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BS 4659 BO2 vs GB/T 1299 4Cr5MoSiV

Minimal Match — 35% match based on chemical composition and mechanical property overlap.

BS 4659 BO2 (BS 4659:1989) and GB/T 1299 4Cr5MoSiV (GB/T 1299-2014) are both steel grades. Both fall under the Tool & Die Steels category. BS 4659 BO2 is typically used for taps, drills, reamers, punches, gauges, while GB/T 1299 4Cr5MoSiV is commonly used for die casting dies, extrusion tooling. BS 4659 BO2 is defined under British Standards (BS), originating from United Kingdom, while GB/T 1299 4Cr5MoSiV is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, BS 4659 BO2 vs GB/T 1299 4Cr5MoSiV is a 59.5% match. As per mechanical properties, the match is 0%. Combined, this makes them a minimal match overall at 35%.

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 GOST 5950 4H5MFS GB/T 1299 4Cr5MoSiV1 IS 1570 (Part 6) 55T8 IS 1570 (Part 6) 50T8
Match Breakdown
CHEMISTRY MATCH
59.5%
MECHANICAL MATCH
0%
OVERALL
35%
Specifications
Property BS 4659 BO2 GB/T 1299 4Cr5MoSiV
Standard BS 4659:1989 GB/T 1299-2014
Category Tool & Die Steels Tool & Die Steels
C (%) 0.85–0.95 0.32–0.45
Mn (%) 1.40–1.80 0.20–0.50
Cr (%) ≤0.30 4.75–5.50
Si (%) ≤0.30 0.80–1.20
Mo (%) Not specified 1.10–1.60
V (%) Not specified 0.30–0.60
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 GB/T 1299 4Cr5MoSiV
Hardness HRC (hardened) 57–62 40–54
Hardness HB (annealed) ≤217 ≤235
Typical Applications
BS 4659 BO2
Taps, drills, reamers, punches, gauges
GB/T 1299 4Cr5MoSiV
Die casting dies, extrusion tooling
Key Differences
Can BS 4659 BO2 Be Substituted With GB/T 1299 4Cr5MoSiV?
BS 4659 BO2 and GB/T 1299 4Cr5MoSiV 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)
GB/T 1299 4Cr5MoSiV
Round Bar → (2 listings)
Diameter: 80–80 mm (3.15–3.15 in)
Length: 2500–2700 mm (98.43–106.3 in)
On M-EX Right Now
BS 4659 BO2
2 active listings and RFQs →
GB/T 1299 4Cr5MoSiV
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between BS 4659 BO2 and GB/T 1299 4Cr5MoSiV?
GB/T 1299 4Cr5MoSiV specifies Mo, V which are not specified for BS 4659 BO2.
Can BS 4659 BO2 be substituted with GB/T 1299 4Cr5MoSiV?
BS 4659 BO2 and GB/T 1299 4Cr5MoSiV 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.