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

Application Of Liberty Engine Materials To The Automotive Industry
The success of the Liberty engine program was an engineer...

Knowing What Takes Place
How are we to know if we have given a piece of steel the ver...

Preparing Parts For Local Case-hardening
At the works of the Dayton Engineering Laboratories Company, ...

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

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

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Double Annealing
Water annealing consists in heating the piece, allowing it to...

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

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

Crankshaft
The crankshaft was the most highly stressed part of the entir...

Conclusions
Martien was probably never a serious contender for the honor ...

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

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

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

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

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

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

Carbon-steel Forgings
Low-stressed, carbon-steel forgings include such parts as car...

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



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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