... ,OM521LA/OM522LA ,OM541LA/OM542LA etc....Material : We use alloy cast iron ,ductile cast iron ,high alloy cast ... German and Japanese piston ring material standards and use precise auto measurement and control furnace to heat- ... system and electroplating liquid circulation system and auto control and pre-alarm system .Phosphating ,gas nitriding ,salt-melting nitriding ,FSD and PCVD .Processing : we use ...