MANUFACTURING METHOD OF DOUBLE WALL PIPE FOR TRANSFERRING CONCRETE AND DOUBLE WALL PIPE FOR TRANSFERRING CONCRETE USING THE SMAE

摘要

PURPOSE: A manufacturing method of a double pipe for transferring concrete and the double wall pipe for transferring concrete manufactured by the same are provided to increase durability of a bumper car because load applying to the bumper car is reduce by reducing self-weight of a double pipe for transferring concrete. CONSTITUTION: A manufacturing method of a double pipe for transferring concrete is as follows. An outer steel pipe is implemented with a nitriding process(S1). An inner steel pipe is implemented with a carbonizing process. The carbonized inner steel pipe is press fitted into the nitrified outer steel pipe.