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BS 4659 BO2 vs CSA G40.21 350WT

Related Material — 65% match based on chemical composition and mechanical property overlap.

BS 4659 BO2 (BS 4659:1989) and CSA G40.21 350WT (CSA G40.21-13 (R2023)) are both steel grades. BS 4659 BO2 is classified under Tool & Die Steels, while CSA G40.21 350WT is classified under Alloy Steel — a different category, which is worth noting alongside the chemistry match below. BS 4659 BO2 is typically used for taps, drills, reamers, punches, gauges, while CSA G40.21 350WT is commonly used for bridges,offshore structures,heavy fabrication,pressure vessels,cranes,structural components. BS 4659 BO2 is defined under British Standards (BS), originating from United Kingdom, while CSA G40.21 350WT is defined under Canadian Standards Association (CSA), originating from Canada.

As per chemical composition, BS 4659 BO2 vs CSA G40.21 350WT is a 85.5% match. Mechanical property data is not available for both grades, so this factor could not be scored. Combined, this makes them a related material overall at 65%.

Frequently Compared With BS 4659 BO2:
GOST 5950 4H5MFS1 EN ISO 683-17 100Cr6 AISI 52100 EN ISO 4957 1.2316 DIN EN ISO 4957 1.2379 DIN EN ISO 4957 1.2344 GB/T 1299 3Cr2W8V GOST 5950 3H2W8F GB/T 1299 4Cr5MoSiV GOST 5950 4H5MFS GB/T 1299 4Cr5MoSiV1 IS 1570 (Part 6) 55T8
Match Breakdown
CHEMISTRY MATCH
85.5%
MECHANICAL MATCH
No shared data
OVERALL
65%
Specifications
Property BS 4659 BO2 CSA G40.21 350WT
Standard BS 4659:1989 CSA G40.21-13 (R2023)
Category Tool & Die Steels Alloy Steel
C (%) 0.85–0.95 <=0.22
Mn (%) 1.40–1.80 <=1.60
Cr (%) ≤0.30 Not specified
Si (%) ≤0.30 Not specified
P (%) Not specified <=0.035
S (%) Not specified <=0.035
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property BS 4659 BO2 CSA G40.21 350WT
Hardness HRC (hardened) 57–62 Not specified
Hardness HB (annealed) ≤217 Not specified
Tensile Strength Not specified 480-650 MPa
Yield Strength Not specified 350 MPa min
Elongation Not specified 18-22 %
Typical Applications
BS 4659 BO2
Taps, drills, reamers, punches, gauges
CSA G40.21 350WT
bridges,offshore structures,heavy fabrication,pressure vessels,cranes,structural components
Key Differences
Can BS 4659 BO2 Be Substituted With CSA G40.21 350WT?
BS 4659 BO2 and CSA G40.21 350WT share some compositional similarity but differ enough that substitution should not be assumed. Review the differences above carefully, and consult the applicable standard or a metallurgist before using one in place of the other.
Forms & Sizes Available on M-EX
BS 4659 BO2
Round Bar → (2 listings)
Diameter: 80–80 mm (3.15–3.15 in)
Length: 3100–3500 mm (122.05–137.8 in)
CSA G40.21 350WT
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 6600–7000 mm (259.84–275.59 in)
On M-EX Right Now
BS 4659 BO2
2 active listings and RFQs →
CSA G40.21 350WT
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between BS 4659 BO2 and CSA G40.21 350WT?
Different category: BS 4659 BO2 is Tool & Die Steels, CSA G40.21 350WT is Alloy Steel. BS 4659 BO2 specifies Cr, Si which are not specified for CSA G40.21 350WT. CSA G40.21 350WT specifies P, S which are not specified for BS 4659 BO2.
Can BS 4659 BO2 be substituted with CSA G40.21 350WT?
BS 4659 BO2 and CSA G40.21 350WT share some compositional similarity but differ enough that substitution should not be assumed. Review the differences above carefully, and consult the applicable standard or a metallurgist before using one in place of the other.