Steel Sheet · Grade
A JIS designation is read against its own standard
SS400 is a designation inside a Japanese Industrial Standard, and it is read against that standard — not against a strength number that floats between systems. The practical problem for a drawing review is that SS400 is very often substituted for, or by, grades from other standard systems on the assumption that the numbers are close. They are different requirement sets. Your job is to check the material that arrived against the specification your drawing actually cites.
Bring the standard your drawing cites, with the edition — it decides what can be offered, and pricing is on request.
Standard first
The grade rides on it
Comparable ≠ equal
No cross-system swaps
Scope of the Designation
Four parts of the call-out, one of which is usually missing
SS400 travels on drawings as two or three characters, and that brevity is where the trouble starts. The designation only carries its meaning inside a document, and the document is the part most often left off.
The named standard
SS400 belongs to a Japanese Industrial Standard covering general structural rolled steel. The designation is meaningful only inside that document, which sets the chemistry, the mechanical requirements and the acceptance testing for the grade it names.
The letters SS400 on their own are not a specification. They are a grade within one, and the standard has to be cited with them.
A consignment whose paperwork names the wrong standard is a deviation, not a delivery.
Conformance Review
Five lines to run the drawing against the certificate
Each row takes something the drawing asserts, states what the inspection document has to show, and gives both dispositions. The review sets the test — it does not verify a document for you and it does not supply a property value.
| Drawing reference | What to compare | Conforms | Deviation |
|---|---|---|---|
| The standard cited on the drawing | The designation and the standard are named together, with the edition the drawing was prepared against. | Conforms when the inspection document cites that standard and edition for the grade supplied. | Does not conform when the document cites a different standard system, or names the grade alone with no standard. |
| The form and size called out | The product form and the nominal thickness the drawing specifies, with units. | Conforms when the supplied form and size fall inside the scope of the standard cited and match the call-out. | Does not conform when the material is a different form, or outside the size range the standard covers. |
| The grade naming on the drawing | The exact designation as written, including any prefix or suffix the standard uses. | Conforms when the certificate names the same designation the drawing calls out. | Does not conform when the certificate carries a grade from another system offered as a substitute. |
| The delivery condition | Any condition or processing the drawing or the governing specification requires. | Conforms when the condition recorded matches what the drawing expects. | Does not conform when the condition is unstated on either side and left to assumption. |
| The acceptance evidence | The tests the drawing's specification requires the material to be released against, and the identification to carry. | Conforms when the document records those tests for the same heat or lot as the material delivered. | Does not conform when the record belongs to another order, or the identification did not travel with the sheet. |
The review structures the comparison — it does not verify a certificate, and it does not replace the acceptance decision your own quality procedure makes. Confirm every value in the standard the drawing actually cites.
Name the standard, always
A grade on its own leaves the requirement open. Writing the standard and the edition beside the designation is what turns a shorthand into a checkable instruction.
Refuse the quiet substitution
A grade from another system offered in place of the one drawn is a variation, however close the numbers look. It needs a decision from the design owner, on the record.
Check the scope reaches you
Confirm the form and the thickness you are buying fall inside the standard's scope before the grade name is relied on to carry the requirement.
Request a Quote
Send the standard your drawing cites
An SS400 enquiry is only as precise as the standard behind it. State the standard and edition, the grade as written, and the form you need — and anything you leave open comes back as open rather than assumed.
The standard cited on the drawing
The designation and the standard are named together, with the edition the drawing was prepared against.
The form and size called out
The product form and the nominal thickness the drawing specifies, with units.
The grade naming on the drawing
The exact designation as written, including any prefix or suffix the standard uses.
The delivery condition
Any condition or processing the drawing or the governing specification requires.
Writing the Order
What the order line has to say beyond the grade name
A complete instruction names where the grade comes from, how it is written, what form it takes and what it has to prove. The grade name is the shortest part of it.
Documentation has to be right before the consignment moves, not after it lands.
The standard and edition: the document the grade belongs to, with the year the drawing was prepared against. This is the line that makes the requirement checkable, and its absence is the defect that causes the most rework.
The designation as written: the grade exactly as the drawing names it, with any prefix or suffix the standard uses. Reproducing the drawing's spelling removes a whole class of mismatch.
The form and thickness: sheet as the product form, with the nominal thickness in the same unit system as the rest of the order. These are also the check that the standard's scope reaches your material.
The acceptance evidence: the tests the order is released against and the identification the material must carry. Agreeing it before manufacture is what makes it available afterwards.
Document Evidence
What the inspection document proves — and to whom
The document is a statement about a specific order made to a specific specification. Its authority comes entirely from that pairing, and it lapses the moment either half is wrong.
It speaks for one specification
A document issued against another standard evidences that standard's requirements. It says nothing about the one your drawing cites, however closely the grades resemble each other in ordinary duty.
It speaks for one order
The record attaches to the material it was issued for. A certificate from an earlier consignment, or from another source, is not evidence for the sheets in front of you.
It needs its identity kept
Hold the heat or lot identification with the material through goods-in and cutting. Once a sheet is separated from its marking, no certificate attaches to it any longer.
Why the substitute feels safe
Comparable properties, different requirements
Grades from different standard systems often land in the same territory for ordinary structural duty. That overlap is real, and it is why substitution is so common: a purchasing team under delivery pressure sees two designations that perform alike in practice and reasonably concludes that either will do. Nothing about the material contradicts them, most of the time.
What the overlap hides is that a specification is a package rather than a number. Each standard brings its own chemistry provisions, its own mechanical requirements, its own rules about which product forms and sizes it covers, and its own acceptance testing. Where the packages agree in outcome, they agree by coincidence of ordinary duty; where they diverge — at a size, a condition, a test — nothing in the grade name warns you. The substitution passes because the common case is genuinely common, and fails on the case that is not.
A reviewer does not need to resolve that technically, and should not try. The useful position is procedural: the drawing names a specification, so the material is checked against that specification, and anything else arrives as a proposed variation for the design owner to accept or refuse on the record. That keeps the technical judgement where the responsibility already sits, and turns a silent substitution into a decision someone can actually make.
Where It Is Specified
The duties this designation is written into
SS400 serves general structural work, and it reaches sheet form where a fabricated part needs a defined structural quality from flat material.
General structural fabrication
Frames, brackets and supports in ordinary structural duty, where the section is sized by the design and the material has to meet a stated quality consistently.
Welded assemblies
Where flat parts are joined into an assembly and the specification needs a documentable material behind the joint, with the procedure confirmed separately.
Parts drawn to a foreign standard
Components specified under a Japanese standard for a project elsewhere — where the drawing's citation governs and the review is against it, not against local habit.
None of these is a suitability determination for a particular part, and none replaces the design approval behind the call-out. Where a governing document sets the requirement, that document decides.
GCC Supply
Plan the destination separately from the specification
The standard and grade answer what the sheet is at handover. The consignee, delivery point and document set answer where it is going — and those are planned on their own route.
A country link is a destination-planning page. None of them implies a local office, warehouse or stock position, and none of them changes the specification.
Commercial Basis
What is confirmed against your enquiry, not published in advance
An order against a named standard turns on several inputs at once, and whether the specification can be met as written is the one that most often decides the answer.
Specification as written
Whether the standard and grade you cite can be met in the form and thickness you need — confirmed per enquiry, never inferred from a grade name.
Availability in form
Whether the designation is obtainable as sheet at your size, rather than only in another product form.
Origin and mill
The producing source is stated against the actual enquiry, not asserted as a standing position.
Documentation
The inspection document and any additional test evidence are confirmed against the standard and edition you cite.
Pricing is on request. No rate, lead time or stock position is published before the standard and form are confirmed.
Related Routes
Where the neighbouring material decisions are answered
Open one only when it settles the question in front of you — a neighbouring grade or family is not evidence that two specifications are interchangeable.
Why Specify It
What a named standard gives you — and what it expects back
Specifying by standard is a trade between certainty and discipline. These are the honest terms.
A requirement you can point at
The standard sets the chemistry, the mechanical requirements and the acceptance testing, so the instruction is a reference rather than a negotiation.
Evidence with a shape
Because the standard defines what acceptance looks like, the inspection document can be reviewed item by item against the drawing instead of taken on trust.
No room for the loose swap
The same precision is the cost. Once the standard is named, a grade from another system is a variation rather than a convenience — and it has to be treated as one.
How the Review Moves
From a drawing call-out to a released delivery
Each step settles something the next one depends on. The standard is fixed on the order, not discovered at goods-in.
- 01
Read the call-out
Take the standard, the edition and the grade exactly as the drawing writes them, and note the form and thickness specified.
- 02
Carry it to the order
State all of it on the enquiry, and record the substitution position so an alternative is either refused or routed for approval.
- 03
Check the scope
Confirm the standard covers sheet at your thickness, and that no governing specification imposes something further.
- 04
Review on arrival
Run the drawing against the certificate — standard, edition, designation, form and identification — before release to production.
Specification, availability and documentation are confirmed against the live enquiry — never inferred from a review outcome or a published list.
Request a QuoteCommon Questions
Questions the SS400 review usually raises
Is SS400 the same as an S235 or A36 grade?
No, and treating them as the same is the mistake this page exists to prevent. They come from different standard systems, each with its own chemistry provisions, mechanical requirements and acceptance testing. Their properties are broadly comparable in ordinary structural duty, which is exactly why the substitution gets made casually — but comparable is not equivalent. Any substitution has to be a documented technical determination by whoever owns the design, not an assumption made on the order.
Which standard do I write on the order?
The one your drawing cites, named with the grade and the edition. If the drawing names a JIS designation, the order and the certificate both have to work to that JIS document. Writing a grade name without its standard leaves the requirement undefined and hands the mill the discretion you were trying to avoid.
What if the certificate cites a different standard?
Then it is not evidence for your order, however close the properties look and however convenient the delivery. A certificate issued against another standard system is a statement about that system's requirements, not about the one your drawing cites. Raise it as a deviation and get it resolved before the material is released to production — that is the whole point of reviewing the document.
Does the size of the sheet affect the requirement?
The standard sets its provisions against the product form and the size range it covers, so the size is part of whether the standard applies as you expect. Confirm the form and the thickness you are buying sit inside that scope, and state them on the order. It is a short check that removes an easy source of mismatch.
Where the duty is general-purpose structural work, the mild steel sheet and carbon steel sheet routes set out the families this grade is most often considered alongside — each still read against its own specification.
Send the standard your drawing cites
Give the standard and edition, the grade exactly as written, and the form and thickness you need. The quotation comes back against the specification you named, with any alternative raised as a variation rather than slipped in.
sales@noordeirasteel.ae · +971 56 398 0860 · Business Bay, Dubai