... , professional UT center and less than 2 complaint cases . 2, material of steel type of 15#,20#,25#,30#.35#,40 ... #,45#,46#,etc.according to customers' different requirements.3,main material are 5CrMnMo,40Cr,42CrMo,20Cr2Ni4,5CrNiMo,15CrNiMo,20CrNiMo,35CrMo,40CrNiMo ... processing on giving materials. 5, excellent heat treatment. 4330 valve rod