Carbon steel tube: 1. Quality Control: API 5L Certificate 2. MOQ: 10,000kg ... .Applications rangepetroleum, smelting, foodstuff, power, papermaking, chemical, medical equipment, aviation, boiler heat, exchanger, gas metallurgy, shipbuilding, construction, etc.Others: 1.Special ... process are made under the ISO9001:2000 strictly. carbon steel tube