 1100°F (595°C), then furnace cool or cool in still air to room temperature.
退火：加热至 1650°F (900°C)，保持2小时，慢冷，温度变化不能高于 25°F (15°C)每小时到 1100°F (595°C)，然后在炉中冷却或在稳定空气中冷却到室温。
楼主的刀尖想要退火看来还挺麻烦。

chungming

原帖由 胡铁花 于 2009-4-16 00:09 发表
谢谢各位！
用砂轮机打磨时会不会在刀尖这个小地方形成足以退火的局部高温呢？哪位刀匠能出来解答一下啊？

是有可能的，平時我看著學生磨高速鋼車刀，都要告誡他們不要把車刀磨到變顏色。
磨的時候確實可以產生高溫，但是要達到退火的高溫也不容易，應該只是回火軟化而已，會稍微軟一點。
刀尖這個部位，很薄很細小，熱量容易集中；但是因為很薄，砂輪容易磨除材料，所以鋼材想要累積到高溫也不容易，早被磨掉了。
結論是，我覺得表面是高溫氧化的跡象，但是不會太影響刀尖的性能。如果是我，放著不理即可。等到刀子使用後、刀尖磨損了，再磨一磨即可。

刀丛里的歌

很可能退火了

敏1.0

作为新手，我感觉很好啊，晕了

BG-42

没什么问题的，楼主别在猜疑了~

罐装极品猫

我觉得不是什么大问题。

可能是热处理时造成的，刀尖的厚度相对刀身来说太薄了导致热处理时受热不均匀。

我手上的蝴蝶610，710，42，3300都有这种情况。

710的刀尖在我用抛光膏打磨之后恢复了正常的金属色，硬度方面也没发现和刀刃其他地方有区别。

胡铁花

有结果了：From: crkinfo@chrisreeve.com
subject: RE: A question.
Date: Thu, 16 Apr 2009 08:31:39 -0600


Tianshu,



Thank you for your email. I’m sorry your friend has the color on the tip of his knife. It was caused from the steel heating up while sharpened. Usually we buff out that mark before it is sent. It appears we missed it on his knife. The good news is the “damage” is all cosmetic. It does not affect the heat treat or performance. I know you mentioned he lived in China. I have received knives from China and sent knives back to people in China. He can send it in for us to fix at no additional charge. I have included instructions in the attachment. I apologize for the inconvenience. Please let me know how he wants to proceed or if you need more information from me. We are closed Friday but back in the office Monday.



Kind regards,

Heather




--------------------------------------------------------------------------------


Sent: Wednesday, April 15, 2009 11:16 PM
To: crkinfo@chrisreeve.com
Subject: A question.



Hi:
One of my friends got a new Sebenza a few days ago,he found the point has a colour like brown ,(shown in the picture).He is worry about the point was annealed.Would you please give him an explaination to why it was happened.He is in China,it is impossible to sent it back to US. He just want to know is it really an annealing,and does the annealing ,burning or something affect using.
Thanks !
Tianshu

[ 本帖最后由 chungming 于 2009-4-20 12:51 编辑 ]

ericf

——那就是什么事儿也没有。可以安心啦！

wxs

原帖由 胡铁花 于 2009-4-19 15:38 发表
有结果了：From: crkinfo@chrisreeve.com
Subject: RE: A question.
Date: Thu, 16 Apr 2009 08:31:39 -0600


Tianshu,



Thank you f ...

我不懂e文，高手帮翻译一下

[ 本帖最后由 chungming 于 2009-4-20 12:52 编辑 ]

chungming

Thank you for your email. I’m sorry your friend has the color on the tip of his knife. It was caused from the steel heating up while sharpened. Usually we buff out that mark before it is sent. It appears we missed it on his knife. The good news is the “damage” is all cosmetic. It does not affect the heat treat or performance. I know you mentioned he lived in China. I have received knives from China and sent knives back to people in China. He can send it in for us to fix at no additional charge. I have included instructions in the attachment. I apologize for the inconvenience. Please let me know how he wants to proceed or if you need more information from me. We are closed Friday but back in the office Monday.
大意是說，這個痕跡是因為開鋒時的高溫所造成的，但是不會影響熱處理與刀子性能。通常他們會拋光掉，但是這把刀子他們忘記了，感到很抱歉！也願意處理！刀主可以將刀子寄回，免費處理。

[ 本帖最后由 chungming 于 2009-4-21 12:53 编辑 ]