XV.CONCLUSIONS.
After perusal of the preceding chapters the reader may form a hasty conclusion that if steel be so sensitive as it is stated to be its use may be difficult and precarious, and that it must be handled in fear and trembling, lest the result should be a dangerous structure, and the builder must be in doubt as to its safety.
The conveyance of any such impressions is not intended at all; emphasis has been laid upon practices that are hurtful in order that every steel-user may know what to avoid, solely that he may then be sure that he has the best, the most reliable, and most useful material that is known to man.
He should avoid uneven heat, excessive heat, or too low heat. The range between orange red and the heat that will granulate is so great that no one who is not a bungler or indifferent need ever get outside of it.
The uniformity of temperature that is insisted upon is so easily seen that any person who is not color-blind should have no trouble in securing it by the simplest manipulations of the furnace.
Practical uniformity of the work put on a piece is readily secured by any mechanic of ordinary skill.
Red-short, cold-short, or honeycombed steel are easily detected, and, under reasonable specifications, the steel-makers can as easily avoid them.
Steel a little higher than most engineers favor in their specifications is certainly as safe as, and likely to be sounder than, extremely ductile steel.
Wild steel, resulting almost certainly in micro-honeycombs, if not worse, can only be avoided by the co-operation of the manufacturer, and engineers should impress this point with energy.
Such micro-unsoundness as is shown in Mr. Andrews’s report upon a broken rail and propeller-shaft can be reduced to a minimum by insisting upon reasonably pure steel.
If sulphur, phosphorus, silicon, and oxygen are kept at a reasonable minimum, sulphides, phosphides, silicides or silicates, and oxides must be at a corresponding minimum.
That there is much room for improvement in the manufacture of steel is evident, and when means of getting rid of oxygen, nitrogen, and all other undesirable elements have been found the steel of the future will be very different in kindliness of working and in endurance of strains than that with which we are familiar.
It is believed, however, that no matter how perfect the manufacture may become, nor what the final theories of hardening, etc., may be, the properties stated in these pages will remain the same as long as steel continues to be essentially a union of iron and carbon.
Some other alloy or compound may displace carbon steel, and present an entirely new set of properties, but there is nothing of the kind in sight now, and engineers need have no fear of having a new art to learn very soon.
To one who has spent an ordinary business lifetime in making steel, studying it, and working with it it becomes a subject of absorbing interest, if not of love; and steel when handled reasonably is so true that “true as steel” ceases to be a metaphor, it is then a fact which fills him with the most entire confidence.
Once more, steel highly charged with sulphur, phosphorus, arsenic, oxygen, and nitrogen is certainly highly charged with so many elements of disintegration; it takes more serious harm from ordinary deviations from good practice, such little irregularities as occur inevitably in daily working, than steel does which is more free from these elements.
Reasonably pure, sound, reliable steel can be had at moderate cost, and all consumers should insist upon having it.
Regular, uniform, reliable working can be had where it is required, and there should be no excuse for irregular grain, overheated work, uneven work, or any other bungling. Where skill is required and reasonable discipline is enforced, good work will not cost any more than bad work.
Many people still hold to the idea that there are many mysteries connected with steel, and that many unaccountable breaks occur which make it an unreliable material. It is hoped that what has been set down in these pages will go far to dissipate these supposed mysteries, and to give confidence to steel-users.
Many breaks are unaccounted for, but it is not within the author’s experience that any fracture ever occurred that could not have been explained if it had been examined thoroughly in the light of what we know now. There is much to be learned, but there are no mysteries.