Railroad steel refers to the steel used in railroad tracks. This steel is known for being very hard and durable in order to withstand the tonnage of trains running over it day after day. Some knife makers believe that railroad steel makes excellent knife blades because of these properties. However, there are some important considerations when it comes to using railroad steel for knives. In this article, we’ll examine the characteristics of railroad steel and look at the pros and cons of using it for knife making.
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What is Railroad Steel?
Railroad steel gets its name from being used for railroad tracks and wheels. It needs to be extremely hardy to handle the demands of heavy train traffic. Most railroad steel is made from high carbon steel containing 0.65-0.85% carbon. It also has various alloying elements like manganese, silicon, and copper added for enhanced strength.
The steel is poured and formed into ingots before being rolled into rails. The rails undergo further heat treatment and tempering to achieve the necessary hardness and toughness. This makes the steel very resistant to wear and deformation from the weight of trains. Railroad steel is typically much harder than other types of steel, rating around 300 on the Brinell hardness scale.
The extreme pressures and friction involved mean railroad steel must have high durability and fatigue resistance. It also needs enough ductility and impact toughness to avoid cracking under the forces. Modern high speed rail lines use specialized steel optimized for performance at higher speeds. But traditional railroad steel is still noted for its hardness and strength.
Advantages of Railroad Steel for Knives
There are some potential benefits for using railroad steel for making knives:
Extreme Hardness
The hardness of railroad steel is one of its biggest advantages for knife making. The high carbon content combined with heat treatment creates steel with exceptional hardness and ability to take and hold an edge. This hardness makes railroad steel perform well as the cutting edge for knives.
Wear Resistance
Railroad steel is designed to withstand prolonged heavy friction and abrasion from train wheels. This wear resistance translates well for knife edges, allowing them to maintain sharpness longer under use. The hardness and toughness help resist deforming and dulling.
Toughness
In addition to hardness, railroad steel has an adequate level of toughness and shock resistance. This is necessary to prevent cracked and broken rail tracks. For knives, it means the steel is less brittle and liable to chip or snap. The toughness provides durability under strenuous cutting tasks.
Corrosion Resistance
Railroad steel contains alloying elements like silicon and copper to help improve corrosion resistance. This can be beneficial for knives that are exposed to the elements. Proper care is still required, but the steel has some weather-resistant properties.
Availability
Decommissioned railroad steel is sometimes sold as scrap metal and can be acquired for knife making at reasonable prices. This availability makes it an accessible steel choice for hobbyist knifemakers on a budget.
Disadvantages of Railroad Steel for Knives
Using reclaimed railroad steel does have some potential drawbacks:
Inconsistent Composition
One issue with scavenged railroad steel is that the exact composition may vary. This depends on the railroad line, age of the steel, manufacturing methods, etc. There can be inconsistencies between different batches. The unknowns make heat treatment and predicting performance more difficult.
Excessive Hardness
While hardness is beneficial for the edge, too much can make the steel brittle and prone to cracking under stress. Railroad steel is extremely hard and may be imbalanced without proper heat treating to add toughness. Novice heat treaters could end up with blades that are too hard and brittle for practical use.
Unknown Origins
It can be hard to verify the origins and composition of mystery railroad steel. There may be questions about possible contamination or undesirable alloys used. The steel’s background offers less control compared to using new, known steel stock.
Difficult to Work
The hardness that gives railroad steel its edge qualities also makes it very difficult to shape and grind. Significant time and effort is required for stock removal. It can quickly wear down grinding belts and necessitate diamond wheels. Annealing cycles may be incorporated to soften it for working.
Prone to Rusting
While it has some corrosion resistance, railroad steel is still predominantly high carbon steel. It can oxidize and rust readily without proper maintenance. Coatings like paint or black oxide may be needed to reduce this tendency.
Key Considerations
Railroad steel has some positive attributes but also requires precautions:
Heat Treating Challenges
Proper heat treatment is essential yet challenging with railroad steel of unknown origins. The hardness and brittleness need to be controlled by normalizing, annealing, and tempering cycles. This requires skilled heat treating knowledge.
Understand Compositions
To use railroad steel most effectively, understanding the major alloy differences is helpful. Knowing the manganese and silicon contents can guide suitable heat treatment. Chemical or spark testing can approximate the composition.
Coatings for Rust Resistance
Some type of protective coating is recommended for railroad steel knives. This helps reduce the propensity to rust. Options include Renaissance wax, force patinas, phosphates, powder coating, or durable paint.
Design for Toughness
The knife design should incorporate features to improve toughness, strength, and resistance to cracking. Avoiding super thin edge bevels and incorporating a full (convex) grind can help compensate for the steel’s hardness.
Specialized Equipment
Working railroad steel requires hardened steel tools, diamond abrasives, and power grinding equipment. Annealing may also necessitate a kiln or high temperature furnace if forge heating isn’t sufficient.
Examples of Knives from Railroad Steel
Here are some examples of knives made from railroad steel by talented knifemakers:
Will Creek Forge – Railroad Spike Knife
This sturdy full tang knife was hand forged from a railroad spike. The blade shape is similar to a Bowie knife with clip point. The maker annealed and normalized the steel for balance of hardness and toughness. The handle scales are black linen micarta.
Texas Farrier Knives – RRB Track Layer Damascus
This blade features damascus steel made from railroad track steel and other metals. Beautiful layered damascus patterns result from folding and forging the metals together. The railroad steel adds hardness while the other alloys improve strength and flexibility.
DownEast Knives – Railroad Cross Section Chef Knife
The maker cut sections from a rail track tie and forged them into a chef’s knife with grippy handles. The railroad steel forms the blade core with Nickel added for easier grinding. The laminated construction allows a softer steel jacketing for additional toughness.
Conclusion
Railroad steel has some excellent properties that can be beneficial for knifemaking when applied carefully. The extreme hardness and wear resistance allow remarkably durable and lasting edges. However, the steel also poses challenges with unknown compositions, brittleness, difficult workability, and rusting.
Proper heat treatment by an experienced bladesmith is essential to balance hardness and toughness for functional knives. The characteristics of railroad steel make it best suited for thicker, larger fixed blade knives where toughness is less critical. With its unique history and properties, it can make for distinctive, high performance knives in the right hands.