© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Bulk Deforming ( 부피 성형가공 ) © © Su-Jin Kim Mechanical Engineering Gyeongsiang National University Korea

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Contents Forging Rolling Extrusion Drawing Tube deforming

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Forging ( 단조 ) Forging is the shaping of metal using plastic deformation takes place by compressive forces. It can be carried out at room (cold forging 냉간단조 ) or above recrystallization temperature (hot forging 열간단조 ). Stronger than an equivalent cast or machined part. Expensive die, press and furnace facilities. Post machining is required. Ductile metal.

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Open-die forging( 자유단조 ) Open-die forging is usually done by hammering a part between two flat faces. It is used to make parts that are too big to be formed in a closed die or in cases where only a few parts are to be made without die. SME 1min ©steelindustriesinc.com

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Open-die forging Berreling is caused by friction force at die-workpiece interface. Friction and the aspect ratio effects forging force. Forging force: F≈σ y A(1+μr/h) Barreling F μ, friction Die h r

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Impression-die forging ( 형단조 ) Workpiece acquires the shape of the die cavity while deformed between the closing dies. Forging force : also called Closed-die forging ( 패쇠단조 ) Die Flash Land Parting line k p : pressure-multiplying factors (3~12)

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Forging Die ( 단조 금형 ) Require multi-stage forging to ensure proper distribution of the material in the die cavities. Parting line is designed based on shape, metal flow, force. Flash clearance is 3% of max thickness. Draft angle > 5~7° for steel. Corner fillets radii for smooth flow. low and wide Ribs Metal fiber flow lines. Die Parting line Draft angle Rib Flow lines Fillet Flash

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Forging die & flash Source geometry and die and flash size. Forging die OX flash

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Impression-die hot forging 1STAGE2STAGE 3STAGE ©gsf.co.kr Bucket Tooth Hot forging

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Continuous Cross Section Rolling Extrusion Drawing

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Rolling ( 압연 ) Metal stock is passed through a pair of rolls to reduce thickness. Hot rolling ( 열간압연 ) > recrystallization temperature > Cold rolling ( 냉간압연 ) (Roll bending) (Roll forming) Flat rolling Ring rolling Structural shape rolling Rolling 3m

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Flat Rolling ( 평판 압연 ) Rectangular cross-section (sheet, plate) Force: F ≈ σ y lw Draft: t 0 - t f < μ 2 R t0t0 tftf R w l F

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Ex) Flat Rolling Force Power Ductile plate (width: 0.1 m, thickness: 10 mm, strength: 400 MPa) is rolled by flat rollers (radius: 0.1 m). The friction coefficient of roller and plate is 0.2 and production rate is 1 m/s. How many times should the plate pass the roller to get 5 mm thickness plate? Please predict approximate rolling Force (kN) and Power (kW).

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Ring rolling ( 링압연 ) Driven and idle roll presses the ring to decrease thickness and increase diameter. Driven roll Idler roll Side roll Ring rolling

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Structural shape rolling ( 형압연 ) Structural shape rolling uses profile rolling techniques where the workpiece is passed through a series of rollers that match the workpieces' cross-section.

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Thread rolling ( 나사 전조 ) Bolt: Bolt Nut 5mhttp:// Threads are formed by pressing a blank with the former(shaped die). Thread Rolling Die Blank

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Extrusion ( 압출 ) Hot extrusion profiles of steel A round billet is placed in a chamber and forced through a die opening by a ram. It creates complex fixed cross-sectionals. Pressure: p≈σ y ( ln(A o /A f )) Die Ram F Billet Container Extrusion 1m AfAf AoAo

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Drawing ( 인발 ) Reduce the cross-section of a road, wire or tube by pulling it through a drawing die Lubrication is essential for good surface finish and long die life Die A0A0 AfAf F

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Spring forming machine Spring forming machine controlled by mechanical cam and link. Spring former

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Rotary Swaging Split dies separate and close to reduce the diameter and produce a taper of tube. Tube Die Mandrel

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Tube (Pipe) Bending Straight tube is bended into the desired form. Be careful to buckle inward during bending. Former Clamp Tube bending

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Tube Hydroforming SME: Com: Hydraulic pump injects high pressure fluid inside a hollow tube to expand until it matches a negative mold. Strong and light structures for vehicles Dies Seals Hydraulic pressure Tube

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Characteristics ( 특징 ) AdvantagesDisadvantages Fast & mass productionExpensive equipment and dies Improved strengthDuctile materials Surface finish and tolerance are better than casting Shape is limited by strain/flow Size is limited by force/equipment Strength is improved because of work hardening, grain refining, fevering, defect closure Surface finish and tolerance are better than casting, worse than machining

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Economics ( 경제성 ) Tool and die cost middle or high but spread over the number of parts For large quantities forging is more economical than sand casting Number of pieces Cost per pieces Sand casting Investment casting Die casting Forging

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes Bulk Deforming Simulation

© 2012 Su-Jin Kim GNU Bulk Deforming Manufacturing Processes References