Welding and allied processes - qualification test of braze welders for safety joints on fuel gas distribution pipework - joining of fuel gas pipework in fuel gas plants located downstream of the general cut - off device 焊接和相关工艺.气体燃料配送管道上安全接头用铜焊设备的合格鉴定试验.位于通用切割设备下游的气体燃料设备中气体燃料管道的连接
