Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ASTM A193 Grade B16 — US Cr-Mo-V Bolting Steel (Equivalent to Durehete 950 / Alloy T31)
ASTM A193 Grade B16 is the US standard Cr-Mo-V bolting steel for high-temperature service up to 540 degrees Celsius. It is the direct procurement equivalent of Durehete 950 (Alloy T31 / Werkstoff 1.7711 / 40CrMoV4-6 / EN 10269), with overlapping chemistry, mechanical and heat-treatment specifications. US procurement specifications that call out A193 B16 can be sourced as Durehete 950 with EN 10269 plus equivalent ASTM A193 dual certification.
Chemistry Comparison
| Element (wt %) | ASTM A193 B16 | Durehete 950 / EN 10269 40CrMoV4-6 |
|---|---|---|
| Carbon | 0.36 to 0.47 | 0.36 to 0.44 |
| Manganese | 0.45 to 0.70 | 0.40 to 0.70 |
| Chromium | 0.80 to 1.15 | 0.90 to 1.20 |
| Molybdenum | 0.50 to 0.65 | 0.50 to 0.70 |
| Vanadium | 0.25 to 0.35 | 0.25 to 0.35 |
| Phosphorus, max | 0.040 | 0.025 |
| Sulphur, max | 0.040 | 0.025 |
Chemistry envelopes are broadly equivalent. EN 10269 carries tighter phosphorus and sulphur ceilings, which is the only material difference at the chemistry level.
Mechanical Comparison (Q+T condition)
| Property | A193 B16 (room temp) | Durehete 950 (room temp) |
|---|---|---|
| Tensile strength, min | 860 MPa (125 ksi) | 820-1000 MPa |
| 0.2% proof stress, min | 724 MPa (105 ksi) | 620 MPa |
| Elongation, min | 18% | 16% |
| Reduction of area, min | 50% | 45% |
| Hardness, max | 321 HBW | 300 HBW |
A193 B16 carries a slightly higher minimum yield (724 vs 620 MPa). For dual-certification orders, the heat treatment is targeted at the higher A193 B16 floor so both specifications are satisfied from the same heat.
Heat Treatment
Both specifications require quench and temper. Austenitise 845-955°C, oil or water quench, temper 650-720°C minimum 2 hours, air cool. The narrower Durehete 950 tempering window (650-720°C) sits inside the A193 B16 acceptable range.
Service Envelope
A193 B16 is qualified to 540 degrees Celsius continuous in ASME Section II Part D. Durehete 950 / EN 10269 40CrMoV4-6 carries the same envelope through Annex A. Above 540 degrees Celsius, escalate to Durehete 1055 (Alloy T41 / 20CrMoVTiB4-10) for the Ti+B microalloying advantage.
Frequently Asked Questions
Is Durehete 950 the same as ASTM A193 Grade B16?
Functionally yes. Chemistry envelopes overlap, mechanical floors are similar, heat-treatment cycle is identical. Dual-certify by targeting heat treatment to satisfy both EN 10269 and A193 B16 minima.
What about A193 Grade B7 — can I substitute that for Durehete 950?
No. B7 is plain Cr-Mo (no vanadium) and is qualified only to 482 degrees Celsius. B16 is the Cr-Mo-V equivalent that matches the Durehete 950 service envelope to 540 degrees Celsius.
Does Durehete 1055 have an A193 equivalent?
No exact equivalent. The Ti+B microalloying in 20CrMoVTiB4-10 is unique to the European EN 10269 family. The closest ASTM bolting steel is A540 B23 / B24.
Can I source A193 B16 with EN 10269 dual certification?
Yes. TorqBolt supplies Durehete 950 with both EN 10269 type 3.1 / 3.2 and ASTM A193 B16 mill certificates from the same heat.
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