Part 6: Handling, Storage and Preservation

Cutting, forming and joining are often considered the operations that act directly on a material. However, before and after these stages, the way a material is lifted, supported, stored and returned to storage after fabrication can also create deformation, corrosion or increase the risk of delayed cracking.

A steel plate that has never been welded or bent can still deflect if it is supported incorrectly. With very high-hardness grades, stress resulting from plate stacking can also interact with moisture and the material condition to increase the risk of delayed cracking.

For this reason, the warehouse is more than a place for storing materials. Handling, storage and preservation should be treated as part of the complete fabrication process.

1. Technical terms used in this article

The following terms appear throughout material handling, storage and warehouse inspection.

Technical term	Meaning
Three-point bending	A plate is supported at two points while load acts in the central region
Permanent deformation	Deformation that does not return to the original condition after the load is removed
Delayed cracking	Cracking that appears after a period of time, potentially while the plate is still in storage
Unoiled cold-rolled plate	Plate with a higher corrosion risk within the scope of the documentation being used
Shop primer	Temporary protective layer on the plate surface that needs to be identified before welding

Among these, three-point bending and delayed cracking require particular attention when storing high-hardness steel.

A storage-related deviation may not cause immediate damage. The problem may only appear after several hours, several days or after the material has already moved to another operation.

2. Three-point bending should be avoided during lifting and plate support

When a plate is supported at two locations while load acts around the middle, the plate is subjected to three-point bending.

A similar condition can occur when:

a long plate is lifted from a single point
the spacing between support points is too large
timber spacers between plate layers are not vertically aligned

This condition is unfavorable because the load creates a large bending moment in the middle of the span where there is no direct support.

If deflection exceeds the elastic capability of the plate, permanent deformation may occur and the plate may not return to its original shape after the load is removed.

Therefore, when storing flat plate, the objective is not only to prevent the plate from falling or shifting. Unnecessary bending loads also need to be minimized.

3. For very high-hardness grades, improper storage may also be associated with delayed-cracking risk

The model involving hydrogen, a hard microstructure and stress is discussed in Part 2: Welding high-hardness steel.

Under storage conditions, similar factors may arise from different sources:

Factor requiring attention	Possible source during storage
Hydrogen	Ambient humidity, rainwater, corrosion
Hard microstructure	Inherent characteristics of the steel grade
Stress	Lifting, supporting and stacking methods

The difference lies in the source of the stress.

During welding, stress may result from weld shrinkage. In storage, stress may result from plate deflection or unsuitable loading maintained over an extended period.

A plate can therefore develop cracking while still in storage even if it has not yet undergone another fabrication operation.

This is also why delayed failures are difficult to trace if receiving records and storage-history information are unavailable.

4. Plate lifting should minimize deflection while suspended

During lifting, the condition of the plate should be observed directly.

Acceptable: when viewed from the side, the plate remains nearly flat while suspended
Requires corrective action: the plate is visibly bent; review the number of lifting points or use an appropriate lifting beam

Single-point lifting of a long plate can subject it to bending during movement.

The number and location of lifting points should therefore be appropriate for the actual plate geometry. Lifting arrangements should not be determined only by weight while ignoring plate length and suspended deflection.

5. Timber spacers between plate layers need to be vertically aligned

The number of support points should increase with plate length. Longer plates require sufficient support points to limit deflection between supports.

Control item	Requirement
Number of support points	Increase according to plate length
Timber spacer position	Spacers between layers are vertically aligned
Acceptable sign	Side view shows a flat plate without obvious deflection between support points
Sign requiring corrective action	Plate deflects between support points; supports need to be added or repositioned

Vertical alignment of timber spacers between layers is particularly important.

If a spacer in the upper layer is offset from the spacer below, the load can be transferred into an area without direct support. The stack itself can then create a bending condition in the plates underneath.

6. Materials need to reach a stable temperature before fabrication and inspection

According to the documentation being used, plates should be brought to room temperature before fabrication and measurement.

Measurements such as:

thickness
flatness

should also be performed after the material temperature has stabilized.

This helps avoid assessing the plate in a thermal condition different from that used as the basis for fabrication or inspection.

Material that has just been moved from a substantially different temperature environment should therefore not automatically be sent directly to fabrication or measurement.

7. Protection from rain helps protect both the surface and the material condition

Steel plate stored outdoors without adequate protection may corrode on surfaces that later need to be welded or lined.

If corrosion has affected the surface, surface preparation needs to be repeated to an appropriate condition before the material proceeds to the next operation.

Rain protection therefore serves two purposes:

reduce surface corrosion
reduce moisture associated with delayed-cracking risk in very high-hardness grades

This is why the surface condition needs to be reassessed before a stored plate moves to welding, lining or further fabrication.

8. Two items need to be clarified from the receiving stage

Certain risks should be identified when the material is ordered or received.

Condition requiring attention	Action
Deep corrosion on the surface intended for lining	Record in the receiving inspection report and account for surface treatment before lining
Unoiled cold-rolled plate	Identify at the ordering stage because of the higher corrosion risk

For the oil-treatment condition of cold-rolled plate, the appropriate time to clarify the requirement is during ordering, not after the material has already arrived at the warehouse.

This information allows warehouse and workshop teams to prepare the appropriate storage method from the beginning.

9. Shop primer needs to be identified before welding

If a plate has a protective shop primer, the primer type needs to be identified before the material proceeds to welding.

It should not be assumed that every shop primer can be welded directly under the same conditions.

The receiving report or material records should state the primer type present on the surface.

Edge preparation before welding should then follow the requirements applicable to both the material and the primer being used.

Surface preparation and pre-welding conditions are discussed in greater detail in Part 2: Welding high-hardness steel.

10. Leftover plate needs to be treated before being returned to storage

After fabrication, leftover plate should not be returned directly to the warehouse.

At least two actions should be completed first:

grind sharp cut corners smooth
attach a temporary label carrying the plate identification number

Sharp corners create stress concentration points. For very high-hardness grades, the documentation specifically warns against allowing plates to remain under three-point bending and returning plates to storage while sharp cut corners remain.

Within the documentation being used, this warning applies specifically to the highest-hardness grades, approximately 550 HBW and above.

For softer grades, the level of risk may differ. However, maintaining the same edge-treatment and support principles helps avoid operating multiple storage procedures within the same warehouse.

Maintaining material identification is equally important.

If a leftover plate becomes separated from its original identification number, the material traceability chain is broken at the storage stage.

11. Associated consumables also have their own storage conditions

A warehouse does not contain steel plate alone.

Electrodes, welding wire, adhesive and hard-compound powder each have their own storage requirements. Their quality can change without immediately visible signs.

Consumable	Storage condition stated in the documentation	Risk if conditions are not maintained
Hardfacing electrodes in sealed packages	Maximum 12 months, dry conditions, minimum temperature 15 °C	May absorb moisture and increase the hydrogen source
Two-component ceramic adhesive	According to packaging instructions, avoid excessive heat	Bonding performance may deteriorate without obvious visual indication
Hard-compound mortar powder	Keep dry and in the original packaging	May form lumps and lose the required condition

These conditions should be managed through consumable records rather than relying only on visual inspection of the packaging.

For welding consumables in particular, a welding procedure may be correctly controlled in all other respects but still encounter problems if the consumables have absorbed moisture during storage.

12. Material condition at receipt should be documented

According to the source material, the manufacturer’s guarantee mainly covers the mechanical properties and dimensional tolerances of the plate at dispatch and does not cover damage arising from subsequent unloading, storage or preservation.

Two records are therefore particularly valuable:

receiving inspection report
photographs taken during unloading

If the material already has deformation or damage when received, these records help establish the original condition.

If a problem only appears after a period of storage, receiving and storage records help narrow down the stage during which the deviation may have occurred.

13. Items that can be checked immediately in the warehouse

Several conditions can be checked quickly by sight and touch during a warehouse inspection.

Item to inspect	Inspection method	Sign requiring corrective action
Plate deflection	View from the side at a low angle	Deflection visible between support points
Alignment of timber spacers	Observe from the end of the plate stack	Spacers between layers are offset
Surface corrosion condition	Visual and direct inspection	Scaling corrosion or pitting below the surface
Sharp corners on leftover plate	Hand inspection	Sharp corners remain

These checks help identify deviations arising during storage rather than waiting until the material has already reached the workshop.

Two conditions should be particularly avoided:

plate stacking that creates three-point bending
returning leftover plate to storage with sharp cut corners

These two issues are identified in the overview article and fall directly within the scope of Part 6.

14. Responsibilities during handling and storage

Responsibilities should be clearly defined from purchasing and receiving through to transfer to the workshop or return to the warehouse.

Task	Responsible person or department
Determine lifting method and support-point arrangement	Warehouse team, verified by supervisor
Confirm oil-treatment condition of cold-rolled plate	Procurement, at the ordering stage
Record primer type on the surface	Warehouse team during receiving
Bring material to an appropriate temperature before fabrication and measurement	Workshop
Grind sharp corners and restore identification before returning leftover plate	Workshop

The responsibility in the final row should remain clear.

The workshop is where new cut edges are created and where the material identification is still available. Edge treatment and relabelling should therefore be completed before leftover plate is handed back to the warehouse.

This work should not be transferred to the warehouse after the plate has already left the fabrication flow.

15. Items to review before transferring the material to the next operation

Before material leaves the warehouse or returns to the workshop, confirm that:

the plate has no obvious deflection caused by improper support
support points between layers are vertically aligned
the surface condition has been inspected
the material has not been adversely affected by rain or moisture beyond the applicable storage conditions
the plate temperature has stabilized before measurement or fabrication
the primer type has been identified if the material is about to proceed to welding
material identification remains complete
leftover plate has had sharp cut corners ground smooth
storage conditions for electrodes, adhesive and mortar powder remain within the applicable requirements
receiving records and original photographs remain available for traceability

The purpose of this review is to prevent a deviation originating in storage from being carried into cutting, welding, lining or installation.

16. Scope of application and references

This article focuses on handling, storage and preservation after material receipt, together with the control points that should be checked before transferring the material to the next operation.

Three points should be noted.

First, the number and spacing of support points depend on plate length, thickness and material grade. This article provides principles for limiting deflection and checking plate condition rather than a single formula applicable to every case.

Second, delayed cracking does not have a fixed time of occurrence. According to the documentation being used, it may appear after several hours or several days.

Third, some information, such as the initial condition of the material, oil treatment and shop primer, needs to be recorded during ordering and receiving. This article uses that information to support storage and material transfer within the warehouse.

EN ISO 8501-1 is referenced for surface preparation before the material moves to the next operation.

The three-point bending mechanism and factors associated with delayed-cracking risk are explained using mechanical and metallurgical principles. Inspections of plate condition, timber spacers, cut corners and warehouse storage conditions are based on workshop practices used in Gia Anh’s methodology.