... can be ordered according to customers design requirements, Main steel gardes:10-45,16Mn,20Cr,15CrMo,35GrMo,27CD4,CK35,SAE1035 ... dimension tolerances highly conform to the requirements of diesel engine tube. In view of oil tubes special quality requirements, we ... use high quality tube blank DIN2391 ST30Al, ST35, ST37, ST45, ST55 from Xingcheng steel or Bao steel which is better in mechanical ...