This chapter is not written to place difficulties in the way of legitimate improvement, but to warn unsuspecting people against quackery. Some of the humbugs are honest productions of well-meaning ignorance, and some that come from designing manufacturers are not entitled to such charitable designation. A knowledge of the simplest properties of steel will enable a thoughtful man to judge as to whether a proposed improvement is likely to be of any value or not, and the warnings given are intended as a protection to the unsuspecting and credulous.
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.
WHAT TO AVOID.
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.