GB/T 1149.4-2021 Active

This part of GB/T 1149 specifies the requirements for product quality that are not typically expressed in the technical requirements of drawings. This part applies to the following piston rings: - Integral cast iron or steel compression rings; - Combined piston rings (oil rings), consisting of cast iron parts and spring parts; - Single and combined steel oil rings, namely steel spiral spring oil rings and steel strip combined oil rings. This part supplements the limits of some quality characteristics specified in the inspection method standard (ISO 66212), and also sets requirements for quality characteristics for which there are no recognized quantitative inspection methods. For example, surface defects are required to be inspected with normal vision (or wearing corrective glasses) without the need for any magnification equipment. The quality characteristics specified in this part supplement the quality characteristics of various types of piston rings specified in other parts of GB/T 1149, such as ring height, radial thickness, and tolerance of the closed gap. This part does not specify acceptable quality levels (AQL). If necessary, the supplier and purchaser should jointly agree on them in accordance with the provisions of ISO 2859. This part specifies the quality requirements for piston rings used in reciprocating internal combustion engines for road vehicles and other purposes, and applies to piston rings with a cylinder diameter ranging from 30 mm to 200 mm.