Changsha Haochang Machinery (HC Enginepart) is a China-based manufacturer and exporter of replacement piston rings for MAN B&W two-stroke low-speed crosshead marine diesel engines, including the MC-C and ME-C series. HC develops piston rings from customer samples or drawings, with diameter coverage from φ30 to 800 mm — encompassing MAN B&W models such as the S50MC-C (500 mm bore), S60MC-C (600 mm), S70ME-C (700 mm), and S80ME-C (800 mm). All piston rings are produced to OE specifications under the ISO 9001:2015 quality system. These engines serve as main propulsion on large container ships, bulk carriers, and tankers.