Infiniti M35/M45 Y50. Manual - part 309

BODY REPAIR

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Precautions in Repairing High Strength Steel

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High strength steel is used for body panels in order to reduce vehicle weight.
Accordingly, precautions in repairing automotive bodies made of high strength steel are described below:

HIGH STRENGTH STEEL (HSS) USED IN NISSAN VEHICLES

SP130 is the most commonly used HSS.
SP150 HSS is used only on parts that require much more strength.

Tensile strength

Nissan/Infiniti designation

Major applicable parts

373 N/mm

2

(38kg/mm

2

 ,54klb/sq in)

SP130

●

Front & rear side member assembly 

●

Front side member closing plate assembly

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Front strut housing

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Lower dash

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Rear seat crossmember

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Other reinforcements

785-1350 N/mm

2

(80-138kg/mm

2

 , 114-196klb/sq in)

SP150

●

Center pillar reinforcement 
(Component part)

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Outer roof side rail reinforcement 
(Component part)

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Read the Following Precautions When Repairing HSS:

1.

Additional points to consider

●

The repair of reinforcements (such as side members) by heat-
ing is not recommended since it may weaken the component.
When heating is unavoidable, do not heat HSS parts above
550

°

C (1,022

°

F).

Verify heating temperature with a thermometer.
(Crayon-type and other similar type thermometer are appro-
priate.)

●

When straightening body panels, use caution in pulling any
HSS panel. Because HSS is very strong, pulling may cause
deformation in adjacent portions of the body. In this case,
increase the number of measuring points, and carefully pull
the HSS panel.

●

When cutting HSS panels, avoid gas (torch) cutting if possi-
ble. Instead, use a saw to avoid weakening surrounding areas
due to heat. If gas (torch) cutting is unavoidable, allow a mini-
mum margin of 50 mm (1.97in).

●

When welding HSS panels, use spot welding whenever possi-
ble in order to minimize weakening surrounding areas due to
heat.
If spot welding is impossible, use M.I.G. welding. Do not use
gas (torch) welding because it is inferior in welding strength.

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The spot weld on HSS panels is harder than that of an ordi-
nary steel panel.
Therefore, when cutting spot welds on a HSS panel, use a
low speed high torque drill (1,000 to 1,200 rpm) to increase
drill bit durability and facilitate the operation.

2.

Precautions in spot welding HSS
This work should be performed under standard working condi-
tions. Always note the following when spot welding HSS:

●

The electrode tip diameter must be sized properly according
to the metal thickness.

●

The panel surfaces must fit flush to each other, leaving no
gaps.

●

Follow the specifications for the proper welding pitch.

Unit: mm

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Thickness (t)

Minimum pitch (l)

0.6 (0.024)
0.8 (0.031)
1.0 (0.039)
1.2 (0.047)
1.6 (0.063)
1.8 (0.071)

10 (0.39) or over
12 (0.47) or over
18 (0.71) or over
20 (0.79) or over
27 (1.06) or over
31 (1.22) or over

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