SM400A

7 source records. Standards, editions and conditions are presented separately; matching grade names do not establish interchangeability.

Refer to each source for mass fractions and analysis type. Missing values are not treated as 0. Manufacturer typical values, standard guarantees and measured heat results must remain separate. Use the material selector for calculations and condition selection.

Open condition selection, comparison and carbon-equivalent tools for SM400A →

SM400A · JIS G 3106-2024

Chemical composition source verified; this does not verify every standard clause, actual supply or measured heat results

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Hot-rolled structural steel (plate, sheet, strip, sections and flat bars; forms and thicknesses subject to conditions)
Original record status: Historical-edition reference
Standard edition: JIS G 3106:2020
Table / clause: Clause 4/Table 1; Clause 5/Table 2 notes a-c; Annex JA/Table JA.1 notes a-c
PDF page references: 9、10、19
Unit: Mass fraction (wt%)
Analysis type: Heat analysis

Carbon-equivalent reference

Estimates are presented separately for each applicable composition condition. Match the actual ordering conditions; ranges must not be combined.

Table 2: ordinary applicable products, thickness ≤50 mm

IIW / CEV：0.0000–0.2300Known-element contribution; incomplete value; missing Mn, Cr, Mo, V, Ni, Cu; coupled-element constraints require separate checks; the entire envelope is not guaranteed to be realizable CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15; an engineering estimate of welding cold-cracking susceptibility for carbon and low-alloy steels.

Pcm（Ito–Bessyo）：0.0000–0.2300Known-element contribution; incomplete value; missing Si, Mn, Cu, Cr, Ni, Mo, V, B; coupled-element constraints require separate checks; the entire envelope is not guaranteed to be realizable Pcm = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B; mainly used for low-carbon low-alloy steels, particularly modern low-carbon pipeline steels; more relevant when C is approximately no higher than 0.11%.

CET：0.0000–0.2300Known-element contribution; incomplete value; missing Mn, Mo, Cr, Cu, Ni; coupled-element constraints require separate checks; the entire envelope is not guaranteed to be realizable CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40; used in welding preheat assessment for ferritic steels, subject to the applicability conditions of EN 1011-2.

Table 2: ordinary applicable products, 50 mm < thickness ≤200 mm

IIW / CEV：0.0000–0.2500Known-element contribution; incomplete value; missing Mn, Cr, Mo, V, Ni, Cu; coupled-element constraints require separate checks; the entire envelope is not guaranteed to be realizable CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15; an engineering estimate of welding cold-cracking susceptibility for carbon and low-alloy steels.

Pcm（Ito–Bessyo）：0.0000–0.2500Known-element contribution; incomplete value; missing Si, Mn, Cu, Cr, Ni, Mo, V, B; coupled-element constraints require separate checks; the entire envelope is not guaranteed to be realizable Pcm = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B; mainly used for low-carbon low-alloy steels, particularly modern low-carbon pipeline steels; more relevant when C is approximately no higher than 0.11%.

CET：0.0000–0.2500Known-element contribution; incomplete value; missing Mn, Mo, Cr, Cu, Ni; coupled-element constraints require separate checks; the entire envelope is not guaranteed to be realizable CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40; used in welding preheat assessment for ferritic steels, subject to the applicability conditions of EN 1011-2.

Table JA.1: only plate agreed between purchaser and supplier, 200 mm < thickness ≤ 450 mm; the upper limit for Mn must be agreed in the contract.

Composition record (conditional branches apply; this is not an unconditional requirement)

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Applicability and limitations

Actually based on JIS G3106:2020 Clause 5 Table 2 and Normative Annex JA Table JA.1; composition is heat analysis mass fraction wt%; The original text of the 2024 edition has not yet been verified; compliance of the new edition shall not be confirmed based on this. Applicable to hot-rolled steel for welded structures; Check the thickness of plates, strips, sections and flat bars separately against Table 1; hot-extruded sections are also subject to Annex JC. This does not constitute a supply guarantee for cold-heading wire.. Please select the thickness and whether it belongs to thick steel plates agreed upon by both the supplier and the purchaser; Ordinary thickness Table 2 and agreed thick plate Table JA.1 shall not be used interchangeably. Dashes and unlisted elements in the table do not mean zero content; additions may be made where necessary.; Do not calculate the complete carbon equivalent based on missing items. For SM400A, evaluate Mn against Mn≥2.5×C using measured C from the same heat; do not use the C upper limit to invent a fixed Mn lower limit.. The upper limit of Mn for agreed thick plates in Annex JA must be stipulated by both the supplier and the purchaser; For SM400B, only Mn≥0.60% is additionally provided; the 1.50% upper limit for ordinary thickness shall not be used. Ceq in this standard uses the JIS-specific formula; The IIW/CEV, Pcm, and CET tools on the website are for engineering estimation within the noted applicable range only, and do not replace the heat treatment, thickness, and agreement requirements of this standard. The JSA corrigendum dated 2021-5 changed explanatory text; it did not change the chemical limits in Table 2 or Table JA.1 reviewed in this batch..

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Original condition-branch records

Table 2: ordinary applicable products, thickness ≤50 mm

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Table 2: ordinary applicable products, 50 mm < thickness ≤200 mm

Element	Composition requirement
C	≤ 0.25 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Table JA.1: only plate agreed between purchaser and supplier, 200 mm < thickness ≤ 450 mm; the upper limit for Mn must be agreed in the contract.

Element	Composition requirement
C	≤ 0.25 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Conditional requirements in the source

Footnote
JA.1-b
Source conditions
Plate supplied only by purchaser-supplier agreement; The Mn maximum requires separate purchaser-supplier agreement; that contractual maximum is currently unavailable, so reverse matching or calculation cannot establish complete conformity with the agreed composition.
Automatic evaluation implemented
No

A condition branch must be selected

Yes

Verification notes

Currently using the original text of the 2020 official old edition; 2024 edition not verified. Please first select thickness and agreed thick plate conditions.

SM400A · Q/BQB 130-2003

Chemical composition source verified; this does not verify every standard clause, actual supply or measured heat results

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Reference record
Original record status: Original standard verified
Standard edition: Q/BQB 130—2003
Table / clause: 4.1.1, Table 3 and notes 1–3
PDF page references: 3、4
Unit: Mass fraction (wt%)
Analysis type: Heat analysis

Source document

Carbon-equivalent reference

Estimates are presented separately for each applicable composition condition. Match the actual ordering conditions; ranges must not be combined.

G deoxidation method; applicable finished plate thickness ≤6 mm

IIW / CEV：0.1333–0.3067 Known-item contribution, not a complete value; missing Cr, Mo, V, Ni, Cu CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15; an engineering estimate of welding cold-cracking susceptibility for carbon and low-alloy steels.

Pcm（Ito–Bessyo）：0.0783–0.2017 Known-item contribution, not a complete value; missing Cu, Cr, Ni, Mo, V, B Pcm = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B; mainly used for low-carbon low-alloy steels, particularly modern low-carbon pipeline steels; more relevant when C is approximately no higher than 0.11%.

CET：0.1000–0.2400 Known-item contribution, not a complete value; missing Mo, Cr, Cu, Ni CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40; used in welding preheat assessment for ferritic steels, subject to the applicability conditions of EN 1011-2.

G deoxidation method; applicable finished plate thickness >6–16 mm

IIW / CEV：0.1950–0.3683 Known-item contribution, not a complete value; missing Cr, Mo, V, Ni, Cu CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15; an engineering estimate of welding cold-cracking susceptibility for carbon and low-alloy steels.

Pcm（Ito–Bessyo）：0.1438–0.2675 Known-item contribution, not a complete value; missing Cu, Cr, Ni, Mo, V, B Pcm = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B; mainly used for low-carbon low-alloy steels, particularly modern low-carbon pipeline steels; more relevant when C is approximately no higher than 0.11%.

CET：0.1650–0.3050 Known-item contribution, not a complete value; missing Mo, Cr, Cu, Ni CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40; used in welding preheat assessment for ferritic steels, subject to the applicability conditions of EN 1011-2.

A deoxidation method; applicable finished plate thickness >6–12.7 mm; Al is total aluminium Al_t

IIW / CEV：0.2000–0.3733 Known-item contribution, not a complete value; missing Cr, Mo, V, Ni, Cu CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15; an engineering estimate of welding cold-cracking susceptibility for carbon and low-alloy steels.

Pcm（Ito–Bessyo）：0.1300–0.2470 Known-item contribution, not a complete value; missing Cu, Cr, Ni, Mo, V, B Pcm = C + Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B; mainly used for low-carbon low-alloy steels, particularly modern low-carbon pipeline steels; more relevant when C is approximately no higher than 0.11%.

CET：0.1600–0.3000 Known-item contribution, not a complete value; missing Mo, Cr, Cu, Ni CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40; used in welding preheat assessment for ferritic steels, subject to the applicability conditions of EN 1011-2.

Composition record (conditional branches apply; this is not an unconditional requirement)

Element	Composition requirement
C	0.05 ～ 0.14
Si	0.1 ～ 0.35
Mn	0.5 ～ 1.0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Applicability and limitations

Q/BQB 130—2003 is a standard for slabs produced by initial rolling for subsequent rerolling. The finished plate thickness in Table 3 means the plate thickness after rerolling the slab, not slab thickness or wire diameter. Table 3 gives ladle analysis in mass fraction wt%; C = capped steel, A = aluminium-killed steel, G = aluminium-silicon-killed steel, K = silicon-killed steel. Read the applicable condition row; unlisted elements are not assumed to be zero. Note 3 to Table 3 requires slabs for thick plate (finished thickness ≥15 mm) to use G aluminium-silicon-killed steel; buyer and supplier must verify applicability of rows involving other deoxidation methods. Product-analysis tolerances for killed steel are separately governed by GB/T 222 and must not be mixed with Table 3 ladle-analysis values.

Original condition-branch records

G deoxidation method; applicable finished plate thickness ≤6 mm

Element	Composition requirement
C	0.05 ～ 0.14
Si	0.1 ～ 0.35
Mn	0.5 ～ 1.0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

PDF page references in the source

Source table row number

G deoxidation method; applicable finished plate thickness >6–16 mm

Element	Composition requirement
C	0.12 ～ 0.21
Si	0.04 ～ 0.3
Mn	0.45 ～ 0.95
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

PDF page references in the source

Source table row number

A deoxidation method; applicable finished plate thickness >6–12.7 mm; Al is total aluminium Al_t

Element	Composition requirement
C	0.1 ～ 0.19
Si	≤ 0.06 (lower limit not stated)
Mn	0.6 ～ 1.1
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)
Al	≥ 0.01 (upper limit not stated)

Combined limits

PDF page references in the source

Source table row number

A condition branch must be selected

Yes

Verification notes

Baosteel original Table 3, merged cells and notes checked row by row; select conditions by deoxidation method and finished-product thickness.

SM400A · JIS G 3106-2020

Chemical composition source verified; this does not verify every standard clause, actual supply or measured heat results

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Hot-rolled structural steel (plate, sheet, strip, sections and flat bars; forms and thicknesses subject to conditions)
Original record status: Original standard verified
Standard edition: JIS G 3106:2020
Table / clause: Clause 4/Table 1; Clause 5/Table 2 notes a-c; Annex JA/Table JA.1 notes a-c
PDF page references: 9、10、19
Unit: Mass fraction (wt%)
Analysis type: Heat analysis

Carbon-equivalent reference

Estimates are presented separately for each applicable composition condition. Match the actual ordering conditions; ranges must not be combined.

Table 2: ordinary applicable products, thickness ≤50 mm

Table 2: ordinary applicable products, 50 mm < thickness ≤200 mm

Table JA.1: only plate agreed between purchaser and supplier, 200 mm < thickness ≤ 450 mm; the upper limit for Mn must be agreed in the contract.

Composition record (conditional branches apply; this is not an unconditional requirement)

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Applicability and limitations

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Original condition-branch records

Table 2: ordinary applicable products, thickness ≤50 mm

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Table 2: ordinary applicable products, 50 mm < thickness ≤200 mm

Element	Composition requirement
C	≤ 0.25 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Table JA.1: only plate agreed between purchaser and supplier, 200 mm < thickness ≤ 450 mm; the upper limit for Mn must be agreed in the contract.

Element	Composition requirement
C	≤ 0.25 (lower limit not stated)
Mn	Not listed; must not be treated as 0
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Combined limits

Elements requiring measured values from the same heat

Combined-element limits

Element coefficient
Mn
1
C
-2.5
Lower limit
0
Requirement
Heat analysis from the same heat, Mn≥2.5×C

Conditional requirements in the source

Footnote
JA.1-b
Source conditions
Plate supplied only by purchaser-supplier agreement; The Mn maximum requires separate purchaser-supplier agreement; that contractual maximum is currently unavailable, so reverse matching or calculation cannot establish complete conformity with the agreed composition.
Automatic evaluation implemented
No

A condition branch must be selected

Yes

Verification notes

Edition 2020, Table 2 and all 11 grades in JA.1, thickness branches and footnotes have been checked; View after selecting the applicable condition.

SM400A · JIS G 3106-2008

Original-source verification is incomplete; this is not a formal standard reference

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Reference record
Verification status: Reference data; original source not verified

Carbon-equivalent reference

IIW / CEV: composition source not verified; standard-range carbon equivalent is not calculated

Pcm (Ito–Bessyo): composition source not verified; standard-range carbon equivalent is not calculated

CET: composition source not verified; standard-range carbon equivalent is not calculated

Composition

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)

Applicability and limitations

A match in the materials database does not establish suitability for cold heading or guarantee finished-product strength. Confirmation must consider wire condition, deformation, heat treatment and tests on actual parts.

SM400A · Q/ASB 271-2017

Original-source verification is incomplete; this is not a formal standard reference

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Reference record
Verification status: Reference data; original source not verified

Carbon-equivalent reference

IIW / CEV: composition source not verified; standard-range carbon equivalent is not calculated

Pcm (Ito–Bessyo): composition source not verified; standard-range carbon equivalent is not calculated

CET: composition source not verified; standard-range carbon equivalent is not calculated

Composition

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
Cr	≤ 0.3 (lower limit not stated)
Cu	≤ 0.3 (lower limit not stated)
N	≤ 0.008 (lower limit not stated)
Ni	≤ 0.2 (lower limit not stated)
P	≤ 0.035 (lower limit not stated)
S	≤ 0.035 (lower limit not stated)
Si	≤ 0.35 (lower limit not stated)

Applicability and limitations

SM400A · Q/ASB 320-2017

Original-source verification is incomplete; this is not a formal standard reference

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Reference record
Verification status: Reference data; original source not verified

Carbon-equivalent reference

IIW / CEV: composition source not verified; standard-range carbon equivalent is not calculated

Pcm (Ito–Bessyo): composition source not verified; standard-range carbon equivalent is not calculated

CET: composition source not verified; standard-range carbon equivalent is not calculated

Composition

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
P	≤ 0.03 (lower limit not stated)
S	≤ 0.03 (lower limit not stated)

Applicability and limitations

SM400A · Q/BQB 303-2018

Original-source verification is incomplete; this is not a formal standard reference

Material category: Carbon steel
Subcategory: Carbon steel
Material form: Reference record
Verification status: Reference data; original source not verified

Carbon-equivalent reference

IIW / CEV: composition source not verified; standard-range carbon equivalent is not calculated

Pcm (Ito–Bessyo): composition source not verified; standard-range carbon equivalent is not calculated

CET: composition source not verified; standard-range carbon equivalent is not calculated

Composition

Element	Composition requirement
C	≤ 0.23 (lower limit not stated)
P	≤ 0.025 (lower limit not stated)
S	≤ 0.025 (lower limit not stated)
Si	≤ 0.35 (lower limit not stated)