ST Rating of Steel Cord Belt

Posted in: , on 16. Feb. 2012 - 19:48

Dear Experts,

The steel cord conveyor belt given Specification is ST 2700 belt width:1200mm, Thichness:12T+5T, Din X

We have two options

Option I : Cable dia:6.2 mm ;Number of cables:97;Cable pitch:12

Option II : Cable dia:7mm ; Number of cables:77 ; cable pitch:15.4

According to strength of belt both is matching.But which is better option, more cable with smaller dia or

less cable with Big dia?



St - Xxxx Cabel Size

Posted on 17. Feb. 2012 - 06:14

Smaller cables should yield a lower cost due to lower core gum volume. You are replacing steel cord volume for rubber core gum volume.

If the cable is large enough you might be able to do it with a single step splice. How large do you need to go? Larger than 7.0 mm unless you change the steel cord material.

I disagree with your selections:

1. 6.2 dia. could be accomplished with 90 cables and 12.74 mm pitch, a two step splice, so why doesn't the belt manufacturers give you better advice. You can do it with less with the right steel cord construction.

2. 7.0 dia. may take 74 cables and 15.5 mm pitch, but, still needs a 2-Step splice. No advantage to 7.0 mm diameter cables. A single or more steps requires a minimum of 0.25 :1 splice core gum gap: cable diameter. For smaller splices this should be increased to 0.35 or larger to carry a respectible shear stress between cables.

We are getting into splice design techniques, which is a big subject and has many points of view, outside your intented question.


Lawrence Nordell Conveyor Dynamics, Inc. website, email & phone contacts: phone: USA 360-671-2200 fax: USA 360-671-8450

Re: St Rating Of Steel Cord Belt

Posted on 17. Feb. 2012 - 05:29


The present system the belt cable dia.5.2 mm and 97 cables(ST2250) due to impact loading of rocks and quatz(sharp edge)

conveyor loading point area cable got damaged and frequent joint failure occured(conveying length:6.5KM)

Hence we decided to buy with high safety factor belt(Sf:8), for trial basis we put 1000mtrs of belt with ST2700

cable dia:6.2 number of cable 97 the splice length was increased from 1300mm to 2050mm(3 step 550mm Lg.)

The belt is running good for past 6 months.

Now my doubt is more number of cable and less dia. is good (or) less cable with big dia is good?

to avoid cable damage due to impact load and joint failure.

Now we want to change the entire belt length of 13200 mtrs.

As per DIN std.ST2500 cable dia.6.8 and 77cables ; ST3150 cable dia.7.6 and 77 cables.

Kindly clarify the same sir,