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metalwork

metalwork. 1st Year Apprenticeship. Metal Work. In this block you will learn about: Metals and their properties Deformation effects after impact Tools used for effective repair Stretching and shrinking Paintless dent removal. Hot rolled thickness ranges 2-8 mm

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metalwork

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  1. metalwork 1st Year Apprenticeship

  2. Metal Work In this block you will learn about: Metals and their properties Deformation effects after impact Tools used for effective repair Stretching and shrinking Paintless dent removal

  3. Hot rolled thickness ranges 2-8 mm generally used for full frames, sub frames (unibody) and crossmembers Cold rolled hot rolled, acid rinsed, cold rolled thin, then annealed better surface quality good workability most unibody panels are cold rolled steel stamping process increases strength Body Steels

  4. Cold Rolling Mill to Stampings

  5. Grain Structures of Steel HSLA Mild Steel

  6. Properties of Steel • Mild Steel • HSS • HSLA • UHSS • AHSS up to 30,000 psi yield strength 30 - 70,000 psi yield strength 75 - 100,000 psi yield strength 100- 160,000 psi yield strength 110 – 180,000 psi yield strength

  7. Gets its initial strength during the heating/cooling treatment from the steel manufacturer Is used mainly for load bearing components in the body structure, however more commonplace today throughout entire body structure May be repaired cold or with controlled heat More difficult to repair than mild steel Yield strength of up to 70,000 psi. Lack of available identification for HSS means treat all steel as HSS! HSS

  8. Like HSS except varying alloying elements (chemicals) are added during the manufacturing process to increase its strength (yield and tensile) May be reworked cold or with controlled heat application Found in areas such as: Door intrusion beams Bumper reinforcements Lock pillars Front and rear frame rails Hinge pillars (A,B,C) Yield strength up to 110,000 psi. HSLA

  9. The strongest of the structural steels found in today's automobiles Often referred to as Boron, Martensitic, Dual phase steels Found in these areas: Front and rear bumper reinforcements intrusion beams A,B,C pillars (some vehicles) No heat whatsoever is to be applied to any component of this designation! These steels are generally not repairable Require special considerations when removing/sectioning UHSS/AHSS

  10. Identification of Steels • Location and application of HSS steels vary widely from manufacturer to manufacturer • Sources of information include: • OEM body repair manuals • Internet sources (OEM approved) • Mitchell manuals (estimating manuals) • If you cannot positively identify the makeup of a component, you must treat it as HSS!

  11. HSS Locations

  12. Part Loading • Tension: • a load that tries to pull parts straight apart • Compression • a load that forces parts straight into one another • Shear • A load that pulls sideways • Cleavage • a load that pulls parts away from each other at an angle • Peel • a load that pulls parts straight away from one another

  13. Loads present during a collision

  14. Terminology • Yield strength: • The minimum amount of force any piece of metal can resist without bending or deforming permanently • Yield Point: • The amount of force that a piece of metal can resist without tearing or breaking • Tensile strength • is measured as the maximum force per unit of area that causes a complete fracture of break

  15. Terminology • Work Hardening • Is the upper limit of plastic deformation, causing the metal to become hard in the bent area • Malleability • is the property which allows deformation under compression or upsetting (shrinking) • Elasticity • is the ability of the metal to be bent or stretched and spring back to its original shape

  16. Terminology • Plasticity: • The property that permits metal to change shape when sufficient force is applied to it • Plastic Deformation: • The ability of the metal to be bent or formed into different shapes ( bent beyond its elastic limit) • Elastic Deformation: • The ability of the metal to be stretched or bent and return to its original state

  17. Terminology • Torsional strength • is the property of a material to withstand a twisting force • Shear Strength • is a measure of how well a material can withstand forces acting to cut or slice it apart • Compressive Strength • is the property of a material to withstand being crushed

  18. Metal Strength Terminology

  19. Plastic Deformation Elastic Deformation

  20. Terminology • Rigidity: • Opposite of plasticity. • example: Cast iron will not bend or deform, it will only break under load • Ductility: • ability of a metal to plastically deform without breaking or fracturing, with the cohesion between the molecules remaining sufficient to hold them together

  21. Heat and Sheet Metal • The point at which Steel melts is 2600 Degrees F • We should know the effects of the temperature change between 400 - 1600 degrees F. • Three Effects: • scaling • changes in grain structure • expansion and contraction

  22. Temperature and Colour Change • Light film of scale (iron oxide) 430 F • Pale yellow / Straw / Brown / Purple / Light Blue • Dark Blue / 600 degrees F • Reddish Glow / 900 degrees F • Blood Red / Dark Cherry 1200 F • Cherry Red 1550 degrees F • Critical Point 1600 degrees F

  23. Shapes

  24. Low Crown High Crown Reverse Crown

  25. Buckles • Buckles occur when metal has been bent past it’s elastic limit • Work hardening has occurred and a new shape is formed • The buckles found in indirect damage are as follows: • simple hinge • collapsed hinge • simple rolled • collapsed rolled

  26. Direct and Indirect Damage

  27. Impact effect on a High Crown

  28. Effect of damage on a Low Crown Panel

  29. Effect of impact on a combination High / Low Crowned Panel Tension can only be removed by “unlocking” the pressure areas

  30. Combination of Buckles two types of rolled buckles simple hinge buckle Collapsed hinge buckle

  31. Steps in Unlocking Damage First in last out

  32. “Collapsed Roll Buckle”

  33. What happens to the Steel upon impact?

  34. In this case, the damage (Hinged Buckle) has caused severe damage to the molecular structure

  35. Hammering helps the atoms to ‘vibrate’ back into shape, or order

  36. Tools • Hammers • Dollies • Spoons • Dent pullers • Body picks • Oxy-Acetylene • Body files

  37. Body Hammers

  38. Hammers

  39. Holding the Body Hammer

  40. Dollies

  41. Holding the Dolly

  42. Using the Corner of the Dolly

  43. Using the Edge of the Dolly

  44. Using the Dolly as a tool for bumping

  45. Spoons

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