How to Harden and Temper 4140 Medium Carbon Steel

[@eduardomaterum9514]

Your tutorial video is definitely of great help to students taking up mechanical technology as well as to all those who are interested in mechanical works/machine works

[@BeardedWebb]

Excellent tutorial, thankyou for posting this.

[@haroldkreye8770]

Thanks for an informative video. The steps you followed, and your explanation of each step were clear and concise. Very well done.

[@marneliematerum300]

Thank you Prof Johnny for another very informative video!

[@profjohnny8624]

Thank Marnelie for subscribing and watching may turorial videos. God Bless!

[@0501delirium]

Thank johny for a good information

[@JoseHernandez-dj9ce]

Thank you for discussing such a very important topic in Machine Tool Operation!

[@jedrow]

What temperature do gear teeth need to come to or is it just a cherry glow? Can you harden them side by side or do you need to stagger them if doing by flame?

[@catherinegutierez-degula6157]

What an insightful video...God bless prof!

[@michaelangelocanizares4133]

What particular oil are you using to harden 4140?

[@gurpreetmankoo]

Thanks Prof. But what if I don't have an electric furnace. Can I do it with just regular coal?

[@profjohnny8624]

Hi Mankoo! Yes you can do it. The method you will use to determine the temperature of steel is to note its color. This method is not as accurate as the method i used (with temperature controller). If you want to buy an electric furnace at a low price, you may just contact me at my cell phone number 09166580548. Thank for watching and subscribing. God bless!

[@Seki522]

Is it okay to use the Universal Testing Machine to test the hardness?

[@michaelangelocanizares4133]

How did you made your oven? I would like to build one suited for 18 inches knives.

[@cat02791]

Thanks Prof. Johnny very helpful..

[@EleanorCodina]

Your so creative Sir

[@juliusmiculob]

Sir good day salamat sa vedio tutorial Po ninyo regarding the deferential indexing Baka Naman pwede Po Po sa sunod na vedio Po Ang ninyo paano mag calculate NGA gearing at paano akabit sa milling for helical gear. Slamat po

[@sagarpatkar4583]

Very nicely explained

[@hoangconguc-hpdq1206]

if the workpiece is tempered in the air, will the hardness be the same to tempered in oil? what different ? thank you!

[@brhanetekie7739]

it would be way softer because this will give more time for carbon to escape before it gets to room temperature.

[@franzschluter5252]

That is false because tempering is carried out at low temperatures. In fact tempering doesn't need to be quenched. Air cooling to room temperature is recommended. For high chrome tool steel such as skd11 quenching might even cause damage. What is important is that you give enough time in the oven for the steel to reach the required temperature

[@ponga782]

Great video!

[@penelopebee6877]

Sir Johnny I’ve been watching your videos, thank you for sharing your experience to us , may we know san tatami makakabili ng hardening powder, please refer us to your supplier . Thank you

[@shermanvaldez2178]

Thank you for the video sir. Very informative. san po pwede makabili ng electric furnace?

[@abecervantes4529]

too much helpful professor johnny materum

[@slhardmaster2514]

Very well sir. Keep this work up

[@eduardomaterum9514]

So helpful video

[@kalbonacpedro]

Sir how to by lathe?

[@profjohnny8624]

Hi Mae, you can call me in my cell phone nos. 09166580548 09081474586

[@LGG0630]

Thank you for the helpful video sir! I have two questions rin po sir... Do the gears in lathe's transmission and automotive has the same hardness? and also do the hand tools need to undergo hardness and tempering process as well? Thank you po sir! and more video tutorials to come pa po!

[@profjohnny8624]

Hi Grae, yes, all transmission gears should be heat treated (hardened and tempered) and the recommended hardness is 32-48 hrc. harder and tougher transmission gears are for heavier load.Hand tools such as hammer, chisel etc. should also be heat treated in orde to have a long service life. Thank you and God Bless!

[@samweldtv]

@@profjohnny8624 I have done it to my Chipping hamer

[@clkgillermokim5423]

okay to, pero pano naman po kapag 18 kilograms yung weight nung piece?

[@jmescobar9556]

Very informative

[@profjohnny8624]

Thank you JM for encouraging remark! God Bless!

[@tsclly2377]

Uh, no sodium nitrite?

[@profjohnny8624]

Yes, what you see is the result that I need, and the gears that I heat treated are already mounted in the headstock of a lathe machine, and it has been a year now that they are being used without any problem with their rigidity. Still running smoothly.

[@samweldtv]

Brilliant.

[@melgross]

32 to 48 is quite a range. 32 is close to dead soft, while 48 is fairly hard. I’m really surprised the range allows that. The tempering process is incorrect. You do NOT quench after hardening. That’s only when you don’t have a tempering oven. Then, you need to see the color of the part and quickly quench so the temperature doesn’t rise above what you need. But a tempering oven raises the temperature to the needed point. Waiting for some time and letting it cool slowly releases the stresses. But quenching adds stresses. That’s fine for a blacksmith, but not for precision machine parts.

[@profjohnny8624]

Thank you, Mr. Mel, for your additional knowledge. There are different methods of tempering, depending on the types of material being used, the type of heating process, and the shape of the product being heated. For as long as the main objective in tempering is obtained, which is to remove internal stresses and make the workpiece stronger, the tempering is good and successful. The workpiece that I heat treated is being used as part of the headstock of one of my lathe machines till now, and it runs smoothly the same as a new one. Thus, it can be said that it was heat treated successfully and correctly.

[@melgross]

@@profjohnny8624 good luck with it. I’m pretty familiar with tempering 4140 and similar steels. This is the first time I’ve ever seem someone with knowledge like yours quench after tempering it. No steel manufacturer has quenching after tempering as a recommended method.

[@Hello-ts5kh]

@@melgross there are a number of low alloy pressure vessel steels that are common to quench from tempering to avoid slow cooling through embrittlement ranges. I believe ASTM A372 even may even require quenching from the temper for grades like HY-80.

[@satnamsondh1176]

Great

[@abdulkhalegalghamdi6635]

👍