1. large size: 80mm-6,30mm OD. 2. nonstandard ones: custom made 3. production capacity: 40,000 tons per year 1. custom made2. large size, diameter: 300mm to 6000mm, weight of single piece: 0.75 ton to 15 tons3. materials: carbon steel, alloy steel and stainless steel4. annual production capacity: 40,000 tons5. certificates: ISO9001:2008, ISO14001:2004, OHSMS18001:20076. test: ultrasonic test l