Yantai Fangle Metallurgy Group Co., Ltd.  

Product Name: Mandrels Bar Made of General-Purpose Hot Work Steels and Special Steel Grades for Seamless Steel Tubes and Pipes Industry Model NO.: as the drawing Application: metal Processing Machinery Parts Material: Alloy Customized: Customized Standard: DIN, ASTM, GB Certification: CE, ISO9001 Condition: New Application Range: Continuous Rolling Mill,Mpm,Fqm,Pqf Trademark: FANGLE Transport Package: Woodern Case Specification: max 20m, Diameter 100mm-500mm Origin: China Product Description The Mandrel is the important tool for MPM or FQM during seamless tubeproduction .When rolling seamless tubes, a pre-pierced steel billet is rolled over a mandrelbar by grooved rolls in a stretch reducing rolling process to produce a tube or a tube blank. The mandrelbar determines the shape of the inner tube surface.During production ,it needs 6-7 pieces mandrel to stand by in turns .its surfacetemperature will reach 700ºC during production and then cooled to 80-120ºC afterproduction ,it requires good quality and long lifetime. Mandrelbars are manufactured with lengths of up to roughly20m and production diameters of currently up to a maximum of 500mm.We have the ability to produce mandrel bars for MPM and FQM, with yearly capacity around 20000 tons.Production process:1) forging 2) rough machining3)magnetic test 4) heating treatment5) ultrasonic test 6) finish machining 7) chromium plating8)thread phosphating 9) packageChemical composition of the steel grade. Hot work tool steel corresponding to the grade AISI H13. The range of chemical composition is as specified below: H13 chemical composition: ChemicalCMnSiCrMoVSS+PContent0.30-0.38≤0.6 0.70-1.20 4.50-5.501.00-1.500.80-1.200.003max0.020maxDetails:MaterialAISI H13, X35CrMo V51 and 4CrMoSi V1Diameterup to 500mmLengthup to 20mThreadingAvailable,phosphotized after chromium platingchromium platinglength: whole working bodyW.th: 0.045/0.08dehydrogenation after chromium platingTestultrosonic test 1.Steel manufacturing The steel shall be produced by the electric arc furnace and has to be vacuum degassed. Hydrogen must be held below 2.5 ppm and Oxygen below 30 ppm.2. Hot Forming. The mandrel bars are to be forged from an ingot. The cross-sectional area of the solid forging shall have a reduction by hot forming from that of the ingot in the ratio of not less than 8 to 1. There should not have any defects.3. Heat Treatment. The hot forming process shall be immediately followed by heat treating processes. .Material must ensure the required structure and mechanical properties.4.Mandrel tests. 4.1 Mechanical properties 4.2 Tensile and impact tests Tensile strength: RM =1050 MPa Minimum (105 kg/mm²) RM = 1280 MPa Maximum (130 kg/mm²) Yield strength: Ys ≥ 880 MPa Elongation: Min .A=10% Reduction of area: Min.Z=30% Charpy V-Notch impact test: Min. Kv ≥ 20j, testing at room temperature. Charpy tests will be in transverse orientations. 4.3Hardness tests 4.4Microscopically Examinations 4.5Microstructure after Heat Treatment 4.6 Austenitic Grain Size 4.7Nonmetallic Inclusion Contents 4.8Non destructive Tests5.Straightness6.Machining7.Chrome plating8.Marking9.Protection and Packing10.Certification