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

Steel Making

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

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

Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

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

Nickel-chromium
A combination of the characteristics of nickel and the charac...

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

The Forging Of Steel
So much depends upon the forging of steel that this operation...

Pyrometers For Molten Metal
Pyrometers for molten metal are connected to portable thermoc...

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

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

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

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

Rate Of Absorption
According to Guillet, the absorption of carbon is favored by ...

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

Heat Treatment Of Steel
Heat treatment consists in heating and cooling metal at defin...

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

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

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

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



Knowing What Takes Place






Category: HARDENING CARBON STEEL FOR TOOLS

How are we to know if we have given a
piece of steel the very best possible treatment?

The best method is by microscopic examination of polished and etched
sections, but this requires a certain expense for laboratory equipment
and upkeep, which may prevent an ordinary commercial plant from
attempting such a refinement. It is highly recommended that any
firm that has any large amount of heat treatment to do, install
such an equipment, which can be purchased for from $250 to $500.
Its intelligent use will save its cost in a very short time.

The other method is by examination of fractures of small test bars.
Steel heated to its correct temperatures will show the finest possible
grain, whereas underheated steel has not had its grain structure
refined sufficiently, and so will not be at its best. On the other
hand, overheated steel will have a coarser structure, depending
on the extent of overheating.

To determine the proper quenching temperature of any particular
grade of steel it is only necessary to heat pieces to various
temperatures not more than 20 deg.C. (36 deg.F.) apart, quench in water,
break them, and examine the fractures. The temperature producing
the finest grain should be used for annealing and hardening.

Similarly, to determine tempering temperatures, several pieces
should be hardened, then tempered to various degrees, and cooled
in air. Samples, say six, reheated to temperatures varying by 100 deg.
from 300 to 800 deg.C. will show a considerable range of properties,
and the drawing temperature of the piece giving the desired results
can be used.

For drawing tempers up to 500 deg.F. oil baths of fresh cotton seed
oil can be safely and satisfactorily used. For higher temperature
a bath of some kind of fused salt is recommended.





Next: Hints For Tool Steel Users

Previous: Temperatures To Use



Add to Informational Site Network
Report
Privacy
ADD TO EBOOK


Viewed 4571