Nissan Sentra Service Manual: Precautions in repairing high strength steel
High strength steel (HSS)
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:
| Tensile strength | Nissan/Infiniti designation | Major applicable parts |
| 373 N/mm2 (38kg/mm2,54klb/sq in) | SP130 |
|
SP130 is the most commonly used HSS.
Read the following precautions when repairing HSS:
- Additional points to consider
- The repair of reinforcements (such as side members) by heating
is not recommended since it may weaken the component.
When heating is unavoidable, do not heat HSS parts above 550В°C (1,022В°F).
Verify heating temperature with a thermometer.
(Crayon-type and other similar type thermometer are appropriate.)
- 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 possible.
Instead, use a saw to avoid weakening surrounding areas due to heat. If gas (torch) cutting is unavoidable, allow a minimum margin of 50 mm (1.97in).
- When welding HSS panels, use spot welding whenever possible
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.
- The spot weld on HSS panels is harder than that of an ordinary
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.
- Precautions in spot welding HSS
This work should be performed under standard working conditions.
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.
Handling of ultra high strength steel plate parts
PROHIBITION OF CUT AND CONNECTION
Do not cut and join the lower lock pillar reinforcement (center pillar reinforcement inside frame parts) because its material is high strength steel plate (ultra high strength steel plate).
The center pillar reinforcement must be replaced if this part is damaged.
Precaution for supplemental restraint system (SRS) "air bag" and "seat
belt pre-tensioner"
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”,
used along
with a front seat belt, helps to reduce the risk or severity of injury to the
dri ...
Preparation
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Other materials:
Symptom diagnosis
Audio system
Symptom table
Related to audio
Related to hands-free phone
Before performing diagnosis, confirm that the cellular phone being used
by the customer is compatible with
the vehicle.
It is possible that a malfunction is occurring due to a version change
of the phone ...
Parking/parking on hills
WARNING
Do not stop or park the vehicle over
flammable materials such as dry grass,
waste paper or rags. They may ignite
and cause a fire.
Safe parking procedures require that
both the parking brake be set and the
transmission placed into P (Park) for
CVT m ...
Engine compartment check locations
MRA8DE engine
Engine oil filler cap
Brake and clutch (if so equipped) fluid
reservoir
Air cleaner
Battery
Fuse/fusible link box
Engine coolant reservoir
Radiator cap
Engine oil dipstick
Drive belt location
Windshield-washer fluid reservoir
...
