What Type of Rail Pad Material Should Be Used with Crane A120 Rail?
The A120 crane rail (compliant with the DIN 536 standard) is a heavy-duty profile with a wide 220mm base. It is designed to support massive wheel loads from heavy overhead cranes, Ship-to-Shore (STS) cranes, and port equipment.Because of these extreme loads, standard pure rubber pads are insufficient. The standard and most recommended solution is the Steel-Reinforced Elastomeric Rail Pad (Continuous Pad).
1. Main Elastomer (Rubber) Materials
The rubber body must offer high wear resistance, anti-aging properties, and excellent compression recovery. The most commonly used materials are:
- NBR (Nitrile Butadiene Rubber): The most widely used material. It offers exceptional oil resistance (crucial for preventing degradation from crane lubricant drips), high abrasion resistance, and strong compressive capacity, making it ideal for most industrial environments.
| Category | Properties / Elements | Typical Value (High-Duty Grade) |
| Chemical Composition | Main Polymer | Acrylonitrile + Butadiene |
| ACN Content | 33% – 45% (Higher ACN = Better Oil Resistance) | |
| Mechanical Properties | Hardness (Shore A) | 70 – 80 |
| Tensile Strength | 15 – 20 MPa | |
| Elongation at Break | ≥ 300% | |
| Compression Set (22h/70°C) | ≤ 25% | |
| Operating Temperature | -20°C$to +100°C |
- EPDM (Ethylene Propylene Diene Monomer): The preferred choice for outdoor and port applications. EPDM provides superior resistance to UV radiation, ozone, and extreme temperature fluctuations, ensuring a longer lifespan in harsh weather conditions.
| Category | Properties / Elements | Typical Value (Outdoor Grade) |
| Chemical Composition | Main Polymer | Ethylene + Propylene + Diene Monomer |
| Ethylene Content | 45% – 75% | |
| Mechanical Properties | Hardness (Shore A) | 65 – 75 |
| Tensile Strength | 10 – 15 MPa | |
| Elongation at Break | ≥ 350% | |
| Compression Set (22h/70°C) | ≤ 20% | |
| Operating Temperature | -40°C to +120°C |
- Specialty Synthetic Rubber (e.g., EVA blends): Crane Rail Pad often use proprietary synthetic blends designed to maximize shock absorption and minimize rail wear.
| Category | Properties / Elements | Typical Value (Premium Grade) |
| Chemical Composition | Main Polymer | Ethylene-Vinyl Acetate (EVA) / Synthetic Blends |
| Reinforcement | Silica / High-Structure Carbon Black | |
| Mechanical Properties | Hardness (Shore A) | 85 – 95 (Higher for A120 load) |
| Tensile Strength | 18 – 25 MPa | |
| Elongation at Break | ≥ 250% | |
| Static Stiffness | Optimized for 1.2M - 1.5M N/mm | |
| UV & Ozone Resistance | Excellent |
2. Internal Reinforcement
- Galvanized Steel Strip: A dedicated A120 rail pad features a thin, high-strength galvanized steel plate (typically 0.5mm to 1mm thick) completely encased within the elastomer.
Why is it necessary? Under the immense wheel load of a heavy crane, pure rubber tends to flatten and extrude laterally (tear or squeeze out from under the rail). The internal steel reinforcement restricts this lateral expansion, ensuring the pad remains perfectly positioned under the A120 rail base.
3. Physical Features & Specifications
To perfectly match the A120 rail, the pad is manufactured with specific physical traits:
- Width: Customarily slightly narrower than the A120's 220mm base (usually around 215mm) to fit properly between the welded rail clips without interfering with the fastening system.
- Surface Structure: Features a grooved design. The micro-convex grooves provide space for the rubber to displace slightly under pressure, while also facilitating water drainage and pushing out dust or sand from under the rail.
- Hardness: Typically ranges between 75 to 85 Shore A. This specific hardness strikes the perfect balance between providing robust structural support and effectively dampening high-frequency vibrations.
How to Match Pad Materials to A120 Crane Rail Material Grade?
The choice of pad material should be influenced by the A120 Crane Rail Material Grade and the intended duty cycle. If a facility uses high-strength A120 steel rails (such as Grade S900 or S1100), the crane is likely operating at high speeds or carrying near-maximum loads. In these cases, a pad with higher Shore hardness and enhanced thermal resistance is required to match the durability of the A120 rail material. A mismatch can lead to the pad failing long before the rail, causing unnecessary downtime.
Furthermore, the chemical material composition of A120 rail must be considered in corrosive environments. In seaside ports, the pad must provide an effective seal to prevent saltwater from accumulating between the A120 rail profile and the baseplates/Steel Soleplates, which can cause corrosion on the rail base. High-quality synthetic rubber pads are designed to form a tight seal under the A120 rail dimensions, effectively acting as a protective barrier for the steel components.
- S700 Rails: Standard reinforced pads are typically sufficient.
- S900/S1100 Rails: Require heavy-duty composite pads with superior compression sets.
- Corrosive Environments: Require EPDM-based pads for maximum chemical and weather resistance.
FAQ
- Is it possible to use natural rubber pads with A120 rails?
It is not recommended. Natural rubber lacks the oil and UV resistance required for A120 overhead crane rail systems. Synthetic elastomers like EPDM or Nitrile are far superior for maintaining the integrity of the DIN536 A120 Rail System in industrial environments.
- How does the rubber pad affect the A120 rail weight per meter?
The A120 rail weight per meter remains 101.2 kg/m. The pad is a separate component of the A120 rail accessories that adds negligible weight but provides essential elastic support for the A120 steel rails.
- How often should A120 rail pads be replaced?
High-quality reinforced pads used with A120 heavy rails can last 10-15 years. However, they should be inspected regularly for signs of extrusion or hardening, which would indicate they are no longer protecting the baseplates/Steel Soleplates effectively.
- Do all A120 rail systems require steel reinforcement in the pads?
For heavy-duty A120 crane tracks with wheel loads over 30 tons, steel reinforcement is highly recommended. It prevents the pad from deforming under the A120 rail dimensions, ensuring the track remains stable.
- Can I use the same pad for A120 and A150 rails?
No. The A120 rail dimensions include a 220mm base, whereas A150 rails often have different base widths. The pad must match the base width of the A120 rail profile exactly to provide proper support.
- What is the benefit of the grooved surface on A120 rail pads?
The grooves allow the rubber to expand into the voids when the crane wheels pass over the A120 Steel Crane Rail. This increases the "resilience" or springiness of the pad, improving vibration damping for the DIN536 crane rail.
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Selecting the correct pad material and reinforcement type is a critical step in engineering a reliable A120 overhead crane rail systems. GNEE RAIL provides the technical expertise and high-quality A120 rail accessories needed to ensure your infrastructure performs at its peak. Our team can help you select the ideal pad material based on your A120 Crane Rail Material Grade and specific operational environment.
Building a durable and safe Crane Track starts with the highest quality materials and professional guidance. Contact us to obtain a solution to discuss your DIN536 A120 Rail System requirements and receive a customized quote for rails and pads. Let GNEE RAIL provide the industrial-grade DIN 536 Standard Crane Rail and technical support needed to ensure your A120 crane tracks are optimized for long-term success.
