HYDROFORMING Presented by: Byron Erath Duane Ellsworth
OUTLINE: • What is Hydroforming • How and where is Hydroforming used • Materials used in Hydroforming processes • Design Considerations • Advantages/Disadvantages • Economics of Hydroforming • Websites and Links • Conclusion
HYDROFORMING Hydroforming uses the force of water or hydraulic fluids to shape a single part. There are two types of hydroforming: 1. Tube hydroforming 2. Sheet hydroforming
TUBE HYDROFORMING • Used when a complex shape is needed • A section of cold-rolled steel tubing is placed in a closed die set • A pressurized fluid is introduced into the ends of the tube • The tube is reshaped to the confine of the cavity
SHEET HYDROFORMING 2 METHODS: • Sheet steel is forced into a female cavity by water under pressure from a pump or by press action • Sheet steel is deformed by a male punch, which acts against the fluid under pressure. Note: Sheet hydroforming provides a work-hardening effect as the steel is forced against the blanks through fluid pressure.
APPLICATIONS • Automotive industry • Sanitary use • Aerospace • Lighter, stiffer parts Chevy SSR Frame
APPLICATIONS (CONT) 1. Body shell 2. Driving shaft 3. Assembled camshaft 4. Exhaust systems 5. Engine cooling system 6. Radiator frame 7. Safety requirements 8. Engine bearer 9. Integral member 10. Cross member 11. Frame structure parts 12. Axle elements
MATERIALS • Steel (mild and harder steels) • Stainless Steel • Aluminum alloys • Research continues to expand the capabilities of the hydroforming process
DESIGN CONSIDERATIONS • Hydroforming is generally defined as either low-pressure or high pressure. • The demarcation point is 83MPa • Constant pressure volumetric expansion < 5% required to shape the part = Low pressure > 5% (but < 25%) = High Pressure
DESIGN CONSIDERATIONS Tool/Dies -Geometry of tools - Material hardness - Surface conditions - Stiffness and accuracy Equipment - Press capacity - Speed/production rate - Force/energy capabilities - Rigidity and accuracy Product - Geometry, thickness distribution - Dimensional accuracy/tolerances - Surface finish - Microstructure, mechanical and metallurgical properties, hardness Deformation zone - Deformation mechanics, model used for analysis - Metal flow, velocities, strain rates, strains (kinematics) - Stresses (variation during deformation) • Work piece/Material • Flow stress as a function of strain, strain rate and microstructure • Workability as a function of strain, strain rate and microstructure • - Surface conditions • - Geometry of tubing ( outside diameter, tube wall thickness, roundness, properties of welding line, etc.)
ADVANTAGES • Hydroforming draws material into the mold • Part consolidation • Weight reduction through more efficient section design and tailoring of the wall thickness • Improved structural strength and stiffness • Lower tooling cost due to fewer parts • Fewer secondary operations (no welding of sections required and holes may be punched during hydroforming) • Tight dimensional tolerances and low spring back • Reduced scrap
ADVANTAGES (CONT.) Results compared to conventional steel body structure: • 50% less weight • 45% less parts (less tools, less assembly) • 45% less welding seams • Tighter tolerances Volvo Hydroformed Structure concept in Aluminum, (Schuler Hydroforming 1998)
DISADVANTAGES • Slow cycle time • Expensive equipment and lack of extensive knowledge base for process and tool design • Requires new welding techniques for assembly.
INFORMATION ON THE WEB • www.hydroforming.net • www.vari-form.com • www.hdt-gti.com • www.revindustries.com • www.autosteel.org • www.schuler-hydroforming.de • www.egr.msu.edu/~aenader • nsmwww.eng.ohio-state.edu/html/tube_hydroforming.html
CONCLUSION • Hydroforming is an innovative forming process • Hydroforming is becoming more popular (ie.automotive and aerospace industries) • The advantages outweigh the limitations • Material selection is broad and continues to increase • Information can be found everywhere!