4 05, 2022

Metals and Steel History: From India and Europe to Modern America

2022-08-05T16:32:28+00:00May 4th, 2022|News Blog|


Iron, the Herald of Things to Come

Metals and steel history spans from India and Europe to modern America. For the ancients, much of life was a mystery. At first, humans only utilized the easy-to-find metals, such as gold, silver, and copper, that didn’t require human intervention to become a final product. Other available metals needed treatment before they could be used. For example, smelting was needed to extract iron from iron ore, which is a chemical compound formed from iron and oxygen. Altogether, prehistory was an age where humanity was at the mercy of the colossal powers that govern the universe.

Even still, humans progressed.

A philosopher named Aristotle perceived the essence of virtue. He theorized that virtue lies at the balance point between deficiency and excess.

“The man who shuns and fears everything and stands up to nothing becomes a coward; the man who is afraid of nothing at all but marches up to every danger becomes foolhardy.” — Aristotle

Aristotle would have recognized steel as a virtuous metal. Steel contains anywhere between 0.05% to 0.25% carbon content, the perfect balance between deficiency and excess. Too little carbon and the metal becomes weaker and soft. Too much carbon and the metal will become brittle.

But getting metal to show its virtue as steel would take technological processes that defied humans for many years. While they used bronze, many civilizations neglected iron because iron technology at the time could only produce a “low-density, sponge-like material.” The main obstacles to higher quality iron were designing furnaces with high enough temperatures and the lack of basic knowledge of elements. Eventually, however, the abundance of iron ore (more abundant than the tin needed to make bronze) made it the metal of choice. This discovery began the Iron Age. With the advent of the Iron Age, steel, an alloy of iron, now found itself in ideal circumstances to surface as the supreme metal. However, steel would have to wait until after the industrial revolution to be mass produced.

To make steel, all that’s needed is a bit of charcoal, iron, and a furnace. However, the smelting can be tricky. If “your gangue is ‘wrong’, your bellows are leaky or especially efficient, your charcoal is too reactive, […] all you produce is slag, useless cast iron, or small useless blooms.” So much mystery shrouded steelmaking, that ritual and religion often got mixed up with science. One superstitious smith in the Middle Ages insisted on “quenching the steel in ‘the urine of a redheaded boy‘.”

Humanity would eventually conquer the process over centuries. Now, we will try to follow the oftentimes obscure history of steel technology.

An Abbreviated History of Steel

Egyptians, Hittites, and the Earliest Known Steel-work

The mighty Egyptians don’t need an introduction. They are the builders of pyramids and the Sphinx, of making papyrus and hieroglyphics, appear prominently in much of the Old Testament, and are well represented in museums across the planet. However, in steel lore, Egyptian […]

30 09, 2020

Steel Processing at National Galvanizing

2020-09-30T19:24:37+00:00September 30th, 2020|News Blog|

Today, modern chemists must face the same problem that one element posed to the Egyptians thatshould have destroyed the pyramids. It’s that ubiquitous element that threatens everything made by humans: water. As frost formed inside the stone structure at night and expanded with the morning, slow cumulative damage should have been done to the pyramids. For many years, this mystery defied the explanation of archeologists, however was eventually solved. A detailed study concluded that ancient Egyptians relied on technology to defy the power of water: they had invented a primitive form of cement.

Water threatens the integrity of modern structures. Steel, the very backbone of modern civilization, rusts when it comes into contact with water. Technology has been the answer for modern man, just as it was for the pyramid builders. Various techniques have been developed to prevent steel from corroding. One of the most sought after by leading industries is galvanizing. Both long-lasting and cost-friendly, galvanized steel can resist rust for 70 years or more. The characteristics of the environment where it is used, and the thickness of the protective coat can influence the lifespan of the steel. Today, a sophisticated process known as hot-dipping is used to galvanize steel. Essentially, galvanizing adds a zinc-iron coating to the metal, forming a protective layer. The multi-step process described below gives galvanized steel its protective qualities:
1) The steel is cleaned in a degreasing solution.
2) After being cleaned, the steel is pickled by running through various tanks containing hot sulfuric acid.
3) The steel is then fluxed in an aqueous solution (typically zinc-ammonium chloride).
4) After the flux, the steel is galvanized through immersion in a vat of molten zinc.
5) Afterward, the steel is inspected for consistency and a complete coating.
Galvanized steel has a low, initial cost, and no need for maintenance. It also provides other important advantages:
• Rust resistance: The iron elements in steel are incredibly prone to rusting, but the addition of zinc acts as a protective buffer between the steel and any moisture or oxygen.
• Easy inspection: It is easy to tell how strong a galvanized coating is just by looking at it. There are also quick stress tests that can determine how thick the zinc coating is.
• Sacrificial anode: This ensures that any damaged steel is protected by the surrounding zinc coating. It does not matter if the steel section is completely exposed; the zinc will still corrode first.
• Longer life: With galvanization, a piece of industrial steel is expected to last 70 years in average environments and can last over 20 years with severe water exposure. No maintenance required.
Galvanization is part of a larger framework in steel preparation. Clients can benefit through facilities that can apply various processes to steel including hot-dipped galvanizing. That’s why National Galvanizing’s state-of-the-art facility enables pickling, galvanizing, galvannealing, and slitting, all in one location. As a joint venture between National Material L.P. and Heidtman Steel, National Galvanizing has an unparalleled structure for quality, high-speed supply that serves the automotive, heavy truck, agricultural, garage door hardware, and HVAC industries, among others.

NMLP […]

12 03, 2020

What is Roll Forming?

2021-02-08T18:27:20+00:00March 12th, 2020|News Blog|

Roll forming is a continuous process which converts sheet metal into an engineered shape using consecutive sets of mated rolls, each of which makes only incremental changes in the form.  The sum of these small changes in form is a complex profile.

The Forming Process

 In conventional stamping the entire part is formed all at the same time. The part shape – and especially how complex it can be is limited when the strains from forming exceed what the metal is capable of achieving before splitting.  In roll formed parts, only a small amount of forming strain is put into the part during each station and even here, only a small section is bent at any given time. Because of this, more complex shapes can be achieved with an appropriately designed roll forming process.

In the forming process, a coil or long individual strips are fed through a roll forming line which converts the flat sheet to a contoured cross-sectional profile. The unique aspect of this approach is the use of consecutive forming stations, each of which nudges the metal towards the desired shape.  Based on the targeted profile, a computer calculates the optimal placing and shape of the rollers for maximum efficiency and designs the track.  The more advanced the desired shape, the more rollers the material goes through. The roll forming line can bend metal, form metal into tubes, create metal maze-like structures, and punch the metal with holes during the process.

A rendered image of four grey rollers placed in a cross-pattern forming a metal profile that resembles a capital, backwards “Z” and “G” joined together at the top.

The rollers are precision-contoured metal dies that shape the incoming sheet metal. In most cases, they are also the powered drive rolls that pull the strip through the roll forming unit. These rollers can be as simple as the cylindrical rollers used to roll luggage through airport scanners, or they can take on more intricate shapes. After the final forming station, the strip is sheared to the ordered product length. Typically, no additional work is needed before shipment, since the final form has been achieved.

3D rendered image of a shiny steel roll former.

Advantages of the Roll Forming Process

 

There are a variety of advantages to roll forming. Because of the “assembly line” efficiency of roll forming, long lengths of metal can be produced and cut in large quantities, which reduces cost.  Secondary processes such as punching or even welding can be integrated into a single production line. The profiles that can be produced using roll formed sheet steel are similar to what is seen in extruded aluminum.

The roll forming process makes creating lighter-weight steel parts easier compared to other shaping processes, since the wall thickness can be targeted based on the structural needs of the component.  Parts can be rolled even if a finish or paint has been applied. While hot forming can produce similarly complex profiles, roll forming is a room temperature process.  As […]

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