Dating back to the mid-twentieth century, the Morgan No-Twist® Mill revolutionized steel wire rod production. With hundreds of installations since then, the No-Twist® Mill has continuously evolved to meet increasing roll speed requirements and quality demands, such as thermomechanical rolling. The recent record-breaking startup at Kaptan Demir Çelik, a steel mill in Marmara Ereǧlisi, Türkiye, features the latest generation No-Twist® Mill and is a testament to the continued legacy and strength of this cutting-edge technology.
From Concept to Reality
The history of the Morgan No-Twist® Mill rests in its name. The product originated with Morgan Construction Company, a legacy company of Primetals Technologies, in Massachusetts, U.S.A. Today, Sutton, Massachusetts is home to the “Center of Competence” in long rolling for Primetals Technologies, continuing a long history of innovation and quality control by supplying innovative wire rod, bar, and combination mill solutions to producers worldwide.
The conception of the No-Twist® Mill began as an idea in the early 1960s to use rolls with a smaller diameter than conventionally used in a finishing mill to run tests to improve the life of the mill roll groove and tolerance of the finished rod. Norman Wilson, one of the senior engineers at Morgan Construction Company responsible for inventing the No-Twist® Mill, set up a laboratory rolling trial using 4-inch diameter rolls. The results were ideal, producing reduced spread with increased area and elongation reduction to both improve product quality and allow for longer rolling campaigns. After that, a more extensive two-stand laboratory mill was constructed, utilizing interchangeable rolls of 4- and 6-inch diameter.
It’s no secret what a massive global impact the No-Twist Mill has had on wire rod production, but who was responsible for this revolutionary invention? Three main individuals—Norman Wilson, John Bjork, and Bob Ferguson – were responsible for most of the research and development involved in the No-Twist Mill’s iteration. All three men worked as engineers at Morgan Construction Company throughout the 1960s and 1970s. Norman Wilson filed the official patent with the United States Patent Office on August 24, 1964. Their extensive contributions to the original No-Twist® Mill, coupled with its subsequent innovations has set the standard worldwide for speed and quality in steel wire rod production.
Following laboratory results, discussions in 1963 with the American Steel & Wire Division of United States Steel led to an agreement to cooperate on developing a prototype wire rod finishing mill with 6-inch rolls at the South Works plant in Worcester, Massachusetts, U.S.A. The experience gained from the prototype quickly led to the development of the 10-stand finishing block with either two 8-inch stands, and eight 6-inch stands, or three 8-inch stands and seven 6-inch stands.
The First Installation
The first official installation of the No-Twist® Mill at Jones & Laughlin Steel (J&L Steel) in 1965 was quickly followed by Bethlehem Steel and U.S. Steel and the introduction of the K-Type No-Twist® Mill (K-NTM), which derived its name due to the horizontal orientation of the input and output shafts to the mill rolls. The debut of the K-Type No-Twist® Mill in 1964 saw speeds reaching 40.6 meters per second and was the first of more than 120 K-Type No-Twist® Mills installed worldwide from then until 1988. For wire rod producers, this dramatic increase in rolling speeds from previous mechanisms felt like the equivalent of going from horse-drawn carriages to the Ford Model T, when compared to previous conventional wire rod mills.
Beginning with 6-inch (150 millimeters) rolls, the K-Type No-Twist® Mill had a maximum rolled steel rod output of 0.5-inches (13 millimeters) with a finishing speed reaching 46 meters per second. As demand expanded throughout the world through the 1970s and 80s, the mill evolved to accommodate a larger range of finished steel rod from 5.5 millimeters to nearly 25 millimeters with increased finishing speeds. An 8-inch (200 millimeters) roll housing was added to the front of the mill to maximize the feed diameter required for larger finished rod sizes. Continuous bearing development and testing allowed the K-Type No-Twist® Mill to become the industry standard with rolling speeds approaching approximately 100 meters per second. However, driven by a passion for innovation, the K-Type No-Twist® Mill only paved the way for experts at Primetals Technologies to produce the next generation.
The Next Generation is Born
Bearing development and testing to increase rolling speed and range of finished products continued as the new V-Type No-Twist® Mill, also known as the Morgan Vee No-Twist® Mill, became industry standard from 1988 into the 2000s. The V-configuration, switching the previous generation’s horizontal configuration to a vertical configuration, allowed for improved operator access and simplified roll and guide changes to minimize stop times. The first Morgan Vee No-Twist® Mill was commissioned in 1987 at Keystone Steel (now Liberty Keystone) in Peoria, Illinois, U.S.A., as part of a rod mill addition with designed speed over 100 meters per second for 7/32-inch up to a maximum diameter of 27/64-inch steel rod for the construction, automotive, aerospace, and commercial industries
The early Morgan Vee No-Twist® Mill used five 9-inch stands and five 6-inch stands to roll a full range of rod, from 5.5 millimeters to 25.0 millimeters in diameter, at maximum design speeds of 150 meters per second. This increase in maximum rolling speed for the smaller rod sizes allowed new rod mills to achieve single strand production levels, which previously required 2 or 4 strands of rolling.
With the development of the 10-inch roll housing in 1997, the maximum size reached 1-7/64-inches with rolling temperatures dropping below 900°C. Standalone or paired with the Morgan Reducing/Sizing Mill, the Morgan Vee No-Twist® Mill remains the industry standard for rod production throughout the world. However, while the rolling speeds to produce ranges of small steel rod products were maximized, a continuous effort in determining how to minimize costs and increase efficiency led to a need to optimize wire rod mills for thermomechanical rolling.
The Answer to Thermomechanical Rolling
Rolling at lower temperatures allows for grain refinement during the hot rolled process while enabling mills to increase both bar and rod product qualities and reduce their overall conversion costs. With the highest capacity rod finishing mill on the market, Primetals Technologies began to plan the next generation No-Twist® Mill solution to continue pushing the limits of long rolling technologies.
The answer became the eDrive technology which involves individually driven mill stands that provide infinite variability per stand, size, and grade to limit strain rate, allowing optimum grain structure. The first eDrive No-Twist® Mill was hot commissioned and quickly operating at full production by 2018 in Arcelor Mittal Sosnowiec, Poland. Using ultra-heavy duty roll housings, rolling temperatures could now reach 750°C, producing ideal rolling conditions for high-quality steel grades demanding thermomechanical rolling. The technology utilizes individually driven cantilevered stands in a 45° horizontal inclination connected through helical gear drive assemblies mounted to a common base in 2, 4, 6, 8, or 10-stand configurations. All eDrive No-Twist® Mill roll housings include manual roll parting adjustment under load with an option for powered adjustments—all while having the highest rolling capacity available.
The eDrive technology, invented by Primetals Technologies, capitalizes on innovations in electrical drives and motor technologies to combine with the mechanical components of the Morgan No-Twist Mill and Morgan Reducing/Sizing Mill. Utilizing individually driven stands, eDrive provides infinite variability per stand, helping reduce both capital and operational expenditures for steel mills. Higher capacity roll housings enable thermomechanical rolling, allowing mills the opportunity to reduce downstream processing. Other benefits of eDrive include:
- Long-term cost savings
- Less power consumption
- Reduced roll shop cost
- Reduced maintenance inventory costs
- Limitless inter stand ratios to suit process requirements
A Record-Breaking Startup
The eDrive No-Twist® Mill was recently successfully installed and commissioned as part of a complete wire rod mill installation, including the Morgan Rod Reducing/Sizing Mill, at Kaptan Demir Çelik in Marmara Ereğlisi, Türkiye. With an annual capacity of 650,000 tons, the facility processes carbon, austenitic stainless steel, and cold heading grades for the engineering and automotive sectors. The startup itself was remarkably quick only taking 21 days from start of hot commissioning until the first saleable product.
Combining the Morgan Rod Reducing/Sizing Mill with the eDrive No-Twist® Mill, this novel configuration allows Kaptan to consistently deliver high-quality finished products at reduced alloying and energy costs. The combination also enables Kaptan to minimize OPEX costs from reduced roll inventories and reduced power consumption. This project expanded Kaptan’s portfolio to include value-added products such as coiled rebar, fine grain rebar, and welding wire for domestic and export markets—positioning Kaptan to be a global leader in high-quality rebar and welding wire.
I can say that the equipment is so good that it pushed us further into the field of high-quality products. It performs so well that we decided to raise the bar in terms of our expectations and ambitions – and the type of products we want to focus on going forward. In that sense, it was a catalyst for change,” Yaşar Çebi, Kaptan Demir Çelik.
Beyond the benefits seen at Kaptan, the eDrive No-Twist® Mill contains advanced speed regulation controls which allow individual stand cascade control. Unused stands can be kept turning slowly, allowing the sealing arrangement to prevent contact water (the water used to spray on mill rolls) from entering the lubrication system.
The No-Twist® Mill serves as a clear example of how far long rolling and wire rod production within the metals processing industry has come within the past 60 years at Primetals Technologies. From the K-Type introduction in the early 1960s to the industry standard Morgan Vee No-Twist® Mill and its continuous rolling speed improvements into the 2000s the No-Twist® Mill has sought to meet and exceed industry demands over decades. The latest generation eDrive No-Twist® Mill bridges electrical and mechanical long rolling technologies into the most cost-effective solution for producers expanding their product ranges to include thermomechanical rolling. With continuous developments the No-Twist® Mill’s evolutionary history promises an even brighter future.
