B-S45C

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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.

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B-S45C · Q/BQB 517-2023

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

Material category: Carbon steel
Subcategory: Cold-heading steel
Material form: Hot-rolled steel wire rod for cold heading
Original record status: Original standard verified
Standard edition: Q/BQB 517—2023
Table / clause: 6.1.1/Table 2, row 13, note a
PDF page references: 13
Unit: Mass fraction (wt%)
Analysis type: Heat analysis

Source document

Carbon-equivalent reference

IIW / CEV：0.5200–0.7153Known-element contribution; incomplete value; missing V; 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）：0.4550–0.5690Known-element contribution; incomplete value; missing 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：0.4800–0.6060 Independent-element envelope of standard ranges, not measured heat results; coupled-element constraints require separate checks, and 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.

Composition

Element	Composition requirement
C	0.42 ～ 0.48
Si	0.15 ～ 0.35
Mn	0.6 ～ 0.9
P	≤ 0.02 (lower limit not stated)
S	≤ 0.02 (lower limit not stated)
Cr	≤ 0.2 (lower limit not stated)
Cu	≤ 0.3 (lower limit not stated)
Ni	≤ 0.2 (lower limit not stated)
Mo	≤ 0.06 (lower limit not stated)

Applicability and limitations

Q/BQB 517—2023 Baosteel official website original text Table 2 Row 13; Heat-analysis mass fractions wt%. Note a below the table: residual Cr≤0.20, Ni≤0.20, Cu≤0.20, Mo≤0.06 wt%; When this row has other provisions, the requirements for the element in this row shall prevail. Elements not listed and special agreement requirements shall not be treated as zero or as default guarantees; Permissible deviations for product analysis shall otherwise be according to GB/T 222. Hot-rolled delivery of wire rod; Tighter P/S limits under Z1 and special surface or inclusion quality requirements must be confirmed against normative Annex A and the contractual ordering codes; do not infer fixed mechanical properties from the chemical-composition table. Ni+Cr≤0.35 is the linked upper limit for the same heat; the individual upper limits of Ni and Cr shall not both be regarded as achievable simultaneously.

Combined limits

Element-sum limits

Elements concerned
- Ni
- Cr
Upper limit
0.35

Verification notes

All 104 rows of Table 1 and 34 rows of Table 2 in the original Q/BQB517:2023 from Baosteel’s official website were checked row by row; not mixed with older editions.