When you are in trouble


1. At first

Damage to rolling bearings is not appropriate for the selection, environment, installation and maintenance, and there is a damage mode that loses function as a bearing.
When determining the cause of the damage to the bearing from the phenomenon at the time of this damage, it is very difficult to estimate the true cause often when the factor is various.
However, it is also possible to determine the cause by thoroughly understanding the terms of use and investigating the damage phenomenon.
Here, we post the damage case of the bearing, and we will show the main causes and measures, so we would like you to help us investigate the cause of the damage.

Reference standard JIS B 1652:2009 rolling bearings-damage and failure-terms, characteristics and causes

2. Classification of rolling bearing damage modes

Fig.1 shows the damage of rolling bearings divided into seven damage modes by cause.
On page 3, we show damage cases and their causes and countermeasures by damage mode. In addition, we will post the matrix of damage in Table 1.

Fig. 1 Classification of damage modes

3. Damage mode

3.1 Fatigue (flaking) (microcracks; spauling or pitching)

Fatigue is a change in material tissue caused by repeated stress esseon in the contact between the rolling body and the trajectory. Fatigue appears as a minute flaking from the surface (spauling or pitching).

PhenomenonWhen the bearing rotates under load, the phenomenon of the rolling surface of the inner ring and outer ring trajectory surface or ball peels off in a scale by rolling tiredness
Cause
  • Excessive load, pre-pressure overload
  • Poor mounting (misalignment)
  • Moisture infiltration
  • Foreign matter mixed
  • Poor lubrication
Measures
  • Load reduction, bearing reselection
  • Securing free side bearings
  • Optimization of space and assembly
  • Improving sealing equipment
  • Lubricant reselection
  • Review of refueling intervals
Photo 1-1 - 3.1
Photo 1-1
Phenomenon
Occurred on the circumference at the end of the orbital plane
Cause
Excessive load, pre-pressure overload, poor mounting (misalignment)
Photo 1-2 - 3.1
Photo 1-2
Phenomenon
Occurs at ball pitch spacing at the end of the track surface
Cause
Pressure due to impact load or poor installation (misalignment) during assembly
Photo 1-3 - 3.1
Photo 1-3
Phenomenon
Occurs at ball pitch spacing in the center of the track surface
Cause
Rust due to internal condensation or moisture infiltration
Photo 1-4 - 3.1
Photo 1-4
Phenomenon
Microcracks (spauling or pitching) occur in the ball running marks in the center of the track surface
Cause
Early material rolling tired

3.2 Wear

The wear, two slip contact surface or, the interaction of irregularities of the surface of the rolling / slip contact surface, the phenomenon of the material is gradually removed.


3.2.1 Abresive Wear

PhenomenonWear phenomenon in which the surface gradually dulls and eventually accelerates as the material is worn from the rolling surface and retainer
Cause
  • Foreign matter mixed
  • Poor lubrication
Measures
  • Improving sealing equipment
  • Lubricant reselection
  • Review of refueling intervals
Photo2-1 - 3.2.1
Photo2-1
Phenomenon
The entire orbital surface is dull and wear-worn
Cause
Dust that has penetrated into the inside of the bearing
Photo2-2 - 3.2.1
Photo2-2

Photo2-1 Ball

Phenomenon
The entire surface of the ball is dull and worn
Photo2-3 - 3.2.1
Photo2-3
Phenomenon
Dullness occurs on the circumference at the end of the orbital surface
Cause
Poor lubrication due to poor installation (misalignment)
Photo2-4 - 3.2.1
Photo2-4
Phenomenon
Dull and wear-generated throughout the orbital surface
Cause
Sludge penetrated inside

3.2.2 Pseudo Brinell pressure (vibration corrosion)

PhenomenonA phenomenon in which corrosion and wear occur while forming a depression in the contact area between the ball and the orbital surface due to periodic vibrations
Cause
  • Small swing movement
  • Poor lubrication
Measures
  • Lubricant reselection
  • Review of refueling intervals
  • Review of swing width

Remarks Pseudo brinell indentation may be classified as corrosion.

Photo 3-1 - 3.2.2
Photo 3-1
Phenomenon
Local dent (wear) occurs at ball pitch spacing
Cause
Poor lubrication due to small-width swinging motion
Photo 3-2 - 3.2.2
Photo 3-2
Phenomenon
The ball running marks on the track surface are worn in a scale
Cause
Poor lubrication due to periodic vibration slower speed
Photo 3-3 - 3.2.2
Photo 3-3
Phenomenon
The ball running marks on the track surface meander, causing wear in a scale
Cause
Poor lubrication due to periodic vibration slower speed
Photo 3-4 - 3.2.2
Photo 3-4
Phenomenon
The ball running marks on the track surface are brown and discolored, causing wear in a scale
Cause
Poor lubrication due to periodic vibration in high-speed operation

3.3 Corrosion

Corrosion is a phenomenon in which a metal material reacts with a chemical reaction with a material in the surrounding environment (such as adjacent metals and gases), melts, or produces corrosion products (rust).


3.3.1 Moisture corrosion

PhenomenonThe phenomenon of surface oxidation by the moisture in the lubricant or in the air reacts with the bearing part
Cause
  • Poor storage condition
  • Long-term stop in high temperature and humid environment
  • Moisture (solvent) infiltration
  • Lubricant inadequacy
Measures
  • Improving sealing equipment
  • Improving storage methods and the environment
  • Review of refueling intervals
  • Lubricant reselection
Photo 4-1 - 3.3.1
Photo 4-1
Phenomenon
Surface oxidation (rust) occurs on bearing outer diameter
Cause
Inadequacy of condensation and storage condition in packaging containers
Photo 4-2 - 3.3.1
Photo 4-2
Phenomenon
Rust occurs at ball pitch spacing on the track surface
Cause
Insufficient condensation and storage condition inside bearings
Photo 4-3 - 3.3.1
Photo 4-3
Phenomenon
Rust occurs at ball pitch intervals during dulling of the track surface and stop driving
Cause
Moisture enters the inside of the bearing and lubrication is poor.
Photo 4-4 - 3.3.1
Photo 4-4
Phenomenon
Abnormal wear occurs while the orbital surface maintains gloss, causing local corrosion (rust) at the end of the track
Cause
Moisture (solvent) enters the inside of the bearing and poor lubrication

3.3.2 Frictional corrosion (fretting collider) (fretting rust)

Phenomenona phenomenon in which the two surfaces in contact (the overlapping surface) repeat relative to each other, resulting in a small slip and wear
Cause
  • Lack of tightening
  • Excessive load
  • Excessive vibration
  • Motion of small width swinging
Measures
  • A review of The Shimora
  • Review of the conclusion method
  • Lubricant reselection
  • Review of refueling intervals
  • Reduced load/vibration
Photo5-1 - 3.3.2
Photo5-1
Phenomenon
Bearing outer diameter surface is oxidized (rusted) to cause wear
Cause
Action of excessive load and excessive vibration
Photo 5-2 - 3.3.2
Photo 5-2
Phenomenon
Oxidation (rust) occurs on the circumference of the bearing inner diameter surface
Cause
The effect of insufficient, excessive load, and excessive vibration
Photo 5-3 - 3.3.2
Photo 5-3
Phenomenon
The fit surface of the adapter exterior is oxidized (rusted) causing wear
Cause
Effect of insufficient tightening, excessive load, and excessive vibration
Photo 5-4 - 3.3.2
Photo 5-4
Phenomenon
The end of the stop screw is oxidized (rusted) causing wear
Cause
Lack of fastening of stop screws, action of excessive vibration

3.3.3 Stress corrosion cracking

PhenomenonA material such as stainless steel is a phenomenon in which the interaction between tensile stress and corrosion environment causes cracks in the material and the cracks develop over time.
Cause
  • Action of water (chlorine), salt water, etc.
  • Excessive fit
  • Effect of tensile stress (stop screw tightening stress)
Measures
  • Improving sealing equipment
  • Management of tightening torque of stop screws
Photo 6-1 - 3.3.3
Photo 6-1
Phenomenon
Cracks between the both screws on the stainless steel bearing
Cause
Action of chlorine-based cleaning agents and tightening of stop screws with excessive force
Photo 6-2 - 3.3.3
Photo 6-2

Photo 6-1 inner ring macro fracture surface

Phenomenon
Cracks gradually progress from the inner inner diameter of the stop screw side
Photo 6-3 - 3.3.3
Photo 6-3

Photo 6-1 inner ring micro-breaking surface

Phenomenon
Fracture surface with metal grain boundaries precipitated (grain boundary cracking)
Photo 6-4 - 3.3.3
Photo 6-4

Photo 6-1 inner ring microstructure

Phenomenon
The inner diameter surface is corroded locally, and cracks develop along the grain boundary.

3.4 Electric corrosion (electric fruiting)

The electrical eclipse is the lack of material from the contact surface caused by the current flowing.

PhenomenonBy the current flows through the lubricating oil film to the bearing, a phenomenon in which the contact area is melted with each other spark occurs at equal intervals on the contact surface of the ball and the track surface.
Cause
  • Lack of insulation
  • Potential difference between outer ring and inner ring
Measures
  • Mounting of ground
  • Change to ceraball bearing and insulate bearings
  • Lubricant reselection
  • Improvement of electrical circuits that do not flow current to bearings
Photo7-1 - 3.4
Photo7-1
Phenomenon
Burning of electrical fluting (sling pattern) at equal intervals on the outer ring track surface occurs
Cause
Insufficient insulation causes sparks in the contact area between the ball and the orbital surface.
Photo7-2 - 3.4
Photo7-2

Photo 7-1 Enlargement

Phenomenon
The material is missing (hollowed out) on the contact surface of the ball, and the hollow area is blackened.
Photo7-3 - 3.4
Photo7-3
Phenomenon
A thin burn of the electric fruiting pattern progresses to the outer ring track surface.
Cause
Spark in the contact area of the ball and the orbital surface with relatively weak current leakage strength
Photo7-4 - 3.4
Photo7-4

Photo 7-3 Inner ring

Phenomenon
A thin burn of the electric fruiting pattern progresses to the inner ring track surface, and it is blackened and discolored.

3.5 Plastic deformation

The plastic deformation, deformed by adding force to the object, permanent deformation that remains after removing the external force.
Permanent deformation occurs when the yield point of the material is exceeded, and there are two typical things

  • Macroscopic : A wide range of yields in the contact area due to the contact load between the rolling body and the trajectory
  • Microscopic : yield that occurs only in a narrow area of contact marks due to the biting (rolling) of foreign matter between the rolling body and the trajectory

3.5.1 Plastic deformation due to excessive load (brinel pressure)

PhenomenonA phenomenon in which a shallow depression or groove of the ball pitch interval occurs in the track surface due to static or shocking overload load on a stationary bearing.
Cause
  • Poor built-in
  • Pre-pressure overload
  • Excessive load
  • Impact load
Measures
  • Improved built-in methods
  • Review of load conditions
Photo 8-1 - 3.5.1
Photo 8-1
Phenomenon
Pressure (dent) by the ball occurs at ball pitch spacing at the end of the inner ring track surface
Cause
Poor built-in or over-pressure
Photo 8-2 - 3.5.1
Photo 8-2

Photo 8-1 Outer ring

Phenomenon
Pressure (dent) by the ball occurs at ball pitch spacing at the end of the outer ring track surface
Photo 8-3 - 3.5.1
Photo 8-3
Phenomenon
A pressure (dent) by the ball occurs in the center of the inner ring track surface.
Cause
Excessive or impact loads
Photo 8-4 - 3.5.1
Photo 8-4

Photo 8-3 Outer ring

Phenomenon
A pressure (dent) by the ball occurs in the center of the outer ring track surface.

3.5.2 Pressure due to foreign matter

Phenomenona phenomenon in which foreign matter is rolled between the track surface and the ball causes a small depression
Cause
  • Foreign matter intrusion of metal powder, dust, etc.
  • Biting of wear powder
Measures
  • Improving sealing equipment
  • Review of refueling intervals
Photo 9-1 - 3.5.2
Photo 9-1
Phenomenon
Countless irregularities occur in the ball running marks on the track surface
Cause
Invasion of dust and foreign matter
Photo 9-2 - 3.5.2
Photo 9-2

Photo 9-1 Enlargement

Phenomenon
Dust and foreign matter bite and dent occur on the orbital surface
Photo 9-3 - 3.5.2
Photo 9-3

Photo 9-1 Ball

Phenomenon
The entire surface of the ball is dented by the biting of foreign matter.
Photo 9-4 - 3.5.2
Photo 9-4
Phenomenon
Countless small dents occur in the ball running marks at the end of the track surface
Cause
Internal wear powder bites due to increased rolling friction inside the bearing

3.6 Destruction and cracks

Cracks occur when the maximum tensile strength of the material is exceeded and propagated. Destruction is a complete separation of parts of a component that are propagated by cracks.


3.6.1 Forced destruction

PhenomenonA phenomenon in which destruction occurs due to local stress concentration exceeding the tensile strength of the material due to excessive stress due to impact or excessive tightening.
Cause
  • Over-tightening
  • Impact load
  • Excessive load
Measures
  • Review of tightening conditions
  • Improving load conditions
Photo 10-1 - 3.6.1
Photo 10-1
Phenomenon
Cracks in the axial direction from the inner ring screw hole
Cause
Tightening by excessive torque of the stop screw
Photo 10-2 - 3.6.1
Photo 10-2

Photo 10-1 Inner ring breaking surface

Phenomenon
The propagation pattern of the fracture surface progresses in the axial direction from the first thread of the screw hole.
Photo 10-3 - 3.6.1
Photo 10-3
Phenomenon
Cracks occur in a mortar shape from the inner ring screw hole, and the propagation pattern of the fracture surface develops radially from the screw hole to the outer diameter side.
Cause
Tightening by excessive torque of the stop screw
Photo 10-4 - 3.6.1
Photo 10-4
Phenomenon
Cracks in the axial direction from the inner diameter of the bearing inner ring with the adapter
Cause
Tightening with excessive torque of the adapter

3.6.2 Fatigue failure

PhenomenonBending generated in the track ring, ball and retainer, a phenomenon that cracks due to fatigue occurs when repeatedly exceeding the fatigue limit stress under tensile or torsionous conditions.
Cause
  • The Progress of Flaking
  • Excessive axial load
  • Poor lubrication
Measures
  • Improving load conditions
  • Lubricant reselection
  • Review of refueling intervals
Photo 11-1 - 3.6.2
Photo 11-1
Phenomenon
Flaking occurs on the outer ring track surface, destroying from the bottom of the track on the circumference
Cause
Development of flaking on the outer ring orbital surface
Photo 11-2 - 3.6.2
Photo 11-2
Phenomenon
Flaking occurs on the surface of the ball and destroys the hemisphere
Cause
Development of flaking on the surface of the ball
Photo 11-3 - 3.6.2
Photo 11-3
Phenomenon
Flaking occurs on the inner ring track surface of the adapterbearing and is destroyed in the axial direction.
Cause
Development of flaking on the inner ring orbital surface
Photo 11-4 - 3.6.2
Photo 11-4

Photo 11-3Inner ring breaking surface

Phenomenon
Cracks develop radially in the interior starting from the flaking portion of the inner ring orbit bottom

3.7 Seizure

PhenomenonA phenomenon in which bearings generate heat during operation, resulting in discoloration, softening, welding of the track ring, ball and retainer leading to damage.
Cause
  • Poor lubrication
  • Excessive load (pre-pressure overload)
  • Excessive rotational speed
  • Under-small internal space
  • Invasion of moisture and foreign matter
Measures
  • Lubricant reselection
  • Review of refueling intervals
  • Review of load conditions
  • Bearing reselection
  • Review of internal space
  • Improving sealing equipment
Photo12-1 - 3.7
Photo12-1
Phenomenon
Ball running marks at the end of the inner ring track surface are brown and discolored, causing flaking
Cause
Increased rolling friction due to pre-pressure overload
Photo12-2 - 3.7
Photo12-2
Phenomenon
Black charred grease adheres to the outer ring track surface
Cause
Poor lubrication due to heat
Photo12-3 - 3.7
Photo12-3
Phenomenon
The inner ring track surface is discolored to purple, causing significant roughness and wear
Cause
Poor lubrication due to dust intrusion into the inside of the bearing
Photo12-4 - 3.7
Photo12-4

Photo 12-3 Ball

Phenomenon
The ball surface is discolored to purple, and the surface is

表1 Matrix of Damage

table 1 Matrix of Damage

Enlarging Matrix of DamageMatrix of Damage PDF