The invention provides steel for a pumping rod resisting casinghead gas
corrosion and a manufacture method thereof. The steel comprises the following chemical compositions by
mass percentage: 0.05 to 0.25 percent of carbon, 0.50 to 2.00 percent of
silicon, 1.10 to 2.50 percent of
manganese, 0.02 to 0.50 percent of
molybdenum, 0.02 to 0.50 percent of
nickel, 0.50 to 1.50 percent of
chromium, 0.01 to 0.10 percent of
vanadium, 0.005 to 0.050 percent of aluminum, 0.02 to 0.10 percent of
niobium, 0.05 to 0.50 percent of
copper, 0.01 to 0.10 percent of
titanium, less than or equal to 0.015 percent of sulphur, less than or equal to 0.020 percent of
phosphorus, and the balance being ferrum. The method is to manufacture a pumping rod wire through a design of adding the
niobium and other trace
alloy elements and corresponding compositions into steel, and controlled rolling and controlled cooling organization control technology. The pumping rod manufactured by the wire has excellent oilwell medium
corrosion resistance, proper strength, excellent plastic tenacity and excellent
welding performance, thereby improving the service life and reliability of the pumping rod, and improving the whole stability of pumping equipment, and further solving the problem that the prior pumping rod has repeated
stress failure caused by endurance of complex casinghead gas
corrosion.