Overmelted.—Steel that has been kept too long in fusion. The finest material may be ruined in a crucible by being kept in the furnace any considerable time after it has been killed. Open-hearth steel may be injured seriously in the same way. Prompt teeming after killing should be the rule.
Pipe.—A pipe is the cavity formed in an ingot when it cools; the walls chill first and nearly to the full size of the mould, then the shrinking mass separates in the middle, forming a pipe. A pipe should be at the top of the ingot; it may occur anywhere by bad teeming.
Point.—One hundredth of one per cent of any element. You have say 10 points of carbon, or 10 carbon; you want it raised a few points to 15 or 18 carbon.
Recalescence.—When a piece of steel is heated above medium orange color and cools slowly, at about medium orange—1100° to 1200° F.—the change of color ceases, then the color rises sometimes to bright orange, and afterwards the cooling goes on; this phenomenon is called recalescence. This is not yet a common shop term.
Restoring.—When a piece of overheated steel is re-heated to recalescence, kept there a few minutes, and then cooled slowly, its grain becomes fine and its fiery lustre disappears; this is called restoring. No nostrums are necessary.
Sappy.—Well-worked, good steel has a bluish cast, a fine grain, and a silky sheen. It is sappy; it is as good as it can be made.
Seam.—A seam is a longer or shorter defect, caused by a blow-hole which working has brought out to the surface and not eliminated. It usually, or always, runs in the direction of working. Seams are distinguished from laps by not being continuous; they are usually only an inch or two in length.
Short (Cold, Red, Hot).—Cold-short steel is weak and brittle when cold.
Red-short steel is brittle at dark orange or medium orange heat or at the common cherry red heat. It may forge well at a lemon heat, and be reasonably tough when cold.
Hot-short steel is brittle and friable above a medium orange color; it may forge well from medium orange down to black heat.