Steel

Editor's Note: Author Amanda Cattermole is a Sustainability and Chemical Management strategist and runs Cattermole Consulting. Beyond sustainability education, we thought it was important to begin an internal analysis of our own processes. Amanda has worked across all aspects of supply chain. For the past two decades, Amanda has worked in a directorial role at Levi's in research and development before founding her consulting firm, Cattermole Consulting. 

Photos: Matthew Christopher Miller

Sustainability is one of Stinner's core values. We are committed to building a brand and business anchored on a triple bottom line philosophy considering the social, environmental and financial impact of our enterprise.

Stinner Bikes builds high-quality bicycles in Southern California. Every Stinner bike is custom made and designed to deliver the simple freedom of a perfect ride. Stinner Bikes uses state of the art materials including steel and titanium for its bike frames. The company sources from local suppliers wherever possible and fully understands the technical performance attributes of the materials used in its bikes.

Thus, for the purposes of transparency and understanding the environmental impact of manufacturing processes used at Stinner, we have commissioned an environmental impact report and lifecycle assessment for the materials used in Stinner bikes. This is the educational portion of the report to provide background information on steel.

Steel

A brief history: Steel manufacturing has been a major part of U.S. industry since the Industrial Revolution. Understanding the steel industry’s history helps clarify how steel is used today and the industry’s attempts at greater efficiency at large (including minimizing environmental externalities). This is not meant to be an in depth report on steel’s history and usage but a starting point for further research and Stinner’s commissioned LCA.

In a period of less than 50 years, between the Civil War and the First World War, America was transformed from a rural republic to an urban nation. The frontier vanished and was replaced with factories and steel mills, transcontinental railroad lines, flourishing cities, and vast agricultural holdings. This can be traced back to the steel industry and the needs of the Civil War.

Andrew Carnegie was largely responsible for the great advances in steel production. He merged his holdings into a corporation that would embrace the majority of iron and steel properties in the nation. The United States Steel Corporation, formed in 1901, was the combination of independent industrial enterprises into federated or centralized companies.

Composition

Steel is an alloy composed of iron and primarily carbon, although, other elements may be present. It is known for its high tensile strength (stress that a material can handle while being pulled or stretched), which makes it a valuable material for the construction industry.

Stinner uses True Temper S3 tubing in its custom made steel bikes. S3 stands for super light, super strong, and super ride quality according to True Temper. Combining craftsmanship with the benefits of customization is best accomplished with steel. The S3 tubing unites the strength and performance of steel with the lightweight advantages of other materials. The S3 tubing used in bikes from Stinner is made from 4130 Chromoly steel sourced from the United States. Chromoly steel is made from iron, chromium and molybdenum, hence the name “chromoly steel.” There are different grades of chromoly steel, depending on the percentage by weight of the alloys. The Society of Automotive Engineers specifies the steel grades (SAE).

Chromoly steels have excellent strength to weight ratios. Chromoly Steel is stronger and harder than standard steel. Chromoly steels vary by alloy composition.

Recyclability

In 2014, the National Bicycle Dealers Association estimated the US market for bicycles at around 6 billion US dollars, or roughly 12.4 Million bikes. 99% of bikes sold in the US are made in Taiwan and China. Many cyclists upgrade or get a new bike on a regular basis, leading to bikes that are either unused or end up in a landfill.

Stinner makes 100% of its bikes in the United States. Stinner uses steel or titanium to make their frames. Both metals can be recycled so that when the bicycle eventually reaches the end of its lifespan, it can be repurposed, sold or recycled. In fact old steel can be endlessly recycled into new bikes.

Steel is 100% recyclable and is North America’s number one recycled material. Over 74 Million tons of steel have been recycled in North America in 2015. Scrap steel is an essential material in making new steel.

Recycling steel accounts for significant energy and raw material savings: The world steel association boasts that over 1400 KG of iron ore, 740 Kg of coal and 120 KG of limestone are saved for every ton of steel scrap made into new steel. This helps the environment and reduces production costs.

For comparison’s sake, carbon fiber is non-recyclable and often ends up in trash heaps.

Production

Making steel is an energy intensive process. According to the North American steel industry, 1.17 tons of CO2 was emitted in 2012 for every ton of steel produced in the US. The majority of the energy is used to melt Iron. The steel industry is aggressively looking to reduce carbon emissions.

The energy to produce a ton of steel has been reduced by 60% in the last 50 years.

SAE GRADE % Chromium % Molybdenum % Carbon % Manganese % Phosphorous % Sulfur % Silicone
4130 0.80-1.10 0.15-0.25 0.28-0.33 0.40-0.60 0.035 0.040 0.15-0.35

This is due to the following initiatives:

  • A higher percentage of recycling.
  • Coal producing energy is being replaced by electric power and other greener power sources.
  • Implementation of management systems.
  • Advancements in manufacturing techniques such as capturing carbon dioxide.

These advancements have led to:

  • A 32% reduction in energy intensity and 37% reduction in greenhouse gas intensity since 1990.
  • Per unit water use in the steel industry is less than half of what it was 20 years ago and more than 95% of the water used is recycled within the plant.
  • Although the steel making process is already highly optimized a new project has been launched to take significant long term steps towards carbon free iron making which will have near zero CO2 emissions.

Concluding Remarks

Steel is certainly the right solution from an environmental and social point of view. However, steel gives a super strong and super light ride quality. It is the perfect triple bottom line material which combines performance, affordability and sustainability.However, no matter what material is used in your bike frame, we urge you to continue to consider bike commuting and mass transit as a primary form of transportation.

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