1. Scope

This standard specifies the product classification, technical requirements, test methods, acceptance rules, marking, packaging, storage, and conveying requirements for general-purpose fabric core flame-retardant conveyor belts with rubber covering (hereinafter referred to as "belts").

This standard applies to general-purpose fabric core flame-retardant conveyor belts used in the chemical, coal, metallurgical, and power industries.

This standard does not apply to flame-retardant conveyor belts used underground in coal mines, nor to flame-retardant conveyor belts with metal skeletons.

2. Normative References

The clauses of the following documents become clauses of this standard through reference in this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. Parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the referenced documents.

GB/T528 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber (GB/T528—1998, eqv ISO 37:1994)

GB/T3512 Vulcanized rubber or thermoplastic rubber - Accelerated aging and heat resistance test in hot air (GB/T3512—2001, eqv ISO 188:1998)

GB/T3684 Specification and test methods for electrical conductivity of conveyor belts (GB/T3684—1983, neq ISO 284:1982)

GB/T3685—1996 Specification and test methods for alcohol blowtorch burning performance of conveyor belts (eqv ISO 340:1988)

GB/T3690 Determination of tensile strength and elongation of fabric core conveyor belts (GB/T3690—1994, ISO 283:1990)

GB/T4490 Dimensions of conveyor belts (GB/T4490—1994, eqv ISO 251:1987)

GB/T5752 Marking of conveyor belts (GB/T5752—2002, ISO 433:1991, IDT)

GB/T6759 Test method for interlaminar adhesion strength of fabric core conveyor belts (GB/T6759—2002, ISO 252—1999, IDT)

GB/T7983 Test method for troughing property of conveyor belts

GB/T9867 Determination of abrasion resistance of vulcanized rubber (rotating drum method) (GB/T9867—1988, neq ISO 4649:1985)

HG/T2194 Specifications for canvas core conveyor belt layer joints

HG/T3046 Specifications for appearance quality of fabric core conveyor belts

HG/T3056 General rules for storage and handling of conveyor belts (HG/T3056—1986, eqv ISO5285:1978)

3. Product Classification

3.1 Specifications
The specifications of the belt are distinguished by the tensile strength of the full thickness of the belt and the width of the belt.
3.1.1 The tensile strength specifications of the full thickness of the belt are as shown in Table 2.
3.1.2 The width specifications of the belt shall comply with GB/T4490.
3.2 Marking
Example:

4 Technical Requirements

4.1 Appearance Quality

The appearance quality of the belt shall meet the requirements of HG/T3046.

4.2 Dimensional Deviations

The deviations of width, length, total thickness, and cover layer thickness of the belt shall comply with the requirements of GB/T4490.

4.3 Layer Joints

The number and position of longitudinal and transverse joints of multi-layer belt cores shall comply with the requirements of HG/T2194.

4.4 Physical Properties

4.4.1 Physical Properties of the Covering Layer

The physical properties of the belt covering layer are shown in Table 1. After aging test (70℃, 168h), the change rate of tensile strength and elongation at break of the covering layer shall not be greater than 25% of the values determined before aging.

Table 1 Physical Properties of the Covering Layer

4.4.2 Full Thickness Tensile Strength

The longitudinal full thickness tensile strength value of the belt as a model shall not be less than the value shown in Table 2 for the strength grade. The minimum longitudinal full thickness tensile strength is equal to the model value of the specified belt.

Table 2 Full Thickness Tensile Strength Grades

4.4.3 Elongation

The full thickness longitudinal reference force elongation of the belt shall not exceed 4%.

Note: Reference force is equal to 10% of the nominal full thickness longitudinal tensile strength multiplied by the basic value of the sample and the middle width.

4.4.4 Interlaminar Shear Strength

4.4.4.1 When using synthetic fiber fabric as the core, the interlaminar shear strength of the belt is shown in Table 3.

Table 3 Interlaminar Shear Strength

4.4.4.2 When using fabric containing natural fibers as the core, the interlaminar shear strength of the belt is shown in Table 4.

Table 4 Interlaminar Shear Strength

4.4.5 Grooving Degree

The straightness of the belt is shown in Table 5.

Table 5 Grooving Degree

4.4.6 Straightness

The straightness of the belt is shown in Table 6. The number of measurements shall be determined through consultation with the relevant parties.

Table 6 Straightness

4.5 Safety Performance

The safety performance of the belt is divided into two levels. The requirements for the flame retardant performance grade are shown in Table 7.

Table 7 Safety Performance

5 Test Methods

5.1 The dimensions of the belt shall be tested according to GB/T4490.

GB/T 10822—2003

5.2 The tensile properties of the cover layer of the belt shall be tested according to GB/T528.

5.3 The wear resistance of the cover layer of the belt shall be tested according to GB/T9867.

5.4 The full thickness tensile strength and elongation of the belt shall be tested according to GB/T3690.

5.5 The grooving performance of the belt shall be tested according to GB/T7983.

5.6 The interlaminar shear strength of the belt shall be tested according to GB/T6759.

5.7 The combustion performance of the belt shall be tested according to method A of GB/T3685.

5.8 The anti-static performance of the belt shall be tested according to GB/T3684.

5.9 Determination of the cover layer of the belt: Spread the belt flat on a flat surface, straighten a 7m or 5m line along any part of the edge of the belt, and place both ends of the line on the edge of the belt. The maximum vertical distance from the measured edge to the straight line is the straightness.
6 Inspection Regulations

6.1 When conducting quality certification and quality arbitration for the belt, all items required in Chapter 4 shall be inspected.

6.2 In a production batch, a certain number of samples shall be drawn according to the provisions in Table 8 for factory inspection of the belt. The length, width, total thickness, full thickness tensile strength and elongation, physical properties of the cover layer (excluding aging properties), interlaminar shear strength and safety performance of the belt shall be inspected.

Table 8 Sampling Quantity

7 Marking, Packaging, Storage and Transportation

7.1 The marking of the belt shall be carried out according to GB/T5752.

7.2 The storage and transportation of the belt shall be carried out according to HG/T3056.

7.3 A quality inspection certificate shall be attached when the product leaves the factory.