A new contract for Santa has finally been negotiated. Please read the following carefully. I regret to inform you that, effective immediately, I will no longer be able to serve Southern United States on Christmas Eve. Due to the overwhelming... Read more of The new southern santa at Free Jokes.caInformational Site Network Informational
Privacy
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Machineability
Reheating for machine ability was done at 100 deg. less than ...

Silicon
Silicon prevents, to a large extent, defects such as gas bubb...

Annealing
There is no mystery or secret about the proper annealing of d...

Drop Forging Dies
The kind of steel used in the die of course influences the he...

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

Suggestions For Handling High-speed Steels
The following suggestions for handling high-speed steels are ...

Conclusions
Martien was probably never a serious contender for the honor ...

Preventing Carburizing By Copper-plating
Copper-plating has been found effective and must have a thick...

Ebbw Vale And The Bessemer Process
After his British Association address in August 1856, Besseme...

Hardening
The forgings can be hardened by cooling in still air or quen...

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

For Milling Cutters And Formed Tools
FORGING.--Forge as before.--ANNEALING.--Place the steel in a ...

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

Furnace Data
In order to give definite information concerning furnaces, fu...

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

Heavy Forging Practice
In heavy forging practice where the metal is being worked at...

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

Separating The Work From The Compound
During the pulling of the heat, the pots are dumped upon a ca...



Tempering Colors On Carbon Steels






Category: HIGH-SPEED STEEL

Opinions differ as to the temperature which is indicated by the
various colors, or oxides, which appear on steel in tempering.

The figures shown are from five different sources and while the
variations are not great, it is safer to take the average temperature
shown in the last column.

TABLE 25.--COLORS, TEMPERATURES, DEGREES FAHRENHEIT
----------------------------------------------------------
A B C D E Average
----------------------------------------------------
Faint yellow 430 430 430 430 430 430
Light straw 475 460 450 ... 450 458
Dark straw 500 500 470 450 470 478
Purple (reddish) 525 530 520 530 510 523
Purple (bluish) ... 555 550 550 550 551
Blue 575 585 560 580 560 572
Gray blue ... 600 ... 600 610 603
Greenish blue ... 625 ... ... 630 627
----------------------------------------------------------

TABLE 26.--ANOTHER COLOR TABLE
----------------------------------------------------------
Degrees
Fahrenheit High temperatures judged by color
---------------------------------------------------------
430 Very pale yellow
460 Straw-yellow
480 Dark yellow
500 Brown-yellow > Visible in full daylight
520 Brown-purple
540 Full purple
560 Full blue
600 Very dark blue /
752 Red heat, visible in the dark
885 Red heat, visible in the twilight
975 Red heat, visible in the daylight
1,292 Dark red
1,652 Cherry-red
1,832 Bright cherry-red
2,012 Orange-red
2,192 Orange-yellow
2,372 Yellow-white
2,552 White welding heat
2,732 Brilliant white
2,912 Dazzling white (bluish-white)
----------------------------------------------------------

These differences might easily be due to the difference in the light
at the time the colors were observed. It must also be remembered
that even a thin coating of oil will make quite a difference and
cause confusion. It is these possible sources of error, coupled
with the ever present chance of human error, that makes it advisable
to draw the temper of tools in an oil bath heated to the proper
temperature as shown by an accurate high-temperature thermometer.

Another table, by Gilbert and Barker, runs to much higher temperatures.
Beyond 2,200 deg., however, the eye is very uncertain.

TABLE 26.--COLORS FOR TEMPERING TOOLS
-----------------------------------------------------------------------
Approximate
color and Kind of tool
temperature
----------------------------------------------------------------------
Yellow Thread chasers, hollow mills (solid type) twist drills
430 to 450 deg.F. centering tools, forming tools, cut-off tools, profile
cutters, milling cutters, reamers, dies, etc.
----------------------------------------------------------------------
Straw-yellow Thread rolling dies, counterbores, countersinks. Shear
460 deg.F. blades, boring tools, engraving tools, etc.
----------------------------------------------------------------------
Brown-yellow Taps, Thread dies, cutters, reamers, etc.
500 deg.F.
----------------------------------------------------------------------
Light purple Taps, dies, rock drills, knives, punches, gages, etc.
530 deg.F.
----------------------------------------------------------------------
Dark purple Circular saws for metal, augers, dental and surgical
550 deg.F. instruments, cold chisels, axes.
----------------------------------------------------------------------
Pale blue Bone saws, chisels, needles, cutters, etc.
580 deg.F.
----------------------------------------------------------------------
Blue Hack saws, wood saws, springs, etc.
600 deg.F.
-----------------------------------------------------------------------





Next: High Speed Steel

Previous: The Effect Of Tempering On Water-quenched Gages



Add to del.icio.us Add to Reddit Add to Digg Add to Del.icio.us Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network
Report
Privacy
SHAREADD TO EBOOK


Viewed 4619