US38140A - Improvement in the manufacture of steel - Google Patents

Description

UNITED STATES PATENT OFricr-O CHARLES ATTWOOD, OF TON LAW IRON WORKS, COUNTY OF DURHAM, ENGLAND.

IMPROVEMENT IN THE MANUFACTURE OF STEEL.

Specification forming part of Letters Patent No. 38,140, dated April 14, 186

To all whom it may concern Be it known that I, CHARLES Arrwoon, of Ton Law Iron Works, in the county of Durham, England, have invented a new and useful Improvement in the Production or Manufacture of Steel and Iron of a Steely Quality; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention essentially consists in the production of steel and of iron of a quality approximate to steel, which may be called steely iron, simply by bringinginto astate of liquefaction by means of heat a mixture of malleable iron of such kinds as in themselves are capable of producing good or serviceable steel and steely iron and of a certain kind or kinds of non-malleable or crude cast-iron-such, for instance, as are usually called spiegeleiscn which are also by their nature capable of being made into good and serviceable steel, in certain proportions to each other, as hereinaf ter specified, by which mixture and liquefaction of those materials hard steel or soft steel or steely iron are respectively produced, ac cording to the different proportions in which such two several materials or ingredients may be severally employed, such proportions also requiring to be varied according to the difference in their quality in respect to the greater quantity of carbon contained in each, and to their greater or less tendency in consequence thereof to make such steel or steely iron of harder or softer quality.

In order to more fully describe my said invention and the manner in which it may be most successfully practiced or employed, I will now proceed to describe or specify the kinds and qualities of malleable iron and of crude cast-iron, respectively, which I employ in mixture, as aforesaid, and also the modes in which the operations may be carried out.

First, as it regards such malleable iron,it is desirable that it should be such as, by whatsoever method or process it may have been produced, has been as well and uniformly as may be deprived of that excess of carbon which is the cause of the non-malleable quality in the several kinds of what is commonly described bythe names of pig-iron, crude iron, or cast metal, and in this respect 1 find such malleable iron as is produced by what is called the paddling process is, if well and uniformly puddled,very suitable, although, if well and uniformly decarbureted, any other sort or kind of malleable iron of quality in other respects as good may equally well be employed.

Secondly, as regards such crude cast metal or cast-iron as is to be employed in such mixture, as aforesaid, I have found the kind best titted for my purpose to be that variety of bright and white cast-iron of acrystalline and highly-lamellar structure and almost silvery whiteness, which is called in England specular iron, or by its equivalent German name, spiegeleisen, as that iron is remarkably uniform as respects the proportion of carbon it contains, and generally of highly superior quality, containing a less proportion than most other sorts of the other matters or in gredients which are injurious to the quality of malleable iron or steel,respcctively, and for the fuller information of persons who may hereafter make use of my invention I may mention that I have not in general found any sensible difference between good samples of this kind of iron as made in Germany and such as has been madein England, or as is or has been made in the United States of North America from an ore there called franklinite. Where excellence and uniformity of quality in the steel or steely iron intended to be produced is especially desirable I prefer to use in the working of my said process or invention the said specular crude iron or spiegeleisen to any other kind or sort with which I am acquainted; but I have also found that the description of white cast metal or crude iron which is commonly called byEnglisli ironmasters refined metal, as made from other kinds orsort-s of either gray or white crude metal by the process which they call the finery process in well-known kinds of fur naces, by aid of blast or otherwise, is for the most part pretty nearly in the same condition in respect of the proportion of carbon contained in it as such specular crude iron or spiegeleisen, and, in so far as it may be in other respects of good quality for steel-making generally, may be used in substitution for such specular iron in making steel or steely iron according to my process; and I have also found that besides such specular iron or spiegeleisen and such refined metal other sorts of white crude iron in general-such as that which is frequently produced from ores in the blast-furnace smelting process which were not to'o impure in other respects, and therefore unfit in its own nature for being converted into serviceable steel-may also be used in substitution for such specular crude iron or spiegeleisen, although with more difficulty and uncertainty as to the proportion in which it should be used from its containing more varying proportions of carbon; and there are some instances in which such white pig-iron,where very servieeably.

Crude refined metal which may have been produced by other means or processes than that of the refinery already mentionedas, for instance, by blowing atmospheric air or steam, or both, into or under the surface of molten crude iron of any kindmay, wheneverit may have been decarbureted to near about the same degree as such other refined metal, be also used in substitution for such specular crude iron in nearly similar proportions and, in so far as it may be otherwise of equal quality or purity with the effect of producing steel or steely iron of equal or nearly equal quality.

In like manner it will be found that crude white or gray metal produced by the remelting of malleable-iron scraps or other malleable iron in contact with fuelas, for instance, in cupola furnaces-or, such as may be produced by so renielting it in contact with fuel in any other manner, may also, in so far as it may have been brought to a nearly similar state as regards its quantity of carbon to such specular iron, be used in substitution for it in so far as fitness in other respects for making steel of the required quality according to any other method may be found to belong to it.

, Though I have have so far described my said invention in so far only as relates to the production of steel or steely iron by melting together into one mass certain proportions of white crude or non-malleable metal of proper quality with certain proportions of malleable iron, also of proper quality, yet I have also found that gray crude iron, whether as it comes in that state directly from the blast-furnace or as it may be produced by any other mode, and even that the sort of gray iron which is usually called mottled iron, as being visibly composed of a mixture of crude gray and crude white metal, may each of them, so long as in other respects of a quality good enough for making serviceable steel by other processes, be similarly used in substitution for such sorts of crude white metal in mixture with malleable iron for making steel or steely iron according .to my process proper care being taken to use the same in due proportion to the difl'erent quantities of carbon which such gray or mottled metal may contain as compared with such sorts of white metal, but with the disadvantage, upon one hand, of being liable to supercarbonize such steel if used in even a small excess of due proportion, and to thereby injure or destroy its malleability, and also with the disadvantage, upon the other hand, of increasing somewhat the difficulty of melting the materials from the smaller proportionate quantity in which it may sometimes or generally have to be employed, and on this account I prefer when using it to take theless rich kind of such gray iron instead of such as iron-masters usually describe as No. I or No. 2, but such as is more generally used in forges for puddling, and even in some cases to take such mottled iron as containing still less of carbon; and I may here remark that whereas the specular white metal or spiegeleisen is sometimes found to have passed in the blast-furnace or in certain rem eltin g processes-as by remeltin g in contact with the fuel in founders cupolafurnaces-into a kind of mixed or mottled iron, this mixed or mottled iron may also be employed in similar proportions, and in general I would indicate that from six to ten parts of gray crude iron with from ninety to ninetyfour parts of paddled malleable iron will make a soft steel or'a steely iron, While for making hard steel as much as from thirty to forty parts of gray crude iron and from sixty to seventy parts of malleable iron may be employed.

As regards the proportion in which white specular crude metal should be used to the malleable iron in the working of my process, I have found that for making soft steel or steely iron-by which last I mean a kind of steel partaking so far of the nature of iron as to be more or less readily capable of being weldedabout six or eight parts of such specular metals to about ninety or ninety-two parts of such malleable iron may be successfully employed, while for making steel of greater hardness---sueh, for instance, as is fit for tools for the turning of chilled cast-iron rolls-as much as from thirty to forty parts of such white specular crude metal to from sixty to seventy parts of such malleable iron may be sometimes used; but, if required for any purpose where still greater hardness is desired or unobjectionable, as much as nearly fifty parts of such white specular crude metal to from fifty to sixty parts of malleable iron may sometimes be made use of without entirely or too far impairing or destroying its malleability or ren dering it incapable of being forged or rolled; but these proportions may be varied when using this or other sorts of crude and malle able iron, according to their own difference as to their quantities of contained carbon, in order to produce a steel or steely iron in which the hardness (which is dependent mainly on its quantity of carbon) shall be such as in each case is required.

When the refined or finers metal is employed hum) A in carrying out my invention, in substitution for the specular crude metals hereinbefore mentioned, such refined or finers metal may be employed in the same or nearly the same proportions to the malleable iron as is herein before directed with respect to the specular white'crude metal. In carrying out my said invention the above-described materials are to be melted into steel or steely iron either in covered pots or crucibles of such size as are usually employed in making cast-steel by the common methods, and such pots or crucibles may be used in the ordinary cast-steel-melting furnaces, or my materials may be melted in large pots similar or nearly similar to such as are used by glass-makers, but of smaller size, and especially of much lower height, in order to prevent their bursting by the weight of metal, which larger pots, when such are used, may be tapped at their bottoms, if that should be preferred to their removal from the furnace, as is usual in the case of smallerpots, or the materials may be melted in an open hearth or chamber of the furnace itself, and of course in that casein much larger masses than can well be done in single pots embedded in the fuel in the ordinary furnaces, audit may be conveniently drawn out by tapping from such hearth or chamber into ladles or directly into ingot or other molds, or may be removed from a such furnaces by any other convenient means that may be preferred, such mode of melting my materialsin such hearths orchambers of the furnace itself having great and special advantages, especially in cases where the metal is required in large quantities or masses; but when my materials are thus melted in such hearths or chambers they should, as far as may be, be protected from casual or other contact with the fuel, as it is entirely by contact therewith that it happens that when melted in common refinery-furnaces, or in what are called founders .cupolas, both steel and malleable iron usually take up or retain so much of carbon as to always alter the quality of the resulting metal, ifnot in every case to render it unmalleable. The materials should therefore be melted in some one or other of the many sorts of air or blast reverberatin g furnaces in which, by doc precaution, the contact of the metal with the fuel or with some portion of it and with its dust or ashes, as also its contact with the uncombined oxygen, which may in such cases be injuriously present in the gases of the furnace, may be sufficiently if not totally prevented; and as I consider furnaces in which blast is used or air-furnaces in which there is a strong draft of air are more difficult to be managed in these respects than is desirable, I prefer and recommend the use of reverberating furnaces in which the draft of air into or through its grate and other openings may be as small as is conveniently practicable, and that it is better to depend for the production of the high degree of heat required in the heating such furnaces in great part or altogether upon the combustion of gasesa point which persons conversant with such operations and furnaces would easilyattain to and effect by one or more of several simple and easy constructions and contrivances-and with reference to these objects I prefer and recommend the use of melting-furnaces in which the heat is so drawn from the gases constructed according to the plan or plans now well known as Siemens Patent Furnace or Furnaces, which I regard in the above-mentioned respects as extremely suitable to be used for making steel by my invention, whether such steel is to be melted by the use of pots placed in such furnaces, especially if used without covers, or in a hearth or chamber of such furnaces; but it will in general be found advisable when melting my materials in hearths or chambers of such furnaces or in uncovered pots which may be placed in them to cover the materials with a thin or superficial coating of melted glass, which may consist of such broken glass as is obtained from ordinary sheet or crown glass or even from common black bottles, both of which are purchaseable at a low rate under the name of cullet, and either of which will be found both cheap and suitable. 1 further desire tointimate that the crude metal and the malleable iron may be mixed in the first instance either cold or after being heated, or one or both of them, especially the crude metal, may be either entirely or nearly melted before being mixed with the other material.

The steel or steely iron may be cast when melted into ingot molds or other molds of any size or form suitable for the uses which such metal is intended, or according as the produce may be intended to be forged or rolled or otherwise manipulated in any particular manner or for anyspecial object; and I desire it may be also noted that the addition of scrapsteel or steely iron of suitable or proper quality, whether produced by my process or ob tained from any other source or means, may be made in larger or smaller quantities to my materials, not only without any actual or material injury or disadvantage, but also to the effect of facilitating the fusion thereof by form ing, as it were, a bath for their more ready liquefaction.

Having now described and particularly ascertained the nature of my said invention and the manner in which the same is or may be used or carried into effect, I would observe, in conclusion,that what I consider to be novel and original, and therefore claim as the invention secured to me by the hereinbefore-in-parv recited Letters Patent, is

The production or manufacture of steel and iron of a steely quality, substantially as hereinbefore described and set forth.

In testimony whereof I have signed my name to this specification before two subscribing witnesses.

Witnesses: CHAS. ATTWOODA WM. Enwn. RoBnvsoN, WILLIAM FENwIoK RAEBURN.