举世瞩目的西气东输工程开工在即，大投资、长距离、大管径、短工期、高质量、地质条件多样、 施工单位众多等是其主要特点。其中焊接工艺的制订及焊接设备的选型涉及许多技术问题，将对施工进度、施 工质量、施工单位的经济效益产生重大影响，应引起足够重视。

The famous project, gas transmitting from west to east, will set off. Its main characters are great investment, long distance, large pipe diameter, short time limit, excellent quality, various geological conditions and many construction enterprises participated. Setting of welding procedure and making choice of welding equipment involve a lot of techniques. They will have important influence on the economic benefit of construction enterprise, construction period and construction quality. Much attention should be paid to them.