Engineering Guide · 3 min read
Chinese Fastener Steel Grades: GB/T 700, 699, 28906 and 3077
Where do Q195, 35#, 35Mn, ML35, ML20MnTiB and 35CrMo fit? Follow seven Chinese GB/T steel families, with composition tables and links to each grade guide.
The short answer: Chinese fastener steel grades are grouped by structural strength, carbon and alloy content, cold-heading requirements, or the manufacturing route used to develop final properties. [1] [2] [3] [4]
GB/T 700 and GB/T 699 cover general structural and quality carbon steels; GB/T 28906 covers hot-rolled cold-heading wire rod; GB/T 3077 covers alloy structural steels. This guide groups the commonly used grades by specification and manufacturing use.
Read the seven material families in order
- Q195, Q235 and Q275 — GB/T 700: general carbon structural steel and its strength families.
- 35# steel, 45# and 35Mn — GB/T 699: defined carbon and manganese ranges.
- ML08Al, ML10 and ML20 — GB/T 28906: low-carbon stock supplied for cold heading.
- ML35, ML40 and ML45 — GB/T 28906: carbon cold-heading grades for quenching and tempering.
- ML20B, ML20MnB and ML20MnTiB — GB/T 28906: boron-assisted hardenability and additional-element choices.
- 40Cr, 35CrMo and 42CrMo — GB/T 3077: chromium and chromium–molybdenum alloy families.
- MFT8, MFT9 and MFT10 — GB/T 28906: a non-quenched-and-tempered production route.
What each step adds to the material choice
| Family | Representative grades | What it adds |
|---|---|---|
| General carbon structural | Q195, Q215, Q235, Q275 | A structural strength family for general steel products |
| Quality carbon structural | 20, 35 / 35#, 45 / 45#, 35Mn, 40Mn | Defined carbon intervals and higher-manganese choices |
| Low-carbon cold heading | ML08Al, ML10, ML15, ML20 | Material specified for cold forming, including incoming rod properties |
| Quench-and-temper carbon cold heading | ML30, ML35, ML40, ML45 | Carbon grades directed toward forming followed by final heat treatment |
| Boron-bearing cold heading | ML20B, ML20MnB, ML20MnTiB, ML20MnVB | A hardenability strategy using small boron additions and designated alloy elements |
| Chromium and CrMo | 40Cr, 35CrMo, 42CrMo, ML35CrMo | Chromium-based alloy controls for hardening and tempering response |
| Non-quenched-and-tempered | MFT8, MFT9, MFT10, MFT8B, MFT9DP | A route intended to omit conventional final quenching and tempering |
Selected composition parameters across the families
| Grade | Source standard | C (%) | Selected distinguishing parameter |
|---|---|---|---|
| Q195 | GB/T 700-2006 | ≤0.12 | Mn ≤0.50% |
| Q235B | GB/T 700-2006 | ≤0.20 | Mn ≤1.40%; agreed carbon option in the source standard |
| 35 / 35# | GB/T 699-2015 | 0.32–0.39 | Mn 0.50–0.80% |
| 35Mn | GB/T 699-2015 | 0.32–0.39 | Mn 0.70–1.00% |
| ML08Al | GB/T 28906-2025 | 0.05–0.10 | Total Al 0.020–0.060% |
| ML35 | GB/T 28906-2025 | 0.33–0.38 | Mn 0.60–0.90% |
| ML20MnTiB | GB/T 28906-2025 | 0.18–0.23 | B 0.0008–0.0035%; Ti 0.04–0.10% |
| 35CrMo | GB/T 3077-2015 | 0.32–0.40 | Cr 0.80–1.10%; Mo 0.15–0.25% |
| MFT8 | GB/T 28906-2025 | 0.18–0.26 | Mn 1.20–1.60%; base ferrite–pearlite family |
Selected heat-analysis limits from the stated standards, with mass-percent units throughout. The detailed articles retain the applicable table notes and additional grade parameters. [1] [2] [3] [4]
Why steel selection develops along these routes
The Q-series article covers structural products such as frames and brackets used in their delivered condition. The 35# and 35Mn article compares carbon and manganese choices for forged or machined parts. The low-carbon ML article uses incoming-rod strength and ductility requirements to explain forming stock, while the ML35 article separates stock preparation from final heat treatment.
The choice between boron-assisted hardenability and chromium and chromium–molybdenum alloying includes the required hardening depth and tempering response. With a non-quenched-and-tempered production concept, strength is established through the selected rod and cold-working sequence.
Where 35K and 10B21 fit
Chinese mill catalogs also list SWRCH35K, often shortened to 35K, and 10B21 alongside GB/T grades. SWRCH35K uses a Japanese-style designation; 10B21 uses an SAE-style designation, as illustrated by Baosteel's supply specification. [5]
Standards covered in this GB/T steel column
- GB/T 700-2006: general carbon structural steels.
- GB/T 699-2015: quality carbon structural steels.
- GB/T 6478-2015: steels for cold heading and cold extrusion.
- GB/T 28906-2025: hot-rolled cold-heading wire rod, including the ML and MFT families.
- GB/T 3077-2015: alloy structural steels.
GB/T 28906-2025 took effect on October 1, 2025 and replaced GB/T 28906-2012 and GB/T 29087-2012. GB/T 6478-2015 remains a separate specification. The edition and product form in the individual article identify the parameters being discussed. [3] [6]
For the completed fastener's mechanical designation, continue with Fastener Grades Explained. The Alloy Steel Fasteners article gives wider material context, and How to Specify a Bolt covers the full part description.
Browse the HexFastener homepage or submit a drawing with the required material callout.
References
- GB/T 700-2006 — Carbon structural steels. Tables 1–2; composition and size-dependent material properties.
- GB/T 699-2015 — Quality carbon structure steels. Table 1; numerical and manganese grade chemistry.
- GB/T 28906-2025 — Hot-rolled steel wire rod for cold heading. Official online text; Clause 4 and Tables 1–6.
- GB/T 3077-2015 — Alloy structure steels. Table 1; chromium and chromium–molybdenum grades.
- Baosteel Q/BQB 517-2023 — Wire rods for cold heading. Table 1 and informative Annex B.
- GB/T 6478-2015 — Steels for cold heading and cold extruding. Material specification and current status.