Straightening Aluminum Program 1. Module 1

Transcription

1 Straightening Aluminum Program 1

2 IMPORTANT NOTICE This material provides general directions for collision damage repair using tested, effective procedures. Following them will help assure the reliability of the repair. I-CAR cannot accept responsibility for any individual repair, nor can it warrant to the quality of such repair. Anyone who departs from the instructions in this program must first establish that neither personal safety nor the integrity of the repair of the vehicle is compromised by the choice of methods, tools, or supplies. I-CAR does not endorse or recommend any brands or makes of vehicles, repair equipment and supplies or other products. The appearance of various makes and brand names in any I-CAR material is purely coincidental and is based on the availability of those products at the time of production. All recommendations presented in this program are based upon research programs or upon tests conducted by laboratories, manufacturers, or selected collision repair facilities. If performed as outlined, these recommendations will provide the basis for a thorough, professional repair by the Inter-Industry Conference On Auto Collision Repair (I-CAR) All Rights Reserved 2

3 MODULE 1 CHARACTERISTICS AND CONSIDERATIONS OF ALUMINUM REPAIR Topic A. Characteristics Of Aluminum Class 0:50 Learning Objectives A-1 The learning objectives for this module include: identifying the types of aluminum used in vehicle construction. Before beginning the class, take a moment to explain to the Students what the recommended prerequisites for this Program are. Tell the Students that information on exterior panel replacement can be found in Panel Replacement Aluminum Program 1. explaining the basic properties of aluminum. identifying the different alloys of aluminum. determining the corrosion issues related to aluminum. identifying the workplace considerations. identifying the tools used for aluminum repair. The learning objectives for this module include: identifying the types of aluminum used in vehicle construction. explaining the basic properties of aluminum. identifying the different alloys of aluminum. determining the corrosion issues related to aluminum. identifying the workplace considerations. identifying the tools used for aluminum repair. 3

4 Topic A. Characteristics Of Aluminum (cont d) A-2 Advantages Of Aluminum Aluminum Steel Aluminum use in the automotive industry has increased. Government regulations on fuel economy and the desire for driving larger vehicles has forced vehicle makers to use a lighter, yet durable material. Aluminum is one way that vehicle makers have met these demands. Some of the advantages of aluminum include its: durability. strength. corrosion resistance. light weight. ability to be recycled. availability. Some of the advantages of aluminum include durability, strength, corrosion resistance, light weight, abilit y to be recycled, and availability. 4

5 Topic A. Characteristics Of Aluminum (cont d) A-3 Molecular Structure Aluminum Steel Steel Aluminum The molecular structure of aluminum is different than steel. When aluminum is formed or damaged, it wants to stay in the shape that it is in. 5

6 Topic A. Characteristics Of Aluminum (cont d) A-4 Work Hardening Audi A-8 Hood When aluminum is formed, it gains strength. This is known as work hardening. Collision damage reforms the metal again, making it even stronger. The repair will require controlled effort to restore the panel to the original shape. WORK HARDENING When aluminum is formed, it gains strength. This is known as work hardening. 6

7 Topic B. Aluminum s Physical Properties B-1 Aluminum Panels Aluminum panels used on vehicles: weigh less than the same thickness mild steel panel. can be as strong as steel. FLEXIBILITY OF ALUMINUM VS. STEEL Aluminum panels used on vehicles weigh less than, and can be as strong as, a mild steel panel of the same thickness. 7

8 C-1 Topic C. Alloys Alloys A chart of the different alloys of aluminum is available from the Aluminum Association publication AT4. The publication is available at: The first digit in the alloy number is what series the alloy belongs to. Adding different elements to aluminum in the alloying process creates different alloys. The element added to the aluminum will determine how much strength the alloy will have. This process creates aluminum with properties better suited to the application. The first digit in the alloy number is what series the alloy belongs to. 8

9 Topic C. Alloys (cont d) C-2 Heat-Treatable Vs. Non-Heat-Treatable Exterior Panels Heat-Treatable Inner Structure Non-Heat-Treatable Heat-treatable alloys are alloys that gain strength when heated. Non-heat-treatable alloys gain strength by work hardening and cold forming. Both heat-treatable and non-heat-treatable alloys may be heated during repairs. Both heat-treatable and non-heattreatable alloys may be heated during repairs. Methods used to strengthen aluminum include heat treating, cold forming, and work hardening. 9

10 Topic C. Alloys (cont d) C-3 Heat-Treatable Alloys Hood 6000 Series Bumper Reinforcement 7000 Series Heat-treatable alloys may be heated to gain strength. The majority of exterior body panels are made using heat-treatable aluminum. This group of alloys includes: 2000 series. This series of aluminum is alloyed with copper. An example is outer and inner body panels series. This series of aluminum is alloyed with magnesium. An example is exterior body panels series. This series of aluminum is alloyed with zinc and small amounts of magnesium or copper series aluminum is very strong. An example is bumper reinforcements. Heat-treatable alloys consist of 2000, 6000, and 7000 series aluminum. 10

11 Topic C. Alloys (cont d) C-4 Non-Heat-Treatable Alloys Non-heat-treatable alloys are alloys that cannot be heat treated to gain strength. The strength of these is due to cold forming. Vehicles with aluminum structures may use non-heat-treatable alloys for the inner structure. This group of alloys includes: 1000 series. This series of aluminum is over 99% pure. An example is electrical wire series. This series of aluminum is alloyed with manganese. An example is the inner structure on vehicles series. This series of aluminum is alloyed with silicon. An example is welding electrode wire series. This series of aluminum is alloyed with magnesium. An example is the inner structure on vehicles. Non-heat-treatable alloys consist of 1000, 3000, 4000, and 5000 series aluminum. 11

12 Topic C. Alloys (cont d) C-5 Temper The physical and mechanical properties of aluminum are known as its temper. The temper is identified by the suffix that follows the alloy number. For heat-treatable alloys, this suffix begins with the letter T for temper. Non-heat-treatable alloys use the letter H for hardness. Softer alloys of aluminum scratch easier than the harder alloys. Some of the harder alloys are comparable to steel in dent and scratch resistance. SCRATCH EFFECT OF DIFFERENT TEMPERS The temper is identified by the suffix that follows the alloy number. For heat-treatable alloys, this suffix begins with the letter T for temper. Non-heat-treatable alloys use the letter H for hardness. 12

13 Topic D. Corrosion D-1 Corrosion Resistance Aluminum is naturally corrosion resistant due to an oxidation barrier. Aluminum forms this barrier immediately after contact with air. The barrier must be removed before any sanding, filling, or refinishing can be done. Aluminum is naturally corrosion resistant due to an oxidation barrier. 13

14 Topic D. Corrosion (cont d) D-2 Galvanic Corrosion Galvanic corrosion, also called sacrificial corrosion, occurs when two different metals are in contact with each other with the presence of an electrolyte. An electrolyte is a non-metallic conductor of electricity, such as moisture. For example, if a bare aluminum panel comes in contact with a bare steel fastener, the aluminum will corrode to protect the steel fastener. Coated fasteners, washers, or gaskets can be placed in between the dissimilar metals to prevent galvanic corrosion. Galvanic corrosion occurs when two different metals contact each other and an electrolyte is present. 14

15 Topic D. Corrosion (cont d) D-3 Filiform Corrosion Filiform corrosion is the creeping type of corrosion that develops under paint film. This usually occurs when bare aluminum is not cleaned properly before refinishing. When the finish gets scratched, moisture, an electrolyte, will get beneath the paint and corrode the metal. Filiform corrosion usually occurs when the finish on an improperly prepared panel's finish is scratched. 15

16 Topic E. Workplace Considerations E-1 Separate Work Areas Work areas for aluminum repair and for steel repair should be kept separate to avoid contamination between steel and aluminum. This can be accomplished by: setting aside a designated work area for aluminum repair. using curtains and walls to separate aluminum repair areas from steel repair areas. 16

17 Topic E. Workplace Considerations (cont d) E-2 Ventilation Airborne steel particles from sanding and grinding can lead to contamination of the aluminum. Ventilation can reduce the amount of metal particles and sanding dust in the air. Attachments on sanding equipment enable the tool to be connected to a vacuum to remove dust and sanding particles. Separate work areas and vacuum attachments will reduce the amount of particles in the air. 17

18 Topic F. Tools Used On Aluminum F-1 Hand Tools Some of the hand tools used for aluminum repair include: hammers. dollies. slappers. spoons. picks. 18

19 Topic F. Tools Used On Aluminum (cont d) F-2 Dedicated Hand Tools And Abrasives Cross-contamination can be prevented by keeping tools and abrasives used on steel separate from the items used on aluminum. This can be accomplished by labeling or color coding tools and abrasives. Cross-contamination can be prevented by keeping tools and abrasives used on steel separate from the items used on aluminum. 19

20 Topic F. Tools Used On Aluminum (cont d) F-3 Power Tool Considerations The same power tools may be used on both steel and aluminum. The housing should be cleaned to remove any contaminants with a clean towel. Compressed air could cause particles to become airborne so is not recommended. Tools used for cutting such as drill bits and saw blades should be kept separate. 20

21 Topic F. Tools Used On Aluminum (cont d) F-4 Tool Maintenance Considerations Some tool maintenance items that will prevent contamination or damage to the aluminum include: cleaning the tool after use. repairing any nicks or gouges in the hammer face. keeping all hand tools used on aluminum separated from steel. 21

22 Topic F. Tools Used On Aluminum (cont d) F-5 Hammers Hammers used when repairing aluminum should not have nicks or gouges. Aluminum is softer than steel and may be damaged by sharp edges of a hammer. Hammers used on an aluminum repair may include: plastic-faced. polished steel face with edges rounded off. wooden-faced. aluminum-faced. Shrinking or serrated-faced-hammers should NOT be used because they may damage or thin the aluminum. Shrinking hammers should not be used on aluminum because they may damage the metal. 22

23 Topic F. Tools Used On Aluminum (cont d) F-6 Dollies Dollies used for aluminum repair include: polished steel. lead shot. wood. rubber. 23

24 Topic F. Tools Used On Aluminum (cont d) F-7 Slappers And Spoons Slappers and spoons may be used to remove high and low areas on the panel. These may include: wood with leather face. spring steel. polished face. 24

25 Topic F. Tools Used On Aluminum (cont d) F-8 Picks Do not get into a discussion on how each tool is used at this time. This will be covered later in the Program. Picks can be used to push up low areas when there is limited access to the back of the panel. Picks should have polished, rounded tips so that they do not damage the panel. A plastic boot can be placed over the tip to prevent scratches and damage to the inner panel. Duct tape or vinyl electrical tape can also be used to cover the tip of a pick. Picks should have polished, rounded tips so that they do not damage the panel. Plastic tips or tape can be used to prevent damage to the inner panel. 25

26 Topic G. Review G-1 Review #1 Galvanic corrosion occurs when: A. two different metals are in contact with each other. B. an improperly coated panel is damaged. C. the paint surface is scratched on an aluminum panel. D. moisture gets beneath the paint film. Galvanic corrosion occurs when: A. two different metals are in contact with each other. B. an improperly coated panel is damaged. C. the paint surface is scratched on an aluminum panel. D. moisture gets beneath the paint film. 26

27 Topic G. Review (cont d) G-2 Review #2 Technician A says that the picks used to repair aluminum panels should have sharp-pointed ends. Technician B says that shrinking hammers should NOT be used on aluminum panels. Who is right? A. A only B. B only C. Both A and B D. Neither A nor B Technician A says that the picks used to repair aluminum panels should have sharp-pointed ends. Technician B says that shrinking hammers should NOT be used on aluminum panels. Who is right? A. A only B. B only C. Both A and B D. Neither A nor B 27

28 Topic H. Conclusion H-1 Conclusion The topics discussed in this module included: characteristics of aluminum. alloys and their use. corrosion issues. 28

29 Topic H. Conclusion (cont d) H-2 Conclusion (cont d) I-CAR Instructors You may choose to hand out quiz #1 at this point for review. The quiz can be printed from the Instructor Preparation portion of this CD-ROM. The quizzes are an optional exercise. Career and Technical School and College Instructors Quiz #1 should be handed out at this point in the class. The quiz can be printed from the Instructor Preparation portion of this CD-ROM. Students can also print this quiz from their CD-ROM. Topics discussed in this module included: tools used for aluminum repair. separate work areas for aluminum. sources of contamination of aluminum. 29