In Figurative Language we employ words in such a way that they differ somewhat from their ordinary signification in commonplace speech and convey our meaning in a more vivid and impressive manner than when we use them in their every-day s... Read more of FIGURATIVE LANGUAGE at Speaking Writing.comInformational Site Network Informational
Privacy
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

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

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

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

Hardening High-speed Steel
In forging use coke for fuel in the forge. Heat steel slowly ...

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

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

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...

Manganese
Manganese adds considerably to the tensile strength of steel,...

Detrimental Elements
Sulphur and phosphorus are two elements known to be detrimen...

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

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

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

Critical Points
One of the most important means of investigating the properti...

Sulphur
Sulphur is another impurity and high sulphur is even a greate...

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Composition Of Transmission-gear Steel
If the nickel content of this steel is eliminated, and the pe...

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

Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...



The Effect Of Tempering On Water-quenched Gages






Category: HARDENING CARBON STEEL FOR TOOLS

The following information has been supplied by Automatic and Electric
Furnaces, Ltd., 6, Queenstreet, London, S. W.:

Two gages of 3/4 in. diameter, 12 threads per inch, were heated
in a Wild-Barfield furnace, using the pyroscopic detector, and
were quenched in cold water. They were subsequently tempered in a
salt bath at various increasing temperatures, the effective diameter
of each thread and the scleroscope hardness being measured at each
stage. The figures are in 10,000ths of an inch, and indicate the
change + or - with reference to the original effective diameter
of the gages. The results for the two gages have been averaged.

TABLE 24.--CHANGES DUE TO QUENCHING
----------------------------------------------------------------
After Tempering temperature, degrees Centigrade
Thread quenching-----------------------------------------
220 260 300 340 380 420
---------------------------------------------------------
1 +25 +19 +17 +15 +13 +11 +11
2 +18 +12 +11 + 9 + 6 + 5 + 5
3 +12 + 6 + 5 + 3 0 0 0
4 +10 + 4 + 4 + 2 ... 0 - 1
5 + 9 + 4 + 4 + 2 0 0 0
6 + 9 + 4 + 3 + 2 0 0 0
7 +10 + 5 + 5 + 3 + 2 + 1 + 2
8 + 8 + 4 + 3 + 2 0 0 + 1
9 + 9 + 4 + 3 + 2 + 1 + 1 + 1
10 + 9 + 5 + 5 + 3 + 2 + 2 + 2
11 + 7 + 4 + 4 + 2 + 1 + 1 + 1
12 + 9 + 5 + 5 + 5 + 4 + 4 + 3

Scleroscope 80 70 70 62 56 53 52
----------------------------------------------------------------

Had these gages been formed with a plain cylindrical end projecting
in front of the screw, the first two threads would have been prevented
from increasing more than the rest. The gages would then have been
fairly easily corrected by lapping after tempering at 220 deg.C. Practically
no lapping would be required if they were tempered at 340 deg.C. There
seems to be no advantage in going to a higher temperature than
this. The same degree of hardness could have been obtained with
considerably less distortion by quenching directly in fused salt. It
is interesting to note that when the swelling after water quenching
does not exceed 0.0012 in., practically the whole of it may be
recovered by tempering at a sufficiently high temperature, but when
the swelling exceeds this amount the steel assumes a permanently
strained condition, and at the most only 0.0014 in. can be recovered
by tempering.





Next: Tempering Colors On Carbon Steels

Previous: Tempering Round Dies



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 3461