Today we’ll look at four types of inter-related rolling mills that produce steel sheets. A jobbing mill rolls steel sheets that range between 1/8″ and 1/2″ in thickness and then send the sheets to a furnace for annealing, producing “blue annealed sheets”. Some plate mills can produce light plates that overlap the output of jobbing mills, but the output of plate mills is not annealed, unlike the jobbing mill. The material sent to a jobbing mill is called “sheet bar” produced by a universal mill or a sheet bar mill and sent to the jobbing mill cold. A jobbing mill uses two-high stands, i.e. stands with two rollers, and consists of a stand with both rollers pinion driven, a roughing stand and a finishing stand.
Continue reading Mesta Memories #21: Sheet Mills and a Pickling Machine
When we think of steel wheels, we normally think of the one on our cars or trucks, but there are other kinds of steel wheels used in industry and heavy equipment. The easiest example I can think of are the steel wheel used to support and drive the treads on a bulldozer or a tank. We tend to think of the toothed wheel that drives the treads as a sprocket nowadays, but 100 years ago it was common to call them steel wheels, and I believe that it’s still a proper term in the industry, although I can’t prove it. Anyway, that’s basically the kinds of wheels that were made on the Mesta Wheel Mill, generally speaking.
The modern equivalent of the Steel Tire Mill would the ring rolling machines you see in forging operations. A common example of a steel tire is on a railroad wheelset, and you can also find them on certain kinds of excavating equipment.
Continue reading Mesta Memories #20: Wheel and Tire Mills
The Mesta Machine Company made a series of smaller mills to complement their bigger slabbing and plate mills, called merchant, bar and structural mills. These are all basically bar mills and produced smaller shaped steel forms for engineering and construction. When I say “smaller”, it is in comparison to the sizes output by the blooming or slabbing mills. You have to remember to think big.
Merchant mills produce a variety of shaped products such as angles, channels, beams, rounds and hexagons, and in the old days they would keep an assortment of stock on hand for buyers of small lots. In the present, merchant mills produce large lots to order, and the keeping of stock on hand has typically passed to other steel sellers.
Bar mills produce steel bar with a rectangular, round, or hexagonal cross section in various sizes and lengths, with bar that is 10mm or less in diameter sold in rolls. Steel reinforcing rod or rebar is typically made on bar mills dedicated to the task (but not always), as best as I can determine (lost my reference, dang it) due to the volume usually produced. A video of a rebar and rod mill is after the jump.
Continue reading Mesta Memories #19 – Merchant, Bar and Structural Mills
Today we’re looking at more types of rolling mills made by the Mesta Machine Company.
Slabbing mills are basically a more specialized form of blooming mill. A slabbing mill is designed to take a hot steel ingot and roll it out into a slab that’s typically from 150mm to 400mm thick. The output of a slabbing mill is an intermediate step in the production of steel plate and is send on to a plate mill for further working and finishing.
There are two videos on steel rolling at the the end of the article.
Continue reading Mesta Memories #18 – Slabbing and Plate Mills
The Mesta Machine Company made many products for the steel making industry, and a large portion of those products were rolling mills. A blooming mill is a type of rolling mill that produces ‘blooms’, a kind of thick, rough-surfaced slab. Here is the definition of a bloom from steelonthenet.com’s Steel Glossary Terms:
“A semi-finished long product of greater than 150 mm square or rectangular cross-section. Blooms can be produced by continuous casting or by rolling from ingot. Continuously cast rounds of 300mm diameter or greater are also referred to as blooms“
Blooms are typically made from cast steel ingots, which are also sometimes called blooms, that are heated in soaking pits until they reach working temperature, then sent to the blooming mill where the ingots are repeatedly sent through one or more sets of powerful rollers that reduce its cross section while increasing its length. Once the desired cross section has been reached, the bloom is usually sent on to the slabbing mill for finishing.
At the end of this article is a video that shows a steam powered blooming mill in operation.
Continue reading Mesta Memories #17 – Blooming Mills
Most of us have and air compressor of some sort in our garages or have worked around the big compressors used in auto body and repair shops, but they pale in comparison to the ones made by the Mesta Machine Company in its heyday. Like most of the machines produced by Mesta, they’re huge and were intended to supply large factories and other industrial works. According to the information pamphlet, Mesta made compressors using up to 4 stages and produced pressures of 1000 psi. I haven’t been able to gather any data on the construction of the Mesta compressors, and I don’t know how they handled the cooling of the air between stages, or even exactly how their pumps worked. They’re impressive looking beasts though.
Continue reading Mesta Memories #16 – Air Compressors and Barometric Condensers
Good morning everyone.
Among the many types of engines that the Mesta Machine Company manufactured are steam reversing engines for rolling mills. As the name would suggest, they are engines that will run either in forward or reverse. The reversing operation was needed in the rolling mills to shuttle the slabs of steel back an forth through the rollers. The direction of the engines was changed, at least in these Mesta models, by pulling a lever that changed the valve timing and the engine would spin down to a halt and then reverse directions. This happened all in about a minutes time from what I can gather from reading about different types of these engines.
You would think, or I least I do, that it would be more efficient to have some sort of clutch and reversing gear mechanism, rather than halt the machine and its flywheel and start it up in the other direction. Evidently that wasn’t the case, because after doing a bit of reading it turns out that the cost of maintenance and breakage of the reverse gear mechanisms far outweighed the efficiency lost by reversing the entire engine. It wasn’t until the AEG Company of Germany came up with a mill stack that used a method call the Ilgner system which used electric motors that the steam reversing engines started to get phased out.
Continue reading Mesta Memories #15 – Reversing Engines
Corliss engines are a type of steam engine that was a popular power source around the turn of the last century, and the variation that the Mesta Machine company built was used primarily in rolling mills and power plants. Corliss engines use rotary valves and have variable valve timing, and were the most efficient engines around until the Una-flow engines were produced.
Detail of a Corliss-type valve gear and cylinder cross section showing the path of high-pressure steam (in red) and low-pressure steam (in blue). With each stroke, the four valves alternate opening and closing, driving the piston back and forth. Image: Wikipedia
Continue reading Mesta Memories #14 – Corliss Engines
The Mesta Machine Company manufactured Una-Flow (know today as “uniflow“) steam engines for use in rolling mills and power plants as an alternative to other engines that they produced. Una-flow engines use steam that flows through the engine’s cylinders in one direction, hence the name. This method of operation gains thermal efficiency by maintaining a thermal gradient along the length of the cylinder and uses less steam than other engines.
Continue reading Mesta Memories #13 – Una-Flow Engines
Click on the image to enlarge
The Mesta Machine Company made large four-stroke engines that were used primarily in the production of electric power. These engines would operate on just about any flammable gas: natural gas, blast furnace gas, producer gas, or by-product coke oven gas. Waste not, want not.
One of the features of the engines that the brochure emphasizes is the use of a “butterfly governor gear” for regulating engine power under various loads. It sounds like some kind of automatic throttle, but I haven’t had the chance to run down the specific mechanism that Mesta used as of yet. It sounds like a cool gadget though.
Continue reading Mesta Memories #12 – Gas Power Engines