I don't know where you get your prior knowledge but if you paid for it ... you deserve a refund!
The tempering stats for Infi are not available ... some knifesmiths maintain Infi is a modified form of A8 Steel. It is'nt according to Jerry but no doubt in terms of tempering we are going to be there or there abouts. "There abouts" is all you need to answer your query. Here are the stats ...
" A-8 is a versatile, air-hardening tool and die steel. It combines good wearing qualities with excellent toughness characteristics. It is well suited for many metals working dies and punches, which operate in the hardness of Rockwell C 55-60. The intermediate carbon and alloy content of A-8 gives it an optimum balance of toughness and wear resistance, makes it particularly adaptable for those applications which are too severe for high carbon-high chromium steels and too abrasive for conventional shock resisting steels.
In the hot work field, A-8 is used with outstanding success whenever erosion, wash, and wear of the lower carbon hot work steels is the primary problem. Because of its higher carbon content, A-8 should NOT BE used where heat checking or breakage is the primary cause of failure. Hot work tools of A-8 may be water-cooled in use if desired.
A-8 should be preheated at 1300-1400º F, then transferred to a furnace at 1825-1850º F soaked at this temperature for 30 minutes for sections 1 inch and thinner, then air cooled. Sections over 1 inch in thickness should be soaked for an additional 10 15 minutes per inch and then air-cooled. A-8 normally is air cooled from the hardening temperature, although for some applications it may be oil quenched. When the pieces have cooled to room temperature, temper immediately.
Temper A-8 immediately after quenching to room temperature. Allow to heat slowly to the desired tempering temperature and hold for a period of 1 to 6 hours, depending upon the size. Remove from the furnace and allow to cool in the still air. For most cold work applications, tempering should be carried out in the range of 300-600º F or higher. Double tempering is recommended for best results with temperature above 600º F
A-8 is an oversized material,
Flats
+/- .015 upto .040 on thickness
+/- .080 upto .125 on width
Rounds
Up to 1" +/- .007 upto .018
1" up to 6" +/- .015 upto .040
6" and up +/- .0625 upto .250
Hardening Temp: 1800ºF thru 1850ºF
Quench Medium: Air Salt Bath
Tempering Range: 300ºF thru 1100ºF
Typical Level: 49 to 61 R/C
Preheat Forging: 1450ºF thru 1550ºF
Forging Temp: 2100ºF thru 2200ºF
Anneal Temp: 1600ºF
Anneal Cooling Method:
Furnace cool to 1000ºF at 100ºF per hr.
Then air cool.
Anneal Hardness: 241 BHN
* Double Tempering is Recommend.
A-8 Material in Stock Color Code: YELLOW and BLACK
Flat Dimensions:
1 ½" x 2" up to 4" x 6"
Non standard sizes, quoted upon request
Round Dimensions: ¾" up to 2 ½"
Non standard sizes, quoted upon request
A-8 Typical Analysis C
Mn
Si
Cr
Mo
W
.55%
.30
.30%
5.00
1.25
1.25
· Slight variations from typical analysis shown may occur in order to maintain the desired graphitizing potential."
I am no knife maker ... nor am I an engineer ... nor do I want to get into an arguement whether Infi resembles A8 ... pick any other steel and you will see similar temperatures ... of which the important one is that "the minimum" tempering temperature is 300F and this goes to 1100F.
When you make a knife you basically "harden" the steel which enables it to take an edge and then you temper the blade to stop it from being fragile and capable of shattering upon impact. This gives strength and malleability. These last two points Infi is famous for and from some information released by Jerry they go to great lengths when tempering the blade ... including cyrogenic cooling etc ... to relieve the stress in the balde after the tempering process has been completed.
So to alter the temper on the knife so it is weakened you need to have the through section heated to 300F .
Now, it may be the case that the spark generated from a ferro rod is "white hot" ... certainly a hotter spark than that generated from flint ... but allowing for the air surrounding the spark and how cooling is going to be induced because of this ... the liklihood that the sparks even remotely affect the temper of the steel to damage the knife is so far removed from reality IMO as to warrant no concern at all.
Ditto using belt sanders to sharpen blades ... another firm favourite issue raised by many who have'nt done sharpening by this method and are quick to criticise it's use ... even polishing Infi using this method ... it is the same answer ...
Unless the knife is at 300F it ain't going to happen ... here the knife is too hot to touch ... capable of sizzling any water it was immersed in ... and to give an idea of the heat required turn your oven on to this temperature and when the light goes out to say it is reached ... open the door ... the "heat" wave is "huge" ... never mind picking anything up that has been in there.
So as to ferro rods damaging the temper on knives ... I would have to say no on all counts. Perhaps not with a certainty born from making them or being a metalurgist ... but from a common sense ability to read and understand the above and from years and years of use.:thumbup:
