Steel Cord Conveyor Belt
Compared with textile-reinforced EP or NN conveyor belts, the steel cord carcass provides higher tensile capacity and much lower longitudinal elongation, helping maintain stable belt length and reduce take-up requirements on long and highly tensioned conveyor systems.
Steel Cord Conveyor Belt Profile
A steel cord conveyor belt, also known as an ST conveyor belt, is a heavy-duty rubber conveyor belt reinforced with multiple high-strength steel cords arranged longitudinally as the primary tensile member. The steel cords carry the operating tension, while high-adhesion core rubber surrounds and bonds the cords into the belt body. Top and bottom rubber covers protect the carcass against abrasion, impact, cutting and environmental exposure.
Steel cord conveyor belts are designed for high-strength, long-distance and high-capacity material conveying, and can also be used in high-tension, shorter-distance applications where greater tensile capacity is required. Their high tensile strength and very low longitudinal elongation make them particularly suitable for demanding conveyor systems with high operating tension and continuous heavy-duty service.
The ST designation indicates the nominal tensile strength of the finished belt in N/mm. For example, an ST1000 conveyor belt has a nominal tensile strength of 1,000 N/mm. Different steel cord conveyor belt constructions and rubber compounds are available for general-purpose, oil-resistant, heat-resistant, acid- and alkali-resistant, cold-resistant, flame-resistant, rip-resistant and elevator applications, depending on the operating environment and conveyed material.
Steel cord conveyor belts are widely used in coal handling, mining, ports, metallurgy, power plants, chemical processing and other heavy industrial bulk material handling systems where high strength, long conveying distance, large capacity and reliable continuous operation are required.
Steel Cord Conveyor Belt Features
◆High Tensile Strength & Heavy-Duty Capacity:
Longitudinal steel cord reinforcement provides the high tensile capacity required for heavy-load and high-tension conveyor systems. Available belt strengths from ST500 to ST7500, corresponding to nominal tensile strengths of 500–7500 N/mm, allow the belt construction to be matched to different conveying capacities, operating tensions and long-distance applications.
◆Very Low Elongation & Long-Distance Stability:
Steel cords provide very low longitudinal elongation compared with conventional textile carcasses, helping maintain stable belt length and reduce take-up travel on long conveyor systems. Steel cord elongation is verified under ISO 7622-1:2013, including measurement under loads corresponding to 10% and 60% of the specified tensile strength.
◆Optimized Cord Geometry & Pulley Compatibility:
Steel cord diameter and spacing are engineered according to the required ST strength rating. Available constructions use steel cords from approximately 3.0 to 15 mm in diameter with cord pitches from about 10 mm to 21 mm, depending on belt strength and construction.
◆Reliable Cord-to-Rubber Adhesion & Impact Durability:
The steel cords are embedded in high-adhesion core rubber to create a strong bond between the reinforcement and belt body, helping transfer operating loads and resist separation under impact and repeated flexing. Cord-to-rubber bonding is verified in both the original condition and after thermal treatment according to ISO 7623:2022, providing measurable control of adhesion durability.
◆Uniform Cord Arrangement & Stable Running:
Steel cords are arranged longitudinally at a controlled pitch to maintain uniform load distribution across the belt width. With available cord spacing controlled within approximately 10–21 mm, the reinforcement system helps maintain consistent tension, stable tracking and good transverse flexibility while supporting the high longitudinal strength required for heavy-duty conveying.
◆Engineered Cover Thickness & Multiple Compound Options:
Top and bottom rubber covers protect the steel cord carcass against abrasion, impact, cutting and environmental exposure. Available min cover constructions range from approximately 4 mm to 10 mm, depending on the ST rating and operating conditions, and can be combined with abrasion-resistant, heat-resistant, oil-resistant, flame-resistant, cut- and gouge-resistant or other specialized rubber compounds.
◆Engineered Splicing & Internal Inspection:
Steel cord conveyor belts are normally joined using engineered hot-vulcanized splices, with cord arrangement and splice dimensions matched to the ST rating, cord diameter and pitch. Vulcanized steel cord joints can be designed and evaluated according to ISO 15236-4, while X-ray inspection can be used to examine internal cord alignment and identify hidden reinforcement damage without removing the rubber covers.
Steel Cord Conveyor Belt Technical Standards
① TRANSCO steel cord conveyor belts are manufactured and verified in accordance with ISO 15236-1:2016, covering the design, dimensions, construction and mechanical requirements of general-purpose steel cord conveyor belts. Preferred ST belt types and construction parameters comply with ISO 15236-2:2017. Chinese-standard products are manufactured in accordance with GB/T 28267.1-2021, GB/T 28267.2-2025 and GB/T 9770-2013.
② Longitudinal elongation and tensile strength are verified through standardized traction testing. Steel cord elongation is tested according to ISO 7622-1:2013 and GB/T 5754.1-2015, while longitudinal tensile strength is verified according to ISO 7622-2:2022 and GB/T 5754.2-2017, ensuring that the ST strength rating corresponds to the required mechanical performance.
③ Steel cord-to-rubber adhesion is verified according to ISO 7623:2022 and GB/T 5755-2021, including bonding performance in the original condition and after thermal treatment. This provides measurable verification of the adhesion between the longitudinal steel cords and surrounding core rubber.
④ Cover-to-core adhesion and belt thickness are controlled through standardized testing. Adhesion between the rubber cover and steel cord core layer is tested according to ISO 8094:2013, while total belt thickness and top/bottom cover thickness are measured according to ISO 7590:2018. Cover rubber grades and physical properties are selected in accordance with the applicable requirements of ISO 15236-1:2016.
⑤ Hot-vulcanized steel cord belt splices are designed and verified in accordance with ISO 15236-4:2004 and GB/T 28267.4-2015. Splice construction is matched to the ST rating, cord diameter, cord pitch and belt construction to provide reliable tensile-load transfer through the joint.
⑥ For special operating environments, heat-resistant, oil-resistant, flame-resistant and antistatic steel cord conveyor belts are manufactured and verified according to the corresponding performance standards. These special properties are matched to the selected rubber compound and operating conditions rather than being determined by the ST strength rating alone.
Steel Cord Conveyor Belt Construction
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Steel Cord Composition |
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A steel cord conveyor belt is mainly composed of top cover rubber, bonding rubber, steel cord reinforcement and bottom cover rubber. This structure provides high tensile strength, low elongation and reliable performance for long-distance, high-tension and heavy-duty conveying applications.
Top Rubber:
The top cover rubber is the working surface of the belt and protects the steel cord carcass from abrasion, impact, cutting, gouging and direct contact with conveyed materials. Cover thickness and rubber compound are selected according to the material and operating conditions.
Bonding Rubber:
The bonding rubber, also called core rubber, surrounds and embeds the steel cords inside the belt. It provides strong adhesion between the steel cords and the rubber body, helping transfer operating loads while improving resistance to separation, fatigue and moisture penetration.
Steel Cord:
The steel cord is the main tensile reinforcement of the belt. Multiple high-strength steel cords are arranged longitudinally to provide high load-bearing capacity, very low elongation and reliable tensile performance. This construction is particularly suitable for high-tension, long-distance and large-capacity conveyor systems.
Bottom Rubber:
The bottom cover rubber protects the underside of the belt from idler contact, pulley friction and continuous mechanical wear. It also helps protect the steel cord carcass and supports long-term belt durability.
Steel Cord Conveyor Belt Specifications
| Belt Type | Minimum Tensile Strength K Nmin (N/mm) | Max. Steel Cord Diameter dmax (mm) | Min. Steel Cord Breaking Force Fbsmin (kN) | Cord Pitch t (mm) | Min. Cover Thickness Si min (mm) |
|---|---|---|---|---|---|
| ST500 | 500 | 3.0 | 7.6 | 14.0 | 4.0 |
| ST630 | 630 | 3.0 | 7.0 | 10.0 | 4.0 |
| ST800 | 800 | 3.5 | 8.9 | 10.0 | 4.0 |
| ST1000 | 1000 | 4.0 | 12.9 | 12.0 | 4.0 |
| ST1250 | 1250 | 4.5 | 16.1 | 12.0 | 4.0 |
| ST1400 | 1400 | 5.0 | 20.6 | 14.0 | 4.0 |
| ST1600 | 1600 | 5.0 | 20.6 | 12.0 | 4.0 |
| ST1800 | 1800 | 5.6 | 25.5 | 13.5 | 4.0 |
| ST2000 | 2000 | 6.0 | 25.6 | 12.0 | 4.0 |
| ST2250 | 2250 | 5.6 | 26.2 | 11.0 | 4.0 |
| ST2500 | 2500 | 7.2 | 40.0 | 15.0 | 5.0 |
| ST2800 | 2800 | 7.2 | 39.6 | 13.5 | 5.0 |
| ST3150 | 3150 | 8.1 | 50.5 | 15.0 | 5.5 |
| ST3500 | 3500 | 8.6 | 56.0 | 15.0 | 6.0 |
| ST4000 | 4000 | 8.9 | 63.5 | 15.0 | 6.5 |
| ST4500 | 4500 | 9.7 | 76.3 | 16.0 | 7.0 |
| ST5000 | 5000 | 10.9 | 91.0 | 17.0 | 7.5 |
| ST5400 | 5400 | 11.3 | 98.2 | 17.0 | 8.0 |
| ST6300 | 6300 | 12.8 | 130.4 | 19.5 | 10.0 |
| ST7000 | 7000 | 13.5 | 142.4 | 19.5 | 10.0 |
| ST7500 | 7500 | 15.0 | 166.7 | 21.0 | 10.0 |
| Belt Width (mm) | Width Tolerance (mm) | Number of Steel Cords | ||||||||||||||||||||
| 500 | +10/-5 | 33 | 45 | 45 | 39 | 39 | 34 | 39 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| 650 | +10/-7 | 44 | 60 | 60 | 51 | 51 | 45 | 51 | 46 | 52 | 56 | 41 | 46 | 41 | 41 | 41 | 39 | 36 | N/A | N/A | N/A | N/A |
| 800 | +10/-8 | 54 | 75 | 75 | 63 | 63 | 55 | 63 | 57 | 63 | 69 | 50 | 57 | 50 | 50 | 51 | 48 | 45 | 45 | N/A | N/A | N/A |
| 1000 | ±10 | 68 | 95 | 95 | 79 | 79 | 68 | 79 | 71 | 79 | 86 | 64 | 71 | 64 | 64 | 64 | 59 | 55 | 55 | N/A | N/A | N/A |
| 1200 | ±10 | 83 | 113 | 113 | 94 | 94 | 82 | 94 | 85 | 94 | 104 | 76 | 85 | 76 | 77 | 77 | 71 | 66 | 66 | 58 | 59 | 54 |
| 1400 | ±12 | 96 | 133 | 133 | 111 | 111 | 97 | 111 | 100 | 111 | 122 | 89 | 99 | 89 | 90 | 90 | 84 | 78 | 78 | 68 | 69 | 64 |
| 1600 | ±12 | 111 | 151 | 151 | 126 | 126 | 111 | 126 | 114 | 126 | 140 | 101 | 114 | 101 | 104 | 104 | 96 | 90 | 90 | 78 | 80 | 73 |
| 1800 | ±14 | 125 | 171 | 171 | 143 | 143 | 125 | 143 | 129 | 143 | 159 | 114 | 128 | 114 | 117 | 117 | 109 | 102 | 102 | 89 | 90 | 83 |
| 2000 | ±14 | 139 | 191 | 191 | 159 | 159 | 139 | 159 | 144 | 159 | 177 | 128 | 143 | 128 | 130 | 130 | 121 | 113 | 113 | 99 | 100 | 92 |
| 2200 | ±15 | 153 | 211 | 211 | 176 | 176 | 154 | 176 | 159 | 176 | 195 | 141 | 158 | 141 | 144 | 144 | 134 | 125 | 125 | 109 | 110 | 102 |
| 2400 | ±15 | 167 | 231 | 231 | 193 | 193 | 168 | 193 | 174 | 193 | 213 | 155 | 173 | 155 | 157 | 157 | 146 | 137 | 137 | 119 | 119 | 110 |
| 2600 | ±15 | 181 | 251 | 251 | 209 | 209 | 182 | 209 | 189 | 209 | 231 | 168 | 188 | 168 | 170 | 170 | 159 | 149 | 149 | 129 | 129 | 120 |
| 2800 | ±15 | 196 | 271 | 271 | 226 | 226 | 197 | 226 | 203 | 226 | 249 | 181 | 202 | 181 | 183 | 183 | 171 | 161 | 161 | 139 | 139 | 129 |
| 3000 | ±15 | 210 | 291 | 291 | 243 | 243 | 211 | 243 | 218 | 243 | 268 | 195 | 217 | 195 | 195 | 195 | 183 | 172 | 172 | 149 | 149 | 139 |
| 3200 | ±15 | 224 | 311 | 311 | 260 | 260 | 225 | 260 | 233 | 260 | 286 | 208 | 232 | 208 | 208 | 208 | 196 | 184 | 184 | 160 | 160 | 149 |
| Cover Rubber Performance & Grades | |||||||
| Test Item | Performance Requirements | ||||||
| GB/T 9770-2013 | HG/T 3973-2007 | ||||||
| H | D | L | H | D | L | ||
| Tensile Strength | Mpa≥ | 24 | 18 | 15 | 20 | 18 | 15 |
| Elongation at Break | % ≥ | 450 | 400 | 350 | 400 | 400 | 350 |
| Ageing Test (70°C, 7d) – Change in Tensile Strength / Change in Elongation at Break | % | -25-+25 | -25-+25 | -25-+25 | -25-+25 | -25-+25 | -25-+25 |
| Abrasion Loss | mm'≤ | 120 | 100 | 200 | 200 | 120 | 200 |
Steel Cord Conveyor Belt Applications
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| Mining & Ore Handling | Long-Distance Overland Conveying | Cement, Quarry & Limestone |
| Steel cord conveyor belts are widely used for transporting iron ore, copper ore, coal and other mineral materials between mining, crushing, processing and stockpiling areas. Their high tensile strength and low elongation make them well suited to long, high-capacity mine conveyor systems carrying heavy and abrasive materials. | Steel cord belts are particularly suitable for long-distance and overland conveyor systems where belt stretch and take-up travel must be carefully controlled. The steel cord carcass allows high operating tension to be transmitted over long center distances while maintaining stable belt length and reliable continuous operation. | Suitable for conveying limestone, crushed rock, cement raw materials and other abrasive bulk materials between quarries, crushers, storage areas and production plants. Steel cord construction is particularly advantageous where conveyor distances, material loads and operating tensions are high. Heat-resistant belt constructions should be selected separately when conveying hot materials such as clinker. |
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| Ports & Bulk Terminals | Power Plants & Coal Handling | Steelworks & Metallurgical Plants |
| Used in port terminals, stockyards and transshipment systems for high-capacity handling of coal, iron ore, aggregates and other bulk commodities. Steel cord belts are suitable for long transfer conveyors connecting stockpiles, loading stations, reclaimers and ship-loading or unloading systems. | Steel cord conveyor belts are used in coal stockyards, transfer systems and fuel-handling conveyor lines where continuous operation and high conveying capacity are required. Low elongation helps maintain stable belt tension over long conveyor routes, while flame-resistant or antistatic performance can be specified where required by the operating environment. | Used for transporting iron ore, coke, limestone and other bulk raw materials within steelworks and metallurgical plants. Steel cord belts provide the tensile capacity required for long and heavily loaded conveyors, while abrasion-, impact- or heat-resistant cover compounds can be selected according to the conveyed material and service conditions. |
Rubber Conveyor Belt Shipping And Packing
TRANSCO provides flexible packing and shipping solutions according to the belt type, width, thickness, roll length, total weight and transportation method, helping protect conveyor belts during storage, handling and international shipment.
| Packaging Forms | ||
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Conveyor belts can be packed in different roll configurations to suit belt dimensions and container loading requirements:
◊Round Roll ◊Double Roll ◊Oval Roll ◊Protective Wrapping |
Each belt roll can be securely wrapped to protect the belt during handling and transportation:
◊Waterproof PP woven cloth wrapping ◊Protective plastic film ◊Edge protection ◊High-strength strapping ◊Custom wrapping colors and markings ◊Reel & Support Options |
Different support structures can be selected according to belt size, roll weight and unloading conditions:
◊Steel Reel / Steel Core ◊Wooden Drum / Wooden Core ◊Wooden Pallet ◊Steel Pallet ◊Reinforced Steel Frame |
| Secure Container Loading | Customized Packing | Packing Recommendation |
| Heavy or large conveyor belt rolls can be securely positioned and reinforced inside the container to reduce unwanted movement during transportation. Roll dimensions, gross weight and packing information can be clearly marked to support safe lifting and unloading. | Packing methods can be customized for sea freight, container transport and project deliveries. Special steel-reel or reinforced-frame packing is available for large, heavy or long-length conveyor belt rolls. | Our team recommends the appropriate roll form, wrapping material, reel structure and loading method according to each conveyor belt specification and destination, balancing product protection, handling efficiency and shipping space. |
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Frequently Asked Questions
Q What does ST mean in a steel cord conveyor belt?
The ST rating describes belt strength, but it does not define the complete belt construction. Cord diameter, cord pitch, belt width, cover thickness and rubber grade must also be specified when ordering or replacing a belt.
Q How do I choose the correct ST strength rating?
A higher ST rating is not automatically better. Increasing belt strength can also change the steel cord diameter, belt thickness, minimum pulley requirements and splice design. For accurate selection, provide the existing belt specification or complete conveyor operating data rather than selecting the belt by ST rating alone.
Q Can I replace an existing steel cord belt with another belt of the same ST rating?
For replacement, the existing ST rating, belt width, cord construction, cord pitch, cover thickness, cover grade, pulley diameters and splice design should be checked together. Matching these parameters is especially important when the new belt must be spliced to an existing belt or operate on the original conveyor system.
Q Why are steel cord conveyor belts preferred for long-distance conveyors?
This makes steel cord belts particularly suitable for long-distance, high-capacity and high-lift conveyor systems where controlling belt tension and elongation is critical to stable operation.
Q How do I choose the correct cover rubber and cover thickness?
Abrasion- and cut-resistant covers are commonly used for ore and rock, while specialized heat-resistant, oil-resistant or flame-resistant compounds are selected when those operating conditions are present. Top cover thickness is normally selected according to material-side wear and impact, while the bottom cover is selected according to pulley- and idler-side wear.
The steel cord carcass and rubber cover should therefore be specified separately rather than assuming that a particular ST rating determines the required cover grade.
Q How are steel cord conveyor belts spliced?
The splice design must match the ST rating, cord diameter, cord pitch, belt construction and operating tension. Existing splice dimensions should therefore be confirmed before replacing a belt, especially when a new belt will be connected to an existing section.
Q Why are steel cord adhesion and internal cord condition important?
Cord-to-rubber adhesion can be verified according to ISO 7623:2022, including testing before and after thermal treatment. For belts already in service, appropriate non-destructive inspection methods can also be used to identify internal cord damage or abnormal conditions that may not be visible from the belt surface.
Q When should I choose rip-resistant or additional transverse reinforcement?
The requirement should be determined from maximum lump size, drop height, material shape, loading-point design and expected impact energy. Additional reinforcement is not necessary for every steel cord belt and should be selected according to the actual application.
