Part 7: Roadmap for mechanism diagnostics and on-site assessment implementation

If the previous 6 articles respectively progressed from identifying wear types, the effects of temperature, material sticking and flow blockage, to wear-location mapping and the chain of operational consequences, this section addresses the corrective roadmap based on the actual condition of each location.

The general sequence consists of three steps: identify the mechanism → measure the actual conditions → select the material group. Correctly identifying the mechanism indicates what needs to be checked; field measurements indicate the severity of the action; only then is there sufficient basis to evaluate material options.

1. The next step depends on the condition of the location

Not every case needs to begin with a full survey. The first step is to determine where the plant currently stands in the diagnostic process.

1.1. When there is a clearly damaged location

If the equipment currently has a deteriorating location, the starting point is to observe directly at the damaged area, not the name of the existing material or the material being considered as a replacement.

The sequence can be carried out as follows:

Step	Activity to be performed	Article to review
1	Identify the area deteriorating most rapidly	Part 1: 4 types of wear and their identifying signs on the surface
2	Interpret the shape and orientation of the damage marks and compare them with the material-flow direction	Part 1: 4 types of wear and their identifying signs on the surface
3	Record operating temperature, peak temperature, and temperature-fluctuation conditions	Part 2: Effects of temperature on the operating limits of materials
4	Distinguish whether the damage lies in the surface, material build-up layer, or fastening location	Part 1 and Part 3: Material sticking and flow blockage: formation mechanisms and identifying signs

The final step is particularly important. If the actual cause lies in the fastening point or material-flow geometry, replacing the lining with a new one may still result in repeated failure even if the material itself is suitable for the wear conditions.

1.2. When the material has already been replaced but the location continues to fail repeatedly

A lack of service-life improvement after replacing the lining is not sufficient to conclude that the new material is still “not good enough.”

Before changing to another option, two possibilities need to be rechecked:

Possibility to be checked	Indication	Further reading direction
Incorrect identification of the wear mechanism	The actual damage patterns do not match the assumed mechanism	Part 1: 4 types of wear and their identifying signs on the surface
The cause is not wear-related	Material builds up on the surface, the flow becomes blocked, or damage is concentrated at the fastening location	Part 3: Material sticking and flow blockage: formation mechanisms and identifying signs or recheck the fastening point

If material is building up on the wall, the problem shifts to material flow and sticking.

If cracking or detachment is concentrated around welds, bolts, or fastening locations, the fastening conditions, temperature, and vibration need to be checked before concluding that the cause lies in the lining.

1.3. When the economic impact of a location needs to be evaluated

If the objective is not only technical identification but also determining the level of impact on operations, at least four data points need to be collected:

Frequency of intervention at the location
Number of downtime hours for each intervention
Whether the damage stops only one item of equipment or affects the entire line
Production value relative to the operating time of the line

The third data point can significantly change the level of priority. A location that causes only a local shutdown and a location that forces the entire line to stop are two different problems even if they require the same repair duration.

The method for tracking the full chain of impacts is presented in Part 6: Technical and operational consequence chain from a wear point.

2. The starting point may differ by department

Not every role in the plant needs to read all seven parts in the same order. The starting point should follow the question that each department needs to resolve.

Reader	Recommended priority sequence
Chief engineer, engineering	Part 1 → Part 2 → Part 5
Maintenance, operations	Part 5 → Part 6; if material sticking and flow blockage occur, proceed to Part 3 and Part 4
Procurement, materials	Part 1 → Part 6 to understand the mechanism before comparing cost of use
Plant management	Part 6 → Part 5 to determine the level of impact and the locations requiring priority
Readers new to the topic	Read sequentially from Part 1 to Part 7

Personnel working directly at the plant can begin with the specific problem they are facing and return to the foundational sections when cross-checking is required.

3. Three actions can be taken before organizing a dedicated survey

Some initial data can be collected using the tools and information already available at the plant. The objective is to narrow down the scope of the problem before deciding on the required level of survey.

3.1. Record damage patterns at the actual damaged location

Begin with the area deteriorating most rapidly and record:

shape of the damage marks
orientation of the marks
material-flow direction
extent of the damage
photographs with a reference scale where conditions permit

The method for interpreting and distinguishing damage patterns is presented in Part 1: 4 types of wear and their identifying signs on the surface.

If the surface has already been ground or weld-repaired, this condition needs to be clearly recorded because part of the original damage pattern may have been lost.

3.2. Record both operating temperature and peak temperature

A temperature measurement under steady-state conditions does not represent the full operating conditions.

At a minimum, the following need to be determined:

Data	How to obtain it
Operating temperature	Measure at the location under steady-state operating conditions
Peak temperature	Combine measurements taken at appropriate times with operating data
Temperature fluctuations	Record the range, duration of change, and number of cycles when there is a risk of thermal shock

The detailed evaluation method is presented in Part 2: Effects of temperature on the operating limits of materials.

3.3. Follow the material flow to narrow down the locations requiring inspection

Instead of starting from an equipment list, the material flow can be followed from inlet to outlet and the following can be marked:

locations where the flow changes direction
locations where the cross-section or velocity changes
locations where the flow transitions from falling to sliding
locations where the material condition changes
locations where multiple adverse conditions occur simultaneously

The method for developing the map and identifying priority locations is presented in Part 5: Wear-location map by industry and equipment.

The required result is a list of locations that need to be monitored on the specific production line being considered, not a general list applied to the entire industry.

4. Conduct a more detailed technical survey when the available data are insufficient for a conclusion

A technical survey should generate data that can continue to be used, rather than ending only with a material recommendation.

The outputs to be targeted include:

Survey activity	Result to be retained
Observe damage patterns and record their orientation and extent	Condition record of the location
Measure the influencing factors at the location	Operating-condition data set
Mark fixed measurement points	Basis for monitoring changes across inspections
Distinguish wear, material sticking, flow blockage, and fastening-related damage	Appropriate evaluation direction
Clearly record insufficient data	Scope and level of certainty of the conclusion

Four situations in which a more detailed survey should be considered include:

the surface has been patched or ground, so the original damage patterns are no longer complete
multiple mechanisms are suspected to be acting simultaneously
the lining has already been replaced two or more times but the condition continues to recur
a baseline needs to be established before a major change in material or solution

A survey result that contains only a material recommendation but does not retain the measurement locations, operating conditions, and initial data will be very difficult to use for evaluating effectiveness later.

5. Some cases do not yet require a dedicated survey

Not every location immediately requires an in-depth survey.

Situation	Initial course of action
Damage patterns are clear and the mechanism can be initially narrowed down	Refer to Part 1: 4 types of wear and their identifying signs on the surface
The location still meets the required operating cycle and does not cause unplanned shutdowns	Continue monitoring and build baseline data
Only the thermal conditions of the material group need to be checked	Refer to Part 2: Effects of temperature on the operating limits of materials
The problem clearly points toward angle, cross-section, or flow geometry	Proceed to material-flow design evaluation

Particularly for material-flow problems, if the cause lies in the wall angle or cross-section, changing the material may only change the timing of blockage occurrence without addressing the primary cause.

Identifying cases that do not yet require deeper intervention helps the plant focus resources on locations that are directly affecting operations.

6. From mechanism identification to material-group selection

After the mechanism has been identified, two steps still remain before reaching a material option: measure the severity of the action and compare the operating conditions with the capabilities of each material group.

Stage	Knowledge group	Objective
Mechanism identification	Material wear mechanisms	Identify the wear type and the factors that need to be checked
Measurement of actual conditions	Field Survey, Measurement and Diagnostics	Convert observations into quantitative data at the location
Solution selection	Principles of Material Selection	Compare actual data with material groups

Surface damage patterns may indicate which mechanism is suspected, but they do not show the wear rate, peak temperature, particle size, impact load, or the level of the current material-flow condition.

These data need to be measured before material options are compared.

7. Notes when applying this knowledge

First, the roadmap in this article helps determine the sequence of work; it does not replace data from each location. The same type of damage pattern under different operating conditions may still result in different levels of damage.

Second, the reading sequence by role is only a guide. One person may simultaneously be responsible for engineering, maintenance, or operations and may need to use multiple content groups.

Third, the cases that do not yet require a dedicated survey are not an absolute list. The final decision still depends on the impact of the location on operations and the completeness of the currently available data.

The appropriate roadmap begins with the mechanism, continues with measurements, and only moves to material-group selection when the operating conditions are sufficiently clear. Maintaining this sequence helps avoid repeated material changes while the actual cause has not yet been identified, while also creating data that can be used to verify the effectiveness of the solution after implementation.