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.
20CrMo gear steel is one of our main products. 20CrMo gear steel has high hardenability, temper brittleness, very good weldability, cold cracking tendency to form very small, good machinability and cold plastic strain.