Steelmaking.ca Home Steel Making Categories Manufacturing and the Economy of Machinery

Steel Making

Heat Treatment Of Axles
Parts of this general type should be heat-treated to show the...

Bessemer Process
The bessemer process consists of charging molten pig iron int...

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

Silicon
SILICON is a very widespread element (symbol Si), being an es...

Chromium
Chromium when alloyed with steel, has the characteristic func...

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

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

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

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

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

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...

Case-hardening Treatments For Various Steels
Plain water, salt water and linseed oil are the three most co...

Quenching Tool Steel
To secure proper hardness, the cooling of quenching of steel ...

Quenching
It is considered good practice to quench alloy steels from th...

The Electric Process
The fourth method of manufacturing steel is by the electric f...

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

A Satisfactory Luting Mixture
A mixture of fireclay and sand will be found very satisfactor...

Standard Analysis
The selection of a standard analysis by the manufacturer is t...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...



For Milling Cutters And Formed Tools






Category: HIGH-SPEED STEEL

FORGING.--Forge as before.--ANNEALING.--Place the steel in a pipe,
box or muffle. Arrange the steel so as to allow at least 1 in.
of packing, consisting of dry powder ashes, powdered charcoal,
mica, etc., between the pieces and the walls of the box or pipe.
If using a pipe close the ends. Heat slowly and uniformly to a
cherry red, 1,375 to 1,450 deg.F. according to size. Hold the steel at
this temperature until the heat has thoroughly saturated through
the metal, then allow the muffle box and tools to cool very slowly
in a dying furnace or remove the muffle with its charge and bury
in hot ashes or lime. The slower the cooling the softer the steel.

The heating requires from 2 to 10 hr. depending upon the size of
the piece.

HARDENING AND TEMPERING.--It is preferable to use two furnaces
when hardening milling cutters and special shape tools. One furnace
should be maintained at a uniform temperature from 1,375 to 1,450 deg.F.
while the other should be maintained at about 2,250 deg.F. Keep the
tool to be hardened in the low temperature furnace until the tool
has attained the full heat of this furnace. A short time should be
allowed so as to be assured that the center of the tool is as hot
as the outside. Then quickly remove the tool from this preheating
furnace to the full heat furnace. Keep the tool in this furnace only
as long as is necessary for the tool to attain the full temperature
of this furnace. Then quickly remove and quench in oil or in a
dry air blast. Remove before the tool is entirely cold and draw
the temper in an oil bath by raising the temperature of the oil
to from 500 to 750 deg.F. and allow this tool to remain, at this
temperature, in the bath for at least 30 min., insuring uniformity
of temper; then cool in the bath, atmosphere or oil.

If higher drawing temperatures are desired than those possible
with oil, a salt bath can be used. A very excellent bath is made
by mixing two parts by weight of crude potassium nitrate and three
parts crude sodium nitrate. These will melt at about 450 deg.F. and
can be used up to 1,000 deg.F. Before heating the steel in the salt
bath, slowly preheat, preferably in oil. Reheating the hardened
high-speed steel to 1,000 deg.F. will materially increase the life
of lathe tools, but milling and form cutters, taps, dies, etc.,
should not be reheated higher than 500 to 650 deg.F., unless extreme
hardness is required, when 1,100 to 1,000 deg.F., will give the hardest
edge.





Next: Instructions For Working High-speed Steel

Previous: Lathe And Planer Tools



Add to Informational Site Network
Report
Privacy
ADD TO EBOOK


Viewed 4641