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Steel Cord Conveyor Belt Ultimate Guide (2026): Types, Grades and How to Choose

A steel cord conveyor belt is a heavy-duty belt built on a carcass of parallel steel cords, and it is normally the right choice when one flight has to carry high tonnage over a long distance, or when the calculated belt tension exceeds what an EP fabric carcass can hold at the required safety factor.

We have built these belts since 1988 at our plant in Ningbo, and the questions we get from mine, quarry, cement, port and EPC engineers are almost always the same: which ST grade, which cord design, which cover compound, which splice, and what it will actually cost landed on site. This guide answers those questions in the order a real project asks them, from the material and capacity data through to the approved drawing and the purchase order.

Nothing here replaces your own duty calculation. Take the numbers below as the ranges we see in practice, and confirm the final construction against the actual duty, the applicable standard and the approved drawing before you release the order. A steel cord belt is a system component, not a consumable: a wrong cord pitch, an over-thick cover or a badly made splice can destroy a 200 m length in a single shift.

Send Your Belt Specification for a Factory Quote

One more thing before the technical part. Most of the money on a steel cord project is saved or lost long before the belt is shipped, in two places: the specification stage, where the ST grade and cover class are fixed, and the supplier selection stage, where you decide whether the person quoting you has ever stood next to a vulcanising press. Everything after that is execution.

01What Is a Steel Cord Conveyor Belt?

A steel cord belt is a rubber belt in which the load-carrying element is a layer of steel cords running lengthwise, spaced evenly across the width, completely embedded in rubber. There is no woven fabric anywhere in the carcass. The cords take the tension, the rubber protects them from the material and the weather, the pulley cover transmits drive force into the belt, and the rubber between the cords keeps them parallel for the whole life of the belt.

That one design decision produces the properties buyers are really paying for. Strength per millimetre of belt width is far higher than any fabric construction, and elongation under load is very low, typically 0.2-0.4% at rated tension against 1.5-2.5% for an EP fabric belt, which is why a long steel cord conveyor can use a short and inexpensive take-up.

If you are still weighing fabric against steel, our steel cord conveyor belt page lists the standard ST grades and cord constructions we make.

How Does It Behave Differently in Service?

Three differences show up within the first month. Tracking: a stiff steel cord belt forgives a slightly off-square pulley but not a misaligned structure, and once it runs against a chute it climbs fast. Impact: with only a few millimetres of rubber over the cords, a 1.2 m drop of lump ore bruises steel instead of plies. Splicing: the joint carries full belt tension, so it has to be made properly once.

Where Are Steel Cord Belts Used?

The classic applications are long overland conveyors from pit or quarry to stockyard, iron ore and copper ore handling, coal terminals, downhill conveyors where the belt regenerates power, cement plant long-distance limestone transport, and tunnelling spoil lines. Typical duty ranges are 2,000-8,000 t/h capacity and belt speeds of 4.0-7.5 m/s on widths of 1,000-2,400 mm. As a conveyor belt manufacturer, we see steel cord specified most often when centre distance goes past about 500 m with heavy material, and almost without exception past 1,000 m.

02Construction of a Steel Cord Conveyor Belt

Steel cord conveyor belt cross section showing the steel cord carcass construction

Steel cord carcass in cross section.

Looking at that cross section from top to bottom, there are five functional layers, each with a job buyers underestimate until something fails.

The Steel Cords

Individual cords, usually 3.0 mm to 13.5 mm in diameter, are laid side by side at a precise pitch. Each cord is itself a stranded product: a number of wires twisted into strands, and the strands twisted into a cord. A 7x7 cord has 49 wires; a 7x19 cord has 133; large ST grades often use 7x37 or thicker open constructions. High-tensile brass-coated wire is standard, and the coating is what bonds the cord to the rubber. Breaking the bond is what starts the corrosion that eventually kills a belt in a wet or coastal plant.

Cord pitch is fixed by the grade. If the pitch is too wide for the load, the belt necks down between cords and the splice becomes unreliable; too narrow and there is not enough rubber between cords for adhesion and corrosion protection.

The Cover Compound and the Breaker Layer

The top cover is a compounded rubber layer, usually 4-10 mm thick on the carrying side, formulated for abrasion, heat, oil or fire resistance depending on the duty. Between the cords and the top cover sits an optional breaker or reinforcement layer, a single ply of steel mesh or fabric that resists lengthwise tearing. On a belt feeding a primary crusher, where tramp metal is guaranteed, that layer stops a 200 mm tear from becoming a 2 km tear.

The pulley cover is generally 3-6 mm and is not the same compound as the top cover on long drives, because it must grip the drive pulley and survive being wrapped around pulleys hundreds of thousands of times.

Edge Construction

A moulded edge is formed under pressure with the cover rubber wrapping the cord layer, so the cords are fully enclosed and protected at the edge; a cut edge is slit from a wider slab and leaves the outer cords closer to the surface. Moulded edge costs more per metre and is worth it on any belt where material sits against the skirt or where the belt runs in a corrosive environment. If your structure forces the belt against a skirt rubber for its whole length, specify moulded edge and expect to pay for it. We explain the trade-off in more detail in this comparison of moulded edge vs cut edge conveyor belt construction.

Whatever the edge style, an industrial conveyor belt of this class is judged on cord-to-rubber adhesion and on how well the cords stay parallel after ten million cycles, not on how the brochure photograph looks.

03Cord Design and How ST Grades Are Built

Buyers often treat "ST1600" as a single interchangeable product. It is not. Two belts can both be called ST1600 and behave completely differently on the same conveyor, because the grade fixes the breaking strength but leaves the cord construction, pitch, rubber gauge and cover class open.

Open Cord, Closed Cord and Twin Cords

A closed cord is a conventional stranded cord with a tight outer layer; it has a smaller diameter for the same strength and is easier to embed in a thin belt. An open cord has a deliberately loose outer layer so rubber penetrates deep into the strand structure, which markedly improves corrosion resistance in wet tunnels and coastal terminals at the cost of a slightly larger diameter. Twin cords place two cords side by side in one plane, used where a single cord would be too large for the belt thickness.

Pitch, Gauge and Why They Are Not Negotiable

Cord pitch is the centre-to-centre distance between cords, and it is set by the grade because the rubber between cords has to carry the shear load from the top cover into the cord layer. Reduce the pitch below the standard figure to save rubber and the belt necks between cords under high tension, the cover cracks at the cord lines, and the splice will not develop its rated strength. Increase it too far and the belt loses transverse stiffness and tracks badly.

The same logic applies to the cord gauge, the distance from the cord plane to the belt surface. Our rule of thumb for a primary crusher discharge belt is not less than 6 mm of top cover over the cord plane: with less, an impact bruises wires; with much more, the belt gains weight, needs more power and can delaminate under flexing.

Because the cord line is the bottleneck, the two steel cord lines in our conveyor belt factory run behind the same incoming-wire inspection routine as the fabric lines: wire diameter, brass coating weight, tensile and torsion test on every batch, recorded against the belt number that will carry the cords.

04Steel Cord Belt Strength Grades and Typical Cord Data

The grade number is the nominal breaking strength of the belt in newtons per millimetre of width. An ST2000 belt 1,200 mm wide therefore has a nominal breaking strength of 2,400 kN before any splice factor is applied. That is the number you divide by the calculated maximum belt tension and the safety factor to check whether the grade is adequate.

The table below shows the grades we produce most often with their typical cord data. Cord diameter and pitch are manufacturing data that follow the applicable steel cord belt standard and our approved drawing for your project; treat the figures as typical and confirm them against the actual duty.

ST Grade Nominal Strength (N/mm) Typical Cord Diameter (mm) Typical Cord Pitch (mm) Where We Usually See It
ST630 630 3.0-3.5 10 Aggregate and cement short overland flights
ST800 800 3.5-4.0 10-12 Quarry to plant conveyors, 800-1,000 mm widths
ST1000 1000 4.0-4.5 12 Coal handling, 1,000-1,200 mm, 2-4 m/s
ST1250 1250 4.5-5.0 12-15 Cement limestone transport, medium overland
ST1600 1600 5.0-5.5 15 Iron ore and port terminals, 1,200-1,400 mm
ST2000 2000 6.0-6.5 15-17 Long overland, 3-6 km, single flight
ST2500 2500 7.2-7.5 17-18 High-lift overland and downhill regenerative lines
ST3150 3150 8.1-8.5 18-20 Very long single flights, 1,600-2,000 mm widths
ST4000 4000 9.1-9.5 20-22 Bulk terminals with very high tension profiles
ST5000 5000 10.9-11.5 22 High-capacity ore lines, 2,000 mm and above
ST6300 6300 12.4-13.0 24 Long single-flight ore and overburden systems
ST7500 7500 13.5 24-26 Highest-tension projects, quoted only against a duty calculation

Typical manufacturing data. Confirm against the applicable steel cord belt standard, your duty calculation and the approved drawing.

Higher Grade Is Not Automatically Better

A common mistake in tender documents is to specify ST2500 "for margin" on a conveyor that only needs ST1250. A higher grade means larger, stiffer cords, a thicker belt, a bigger minimum pulley diameter, heavier spliced joints and a harder belt to train. We have seen 1,400 mm wide ST2500 installed where ST1600 would have run perfectly, and the operators spent two years chasing edge damage caused by the belt's own stiffness against the skirt.

Pick the grade from the tension calculation and the required safety factor, then add margin only where maintenance standards or a planned capacity increase justify it.

05Cover Grades: Choosing the Right Rubber Compound

If the cord layer decides whether the belt is strong enough, the cover decides how long it lasts. Steel cords rarely fail first on a well-designed conveyor; the cover wears through, cracks, or gets torn, and then the cords start corroding. So the cover specification deserves as much attention as the ST grade, and it is where a cheap quotation usually saves its money. on a rubber conveyor belt.

Cover classes are usually written as DIN 22102 designations, RMA grades, AS 1332 categories or an equivalent project specification. The abrasion figure quoted in each system is measured with the ISO 4649 method on a laboratory sample, so it compares compounds under one set of conditions. It does not describe how the cover behaves when it is hot, wet and full of sharp quartz at the same time. Confirm the requirement against the actual duty before you accept any class label as a substitute for a specification.

Cover Class (typical designation) Typical Abrasion Loss (ISO 4649 A, mm³) Typical Duty Materials We Usually See on It
DIN 22102 W (abrasion resistant) ≤ 120 High cutting abrasion, dry material Crushed granite, quartz, iron ore fines, sinter
DIN 22102 X (general purpose) ≤ 150 Mixed duty, moderate abrasion Limestone, coal, sand and gravel, clinker
DIN 22102 Y (fatigue resistant) ≤ 200 Small pulleys, many flex cycles, low abrasion Grain, fertiliser, wood chips, packaged bulk
DIN 22102 K (fire resistant) ≤ 200 Underground and enclosed structures Coal, tunnel spoil, biomass in covered galleries
Heat resistant (EPDM-based) 150-250 Continuous hot material, typically up to 120 °C cover temperature and short peaks higher Clinker, cement, sinter, foundry sand
Oil and chemical resistant 150-250 Hydrocarbon or acid contact, low abrasion Coke breeze, oily scrap, fertiliser, recycled material
Cold resistant (down to about -40 °C) 150-250 Freezing outdoor operation, no warm-up allowed Coal, ore and aggregate in cold climates

Typical, confirm against the actual duty, the current edition of the standard and the approved drawing.

Two practical notes from the shop floor. Abrasion resistance and cut resistance are different properties: a compound that resists sliding wear well can still be sliced open by a jagged lump, which is why belts after a primary crusher often need a breaker layer as much as a harder cover. And heat fights abrasion. If the material arrives at 130 °C and is also highly abrasive, you cannot simply take the hardest compound in the catalogue; you need a heat-resistant base with the best abrasion figure that family can deliver.

If the material is hot as well as heavy, read the notes on cement plant conveyor systems before you lock the cover class.

06Steel Cord Belt Types for Specific Duties

"Type" is used loosely in this industry. On a purchase order it usually means the combination of cord construction, cover class, gauge and any special layer, so write it as a full description rather than a three-word label. The variants below cover most of what real projects specify.

Abrasion-Duty Belts

Standard steel cord carcass with a W-class cover of 6-10 mm on the carrying side. This is the workhorse of quarry, aggregate and iron ore service. On belts where the feed is a 300 mm top size rather than a screened product, we add an impact zone: either extra cover gauge over the first 10-20 m behind the loading point, or a thicker belt for the whole length if the loading point moves.

Heat-Resistant and Fire-Resistant Types

Heat-resistant belts use an EPDM-based cover that resists hardening and cracking at elevated temperature, and they are specified for clinker, cement and sinter. They are not fire-resistant, and they are not interchangeable with fire-resistant belts, which are a separate class tested for flame propagation under ISO 340 and used underground or inside covered galleries. In a coal mine the fire requirement is a safety requirement: put it in the tender as a tested property with the certificate, not as an adjective. Our fire-resistant vs flame-resistant conveyor belts note explains what each certificate actually covers.

Tear-Protected and Rip-Detection-Ready Types

Where tramp metal is certain, the belt gets a steel mesh or fabric breaker layer under the top cover, and the cord body is ordered with a defined position tolerance so a future rip detection loop or transponder can be placed consistently. Specify this at the enquiry stage: retrofitting detection to a belt ordered without cord-position control wastes the investment.

High-Speed and Downhill Types

High-speed lines need a lower-friction pulley cover and predictable splice geometry, since every splice passes several pulleys per minute. Downhill regenerative conveyors need a belt that holds back load without the take-up travelling constantly, and 0.2-0.4% elongation keeps that stroke short even over a 5 km flight.

Plants that standardise several conveyors on one cord grade and cover class often buy wholesale conveyor belts in a single campaign to keep the belt numbers and the splicing crews consistent. That approach works well when the duty range really is similar, and badly when one conveyor in the group is a crusher discharge belt being asked to do a stockyard belt's job.

07Steel Cord vs EP Fabric Belt: How Do You Decide?

This decision changes the cost of the whole conveyor, not just the belt. Neither construction is universally better; the duty profile picks the winner, and the crossover point is lower than many buyers assume.

Selection Factor EP / Fabric Belt Steel Cord Belt
Practical centre distance Usually under 300-500 m in heavy duty Comfortable beyond 1,000 m, built to 10 km and more
Belt strength per mm of width Typically 100-2,500 N/mm depending on plies and grade 630-7,500 N/mm
Elongation at rated tension About 1.5-2.5%, needs a long take-up About 0.2-0.4%, short take-up travel
Impact and puncture tolerance Higher, plies distribute a point load Lower, cords can be bruised and broken by large lumps
Transverse tear resistance Good, a rip slows as plies separate Poor unless a breaker layer is added
Minimum pulley diameter Smaller, easier on existing structures Larger, drives pulley and shaft sizing
Splice requirement Vulcanised step splice or mechanical clip in emergencies One-step or multi-step vulcanised splice, made correctly once
Relative price per metre Lower, and cheaper to replace a short section Higher, offset by far fewer splices and transfers

Typical, confirm against the actual duty and the approved belt drawing.

Three rules of thumb we use when advising buyers. If the flight is short but the impact is brutal, stay with a heavy EP belt and put the money into impact idlers. If the flight is long and the material moves in a steady stream, steel cord wins on elongation and on maintenance access alone. If the tension profile sits at the crossover, run the calculation both ways and compare the installed cost, including take-up, pulley diameters, foundations and splice hours. Any competent conveyor belt supplier should do that comparison with you before you commit.

08How to Choose a Steel Cord Conveyor Belt: Step by Step

Choosing is a sequence, and skipping a step is what produces claims. This is the order we work in.

Step 1: Collect the Duty Data

We ask for material, bulk density, maximum lump size, temperature, moisture and whether the material is oily, sticky or chemically aggressive. Then the geometry: centre distance, lift or drop, trough angle, belt speed, idler spacing and pulley diameters. Capacity in t/h is only useful once those are known, because the same tonnage on a steeper incline or a narrower belt produces a completely different tension.

Step 2: Confirm the Belt Tension and Grade

Effective tension comes from friction and lift; the maximum belt tension comes from the drive arrangement, the starting conditions and the counterweight. Apply the safety factor your project standard requires and round up to a standard ST grade. Steel cord belts are often designed with a factor around 6.7 in international practice, but check the governing standard and the project specification, because some owners apply different values for steady and transient conditions.

Step 3: Fix Width, Cover Gauge and Class

Width follows from lump size and capacity, then gets checked against the cord pitch so that the outer cords sit at the correct distance from the edge. Cover gauge follows from abrasion and temperature. This is also where you decide moulded or cut edge, whether the pulley cover needs a different compound, and whether a breaker layer is justified.

Step 4: Plan the Splice Before You Order

Steel cord belts ship in lengths that suit transport and the splice plan, not necessarily in one piece. Decide the splice positions, the type, the step pattern and who will make it. A belt delivered as a single 4,800 m roll is useless if the site cannot pull it in. Where a stockyard needs a spare on the rack, a local conveyor belt distributor can cover the emergency length while the main belt still comes factory direct.

Step 5: Ask the Right Questions of the Supplier

Ask which cord supplier provides the wire, what the adhesion value is on the release test, whether splice material and drawings come with the belt, whether you get the test report for your belt number rather than a generic certificate, and whether a technician can attend the first splice. If the answers are vague, the price was never the real saving. A vetted conveyor belt factory audit checklist gets you there faster than three rounds of e-mail.

09The System Around the Belt: Pulleys, Idlers and Drives

A steel cord belt is only as good as the hardware it runs on, and this is where a lot of projects lose money that was saved on the belt. Two points matter more than the rest.

Pulley Diameter and Idler Selection

Steel cord belts need larger minimum pulley diameters than fabric belts of the same strength, because the cords must bend without exceeding their fatigue limit every revolution. If the existing pulley is undersized, no compound change will fix it; change the pulley or step down to a grade with more, smaller cords. Idler selection matters almost as much: impact idlers with rubber rings at the loading point, troughing idlers sized to width and speed in the middle, return idlers at the spacing your sag limit allows. We supply the matching hardware with the belt for that reason, from conveyor pulleys and conveyor rollers through to troughing idler sets.

Drives, Gearboxes and Power Transmission

Drive sizing on a long conveyor is a specialist calculation, and once it is done, the drive train itself still has to work. Many of the conveyors we supply sit on gearboxes whose cooling fans, pumps and auxiliary drives run on classical or narrow V-belts, and those belts fail far more often than the main belt does. We began as and still operate as a transmission belt manufacturer alongside the conveyor belt business, so a project can standardise on one supplier for the belt, the splice material, the idlers and the drive belts.

For a plant with a maintenance store, a single V-belt manufacturer relationship means one set of drawings, one packing standard and one shipping schedule per quarter instead of four.

10Splices: Where Most Long Conveyors Succeed or Fail

A vulcanised steel cord splice typically develops a high proportion of the belt's rated strength when it is made correctly under workshop conditions, and considerably less when it is made in the rain with the wrong rubber and a cold press. The splice is an engineered joint, not a repair.

One-Step and Multi-Step Splices

In a one-step splice every cord meets every cord in a single stage across the width. A multi-step splice breaks the joint into two or more stages along the belt length, so the load path is staggered and the joint is shorter for the same pull-out area. Multi-step joints need more skill and a longer press, and they are worth it on the highest-tension lines.

What We Ask For Before Shipping a Splice Kit

We need the belt grade, width, cord diameter and pitch, the splice type, the direction of travel, the press dimensions and the site temperature. We then supply a splice drawing matched to that belt number with the correct splice rubber, cover rubber and wash solution, because the compound in the belt body is not the compound that goes into the joint. Use cover compound inside a splice and adhesion to the brass-coated wires will be inadequate; the joint will fail within a few hundred running hours.

Whether your team makes the joint or ours does, plan the press day early. On a long flight, the splice duration is often the difference between a two-day shutdown and a five-day one. Field notes on this are in our conveyor belt field service summary and in the shipping and packaging guide, which also covers how long lengths are coiled and marked for splice access.

11Quality Control and Testing: What a Buyer Should Ask For

Steel cord wire stranding line producing the cord carcass for a steel cord conveyor belt

Cord stranding before rubber calendaring.

Testing a conveyor belt is not one test. It is a chain of checks that starts with incoming wire and ends with the packing list, and a buyer's leverage is in asking for the records of that chain rather than for a certificate with a logo on it. Incoming wire is checked for diameter, coating and tensile properties; the cord-to-rubber adhesion build is monitored during calendaring; and after vulcanisation the belt is measured for width, thickness, cover thickness at defined points and cord position, with samples tested for cover tensile strength, elongation, abrasion and adhesion. Heat-resistant and fire-resistant classes carry additional tests defined by the relevant standard, and those results are what a mine safety department or a port operator will actually want to see.

Our own quality management system is certified to ISO 9001, and the records for your belt number are retained. When we are asked what documentation can be issued with an order, we answer with the list rather than a promise: material certificates for the wire and compounds, dimensional inspection report, laboratory test report for the actual belt, splice drawing, packing list and loading photos. The details are set out on our quality assurance page and in this explanation of what laboratory tests can be included in a belt order.

One request we get and always refuse to fake: an abrasion figure the compound was not released against. If a buyer wants W-class performance, the compound is formulated and tested to it, and the report says so. That is why we ask for the report before the order rather than after a failure. For a wider picture of what a test file should contain, see the rubber conveyor belt factory testing guide.

How Do Steel Cord Conveyor Belt Manufacturers Differ on Paper?

Two steel cord conveyor belt manufacturers can quote the same ST 1600 width and still hand over belts that age differently. What separates them is rarely the headline strength figure. It is what they are willing to put in writing: cord pitch, the number of strands per cord, cord-to-rubber adhesion from the pull-out test, the cover compound code, and the tolerance they accept on width and length. We put all five on the order confirmation, because a belt running at 4 m/s over six kilometres has no room for a casual assumption. Buyers who compare quotations without those five lines are comparing catalogue covers, not belts.

It also matters where the conveyor belt steel cord itself comes from. A producer that draws and strands cord in-house controls the wire surface treatment, and surface treatment is what the rubber actually grips. A producer that buys finished cord inherits whatever treatment it was given. Ask which one you are buying, and ask for the incoming cord certificate as well as the finished belt report. When a steel cord belt conveyor is designed around one supplier's cord data, switching source late in the project is expensive, so the question belongs in the RFQ rather than in the post-mortem. On long overland and terminal projects we usually point buyers at our notes on steel cord conveyor belts for long-distance mining projects, because the questions that decide the outcome are the same ones that decide the splice.

12Steel Cord Conveyor Belt Price: What Actually Drives the Number

There is no useful list price for a steel cord belt, and any supplier who gives you one without seeing your duty data is guessing. What we can do is show which variables move the number, so you can compare offers that are genuinely comparable instead of two different products.

Cost Driver How It Moves the Meter Price What the Buyer Controls
ST grade and cord size Largest single factor; wire volume and cord cost rise steeply above ST2500 Specify from the tension calculation, not from habit
Belt width Roughly proportional, plus edge waste that grows on non-standard widths Check whether a standard width would meet the capacity
Cover gauge and class Every extra millimetre of cover is more compound and more press time Match gauge to real abrasion and impact, not to the worst day
Cord construction Open or twin cord costs more than closed cord for the same grade Pay for it only where corrosion or splice geometry demands it
Breaker or reinforcement layer Adds material and process time Weigh it against the cost of one long rip
Edge type Moulded edge costs more than cut edge Choose by skirt contact and environment
Order quantity Setup and test costs amortise across the run Group belt numbers where the duty allows
Lead time Rush production displaces scheduled work Plan the shutdown rather than paying for urgency
Testing and documentation Third-party inspection, extra sample tests and certified reports Decide what the project actually requires in the tender
Packing and shipping Coil size, steel core, container filling and port route Give us the destination port early so we can optimise the coil plan

Indicative relationships only. Confirm every figure against your own duty data and approved drawing.

As a reference point, steel cord belting in normal industrial grades typically lands in a broad band that starts several times the price per metre of a comparable EP belt and widens as the grade, width and documentation requirements rise. We do not publish a price table because the same ST1600 specification can differ enormously between a single 300 m length and a 12 km project with inspection and splice support. How factories build a quotation is explained in bulk order conveyor belt price and in factory direct conveyor belt pricing.

Our standard terms go in the offer rather than making you ask: orders from about 50 m per specification, roughly 30 days production, samples in 2-5 days, T/T 30% deposit with the balance before shipment or L/C, and OEM or ODM work with logo printing and custom width, thickness and colour. Send the duty data to sales@sinoconve.com for one quotation, not four.

13Installation, Tracking and Maintenance

Heavy duty conveyor system at an industrial bulk handling plant where a steel cord conveyor belt is installed

A long overland flight under load.

Most problems we are called about in the first year are installation and training issues, not manufacturing defects. On a steel cord belt those are expensive, because a long belt is not easy to remove and refit.

Pulling In and Tensioning

Pull the belt with a proper belt clamp and a controlled winch, never a wire rope through a splice window, and keep the pulling tension well below the belt rating. Set the take-up to the cold-start tension on the drawing. A steel cord belt needs very little travel to reach working tension, so if the take-up is near the end of its stroke after tensioning, something in the calculation or the length is wrong, and it is cheaper to find that out before the splice than after.

Why Does a Steel Cord Belt Mistrack?

Because of structure, almost always. Check pulley squareness, idler alignment against the belt centreline, the level and plumb of the frame, and whether the loading point is feeding off-centre. A steel cord belt that is nudged off line by an off-centre load of 8,000 t/h will run against the chute within a few hours. Self-aligning idlers help, but they treat the symptom: fix the feed first. Our notes on the most common causes of conveyor belt mistracking and on self-aligning rollers and belt tracking downtime go through the checklist in order.

Inspection Routine That Pays For Itself

A weekly walk looking at four things catches almost everything early: cover wear over the cords at the loading zone, edge condition against the skirt, the splice for exposed cord ends and surface cracks, and idlers for seized bearings and worn rings. Record cover thickness with a simple gauge and compare with last month. When cover over the cords falls to 2-3 mm, plan the replacement into the next shutdown instead of waiting for a wire to break. In high humidity or coastal air, add the checks described in conveyor belts in wet and high-humidity applications.

The same logic applies to the hardware under the belt. A failed impact idler will bruise cords on the next pass, so how impact rollers protect conveyor belts is worth reading before the next transfer-point redesign.

14Failure Modes and the RFQ Checklist

Every steel cord belt failure we are asked to investigate falls into a small number of categories, and in our experience very few of them are caused by the belt being weaker than specified.

  • Cord breakage at the loading point, caused by repeated impact on insufficient cover or a failed impact idler.
  • Splice pull-out or splice fatigue, usually from an incorrect step pattern, wrong splice compound or a joint made under bad conditions.
  • Cover wear through to the cords, because the abrasion class was chosen below the real duty.
  • Corrosion of the outer cords at the edges, typical of cut-edge belts running wet or in salt air.
  • Cord-to-rubber separation along the belt, from overheating in the press during manufacture or from excessive flexing on undersized pulleys.

The cleanest defence against most of that list is a complete enquiry. When you send a requirement, include belt width, length in metres and number of lengths, ST grade or the duty data so we can calculate it, cord construction if already fixed, cover class and gauge for both sides, edge type, maximum material temperature, fire or certification requirements, destination port, required delivery date and whether you need splice support on site. A pro-forma checklist is available in this guide to conveyor belt RFQ preparation, and the same data set is what makes competing offers comparable.

Request a Quotation

15Frequently Asked Questions

How do I know which ST grade I need?

Work from the calculated maximum belt tension and the safety factor your project standard requires, then round up to a standard grade. A 1,200 mm wide overland conveyor carrying 3,000 t/h over 2 km commonly lands between ST1600 and ST2500, but belt speed, lift, trough angle, idler friction and the starting arrangement all move the number. Send the profile data and the take-up position, and we will run the check before quoting.

What is the minimum order quantity and the lead time?

Conveyor belts start from about 50 m per specification. Standard production lead time is around 30 days after drawing approval and deposit, with 15-20 days achievable for urgent lengths when the press schedule allows. Sample lengths are typically ready in 2-5 days. Payment terms are normally 30% T/T deposit with the balance before shipment, or L/C for larger projects.

Can a steel cord conveyor belt be spliced on site?

Yes, provided the joint is vulcanised with the correct splice rubber, the right step pattern and a press that can hold the required temperature and pressure for the full cure. We supply the splice drawing, splice compound, cover compound and wash solution matched to your belt number. If the site is making its first steel cord joint, or the flight is high-tension, ask us for a technician to supervise the first splice.

Do you supply heat-resistant and fire-resistant steel cord belts?

They are two different products. Heat-resistant belting uses an EPDM-based cover for continuous hot material, typically up to about 120 °C cover temperature, with short excursions higher. Fire-resistant belting is tested for flame propagation to the standard your project names, such as ISO 340 or an equivalent national requirement. Confirm the class, the test and the certificate against the actual duty and the approved specification.

What information do you need before you can quote?

Material and maximum lump size, bulk density, temperature, capacity in t/h, centre distance and lift, belt speed, trough angle, pulley diameters, required ST grade or the data to calculate it, cover class and gauge for both sides, edge type, belt length and number of lengths, fire or certification requirements, destination port and required delivery date. With that set we can return a properly priced offer rather than an estimate.

Why does a steel cord belt cost more than an EP belt?

High-tensile stranded wire costs far more than fabric plies, and the cord layer needs tighter process control, more rubber between cords and more testing. The premium is partly offset by fewer splices over the same distance, a short take-up instead of a long one, and lower rolling resistance on long flights. On the right duty, the installed cost can come close to the fabric alternative.

16Related Products You May Need

Product Product Product
Rubber Conveyor Belt
General-purpose fabric and rubber belts for short and medium duty conveyors.
EP Conveyor Belt
Polyester-nylon carcass belts for the duties below the steel cord crossover point.
Steel Cord Conveyor Belt
The ST grades covered in this guide, from ST630 to ST7500.
Chevron and Sidewall Conveyor Belt
Cleated and sidewall belting for steep incline conveying.
V-Belts and Timing Belts
Drive and power transmission belts for gearboxes, fans and pumps.
Full Product Catalog
Every belt, idler, roller and pulley we manufacture.

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Contacts: Leo Lei
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Address: Room 1602, sanlong building, tiangao street, south cbd, yinzhou district, ningbo, zhejiang ,china


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