The Packing Department
: HEAT TREATMENT OF STEEL: The Working Of Steel
In Fig. 56 is shown the packing pots where
the work is packed. These are of malleable cast iron, with an internal
vertical flange around the hole A. This fits in a bell on the
end of the cast-iron pipe B, which is luted in position with
fireclay before the packing begins. At C is shown a pot ready
for packing. The crown gears average 10 to 12 in. in diameter and
weigh about 11 lb. each. When placed in the pots, they su
the central tube, which allows the heat to circulate. Each pot
contains five gears. Two complete scrap gears are in each furnace
(i.e., gears which fail to pass machining inspection), and at
the top of front pot are two or more short segments of scrap gear,
used as test pieces to gage depth of case.
After filling to the top with compound, the lid D is luted on.
Ten pots are then placed in a furnace. It will be noted that the
pots to the right are numbered 1, 2, 3, 4, indicating the position
they are to occupy in the furnace.
The cast-iron ball shown at E is small enough to drop through
the pipe B, but will not pass through the hole A in the bottom
of the pot. It is used as a valve to plug the bottom of the pot
to prevent the carburizing compound from dropping through when
removing the carburized gears to the quenching bath.
Without detracting from the high quality of the work, the metallurgist
in this plant has succeeded in cutting out one entire operation
and reducing the time in the hardening room by about 24 hr.
Formerly, the work was carburized at about 1,700 deg.F. for 9 hr. The
pots were then run out into the yard and allowed to cool slowly.
When cool, the work was taken out of the pots, reheated and quenched
at 1,600 deg.F. to refine the core. It was again reheated to 1,425 deg.F.
and quenched to refine the case. Finally, it was drawn to the proper
temper.
More
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Short Method Of Treatment
In the new method, the packed pots are run into the case-hardening furnaces, which are heated to 1,600 deg.F. On the insertion of the cold pots, the temperature naturally falls. The amount of this fall is dependent upon a number of variables, but i... Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling. Pins for forced fits can be enlarged several thousandths of an inch by rapid heating to a dull red and quenching in water. The theory is that the metal is expanded in heating and that th... Silicon
SILICON is a very widespread element (symbol Si), being an essential constituent of nearly all the rocks of the earth. It is similar to carbon in many of its chemical properties; for instance it burns very readily in oxygen, and consequently native ... Silicon
Silicon prevents, to a large extent, defects such as gas bubbles or blow holes forming while steel is solidifying. In fact, steel after it has been melted and before it has been refined, is wild and gassy. That is to say, if it would be cast into mo... Standard Analysis
The selection of a standard analysis by the manufacturer is the result of a series of compromises between various properties imparted to the steel by the addition of different elements and there is a wide range of chemical analyses of various brands... Steel Before The 1850's
In spite of a rapid increase in the use of machines and the overwhelming demand for iron products for the expanding railroads, the use of steel had expanded little prior to 1855. The methods of production were still largely those of a century earlie... Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of cold-rolled steel. Heat treatment of cold-worked steel is a very delicate operation. Cold working hardens and strengthens steel. It also introduces internal stresses. Heat-treatments are d... Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be recommended for tools which have to withstand shocks, such as for cold chisels or punches. These steels are, however, particularly useful where it is necessary to cut tempered or heat-treate... Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the austenitic state. (See page 108.) It is then soft and ductile. As the steel is heated above the critical temperature the size of the austenite crystals tends to grow rapidly. When forging... Suggestions For Handling High-speed Steels
The following suggestions for handling high-speed steels are given by a maker whose steel is probably typical of a number of different makes, so that they will be found useful in other cases as well. These include hints as to forging as well as hard... Sulphur
SULPHUR is another element (symbol S) which is always found in steel in small quantities. Some sulphur is contained in the ore from which the iron is smelted; more sulphur is introduced by the coke and fuel used. Sulphur is very difficult to get rid... Sulphur
Sulphur is another impurity and high sulphur is even a greater detriment to steel than phosphorus. High sulphur up to 0.09 per cent helps machining properties, but has a tendency to make the steel hot short, i.e., subject to opening up cracks and se... Surface Carburizing
Carburizing, commonly called case-hardening, is the art of producing a high-carbon surface, or case, upon a low carbon steel article. Wrenches, locomotive link motions, gun mechanisms, balls and ball races, automobile gears and many other devices ar... Take Time For Hardening
Uneven heating and poor quenching has caused loss of many very valuable dies, and it certainly seems that when a firm spends from $75 to $450 in cutting a die that a few hours could be spared for proper hardening. But the usual feeling is that a to... Temperature For Annealing
Theoretically, annealing should be accomplished at a temperature at just slightly above the critical point. However, in practice the temperature is raised to a higher point in order to allow for the solution of the carbon and iron to be produced mo... Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading and recording of all temperatures are in the hands of one man, who occupies a room with an opening into the end of the hardening department. The opening is about 15 ft. above the floor level... Temperatures To Use
As soon as the temperature of the steel reaches 100 deg.C. (212 deg.F.) the transformation begins, increasing in intensity as the temperature is raised, until finally when the lower critical range is reached, the steel has been all changed into the ... Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by the various colors, or oxides, which appear on steel in tempering. The figures shown are from five different sources and while the variations are not great, it is safer to take the averag... Tempering Round Dies
A number of circular dies of carbon tool steel for use in tool holders of turret lathes were required. No proper tempering oven was available, so the following method was adopted and proved quite successful. After the dies had been hardened dead ... Tensile Properties
Strength of a metal is usually expressed in the number of pounds a 1-in. bar will support just before breaking, a term called the ultimate strength. It has been found that the shape of the test bar and its method of loading has some effect upon the ... Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill file does not bite in the least. Having passed this file test at several points, the gears go to the center-punch test. The inspector is equipped with a wooden trough secured to the top of ... The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-treatment department, there is none that offers greater possibilities for profitable returns than the systematic cleaning, blending and reworking of artificial carburizers, or compounds. ... The Effect
The heating at 1,600 deg.F. gives the first heat treatment which refines the core, which under the former high heat (1,700 deg.F.) was rendered coarsely crystalline. All the gears, including the scrap gears, are quenched direct from the pot in this ... The Effect Of Tempering On Water-quenched Gages
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 we... The Electric Process
The fourth method of manufacturing steel is by the electric furnace. These furnaces are of various sizes and designs; their size may be sufficient for only 100 lb. of metal--on the other hand electric furnaces for making armor-plate steel will hold ... The Forging Of Steel
So much depends upon the forging of steel that this operation must be carefully supervised. This is especially true because of the tendency to place unskilled and ignorant men as furnace-tenders and hammer men. The main points to be supervised are t... The Influence Of Size
The size of the piece influences the physical properties obtained in steel by heat treatment. This has been worked out by E. J. Janitzky, metallurgical engineer of the Illinois Steel Company, as follows: With an increase in the mass of steel th... The Leeds And Northrup Potentiometer System
The potentiometer pyrometer system is both flexible and substantial in that it is not affected by the jar and vibration of the factory or the forge shop. Large or small couples, long or short leads can be used without adjustment. The recording instr... The Modern Hardening Room
A hardening room of today means a very different place from the dirty, dark smithshop in the corner with the open coal forge. There, when we wanted to be somewhat particular, we sometimes shoveled the coal cinders to one side and piled a great pile... The Packing Department
In Fig. 56 is shown the packing pots where the work is packed. These are of malleable cast iron, with an internal vertical flange around the hole A. This fits in a bell on the end of the cast-iron pipe B, which is luted in position with fireclay be... The Penetration Of Carbon
Carburized mild steel is used to a great extent in the manufacture of automobile and other parts which are likely to be subjected to rough usage. The strength and ability to withstand hard knocks depend to a very considerable degree on the thoroughn... The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely necessary that a measuring instrument be used which will give the operator an exact reading of heat in furnace. There are a number of instruments and devices manufactured for this purpose but ... The Quenching Tank
The quenching tank is an important feature of apparatus in case-hardening--possibly more so than in ordinary tempering. One reason for this is because of the large quantities of pieces usually dumped into the tank at a time. One cannot take time to ... The Theory Of Tempering
Steel that has been hardened is generally harder and more brittle than is necessary, and in order to bring it to the condition that meets our requirements a treatment called tempering is used. This increases the toughness of the steel, i.e., decrea... The Thermo-couple
With the application of the thermo-couple, the measurement of temperatures, between, say, 700 and 2,500 deg.F., was made more simple and precise. The theory of the thermo-couple is simple; it is that if two bars, rods, or wires of different metals a... Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or by being packed. Packing is by far the most satisfactory method as it prevents scaling, local hard spots, uneven annealing, or violent changes in shape. It should be brought up slowly to ju... Tungsten
Tungsten, as an alloy in steel, has been known and used for a long time. The celebrated and ancient damascus steel being a form of tungsten-alloy steel. Tungsten and its effects, however, did not become generally realized until Robert Mushet experim... Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herewith. Figure 92 is a lead pot furnace, Fig. 93 is a vertical furnace with a center column. This column reduces the cubical contents to be heated and also supports the cover. A small too... Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pressing and drop forgings. Mining drills to harden only. Easily weldable. SMITHS' TOOL TEMPER.--No. 3-1/2: Large punches, minting and rivet dies, nailmakers' tools, hammers, hot and cold se... Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the facilities available in the locality where the shop is situated and the nature and quantity of the work to be done. The furnaces can be heated with producer gas in most cases, but when space... Vanadium
Vanadium has a very marked effect upon alloy steels rich in chromium, carbon, or manganese. Vanadium itself, when combined with steel very low in carbon, is not so noticeably beneficial as in the same carbon steel higher in manganese, but if a small... William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association was published in the Scientific American on September 13, 1856.[95] On September 16, 1856, Martien filed application for a U.S. patent on his furnace and Mushet for one on the application o...