| Show from the london saturday review i the great invention of the age A I 1 hew new way to make steel heat pro ducep by cold air I 1 when men it was announced at the late meeting of the british association that a paper would be read on a new method of converting cast into malleable iron without the use of fuel the intelligence was received by many with a smile of incredulity and not a few practical men went to the meeting of section G expecting i I 1 to be entertained by the visionary schemes of some ingenious but idle enthusiast their expectations were utterly falsified conviction was forced upon minds frem which no ready assent could could have been hope hoped d a great invention wab was lucidly and unostentatiously propounded and men who went prepared for an i exhibition of temerity if not of folly remain i ed to express their concurrence in the graceful tribute of admiration paid by mr to one of the greatest discoveries of the age every one felt after hearing mr Besse merls merla I 1 paper that if any reliance could be placed upon PO n the facts stated to the association a new era was at hand in all those numerous and important branches of manufacturing industry which concern the wr working irking of wrought iron and steel without further reference to the paper communicated munica ted to the association we will now describe what we have seen at mr bessemer s premises at baxter house leaving our readers to say whether we have overstated the importance of the subject it is necessary to premise that common cast iron contains somewhere about 4 or 5 per cent of carbon as well as a variable quantity of Bili clurn ciuro and other earthy bases phosphorus and sulphur the object of every process for making malleable iron is the separation and removal of these foreign substances the best malleable iron contain contains about i ner cent of carroul car carbon boul but the process of extrac extras i dionis tion is difficult and expensive the fusibility of iron depends upon the quantity of carbon present aud and no commercially available method has till now been discovered by which iron after parting with a very large proportion oe of carbon can be brought brous ht to remain in a state more nearly approaching L f fusion than that of a pasty mass steel is produced from iron from which the carbon and other impurities have been extracted by a tedious and costly process the object of which is the restoration of a portion portion oe of the carbon which previous processes ses have ave remove 1 J I steel contains according to the purposes for which it is wanted from rather more than i MY per er cent to rather less than 2 per cent of carbon malleable iron or iron comparatively free from carbon is usually produced in this country in the following manner ahe the melted iron as extracted from the ore in the smelt smelting smelling sm elting in 0 or r blast furnace is run out into bars a few feet in leneth length technically termed pigs these pil pigs s when cold are removed from the sand molds molds into which they were run and transferred to a second furnace called the fining furnace where they are again reduced to a state of fusion and finally the mass thus produced is placed in a third furnace where it undergoes the process sis of pud dlin L omitting all matters of detail the essential part of 0 tb this is ope operation ration tation is the reduction of the iron to a pasty mass which is stirred and rolled about by the workman until a large ball or bloom of iron imn weighing from 60 to 70 pounds is conglomerated at the end of the rod with which he works and is judged to be in a fit state for th the final process it is then withdrawn from the fire and taken to a Itil tilting tine tino hammer and a pair of squeezers squeeze rs or to a Nas myths steam forge where it is subjected to a very heavy pressure and a qua quantity n of melted slag and refuse mixed with the iron squeezed out for the purpose of our present comparison we need follow the process no further other methods of or producing malleable iron dirc dirt directly atly from tb the e ore are in use in various parts of the continent but they are extremely expensive require a rich ore and a very pure fuel are only applicable upon a small scale and sacrifice a very large per in in some cases from froba 40 to er cent of the metal of all our more important mechanical anical operations perhaps Z is the most imperfect and unsatisfactory it is very expensive both from the fhe quantity of fuel consumed which is about equal to the weight of metal treated and the severe nature of the labor required during daring the recent hot weather it was found necessary to stop nearly all the staffordshire furnaces two men having fallen dead at their work the result is the production of an iron BO so far from being chemically pure that it is astonishing toni shing how mur mue much h we have been able to effect with so imperfect a material from the Jim immense mense demand for iron which has prevailed for some isome years past and the stimulus that has thus been given to tle tie the production of increased quantity the quality has very seriously deteriorated ri the difficulty experienced by the government daring during the late war in procuring iron iron of a suitable for the purposes of warfare is colvell tod welt well known to need more than a passing passim reference mr Besse experiments e rim ants have been conducted upon the pi pig iron on lie ile proposes that for the purposes of in manufacture aduf c ture the smelted smelter iron as it leaves the blast furnace shall be run immediately into the convell converting lingas vessel el presently to be described bit for the e purposes of experiment it has deen teen been more convenient to melt malt down pig piff iron as the metal is much sooner reduced to a state of fusion the experiment peri perl ment there therefore foreY takes up the process at ft ahe point poin t at which the metal is ordinarily placed in the fining furnace it must be remembered however that one important end answered by his invention is tc to do away with w ith the consumption of fuel required for this intermediate process the converting vessel where the change oj of the melted metal from ordinary cast iron tc to malleable iron or steel is to take place place consists externally of a cylinder 0 of iron surrounded roun dad daJ near the bottom by a hollow riny ring an annular pipe in fact af fifthe the same meal metal communicating with five small pipes ac placed e li at equal distances round the cylinder these 1 1 pipes are carried through the outer inner structure of the vessel and each of f enters the chamber within near the junction ol 01 the side with the floor by an aperture about aboul three eighths ef of an inch in diameter ec by a boatin coating of the best fire clay the ile exter external nal nai cylinder is lined with a lining of fire bricel brick and the internal tun cons consists ats of two chambers or stories communicating ni by a small cylindrical 0 opening pahi in th center the lower chamber in into t 0 m which th melted iron is introduced is a simple the upper crl cri amber chamber has bag a floor inversely arched so that any melted metal forced u through the opening from the lower may trickle back again and the roof is in th shape of a cupola or dome two apertures aper tures i f few evv inches laches square placed opposite each other between the floor and the top of this chamber communicate with the external air A powerful blast worked by a small engine can be let into the hollow ring which girds th outer cylinder and thence of course enten enters the lower chamber through the pipes A hole at the bottom of the chamber secure in jn the tho usual manner furnishes the means 01 tapping the vessel and running off the into the molds prepared for I 1 it uen men wh en everything is ready for the tha operations operation to commence the blast is set on to t 0 blow the converting vessel the melting furnace i tapped and the melted meite diron iron uron of the usual deep orange orange tint pours slowly down the channel into the lower chamber of the converting vessel through an aperture which is then closed up and the pressure of the blast is about 9 0 or 10 pounds to the square inch stron enough to force the air completely through the superincumbent mass of fused iron and out through the apertures aper tures near the top of the vessel As the action is continued every particle of the melted metal is brought in turn into contact with d a stream of air to use ase the language of chemistry an energetic ener euer zetic combination takes tze s places between the oxygen oxygen of the air air pumped in and the carbon mixed with the iron in pc popular ular language filep fire instead of being supplied externally round and about the mass of iron is kindled and sustained throughout every particle of the liquid metal A heat beat is thus general generated ted vastly greater than ban that which bich can be supplied by mere mera external combustion what is taking place is indica indicated ted teJ by the tongues of flame which in two or three minutes begin to shoot forth from the apertures aper tures in the vessel and which gradually dually increase in body and in intensity until Fa the whole mass is in a state of agitation almost like boiling water the difference being however that the agitation is caused by the external force of the air blown rapidly and continuously through the liquid iron not by the conversion of th the e substance itself into an expansible vapor as in the case of genuine ebullition however this state may very fairly be called the boil yand r and it is indicated by the blowing out through the apertures aper tures of large quantities j of melted slag the refuse which is squeezed out of the puddle ibra lera rys bloom under the action of immense pressure but which is here driven off simply by the action of the blast because being b I 1 i much lighter fighter than the iron it rises to the top tike ilke ike scum upon the surface of water now that the metal is in a state of perfect fluidity it is supposed that at this period a very important iio flo 1 tant change begins to take tike place and that that thai t part of the carbon which is in a state not of mechanical mixture but of chemical combination with the iro iron n is I 1 now col compelled apelles apel led by the agency of the increasing heat to part from the metal and yield itself a captive to the superior affinity of the oxy oxygen en this boil boli takes place from ruteen fifteen to twenty or twenty five minutes after the commencement ef of the process and continues with more or less violence until all the carbon is burned out the moment that this ia is effected and that no more carbon or only a very small quantity remains the metal must be run out otherwise the action of the air would cool corl the metal and make it set hard with great rapidity it may be run out into molds of any size or shape but the most advantageous form is that of a deep and narrow mold as then the slag which has not been already removed and which comes last out of the hole at the bottom of the converting vessel lies in a thin cake at the top of the casting and is easily taken off by a pair of shears it will be obvious that one ono principal feature in in j the tile process is that the op operator prator orator deals with the metal in a state tats of a desideratum hitherto unattainable with iron containing only a small quantity of carbon hence dt it can not merely bo be procured in masses of any s size bize lz e whereas the can only produce GO 60 or 73 lbs ibs in a lump but it will possess ho the distin distinguishing gaishin 4 character of all fluids it will ba be perfectly homogenous the texture composition and quality will ba be the tha same throughout every part of the mass that the fluidity is really greatly increased notwithstanding the sub tub subtraction traction of the tha carbon ia is shown by the fact that it is found desirable to diminish the power of the blast from 9 or 10 pounds to about 5 pounds daring during the latter part of the process as well as by the tha rapidity with which the metal runs out of tho the furnace and its brilliant white whiteness ness sess it ia impossible to overrate the advantage advant age aga of or having a really homogenous product in larce large masses of malleable iron procured in the ordinary way by welding together tog ellier a number of the pud peddlers blooms there often occur knobs and j fragments of metai metal much harder than the rest and many manufacturers consider soft malleable iron quite as trying to their toels tools as hard steel from the unexpected increase of resistance suddenly offered ol 01 by particular parts of tie tle lie miss mass and the consequent unequal strain upon different portions of the tha machinery the greater the mass mais required the tha greater the difficulty of obtaining a I 1 metal upon all parts of which equal reliance can bo be placed and hence where a very heavy strain I 1 iu hi a direction different from that of the fib fiber r ia is I 1 expected strength is often obliged to be sought in an enormous thickness of material the prodigious weight of anchors ia is rendered necessary by the im impossibility tE os ability of calculating accurately the strength streng strength of the metal in any particular part so that mat ilia size of the whole must be increased to meet the chance of a bad piece of metal occurring here and there one ono of mr Besse Bees emers merls numerous patents is for the application of his liis invention to the construe tion lion of anchors in which he lie hopes to attain equal strength with a greatly diminished weight it is haiola liec tiec necessary essary to point out the i saving in labor abor and fuel eh acted by the new ne process process especially in the manufacture of steel mr ir bessemer believes that steel such as is now worth from to jago XGO a tun may be produced at a cost to the manufacturer of less than then fio ZIO 10 a i tun ton in the manufacture of malleable iron also aleo i the saving will be very vary great tho less than ihan in the case of steel indeed one ons on of tile results retails of the 1 invention will be the curious anomaly that steel F will be produced at a little less risk aud and therefore at a little lebs lees cost than malleable iron for it is obvious that I 1 by tapping the furnace before the I 1 complete combustion of the carbon lias has ahen taken aken place steel wll will be produced instead of iron 1 practice and experience will no doubt in time enable the workman so to regulate the operation as to produce to a nicety any particular quality of iron or steel required but until this practical knowledge has been gal gained ried lied there here will be some difficulty in calculating the exact length of time to bo be occupied in the tha conversion if ir therefore the process should be continued a little too long for steel fleet malleable iron will be obtained if it be continued a little too long look for malleable iron the metal will be set in the furnace the boil boll appears to be the critical period whatever be the time occupied in arriving at the boil it is found that from twelve to fifteen minutes are requisite to produce malleable iron and from seven to twelve minutes to produce the different qualities of steel how effectually the carbon can ba be rei rel removed noved is show shown by an analysis is 0 of r a c hancer i specimen of mr Bess emers malleable iron made by dr henry who we believe was strongly inclined to doubt whether the process could really be so successful as it was stated to be ile he found the quantity of carbon present to be less than I 1 3 oth pr p r cent or lets lebs than l part of the matsi metal of silica a trace merely was doand by the application of means already well understood der stood the sulphur and oi na it wll wil be as completely removed A consider lidde |
