The Concrete Pump Boom Elbow is made of special quality steel which is quenched and carried out carburizing chemical treatment on the inner wall. Concrete Pump elbowConcrete Pump elbowsConcrete Pump Elbows The Concrete Pump Boom Elbow is made of special quality steel which is quenched and carried out carburizing chemical treatment on the inner wall. The hardness of the flanged bushings can reach 58-60 degrees and the serving life of pipeline can increase 3-5 times,which enables users to save time and cost, enhancing the production efficiency. Putzmeister Schwing Cifa Casting