A woman is only a woman, but a good cigar is a smoke.--_Rudyard Kipling_. AUNT MARY--(horrified) "Good gracious. Harold, what would your mother say if she saw you smoking cigarets?" HAROLD (calmly)--"She'd have a fit. They're her cigarets.... Read more of SMOKING at Free Jokes.caInformational Site Network Informational
Privacy
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Tungsten
Tungsten, as an alloy in steel, has been known and used for a...

Annealing
ANNEALING can be done by heating to temperatures ranging from...

Annealing Work
With the exception of several of the higher types of alloy s...

The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely nece...

Process Of Carburizing
Carburizing imparts a shell of high-carbon content to a low-...

Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

Judging The Heat Of Steel
While the use of a pyrometer is of course the only way to hav...

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

Lathe And Planer Tools
TO FORGE.--Gently warm the steel to remove any chill is parti...

Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
For extremely high temperature, the optical pyrometer is lar...

The Penetration Of Carbon
Carburized mild steel is used to a great extent in the manufa...

Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be re...

Effects Of Proper Annealing
Proper annealing of low-carbon steels causes a complete solu...

Rate Of Cooling
At the option of the manufacturer, the above treatment of gea...

Correction By Zero Adjustment
Many pyrometers are supplied with a zero adjuster, by means ...

Mushet And Bessemer
That Mushet was "used" by Ebbw Vale against Bessemer is, perh...

Hardening High-speed Steels
We will now take up the matter of hardening high-speed steels...

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

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



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 3484