... super quality in China .They have been used on SCHWING, PM, KYOKUTO, SANY, ZOOMLION, CIFA, SINOTRUK(CNHTC), FOTON, XUGONG,CHUTIAN, HAINUO ... out carburizing chemical treatment on the inner wall.It has a high wear-resistant. The HRC of it's inner wall ... .5148 5148 This is the drawing of concrete pump pipe PM DN125*4.5mm*3000mm jiang bang vconcrete pump pipe