ASTM A182 F6NM Forged Round Bars — Charpy Tested at -60°C (-75°F), Russian Client
A delivered project: forged ASTM A182 F6NM (UNS S41500) round bars, Charpy impact tested at -75 °F (-60 °C), supplied to a Russian client for low-temperature service.
Project summary: We forged and supplied ASTM A182 F6NM / UNS S41500 round bars at Ø250 mm × 1 000 mm long for a Russian customer. The bars were hardened and double tempered, then Charpy V-notch impact tested at -75 °F (-60 °C), returning 202 / 175 / 202 J with 100% shear fracture and full mill test reports. F6NM was chosen for its combination of stainless corrosion resistance and dependable low-temperature toughness.
Delivered F6NM Round Bar — Test Results
The values below are taken from the actual mill test report (heat 723869, test piece 610V2), tested longitudinally to ASTM A370.
| Property | Requirement | Actual result |
|---|---|---|
| Yield strength (Rp0.2) | 75 000–95 000 psi (517–655 MPa) | 78 000 psi (538 MPa) |
| Tensile strength (Rm) | 95 000–120 000 psi (655–827 MPa) | 106 400 psi (734 MPa) |
| Elongation (A) | ≥ 18% | 25% |
| Reduction of area (Z) | ≥ 35% | 76% |
| Charpy V-notch at -75 °F (-60 °C) | ≥ 32 J | 202 / 175 / 202 J |
| Lateral expansion | — | 0.091 / 0.09 / 0.091 in (≈ 2.3 mm) |
| Shear fracture | — | 100 / 100 / 100% |
| Hardness | ≤ 255 HBW | 235 HBW (≈ 19–20 HRC) |
The Charpy energy is around six times the specified minimum, and the 100% shear fracture confirms fully ductile behaviour at -60 °C — exactly what is required for safe low-temperature pressure service.
Delivered Specification
| Item | Detail |
|---|---|
| Grade | ASTM A182 F6NM / UNS S41500 / AISI 415 (13Cr-4Ni soft martensitic stainless) |
| Product form | Forged round bars |
| Dimensions | Ø250 mm × 1 000 mm (1 m) long |
| Heat treatment | Hardened 1015 °C / 11 h, air; tempered 690 °C / 10.5 h, air; tempered 615 °C / 21 h, air; cooled below 32 °C (90 °F) between treatments |
| Test standard | ASTM A370; standard round tensile specimen Ø0.500 in, 2.00 in gauge; full-size 10 × 10 mm Charpy |
| Destination | Russia |
| Documentation | Full mechanical and impact test reports (MTR, EN 10204 3.1) |
Chemical Composition (Heat 723869)
| C | Si | Mn | P | S | Cr | Mo | Ni | Cu | V | Al | N | H (ppm) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.01 | 0.34 | 0.55 | 0.013 | 0.01 | 12.69 | 0.53 | 3.83 | 0.05 | 0.021 | 0.004 | 0.0117 | 2.0 |
The very low carbon (0.01%) with 12.69% chromium and 3.83% nickel is the chemistry that gives F6NM its low-temperature toughness, while the hardening and double-temper cycle develops the fine tempered martensite and stable reverted austenite behind the high Charpy values above.
Why F6NM for This Project
The client needed bars that stay tough in a cold climate while resisting corrosion, which is exactly where F6NM fits. As a soft martensitic 13Cr-4Ni stainless steel, it holds dependable Charpy toughness well below zero, so it is routinely qualified to -40 °C and, as this delivery shows, comfortably down to -60 °C (-75 °F). For the full engineering background, see our guides on the F6NM Charpy impact test requirements and the F6NM minimum design metal temperature (MDMT).
Every bar was supplied with mill test reports tying the result to the -75 °F (-60 °C) test temperature, so the buyer's QA team could verify toughness against their drawing. We supply the same grade in other forms as well, including A182-F6NM rings, flanges, valve bodies and round bars.
Frequently Asked Questions
Can you supply F6NM forged round bars impact tested at -60 °C (-75 °F)?
Yes. We have delivered ASTM A182 F6NM / UNS S41500 forged round bars Charpy impact tested at -75 °F (-60 °C), returning 202 / 175 / 202 J with 100% shear fracture, supported by full mill test reports on each heat lot.
What sizes of F6NM round bar can you forge?
This project was delivered at Ø250 mm × 1 000 mm long. We forge F6NM round bars across a wide range of diameters and lengths to order, each with full mechanical and impact test documentation.
Is F6NM suitable for cold-climate and low-temperature service?
Yes. F6NM is a soft martensitic stainless steel routinely qualified to an MDMT of -40 °C and, as shown by this delivery, down to -60 °C (-75 °F), combining low-temperature toughness with the corrosion resistance of a stainless steel. For guaranteed cryogenic service at -196 °C, an austenitic or 9% nickel grade is used instead.
Need Low-Temperature F6NM Round Bars?
Jiangsu Liangyi Co., Limited supplies forged A182-F6NM / UNS S41500 / AISI 415 round bars and other forms, impact tested and certified to your specified minimum design metal temperature, with full mill test reports for cold-climate service. Contact us at forgepieces.com, +86-510-86107550 or sales@forgepieces.com.
