Drum It Up! Steel Drum Industry News, Trends, and Issues

Archive for the ‘Stainless Steel’ Category

Stainless Steel does not Rust…Wrong!

November 19th, 2019 by Howard Skolnik

Filed under: Skolnik Newsletter, Stainless Steel

Stainless steel is a ubiquitous material with a wide variety of applications—from

use in medical devices, to automotive parts, to jewelry and cooking utensils. Much of the “magic” of this metallic material is that as stainless, in theory, it doesn’t rust. However, if you have ever owned or used a stainless steel product it is likely that you have noticed rust (corrosion) and you may have even questioned if its name is a misnomer. Why does a material touted as “stainless” rust?

Most people are familiar with metals, to include stainless steel, corroding when it’s exposed to environments such as seawater. Often, without understanding the exact science of what is occurring, people accept that exposing a metal product to seawater has a damaging effect. The science behind corrosion from seawater is that the water contains chlorine, which is corrosive to metals, including stainless steel. However, corrosion of stainless steel can also occur without producing any corrosion products to analyze (other than rust), and when an obvious corrosive environment is unable to be detected.

To understand what makes stainless steel rust it is first important to understand the science that typically prevents it from rusting. Steel is made of iron and carbon, and stainless steel contains iron, carbon, and anywhere from 12-30% chromium. Stainless steel can contain other elements such as nickel and manganese, but chromium is the key element which makes it rust resistant.

Have you ever used a steel wire wheel or steel wool to clean off a stainless steel tool, and then the stainless tool rusted in the same spot which was brushed clean? Or have you seen a stainless steel container or sink rust? Stainless corroding in the absence of a corrosive element (such as chlorine) is usually from very tiny steel particles touching the stainless steel surface. Chromium can protect stainless steel if the localized concentration is in excess of 12%, but if you cover the stainless surface with sufficient steel particles, then the localized concentration of chromium can fall below the 12% threshold and the chromium oxide layer fails to protect the stainless steel from oxygen attack. If this type of corrosion happens to stainless steel, it is fixable by: (A) Cleaning off all the rust, and then (B) removing the tiny steel particles by thoroughly cleaning the stainless steel part, usually with a solvent. These two steps should allow the chromium oxide layer to protect the stainless from further oxidation. Check out our extensive line of stainless steel drums.

Avoiding another Monte Testaccio — The beginning of wine transport.

December 11th, 2018 by Jon Stein

Filed under: Skolnik Newsletter, Stainless Steel, Wine

Humans have been imbibing wine for thousands of years. But, the question of how wine got from one place to another, is fascinating to explore. While it’s relatively easy to carry vine cuttings on long journeys, bringing finished wine with you is a much more difficult task. If there’s truth to the old cliché that necessity is the mother of invention, then as a species, we’ve shown a serious need to drink wine. Transporting wine is a tricky task, as your storage vessel needs to accomplish four different goals:

  • Air must be kept out of the vessel to prevent oxidation.
  • The vessel must be strong enough not to easily break, without being so heavy that it cannot be easily moved (especially when hand labor was the rule).
  • In many cases, the vessel needs to be opened and then resealed.
  • The vessel itself shouldn’t interact with the wine (though we’ll see that a very large asterisk follows this rule).

In addition to those goals, the vessel needs to be stored in an environment that has a stable temperature. If wine is exposed to heat for too long it will “cook” and lose its flavor.

Amphorae — Were the ancient world’s standardized way to transport wine, olive oil and other prized liquids. Amphorae came in many sizes, similar to both the bulk transport formats we use today as well as the world’s common wine bottle sizes. These wax-lined (pine and bees wax were common) ceramic containers, invented by the Egyptians, were gradually adopted by nearly all the wine drinking/producing civilizations throughout the Mediterranean and Mesopotamian regions. They reached their peak in usage and standardization in ancient Greece and Rome. They were easy to produce and, importantly, easy to transport. Their shape was round with a tapered bottom, two handles and a long, slim neck. The amphora’s tapered bottom also proved to be useful in keeping its contents from sloshing around during a sea journey. This was accomplished by filling a ship’s hold with sand, and then partially burying each amphora in the sand. Looking at an amphora you can see the similarities to a modern wine bottle, from the long neck, which keeps the wine away from oxygen, to the sediment-collecting concave bottom of most wine bottles, the ‘punt.’ The Romans continuously improved their physical design — the goals being to reduce weight without sacrificing strength and to pack more and more amphorae into the cargo holds of ships. This excerpt from David Stone Potter’s book Life, Death, and Entertainment in the Roman Empire, shows the massive scope of the Roman ‘logistics’ system:

A year’s supply of 20,000,000 liters oil translates into about 285,714 amphorae, and 100,000,000 liters of wine would require 4,000,000 amphorae, and that’s just for the city of Rome. The author is quick to note that these are estimates based upon some consumption and population assumptions. Still, these are not unreasonable assumptions: archeologists have estimated that Monte Testaccio ‘an artificial hill’ in Rome, is composed of 53 million or so broken amphorae, discarded over the course of 150-300 years. Rome’s Monte Testaccio is one of the largest spoil heaps (landfills) found anywhere in the ancient world, covering an area of 20,000 square meters (220,000 sq ft) at its base and with a volume of approximately 580,000 cubic meters (760,000 cu yd).

Stainless Steel — While today we recognize that oak barrel aging is fundamental to the production of many wines (or oak substitutes such as chips in stainless steel barrels), the use of stainless steel has grown, from the large storage tanks to the straight sided and “barrel” shaped drums now being used to store and transport wine. Monte Testaccio? Never again, but here at Skolnik Industries, our stainless steel wine barrels are reusable, easy to clean, and recyclable at the end of their service life. check out the full line of our Stainless Steel Wine Drums here.

304 vs 316 Grade Stainless Steel Drums

November 5th, 2018 by Natalie Mueller

Filed under: Stainless Steel

By definition, stainless steel is a steel alloy with a minimum of 10.5% chromium content by mass. However, there isn’t just one kind of stainless steel. There are numerous grades of stainless steel all with variations in density, elasticity, thermal conductivity and other properties. When it comes to a stainless steel that must endure corrosive environments, which most stainless steel industrial containers must, austenitic stainless steels are the most popular choices. But even then, there are two popular grades: 304 and 316 stainless steel. So, what grade stainless steel drum is right for you?

304 stainless steel is generally the most common austenitic steel used due to it’s high nickel and chromium content. The high chromium content gives 304 stainless steel drums and other products excellent corrosion resistance.

316 stainless steel also has high amounts of chromium and nickel, but with a significant amount of molybdenum, grade 316 stainless steel possesses an even higher level of corrosion resistance.

What grade of stainless steel you need largely depends on your use. In the case of stainless steel drums, it largely depends on the materials you wish to contain or ship and any regulations governing those materials.

For example, while 304 is often used in commercial food processing, 316 is considered one of the most suitable choices for marine applications, medical devices and chemical processing or storage. 304 has better formability and is generally more affordable, but 316 may be a better choice when working with/containing corrosive environments or where greater strength and hardness are required.

At Skolnik, we know our steel and are happy to guide our partners to the most efficient and effective material and container for their needs.

The Five Families of Stainless Steel

June 28th, 2018 by Natalie Mueller

Filed under: Stainless Steel

At Skolnik we offer a host of steel containers — our stainless steel drums offer an ideal solution for products requiring the purity, compatibility and strength of stainless steel. But just like Skolnik offers different families of products, there are different families of stainless steel. Five to be exact: austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, duplex stainless steel and precipitation hardening stainless steel. The families are classified by their crystalline structure.

 

Austenitic stainless steel is the largest family. About two thirds of all stainless steel produced falls into this category. Their crystalline structure is achieved by alloying with sufficient nickel and/or manganese and nitrogen. These stainless steels maintain their microstructure at all temperatures so they can’t be hardenable by heat treatment, but can be strengthened by cold working to an extent.

Austenitic stainless steel is great for formability and weldability, they are also essentially non magnetic. They’re often used for tanks, containers, storage vessels, architecture and the like.

 

Ferritic stainless steel has a structure more similar to carbon steel, contains between 10.5% and 27% chromium with very little or no nickel. Due to the chromium structure, ferritic stainless steel also holds its structure at all temperatures and is not hardenable by heat treatment. However, they are magnetic and are problematic to weld.

Welding creates microstructural problems so ferritic stainless steel is not used in the construction of large, heavy walled vessels and tanks and structures.

 

Martensitic stainless steels form a family that can be heat treated to provide the adequate level of mechanical properties. Martensitic stainless steels are magnetic and are less corrosion resistant than ferritic and austenitic due to a lower chromium content.

However, their high carbon content enables them to be significantly hardened so they are commonly used for knives, razor blades, cutlery and tools.

Duplex stainless steel’s structure is a combination of that of austenite and ferrite, usually at a 50/50 or 40/60 mix. It’s characterized by high chromium and molybdenum with lower nickel contents. The mixed microstructure results in higher resistance to chloride stress corrosion.

Duplex stainless steel can be difficult to weld properly, but can sometimes be a cost-effective solution for chemical processing, transport and storage, and marine environments.

 

Precipitation hardening stainless steel has corrosion resistance comparable to austenitic varieties but can be hardened to even higher strengths than martensitic steel. Precipitation hardening stainless steel is often used for gears, valves and other engine components, nuclear waste casks, and other pieces in aerospace and other high-tech industries.

 

Beyond that, there are over 150 grades of stainless steel.

Skolnik stainless steel drums are available in a variety of gauges and sizes and are stainless types 304 and 316, both austenitic, and 409, a ferritic stainless steel. And our products are built thicker, heavier and stronger than industry standards require.