A good description of the production of "blister steel", though Huntsman process crucible steel, done around 1745 was a sea-change in steel production. Huntsman steel made predictable springs possible, thus making an accurate marine chronometer possible, and the fixing of latitude. Then everything changed.
Huntsman did make a big difference, but blister steel still had to be made first since it was and is the "mother" steel for crucible aka cast steel (the latter name, commonly used in the past, is a continuing source of confusion, until one understands the three types of steel making used during the 18th-19th Centuries (a fourth method appeared in the mid-1900's)
here is a quick over view of the three main types of steel:
1) Blister-steel: Steel formed by roasting wrought iron bars in contact with carbon in a cementing furnace. It is so called from the blistered appearance of it's outer skin. To improve the quality, it was subjected to two subsequent processes, which converted it into shear-steel and cast-steel. Blister steel was NOT a one off method for individual blades, but rather a method of making large amounts of steel - this method was developed circa the 1500's. James Hanson mentions in his Fur Trade Cutlery Sketch Book, that the bars of wrought iron used for making blister steel could be as large as 1/2" x 4" x 20 feet.
2) Shear-steel: Blister-steel was sheared into shorter, manageable lengths, heated, and tilt hammered to homogenize the steel which improved the quality. Several bars are welded together and drawn out. The bar is sometimes cut, fagoted, reheated, and again tilted. This may be repeated. The terms single shear and double shear indicate the extent to which the process is carried. It was widely used for blades of all types through the end of the 19th Century.
3) Cast-steel (aka crucible steel): Blister steel which has been broken up, fused in a crucible, cast into ingots, and rolled. The blocks of steel are melted in crucibles of re fractory clay, and the molten metal is poured into ingot-molds of cast-iron. These are opened, to let out the red-hot ingot, which is then passed to the rolls.
The process of making cast/crucible steel was developed by Benjamin Huntsman, of Sheffield, England, circa 1745. Oddly, crucible steel at first was not greeted well by the Sheffield makers while the French cutlers soon recognized it's qualities. The Sheffield makers even went so far as to ask the government for an embargo on the raw steel.
By 1840 the English had developed the cast steel method to the point that English steel made in this way became 40% (about 20,000 tons a year -
up from the 200 tons a year produced by the English using all previous methods) of all steel produced in Europe. Other steel centers of note during the period were: Germany (manganese and other trace minerals in the local ore made it a better than normal alloy), Spain, and Sweden). A few years later, in the 1850's, the Bessemer process was developed which increased steel production immensely.
FWIW - I've been black smithing since 1962 especially knives and hawks and understanding as much as possible about those of the 18-19th Centuries is an on going passion. I don't do much smithing these days though due to a severe neck injury, but I still like to keep up with the info available. Anyway glad to be of some help and I reckon one learns a few things over time no matter how slow one is........
