ST1250 Steel Cord Conveyor Belt

CBC India's ST1250 steel cord conveyor belt occupies the upper tier of the ST-class range specified for conveying systems where the ST1000 grade approaches its structural ceiling in terms of operating tension, haul distance, or material volume. Per DIN 22131 and ISO 283, the "1250" designation guarantees a minimum breaking strength of 1,250 Newtons per millimeter of belt width, making this the correct specification for overburden removal in large open-pit mining operations, high-throughput bulk ore terminals, and clinker transport circuits in major cement production facilities.

Construction

The ST1250's tensile core is built on galvanized steel cords in 7×19 strand configuration the higher wire count per cord providing superior fatigue resistance under the increased bending loads associated with this tensile class. Individual cord diameters run approximately 4.5 mm at a 12 mm pitch, with each cord delivering a minimum breaking force of 16–20 kN, brass-bonded to the skim rubber compound during vulcanization for sustained adhesion integrity across the belt's full operating life. Total belt thickness ranges from 28–32 mm with a reference mass of approximately 25 kg/m². Minimum pulley diameters are specified at 1,250 mm, maintaining individual wire stress within fatigue-safe limits at the rated operating tension. Standard belt widths span 1,000 mm to 2,600 mm, with roll lengths up to 500 m per section.

Top and bottom covers are each specified at 6 mm, compounded to DIN Grade Z as standard the highest abrasion resistance classification in the DIN 22102 framework with heat-resistant formulations available for service temperatures up to 250°C. Flame-retardant and antistatic variants comply with ISO 284 and EN 16974 for underground coal mining installations. Oil-resistant compounds are available for chemical processing and fertilizer handling environments.

Performance

Working elongation remains below 0.2% at rated tension tighter than lower ST grades providing precise belt tracking and stable tension distribution across single-flight spans exceeding 3 km. Operating tensions reach 1,050 PIW at conveying speeds up to 7.0 m/s. Deep troughability increases cross-sectional load capacity by 40% over equivalent-width stiffer constructions, while optimized cord flex geometry reduces drive power consumption by approximately 25% versus fabric ply alternatives. Impact resistance accommodates lump material up to 400 mm without cover deformation or cord displacement.

Installation and Maintenance

Finger-spliced hot vulcanization achieves 100% joint efficiency per DIN 22131 Part 3, with electromagnetic or ultrasonic scanning providing non-destructive cord integrity monitoring throughout service. Rip-stop breaker plies and continuous rip detection systems extend inspection intervals and protect against longitudinal belt damage in sharp-edged material applications. With a structured predictive maintenance programme, ST1250 belts deliver a documented service life of 10–20 years across the world's most demanding bulk handling installations.

Technical specification of ST1120 Conveyor Belt

Standard Steel Cord Conveyor belt Range As per DIN 22131

Available Stocks of ST1250 conveyor belt