Drill String Cross-over Sub uses AISI4145H chromium-molybdenum steel, execute API specification.We can produce the same-dia type, reducers type and L-type three types, the screw can be cold thread rolling, copper or phosphate treatment.
QStE340TM steel is a kind of automotive structural steel. QStE340TM steel work / steel structure / steel machining parts are made of QStE340TM steel as raw material.
GB/T1591 Q345A I beam /angle/ channel steel decreases the yield value as the thickness of the material increases. And may be less than 345, so when the mechanical design strength must be less than the value of 345, otherwise there will be problems.