Utah's Iron and Steel Industries

Index For This Page

This page was last updated on July 25, 2026.

(Return to the Iron and Steel Page)

First Steel Manufacture In Utah (1911)

The breakthrough for local steel manufacture in Utah occurred in 1911 when Joseph A. Silver of the Silver Brothers Iron Works mastered the side-blown converter, or Tropenas process. By implementing this method, Silver Brothers became the first company in Utah to successfully manufacture true steel castings, breaking the state's reliance on eastern steel foundries for complex, high-strength machine parts.

Until the Silver Brothers installed their side-blown converter in 1911, steel casting in Utah only used the cupola or crucible furnace process. In late-19th and early-20th-century foundries, cupola and crucible furnaces were the backbone providing molten iron and steel made by melting scrap iron and scrap steel, and used to make iron and steel castings for engine blocks, machinery frames, pipe, and cast fittings, because they melted tons of cheap scrap iron and scrap steel efficiently using layers of scrap and coke.

(Read more about cupola and crucible furnaces, below)

Prior to Silver Brothers installing a Tropenas side-blown converter in 1911, which was Utah's first application of the converter steel-making process, local foundries relied on cupola furnaces to produce iron castings, and crucible furnaces for any small-scale steel melting.

Silver Brothers poured Utah's first converter steel in 1911, and in November 1917, Utah Iron & Steel poured the state's first open-hearth steel at its Midvale plant.

Utah Iron & Steel's open hearth furnace at Midvale was completed on or about June 15, 1917, with test runs starting soon after. The first pour on November 1, 1917 was the first open-hearth steel poured in Utah, but open-hearth steel had already been produced west of the Mississippi River for well over a decade:

The American Foundry and Machine company in Salt Lake City in March 1917, was the first to manufacture steel in Utah using its newly installed three-ton Rennerfelt electric furnace for producing steel castings. Scrap iron and scrap steel was fed into the electric furnace and, depending on the desired end product, the resulting molten iron or molten steel poured into waiting molds.

(Read more about the Rennerfelt electric arc furnace, below)

Tropenas Process

On June 12, 1911, the Salt Lake Telegram reported that the Silver Brothers' Iron Works in Salt Lake City was installing a converter and steel casting equipment. Expected to be completed in about two weeks, the upgrade would allow the plant to produce a wide range of high-quality, cast steel machinery parts for mining, milling, and manufacturing. One converter was being installed, with another planned if business grew. Silver Brothers produced its first converter steel in late July 1911.

Unlike a standard Bessemer converter where high-pressure air was forced up through the bottom of the liquid metal, a Tropenas or side-blown converter introduced air through tuyeres (nozzles) located along the side or surface of the molten iron bath.

Air blowing across the surface oxidized carbon and silicon, causing combustion reactions right at the top surface. This generated extreme top heat, producing liquid steel. High fluidity was essential so the liquid metal could flow easily into complex, thin-walled sand molds without freezing mid-pour.

Standard Bessemer vessels handled massive 15- to 30-ton batches, or "heats," whereas foundry side-blown converters were compact, typically handling half a ton to three tons per batch.

Because side-blown converters could not melt cold scrap on their own, foundries operated them alongside a cupola furnace. The cupola furnace melted pig iron and scrap into liquid iron first, which was then fed directly into the converter for refining into steel.

Alexandre Tropenas filed his first patents in England in 1891-1893, and his first U. S. patent in January 1894. The Tropenas process saw its first major success in Sheffield in England, the world's steel making capital at the time. The major Sheffield steelworks adopted the converter around 1892–1893 to replace slow, expensive crucible steel melting for complex castings. By 1897, the British War Office installed Tropenas converters at the Royal Arsenal in Woolwich to produce specialized high-strength steel shells and carriage components.

("Notes On The Tropenas Steel Process. By Alexandre Tropenas." Journal of the American Foundrymen's Association, Volume 5, Number 25, July 1898, pages 118-141, with photos and diagram.)

(Alexandre Tropenas died on July 14, 1915, at the age of fifty-five. He introduced the Tropenas converter for the production of steel castings. The first converter of this type, having a capacity of 800 lbs., was put down at the works of Edgar Allen & Co., Sheffield, about 1891. The process was also adopted at Woolwich Arsenal. It was introduced into the United States in 1901. He was elected a member of the British Iron and Steel Institute in 1894.)

The process made its way across the Atlantic to the United States in 1898, quickly transforming American steel foundries. The first U.S. installations were built in steel foundries in Pennsylvania, Illinois, and Wisconsin. Prior to 1898, small U.S. foundries struggled to produce high-temperature steel castings without building large, continuously operating open-hearth furnaces. The Tropenas converter allowed small-to-medium foundries, especially those making railroad equipment, mining machinery, and gears, to produce the small "heats" needed for low-production steel casting.

Bessemer Process

The Bessemer Process was developed by Henry Bessemer in the 1850s. This process shoots cold air from the bottom, up through molten pig iron inside a pear-shaped container (a converter). The oxygen in the air reacts with impurities in the pig iron (like carbon and silicon) to burn them out. It is incredibly fast (taking about 15 to 20 minutes), but it requires 100 percent molten pig iron straight from a blast furnace. It cannot melt cold scrap metal because the process relies entirely on the chemical heat generated by the impurities burning off; adding cold scrap would freeze the melt.

By 1910, the amount of steel made using the Bessemer process was 37 percent, and by 1939 it was just 1 percent. The year 1908 was when the tons of steel made using the open hearth process surpassed tons of steel made using the Bessemer process.

(No steel plant in Utah are known to have used the Bessemer bottom-blown converter process for making steel.)

(Read the Wikipedia article about the Bessemer process)

Open Hearth Process

Utah Iron & Steel's open hearth furnace at Midvale was completed on or about June 15, 1917, with test runs starting soon after. The first pour on November 1, 1917 was the first open-hearth steel poured in Utah.

The open-hearth furnace is entirely separate from the Bessemer converter process. They were the major competing steel making technologies of the late 19th and early 20th centuries, along with the side-blown, or Tropenas converter. All three were a way to melt scrap iron and scrap steel to manufacture iron and steel castings.

The open hearth furnace was usually rectangular in shape, the center and upper portion of which is the hearth proper, which is supported on a structural bed, and beneath it are two pairs openings. The fuel gas under pressure and air are introduced through one set of bottom openings, entering the hearth at one end, combustion taking place over the metal charge. The waste products of combustion passing through the other pair of openings. On one side of the furnace were doors through which a charge of pig iron, steel or other scrap, and ore is thrown in to be melted, and on the other side is the tap hole. (Journal of the American Foundrymen, July 25, 1898, page 148)

While the open-hearth furnace is famous for its ability to recycle scrap, it is not applicable only to scrap. It was highly versatile and could process a wide mix of raw materials.

The Open-Hearth Process was developed slightly later in the 1860s, this process uses a large, shallow hearth where a mixture of materials is melted using external heat (gas or oil burners) assisted by preheated air. Because it relies on an external fuel source rather than the internal chemical energy of the molten iron, it can take anywhere from 5 to 10 hours to complete a single batch.

(Read the Wikipedia article about the open-hearth furnace)

The open-hearth process was invented in the 1860s through the combined breakthroughs of a German-British engineer and two French industrialist brothers. Because it relied on two distinct stages of innovation, its invention timeline is typically broken down by these milestones:

Because of this joint development, the open-hearth method is historically referred to as the Siemens-Martin process. It quickly spread globally and was introduced to the United States in 1868. By the turn of the 20th century, the open-hearth process surpassed the converter process to become the dominant global steel making method.

In early 1911, the railroads were demanding open-hearth steel for their rails, instead of Bessemer steel due to the nitrogen embrittlement issue.

The great commercial advantage of the open-hearth furnace was its incredible flexibility. It didn't just use scrap; instead, it typically melted a combination of ingredients.

Depending on economic conditions and what was available, an open-hearth operator could adjust the mixture of what was put into the mixture, from a hot metal (mostly molten pig iron and iron ore) to a cold scrap (mostly scrap metal mixed with a little solid pig iron to introduce enough carbon for the reaction).

Because converters couldn't melt scrap, the rising mountains of industrial scrap metal generated by railroads and factories in the late 1800s were useless to them. The open-hearth furnace turned that cheap, discarded scrap back into high-quality steel, ultimately overtaking the converter process as the dominant steel making method by the turn of the 20th century.

The open-hearth process is far more versatile than the converter process for making various steel alloys. Its slower, more controlled operation allows metallurgists to test molten samples and precisely add alloying elements like chromium, nickel, or molybdenum. The open-hearth method easily outperforms the converter process for making diverse alloys.

Steel made using the Bessemer process was subject to nitrogen embrittlement, since the Bessemer process blows atmospheric air (which is mostly nitrogen) directly through molten iron, resulting in high nitrogen levels that can make steel brittle and unsuitable for drawing or complex fabrication. Open-hearth furnaces do not suffer from this nitrogen absorption.

Open-hearth furnaces can process charges containing high amounts of scrap steel, which naturally allows for a wider range of base materials and recycling. The converter process is highly restricted by the specific chemical composition of the initial pig iron.

Both methods have largely been replaced by the Basic Oxygen Process (BOP) and electric arc furnaces, but the open-hearth method was the industry standard for creating specialized and structural alloys for decades.

Cupola vs. Crucible

The primary difference between a cupola furnace and a crucible furnace lies in how heat is applied and whether the fuel comes into direct contact with the metal.

In late-19th and early-20th-century foundries, cupolas were the backbone for structural ironwork (engine blocks, machinery frames, pipe, and cast fittings) because they melted tons of cheap scrap iron efficiently using coke.

Conversely, crucibles were used whenever a foundry needed pure compositions— such as brass bearings, bronze ornaments, or high-carbon tool steel—where direct contact with burning coal or coke fumes would ruin the metallurgy of the alloy.

Cupola Furnace

A cupola resembles a mini blast furnace—a tall steel cylinder lined with heat- resistant firebrick.

Crucible Furnace

A crucible furnace is essentially a well-insulated chamber (fueled by gas or oil, or later, electricity) containing a removable, highly heat-resistant pot made of clay-graphite or silicon carbide.

Rennerfelt Electric Arc Furnace

Invented by Ivar Rennerfelt in Sweden around 1912, the furnace used a unique three-phase system with two side electrodes and one vertical top electrode. This configuration forced the electric arc downward directly onto the bath (acting like a blowtorch) without making direct contact with the slag, which significantly reduced electrode consumption and offered tight metallurgical control compared to earlier Heroult or Girod designs.

The first Rennerfelt electric arc furnace in the United States was installed in late 1914 (becoming fully operational in early 1915) at the W. S. Tyler Company in Cleveland, Ohio. This initial unit was a small 600-pound capacity furnace imported and erected by the New York engineering firm Hamilton & Hansell, who served as the North American agents for Swedish inventor Ivar Rennerfelt.

Late 1914 / Early 1915 — W. S. Tyler Co. (Cleveland, Ohio): Used primarily for specialty melting, brass/bronze alloys, and testing steel compositions for wire cloth backing.

1915 — American Foundry & Machine Co. (Salt Lake City, Utah): Ordered in mid-1915 and placed into operation by late 1915/early 1916, this 1-ton unit was one of the very first full-scale commercial steel foundry installations of the Rennerfelt design in the country (and the first electric furnace of any kind operating in the Intermountain West).

1915–1916 — Broader U.S. Adoption: Following these early successes, additional Rennerfelt furnaces were rapidly installed across the country, including units at the Charleston Navy Yard, Crucible Steel Company, and the Old Dominion Iron & Steel Works.

Rennerfelt vs. Héroult

The Rennerfelt design provided distinct advantages for small foundries like American Foundry & Machine Co. in 1917.

(The first electric arc furnace west of the Mississippi, in fact in the entire Western Hemisphere, was a Héroult electric arc furnace installed in 1907 in Heroult, California, by the Noble Electric Steel Company. The furnace was designed for the direct smelting of local high-grade iron ore "magnetite" into pig iron using hydroelectric power generated from nearby Pitt and McCloud rivers. The Héroult furnace was named after its French inventor, Paul Héroult, who personally traveled to California to assist with its installation. The site was later submerged in 1945 by the creation of Shasta Lake behind Shasta Dam. -- The Materials Information Society historical marker)

Héroult (Direct Arc): The electric arc strikes directly between the vertical carbon/graphite electrodes and the metal charge. Current travels down through one electrode, through the molten slag and metal bath, and back up into another electrode. This generates extreme localized heat directly inside the bath, making it exceptionally efficient for chemical refining and large-scale steel production.

Rennerfelt (Indirect / Deflected Arc): The arc is struck between the three electrodes in the air space above the melt rather than touching the metal directly. Because of the physical arrangement of the electrodes, the magnetic field pushes the intense electric flame downward onto the center of the bath—acting like an "electric blowpipe" or torch.

Héroult: Uses three heavy vertical carbon electrodes suspended over the bath, fed by standard three-phase alternating current.

Rennerfelt: Uses a unique three-electrode arrangement fed by two-phase current: Two electrodes enter horizontally from opposite sides of the shell. One electrode enters vertically through the center of the roof. The vertical electrode carries the return current for both side phases, creating the electromagnetic force that deflects the arc downward.

Direct-arc furnaces like the Héroult often suffered from severe electrical power surges when cold, uneven scrap metal shifted and short-circuited the vertical electrodes. Because the Rennerfelt arc burned freely above the charge, power consumption remained steady throughout the melt.

Because the electrodes didn't touch the molten pool in the Rennerfelt, there was zero risk of carbon dissolving into the melt from the graphite tips. This made it easier to produce low-carbon high-grade steel castings.

Flexibility: The independent arc made the Rennerfelt easy to operate for small batch melting, intermittent casting shifts, and melting non-ferrous alloys (like copper, bronze, and brass) without burning off volatile metals.

More Information

Journal of the American Foundrymen's Society (1896-1945) at Archive.org -- An excellent resource to learn about the early development of iron and steel making, especially useful for the period before and immediately after World War I.

###