HT confusion

[ross_lad]

im not going to attempt to hide my ignorance because it won't get me anywhere....
I have seen other blacksmiths temper tools by simply heating them up to a blue (or whatever appropriate color for the tool) and quench at that heat to temper, and i have copied the practice on my own tools with success.
However, after reviewing some old threads, i see that it seems blades require hours at a steady temp.
Could someone please give a steady explanation?

[ThomasPowers]

So you have already normalized, hardened and all you need to do is to draw temper? Heat treating is a multi step process!

The suggested time for most metal heating is 1 hour per inch of thickness; most blades are a whole lot thinner than an inch! OTOH many bladesmiths will draw temper multiple times to make sure no hard spots are left.

[ross_lad]

right,
and does the blade simply air cool after drawing temper?
why do punches and such differ?
mostly the same steel types are used...is it just the amount of stress that will be put on the object when it is used?
and what is the appropriate temperature for tempering a blade?

[Sam Salvati]

Ross, to get a nice complete temper it is best to soak the blade in an oven at the proper temperature for atleast an hour. after the tempering cycle of that one hour you can pull it out and quench it or let it air cool, does not matter. You will not have to do a second temper if you are using a plain carbon steel. The difference between swords/knives and punches/chisels is the geometry, chisels and punches are very steep angled edges, as they are generally impacting much tougher harder objects, while blades are meant for fine edge angles and cutting softer targets.

What steel are you using?

[ross_lad]

wow man, thanks. ok, i'll be using toyota truck leaf springs, not sure if 5160 or 1080, but that cleared up my confusion. thanks again. so basically, swords - in their proper use - need more of a stress relieving heat treatment than a simple tool because of the possible abuse in battle (or maybe just cutting stuff today)?

[ross_lad]

oh, and for quenching the blades, i've scrounged up about a 3 inched wide fencepost, but im worried about the oil boiling before the blade is fully cooled. Do you know a good container for such purposes?

[Sam Salvati]

oh, and for quenching the blades, i've scrounged up about a 3 inched wide fencepost, but im worried about the oil boiling before the blade is fully cooled. Do you know a good container for such purposes?

A coffee can will get you by just fine, no plastic no wood for a quench tank (unless using water which you are not), go to the hardware store and get a section of the biggest iron plumbing pipe they have, with threads on one end then get a cap to go over one end, cap it off then fill it with oil. Warm your oil to around 100F-120F (motor oil or vegetable oil).

wow man, thanks. ok, i'll be using toyota truck leaf springs, not sure if 5160 or 1080, but that cleared up my confusion. thanks again. so basically, swords - in their proper use - need more of a stress relieving heat treatment than a simple tool because of the possible abuse in battle (or maybe just cutting stuff today)?

No problem man. Toyota leaf springs might be 1080, might be 5160, might be something entirely different, you do not know and there is no way to easily tell short of sending one away for analysis. But with leaf springs you can roughly get by and get a acceptable using knife with a warm oil quench, then temper at 400F for 1 hour.

I hope you are not trying to make swords right out of the gate, swords take ALOT of expierience and understanding, it is best to make atleast a few knives first then try a sword, realise you know NOTHING, then go back to knives for awhile hehe .

What I am saying is, the stresses imparted to a blunt object like a punch or chisel are much different than those out the length of steel for a sword, it really depends what you want your sword to do, do you want to cut soft targets and have it hold it's edge for longer? Then a light temper at 400F or 450F will suffice, but if you want it tougher for harder objects, then a temper at 475F or 500F will be perfect.

[ross_lad]

lots of great info. i'll be saving it for later use. i have made a few decent knives, and i'm definitely still learning every day. i'll probably try short daggers before taking on a project like a sword. the information that you have given will definitely make sure i know at least one part of what i'm doing when i do attempt it . thanks much. peace bro.

[ThomasPowers]

The correct temperature for tempering a sword depends on alloy, quench medium, design and hardening process and can range from untempered (as a lot of traditional japanese blades were that are differentially hardened) to around 1000 degF for some very modern high alloy steels.

350 degF to 600 degF is a more typical range with the lower range for lower carbon blades and the higher range for higher carbon steels. This is where you *REALLY* need to know what you are using or do the junkyard steel testing to figure out what that particular steel needs for heat treat.