China follows (2007 latest grating version) standard. Besides, United States, Britain, Australia and New Zealand also have their own standards. Steels according to GB700-88, GB1220-92.
Steel grilling production process is generally divided into two kinds: pressure welding and hand-made. The first one uses high pressure resistance pressure welder, forcing rail into the flat steel inside through the welding and hydraulic power, which can get high quality steel grating with stability and strength. Hand-made grating drills hole, then spot welded in the hole, there will be gaps between flat steel and bar, not each point could be contact, so welding is not solid and the strength is poor.