You order AH36, DH36, and Grade A plates together. They look identical. One wrong plate in the wrong zone.

You manage multi‑grade supply by identifying and segregating grades at receiving, using color‑coding and labels to prevent mix‑ups, maintaining traceability even when heat numbers overlap, and planning production so each structural zone gets the correct grade.

I have seen projects where a DH36 plate was accidentally used in a Grade A zone – and the classification surveyor caught it. The rework cost $15,000 and took two weeks. The yard had no system to prevent grade mix‑ups. Let me walk you through the simple system that stops this from happening.

How Do You Clearly Identify and Segregate Different Steel Grades at Receiving and Storage?

The truck arrives. The driver unloads all plates together. Your team puts them in one pile.

You identify and segregate grades by checking each plate’s stamp and label before unloading, moving plates directly to grade‑specific storage zones, and using quarantine for any plate with unclear marking. No mixing at any point.

The unmarked plate that caused a week of testing

A shipyard in Vietnam received 300 tons of plates: AH36, DH36, and Grade A. The supplier’s labels fell off during shipping. The yard had no system to identify which plate was which. They had to test every plate – cutting samples, sending to a lab. That cost $4,000 and took one week. After that, they changed their receiving process.

So let me show you how to do it right.

First, three receiving rules that prevent mix‑ups.

Rule	Action
1. Do not unload without checking	Before lifting any plate, read the stamp or label. If unclear, set aside.
2. Assign a receiving zone per grade	Have marked bays: Zone A (AH36), Zone B (DH36), Zone C (Grade A).
3. Move directly to zone	Forklift takes plate from truck straight to its zone. No staging area.

Second, what to do with unclear or missing marks.

Situation	Action
Stamp is readable but faded	Mark with spray paint (color by grade) before storing
Stamp is completely unreadable	Quarantine – do not accept. Call supplier for verification.
Label fell off but stamp is there	Use stamp, apply new label
No stamp and no label	Reject the plate. Do not accept it.

I stamp my plates clearly. My clients never have to guess.

Third, storage zone layout for multi‑grade projects.

Zone	Grade	Color Code (Spray on end)	Maximum Capacity
A1	AH36	Yellow	200 tons
A2	DH36	Orange	150 tons
A3	Grade A	White	100 tons
A4	Unknown / Quarantine	Red	20 tons

Keep at least 2 meters between zones. Use painted lines or chains as boundaries.

Fourth, the receiving log. Every plate that arrives is recorded.

Date	Plate ID	Grade	Heat Number	Zone	Checked By
Mar 10	P101	AH36	H22031	A1	Tom
Mar 10	P102	DH36	H22032	A2	Tom

This log helps you trace any future problems.

Your receiving and segregation checklist

• You have grade‑specific receiving zones marked on the yard floor
• You check every plate’s stamp or label before unloading
• You use quarantine zone for unclear marks
• You keep a receiving log

What Color‑Coding and Labeling Systems Prevent Grade Mix‑Ups During Fabrication?

The plate is in the cutting area. The welder grabs the nearest one. It is the wrong grade.

Color‑coding – painting the edge or end of each plate with a grade‑specific color – gives an instant visual check. Labeling with weather‑resistant tags provides backup. Together, they make grade identification obvious even from a distance.

The yellow paint that saved a weld

A fabricator in Malaysia had AH36 and Grade A plates in the same workshop. They looked identical. One worker almost cut a Grade A plate for a critical bottom shell. Then he saw the yellow paint on the end of the AH36 plates. He stopped. He grabbed the yellow one. The mistake was avoided.

So let me share the color‑coding system.

First, a simple color code that everyone can remember.

Grade	Paint Color on Plate End	Spray Mark on Top
AH36	Yellow	Yellow stripe
DH36	Orange	Orange stripe
Grade A	White	White stripe
Grade B	Blue	Blue stripe
Unknown	Red (quarantine)	Red X

Paint the end of each plate when it arrives. Use oil‑based paint that lasts. Reapply every 3‑6 months if plates sit long.

Second, labeling – two levels of backup.

Label Type	Location	Material	Lifespan
Bundle tag	Tied to bundle	Laminated paper, wire	3‑6 months
Individual plate sticker	Stuck on plate	Weather‑resistant vinyl	6‑12 months
Paint marking	On plate end	Oil‑based paint	12‑24 months

I use all three for my shipments. My clients tell me it makes their job much easier.

Third, where to apply the color code.

• On both ends of each plate (visible from forklift)
• On the top surface near the edge (visible to crane operator)
• On the cutting list (match color to work order)

Fourth, training your team on the color code. Post a chart at the receiving bay, storage yard, cutting station, and welding area.

Grade	Color	Used For
AH36	Yellow	Hull structure, most plates
DH36	Orange	High‑stress areas, cold zones
Grade A	White	Superstructure, non‑critical

Do a 5‑minute refresher every Monday. It works.

Your color‑coding and labeling checklist

• You have a defined color code for each grade
• You paint plate ends when they arrive
• You use weather‑resistant labels as backup
• Your team knows the color code (post a chart)

How Do You Maintain Traceability When Multiple Grades Share the Same Heat Number or Mill Runs?

The MTC says the heat number is H22031. Two grades have that same heat number. How do you tell them apart?

When multiple grades share a heat number, you rely on secondary marks – grade stamp, paint color, and separate bundle numbers. The MTC alone is not enough. You must create a secondary traceability system that links each piece to its grade, not just its heat number.

The heat number that covered two grades

I delivered a project with 200 plates. All had the same heat number on the MTC. But half were AH36 and half were Grade A. The mill had rolled them differently. The client’s quality manager was confused. I had already stamped each plate with "AH36" or "A" next to the heat number. I also painted ends yellow for AH36, white for Grade A. No mix‑ups.

So let me explain how to handle this situation.

First, why multiple grades can come from one heat number. The chemistry of the liquid steel can meet requirements for multiple grades. The mill decides the final grade based on rolling and cooling.

Same Heat Number	Different Rolling	Different Grade
H22031	Controlled rolling + accelerated cooling	AH36 (higher strength)
H22031	Normal rolling + air cooling	Grade A (lower strength)

Second, the traceability chain for shared heat numbers.

Element	What to Check
Heat number on MTC	Same for both grades
Grade stamp on plate	Different (AH36 vs A)
Paint color on end	Yellow vs White
Bundle number	Separate bundles for each grade
Packing list	Clearly links bundle number to grade

Do not rely only on heat number. Use all four identifiers.

Third, a sample traceability record for a shared heat number.

Plate ID	Heat Number	Grade Stamp	Paint Color	Bundle	MTC Reference
P101‑P150	H22031	AH36	Yellow	B101	MTC‑AH36‑H22031
P151‑P200	H22031	A	White	B102	MTC‑A‑H22031

Fourth, how to verify at receiving when heat numbers are shared.

Step	Action
1	Check packing list – are heat numbers repeated with different grades?
2	Look at each plate – does it have a grade stamp next to the heat number?
3	If only heat number (no grade stamp) – quarantine. Contact supplier.
4	If grade stamp exists – use that, plus apply your paint color.

Your shared heat number checklist

• Supplier informed you in advance if multiple grades share a heat number
• Each plate has a grade stamp (not just heat number)
• Separate bundles for each grade
• Packing list and MTCs clearly distinguish grades

I always stamp grade on every plate. My clients never have to guess.

What Production Planning Strategies Ensure the Correct Grade Is Used for Each Structural Zone?

The work order says "AH36 for bottom shell." The cutting operator sees a plate with yellow paint. Good. But what about the next zone?

Production strategies include color‑coding work orders to match plate paint, using a two‑person verification before cutting, separating workstations by grade, and keeping a cut log that records which plate went into which zone.

The two‑person rule that stopped a $20,000 mistake

A shipyard in Thailand had a near‑miss. A cutter picked a Grade A plate for a DH36 zone. The foreman walked by and saw the wrong color. He stopped it. After that, they implemented a rule: before any cut, two people must verify the grade. The cutter reads the color on the plate. The foreman checks the work order color. They both say the grade aloud. No mistakes since.

So let me share the production strategies that work.

First, color‑coded work orders. Match the paper color to the plate paint color.

Grade	Work Order Paper Color	Plate Paint Color
AH36	Yellow	Yellow
DH36	Orange	Orange
Grade A	White	White

The cutter looks at the work order color, then looks for a plate with matching paint. If they do not match, stop.

Second, the two‑person verification rule.

Step	Person 1 (Cutter)	Person 2 (Foreman)
1	Read work order grade	Confirm
2	Check plate paint color	Confirm
3	Say grade aloud	Say grade aloud
4	Cut	–

This takes 10 seconds. It stops 99% of errors.

Third, separate workstations by grade (if space allows).

Workstation	Grade	Equipment
Station 1	AH36	Plasma cutter A
Station 2	DH36	Plasma cutter B
Station 3	Grade A	Band saw

If a plate of the wrong grade ends up at a station, the operator will notice because the station should only have one color.

Fourth, a cut log that records grade assignment.

Date	Work Order	Plate ID	Grade	Cut Length	Used In Zone	Verified By
Apr 10	WO‑101	P101	AH36	12m	Bottom shell	Tom

This log lets you trace any future issue back to the exact plate.

Your production planning checklist

• Work orders are color‑coded to match plate paint
• Two people verify grade before every cut
• Separate workstations for different grades (if possible)
• You keep a cut log for traceability

Conclusion

Segregate at receiving, color‑code plates, maintain traceability for shared heat numbers, and verify grade before every cut. That is how you manage multi‑grade marine steel plate supply.