發送短信 : Metal powder addition in submerged arc welds

 ______     ______   _    _     _____    _    _   
|      \\  /_   _// | |  | ||  |  ___|| | |  | || 
|  --  //   -| ||-  | |/\| ||  | ||__   | |/\| || 
|  --  \\   _| ||_  |  /\  ||  | ||__   |  /\  || 
|______//  /_____// |_// \_||  |_____|| |_// \_|| 
`------`   `-----`  `-`   `-`  `-----`  `-`   `-`