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Steel Making

Nickel
Nickel may be considered as the toughest among the non-rare a...

Annealing In Bone
Steel and cast iron may both be annealed in granulated bone. ...

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

Corrosion
This steel like any other steel when distorted by cold worki...

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

Properties Of Alloy Steels
The following table shows the percentages of carbon, manganes...

Gears
The material used for all gears on the Liberty engine was sel...

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

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

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

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

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

Phosphorus
PHOSPHORUS is an element (symbol P) which enters the metal fr...

Leeds And Northrup Optical Pyrometer
The principles of this very popular method of measuring tempe...

The Influence Of Size
The size of the piece influences the physical properties obta...

Care In Annealing
Not only will benefits in machining be found by careful anne...

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

Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or b...

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

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...



Detrimental Elements






Category: HIGH-SPEED STEEL

Sulphur and phosphorus are two elements known
to be detrimental to all steels. Sulphur causes red-shortness
and phosphorus causes cold-shortness. The detrimental effects
of these two elements counteract each other to some extent but
the content should be not over 0.02 sulphur and 0.025 phosphorus.
The serious detrimental effect of small quantities of sulphur and
phosphorus is due to their not being uniformly distributed, owing
to their tendency to segregate.

The manganese and silicon contents are relatively unimportant in
the percentages usually found in high-speed steel.

The detrimental effects of tin, copper and arsenic are not generally
realized by the trade. Small quantities of these impurities are
exceedingly harmful. These elements are very seldom determined
in customers' chemical laboratories and it is somewhat difficult
for public chemists to analyze for them.

In justice to the manufacturer, attention should be called to the
variations in chemical analyses among the best of laboratories.
Generally speaking, a steel works' laboratory will obtain results
more nearly true and accurate than is possible with a customer's
laboratory, or by a public chemist. This can reasonably be expected,
for the steel works' chemist is a specialist, analyzing the same
material for the same elements day in and day out.

The importance of the chemical laboratory to a tool-steel plant
cannot be over-estimated. Every heat of steel is analyzed for each
element, and check analyses obtained; also, every substance used
in the mix is analyzed for all impurities. The importance of using
pure base materials is known to all manufacturers despite chemical
evidence that certain detrimental elements are removed in the process
of manufacture.

The manufacture of high-speed steel represents the highest art
in the making of steel by tool-steel practice. Some may say, on
account of our increased knowledge of chemistry and metallurgy,
that the making of such steel has ceased to be an art, but has
become a science. It is, in fact an art; aided by science. The
human element in its manufacture is a decided factor, as will be
brought in the following remarks:


The heat treatment of steel in its broad aspect may be said to
commence with the melting furnace and end with the hardening and
tempering of the finished product. High-speed steel is melted by
two general types of furnace, known as crucible and electric. Steel
treaters, however, are more vitally interested in the changes that
take place in the steel during the various processes of manufacture
rather than a detailed description of those processes, which are
more or less familiar to all.

In order that good high-speed steel may be furnished in finished
bars, it must be of correct chemical analysis, properly melted and
cast into solid ingots, free from blow-holes and surface defects.
Sudden changes of temperature are to be guarded against at every
stage of its manufacture and subsequent treatment. The ingots are
relatively weak, and the tendency to crack due to cooling strains
is great. For this reason the hot ingots are not allowed to cool
quickly, but are placed in furnaces which are of about the same
temperature and are allowed to cool gradually before being placed
in stock. Good steel can be made only from good ingots.

Steel treaters should be more vitally interested in the important
changes which take place in high-speed steel during the hammering
operations than that of any other working the steel receives in
the course of its manufacture.





Next: Quality And Structure

Previous: Standard Analysis



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