Qingdao Powerful Machinery., as a manufacturer of chain, can only control the specifications of our chain products in accordance with industry and other standards for chain manufacturing. It would be impossible for any warning to contain all of the possible misapplications associated with the use of chain products. Our warnings are intended to identify only those risks which are most common.
Working Load Limit (WLL)
The “Working Load Limit” (rated capacity) is the maximum load that shall be applied in direct tension to an undamaged straight length of chain.
The “Proof Test” (manufacturing test force) is a term designating the minimum tensile force which has been applied to a chain under constantly increasing force in direct tension during the manufacturing process. These loads are manufacturing integrity tests and shall not be used as criteria for service or design purposes.
Minimum Breaking Force
The “Minimum Breaking Force” is the minimum force at which the chain during manufacture has been found by testing to break when a constantly increasing force is applied in direct tension. Breaking force values are not guarantees that all chain segments will endure these loads. This test is a manufacturer’s attribute acceptance test and shall not be used as a criteria for service or design purposes.
The Working Load Limits and the associated safety factor of each product may be affected by wear, misuse, overloading, corrosion, deformation, intentional alteration and other use conditions. Regular inspection must be conducted to determine whether use can be continued at the assigned Working Load Limit, a reduced Working Load Limit or whether the product must be withdrawn from service. The terms “Working Load Limit”, “Proof Test” and “Minimum Breaking Force” contain no implication of what load the chain will withstand if the chain is used in such conditions of abuse and misuse.
The Working Load Limit of a sling or assembly must not exceed the lowest Working Load Limit of the components in the sling or assembly.
USE ONLY GRADE 80 OR GRADE 100 ALLOY CHAIN AND ATTACHMENTS FOR OVERHEAD LIFTING.
OUR PRODUCTS ARE INTENDED TO BE USED AT OR BELOW THE MAXIMUM WORKING LOAD LIMITS SPECIFIED IN CONSTANTLY INCREASING FORCE APPLICATIONS UNDER DIRECT TENSION OR IN A STRAIGHT LINE PULL.
THE CONDITIONS INVOLVING USE IN CERTAIN ENVIRONMENTAL SITUATIONS SUCH AS UNUSUAL (HIGH OR LOW) TEMPERATURE, CHEMICAL, ETC…, CAN CAUSE CHANGES IN CHAIN PERFORMANCE.