Both are 490 MPa tensile class. SM490A (JIS G3106) controls chemistry (C ≤0.20, Mn ≤1.60) and is the weldable-structural grade intended for welded construction; SS490 leaves chemistry open. Choose SM490A for welded primary structures.

Grades · Structural & HSLA Steel · SS490

SS490

Data verified

SS490 is the higher-strength grade of JIS G3101, a 490–610 MPa tensile class structural steel with yield of at least 285 MPa in thin sections. Like SS400 it is specified by properties only, with phosphorus and sulfur capped and no carbon control.

DIN1.0044 (S275JR, near)

AISIA572 type (near)

JISSS490 (JIS G3101)

CategoryStructural & HSLA Steel

Chemical composition

Element	Content (%)
P	≤0.050
S	≤0.050
C / Si / Mn	Not specified by JIS G3101 — the grade is defined by its tensile properties, not by chemistry

Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.

Properties

Tensile strength	490–610 MPa
Yield strength	≥285 MPa (≤16 mm)
Density	7.85 g/cm³

Heat treatment

None — used hot rolled, as SS400.

Equivalent grades

Standard	Designation
din	1.0044 (S275JR, near)
aisi	A572 type (near)
jis	SS490 (JIS G3101)
gb	Q275 (near)

Compare side by side: SS490 vs SS400 · SS490 vs SM490A

Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.

Applications & Processing

Applications: Heavier building and bridge members, machinery frames, structural sections and plate where SS400 is not strong enough.

Processing: Weldable with normal structural practice; because carbon is not standardised, confirm weldability from the mill certificate on thick sections.

FAQ

SS490 or SM490A?: Both are 490 MPa tensile class. SM490A (JIS G3106) controls chemistry (C ≤0.20, Mn ≤1.60) and is the weldable-structural grade intended for welded construction; SS490 leaves chemistry open. Choose SM490A for welded primary structures.

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Source: JIS G3101 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.