IRON AND STEEL.

Wellington Independent, Volume XXVI, Issue 3327, 24 October 1871, Page 2

IRON AND STEEL.

» TO THE EDITOR OP THE INDEPENDENT. Sir, — In your issue of Thursday, the 19fch, I observed a letter on " Iron and Steel," j signed by Mr James Davis, jun. Tha writer mentioned my name, and criticised my project of smelting the Taranaki iron sand freely. Now, as I take exception to a few of Mr Davis's statements, I should like, with your permission, to say a few words in support of my difference of opinion. Mr Davis says to the effect, tliafc the amount of carbon in combination with iron fixes the name of the metal as " grey," " white," " mottled," " velvety black," &o, &c. I any, thfr pressure of carbon alone does not determine the description of iron ; for, its character depends upon the presence or absence of two, three, or more impurities and alloys, in a greateror less quantity ; also, whether the metal bfr produced from the furnace by a light or heavy burden. Besides, color, after all, is no great criterion of quality, as white iron can be made grey by annealing, and vice versa. Mr Davis also remarks that both the " ring" of a bar nnd the inspection of its polished surface ara .utterly valueless as indications of quality. Here I differ with him most decidedly, for experts can tell by the " ring" whether the metal they are testing is pig iron, malleable iron, blistered, sheer, or cast steel ; indeed, some old Staffordshire hands can distinguish grey iron from whitu by that very "ring" which Mr Davis asserts to be valueless as a test of quality. For the matter of polish, cast iron, a very impure form of the metal, i» not susceptible of a high polish ; malliabls iron will not attain so brilliant a surface &s cast steel ; while titanic steel will acquire a greater lustre than any combination of iron and carbon hitherto known. So, with all due deference to Mr Davis and hie opinions, I fancy both " ring" and " polish" may be accepted as tests of quality. Mr Davis'a definition of steel — and he confessed to some difficulty in arriving at it — is scarcely correct. Steel is occasionally impregnated with so muchcarbon that it will not work under the hammer in the ordinary way — for instance, " Mushet's titanic steel." This metal contains a greater amount of carbon than other steels, and oan only be worked by a formula provided by Mr Mushet for thoße who may purchase his production. Treated in the common fashion, it is found bard, brittle, and thoroughly impracticable ; but, manipulated according to the directions of the inventor, the most valuable form of steel hitherto known. Of course, sir, I cannot expect you to find space for a very lengthy criticism of Mr Dnvis's statement, so I will be as brief as pos« Bible. That gentleman apprehends the metal produced from the furnace by my process will be " cast iron." This apprehension is incor* reofc, for, according to Mr Davis's assertion— and otli3rs have eaid the same — cast iron not only contains an excess of carbon, but one or more impurities, such as sulphur, silica, phos» pliorus, or manganese ; the preaonce of the last, by the way, is beneficial. Now, th# metal revived from the Taranaki iron sand, and coming from the furnace by my method, is far and away purer than the best malleable iron of commerce, and has nothing between its form and the condition of merchantable steel worth £50 per ton, save an excess of carbon. In spite of Mr Davis's unhesitating assertion to the contrary, I reiterate that I am prepared to produce a metal I call crude steel, reduoe the carbon to a proper quantity,, and render it worth £50 per ton, at a cost of £15 for the like weight. Taranaki sand, as Mr Davis admits, undoubtedly contains iron in a very pure form— the purest yet discovered in the world — and it is not combined with silica. A brown sand containing silica is spuringly intermingled with the ore, but it is only a mechanical mixture, and can bo detected with greater readiness than the presence of sand in sugar ; it is nob — certainly not — a ohemical combination. As a mere mixture it ia a valuable flux, and therefore beneficial. I base my calculations for smelting the Taranaki sand upon its extreme purity and (although I say it) a thorough knowledge of the matellurgy of iron and steel, Had lan ore to treat resembling any one, even the purest, of the tbirty-two known ores of Europe, America, or elsewhere, I (like Mr James Davis, jun.) should hesitate accepting the responsibility of constructing i iron works in New Zealand for twice thirty thousand pounds : but as my ore when smelted, with charcoal for fuel, is pure, I have no difficulty to contend with, except an overdose of carbon. This I am prepared to overcome, either by completely decarbonising my first result from the furnace, and resorting to " cementation" for the production of com* meroial steel, or by following the deoarbon* ising process, and saving a small matter of expense for cementation ; or, I could even produce a metal equal to the best steel known, and it shall contain not one atom of carbon. Whichever method I may be onlled upon to follow, I am prepared to show satisfactorily, by figures, to tho committee appointed by the meeting held at the Empire Hotel last Mon« day, that I oan produce steel worth £50 per ton in the English market for less than £16. I beg to assure Mr James Davis, junr., that there has been no misapprehension in quoting his brother's letter. The probability is, that Mr E. H. Davis had a better knowledge of the Taranaki sand than his brother James, and aotually did know what he was writing about. I agree with Mr James Davis, junr., that his brother never said or wrote that _ a blast furnace and its adjuncts could be built at Taranaki for £1800. Neither did anybody else, that I am award of, but I said, after competent men had made the calculations, that such a furnace as I should require — mind, please, only the furnace— could be~conßtruoted for that amount. lam still of that opinj^.^ In conclusion Sir, I, as well as Mr Jan.es?"Jp& Davis, junr., have the honnor to recommend .^ •: your readers to recolleot that annealed cast iron is not steel; at the same time, they might just as well remember that thoroughly annealed cast iron ia no longer cast iron, but malleable iron, and by the process of oementation may be made steel.r-I am, &0., E. M. Smith, Armourer and Artificer of Motal.