steel grating, Professional grating manufacturer, Best quality, price & service, ISO9001-2000,Grating Specialist 1. ... , walkway and ditch covers which require high security.Notes: common welding standard: single-side full welding every 6 bearing bars. Bearing ... , guardrail, sunshade gate, etc. Notes: common welding standard: single-side full welding every 4 bearing bars. Bearing bar centers at 60mm ...