ABCDEFGHIJKLMNOPQRSTUVWXYZ
1
InspectaDent — Vehicle Material & Construction Quick Reference
2
Customer-friendly explanation + concise technical construction notes for PDR conversations. Always verify model-specific OEM material and repair information before structural work.
3
4
Material / ConstructionQuick customer explanationTechnical explanationHow it is made / strengthenedTypical vehicle usePDR behaviourTechnician watch-outs
5
AluminiumA lightweight metal used to reduce vehicle weight. It is generally stiffer and less forgiving to reshape than ordinary mild steel, so repairs can take more time and specialist technique.Automotive aluminium outer panels are commonly formed from heat-treatable or non-heat-treatable aluminium alloys. Their mechanical properties depend on alloy chemistry, temper, forming history and any subsequent heat treatment or paint-bake cycle.Sheet is rolled to controlled thickness, alloyed for the required strength/formability, stamped into the panel shape and may be solution-treated, quenched, naturally/artificially aged or work-hardened depending on the alloy and temper.Bonnets, doors, wings, tailgates, roofs and structural components, especially where weight reduction matters.Lower elastic modulus than steel but material and panel design can make it feel resistant to movement. Work-hardening and limited heat tolerance can affect repair strategy. Clean, controlled pushes and accurate temperature management are important.Confirm material first. Aluminium needs dedicated/clean tooling where contamination matters. Avoid uncontrolled heating; excessive heat can alter temper, coating or adhesive systems. Access and panel bracing may dominate difficulty.
6
Mild / conventional steelThe traditional car-body metal. It is relatively easy to press into shape and, depending on the dent and access, often responds predictably to PDR.Low-carbon sheet steel combines useful ductility, formability and weldability. Strength comes from its iron-carbon composition, processing and the geometry of the finished panel rather than very high alloy strength.Steel strip is rolled to thickness, annealed/processed for formability, coated where required and stamped in large dies. The formed panel is then joined to reinforcements by spot welding, laser welding, brazing, adhesive or mechanical joining depending on design.Many exterior skins and traditional body panels.Usually the most familiar PDR material. It can often be progressively moved back through controlled pushes or glue pulling, but crown tension, bracing, stretched metal and body-line geometry still govern difficulty.Do not assume every steel panel is conventional steel. Modern vehicles mix several grades in one assembly. Identify reinforcements and bonded/double-skin areas before choosing access.
7
HSS — High-Strength SteelA stronger grade of steel than ordinary mild steel. Manufacturers use it to save weight or add strength, but it can require more controlled force during repair.HSS is a broad engineering category rather than one single alloy. Strength is increased through composition and processing such as grain refinement, precipitation strengthening, work hardening or phase control while retaining useful formability.Produced through controlled rolling, alloying and thermal processing. Different grades are selected according to the balance required between strength, elongation, forming and crash performance.Body structures, reinforcements and some outer/closure panels depending on model.Can feel springier or more resistant than conventional mild steel. Panel thickness, grade, shape and work hardening influence how readily a dent releases.Do not identify HSS by feel alone. OEM repair information/material maps are preferable. Excessive heat or inappropriate straightening can change properties on some grades.
8
AHSS — Advanced High-Strength SteelA family of very strong modern steels used to make vehicles lighter and safer. The metal can be much less forgiving than ordinary steel, so repair methods need to respect the exact grade and location.AHSS includes multiple microstructure-based families such as dual-phase (DP), complex-phase (CP), transformation-induced plasticity (TRIP) and martensitic grades. Their high strength is engineered through controlled phase composition and processing, not simply by making the sheet thicker.Carefully controlled alloy chemistry, rolling, cooling and heat cycles create combinations of ferrite, martensite, bainite or retained austenite. The exact route depends on the grade and required strength/ductility.Crash structures, pillars, rails, intrusion beams, reinforcements and increasingly mixed-material body assemblies.Where present in or behind a repair area, higher strength and springback can increase effort and alter leverage requirements. An outer skin may still be a different material from the reinforcement behind it.Never assume the outer skin and inner structure are the same grade. OEM procedures matter. Heating, drilling, sectioning or conventional straightening restrictions can be strict on structural AHSS.
9
UHSS / Martensitic / press-hardened steelExtremely strong steel normally used in safety-critical structure. It is designed to resist deformation in a crash, not to be casually reshaped.Ultra-high-strength steels include very high-strength martensitic and press-hardened/boron steels. Press hardening forms heated sheet in a cooled die so the final component develops a predominantly martensitic microstructure and very high tensile strength.For press-hardened components, specially alloyed sheet is heated into the austenitic range, transferred to a forming die, pressed and rapidly quenched in the die. This combines forming and hardening in one controlled process.A/B pillars, roof rails, rocker/sill reinforcements, bumper and intrusion structures, safety-cell components.Usually more relevant to what is behind an outer panel than to routine cosmetic PDR skin work. Its rigidity can severely restrict access or movement of the surrounding assembly.Treat as structural/safety-critical. Do not apply uncontrolled heat or structural straightening assumptions. Follow OEM repair/replace rules.
10
Bake-hardenable (BH) steelSteel designed so that after the panel is pressed into shape, the heat from the factory paint-baking process makes it stronger. That lets manufacturers keep good forming ability while improving dent resistance.Bake-hardenable sheet is supplied with good formability. After forming, controlled strain plus the paint-bake thermal cycle causes interstitial carbon/nitrogen to lock dislocations, increasing yield strength in the finished panel.The panel is stamped while relatively formable. During the later paint curing/bake process, a controlled metallurgical ageing effect raises its yield strength.Outer body panels such as doors, bonnets, roofs and other closures where surface quality and dent resistance are important.May resist initial movement more than basic mild steel and can show springback. It is still repairable in suitable situations, but panel shape, thickness and access remain critical.Do not confuse factory bake hardening with a technician simply heating a panel. The strengthening is a controlled material/process combination at manufacture.
11
Hot-stamped / press-hardened steel (PHS)A steel part that is formed while very hot and then rapidly cooled in the mould, producing an exceptionally strong safety component.PHS commonly uses boron-alloyed steel. Heating creates an austenitic structure; forming and rapid die quenching transform it largely to martensite, creating very high strength with relatively thin sections.Blank is heated, transferred to a water-cooled press tool, formed and quenched under pressure. Some parts use tailored properties or partial hardening to create different strength zones in one component.Safety cage, pillars, rails, reinforcements and intrusion protection.Normally an access/structural consideration rather than a cosmetic outer-skin material. It can make areas behind dents exceptionally rigid or inaccessible.Structural repair restrictions are significant. Do not heat or straighten without model-specific OEM permission. Replacement may be mandated after certain deformation.
12
Galvanised / zinc-coated steelSteel protected with a thin zinc coating to slow corrosion. The steel underneath determines how the panel behaves; the zinc is mainly there for rust protection.Zinc or zinc-alloy coatings provide sacrificial corrosion protection. The substrate may be conventional, HSS or AHSS, so 'galvanised' describes the coating system rather than the strength grade.Steel strip can be hot-dip galvanised or electrogalvanised before forming. Automotive coating stacks then add pretreatment, e-coat, primer, basecoat and clearcoat.Very common throughout modern vehicle bodies.PDR response follows the underlying steel grade and panel geometry. Cosmetic PDR preserves the original corrosion-protection system when paint remains intact.If coatings are damaged during access, drilling or aggressive abrasion, corrosion protection may need reinstatement according to repair procedures.
13
Magnesium alloyAn exceptionally light metal used selectively where manufacturers want to save weight. It is less common than aluminium and requires specialist handling.Automotive magnesium alloys are usually cast rather than used as large conventional exterior sheet skins. They offer very low density but have different corrosion, joining and thermal characteristics from steel or aluminium.Commonly die-cast into complex shapes using controlled alloy composition and protective coatings. Some wrought applications exist but are less common in mainstream body skins.Selected inner structures, carriers, seat/frame components and specialist lightweight applications.Not a routine PDR outer-skin assumption. If encountered, identify the exact component and OEM guidance before treating it like aluminium.Material identification is essential. Avoid cross-contamination and inappropriate heating/abrasion. Follow OEM-specific procedures.
14
Composite / CFRPInstead of metal, the panel is made from fibres held in a resin. It can be very light and stiff, but it does not behave like metal and normally cannot be 'pushed back' in the same way.Carbon-fibre reinforced polymer (CFRP) uses high-strength carbon fibres embedded in a polymer matrix. Loads are carried primarily along fibre directions; laminate orientation and resin system determine stiffness, strength and failure behaviour.Layers of fibre fabric or pre-impregnated material are laid in selected orientations, moulded and cured using heat/pressure, resin transfer moulding or related processes. Some panels use sandwich or hybrid constructions.Performance cars, roofs, bonnets, structural tubs and selected premium/lightweight components.Conventional metal PDR principles generally do not apply. A visible deformation may involve matrix cracking, delamination or fibre damage even when the surface looks recoverable.Do not treat as metal. Inspect for cracking/delamination and follow composite repair or replacement procedures.
15
Thermoplastic / plastic exterior panelA moulded plastic body panel. It can flex and sometimes recover with controlled warming, but it behaves completely differently from steel or aluminium.Automotive thermoplastics may include polypropylene blends, TPO, ABS, polycarbonate blends and other engineered polymers. Their stiffness and recovery vary strongly with polymer, fillers, temperature and component design.Material is heated until flowable and injection-moulded, thermoformed or otherwise moulded into shape, then cooled. Pigmented-through or painted finishes may be used.Bumpers, trims and, on some vehicles, wings/outer panels or closure components.Traditional rod-and-leverage PDR is often unsuitable. Heat-assisted reshaping may be possible for certain flexible parts, but painted plastic can distort, stress-whiten or damage coatings.Identify polymer/component first. Temperature control is critical. Inspect mounting points, tears and paint damage; replacement or plastic repair may be more appropriate.
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100