ASTM A473 UNS S41500: Forging Properties

ASTM A473 UNS S41500: Forging Properties

Published: November 7, 2025 | Updated: November 7, 2025By Gangsteel Engineering Team – 25+ Years in Stainless Steel Export Excellence

Forging isn't just a process—it's an art that transforms raw metal into components capable of withstanding the harshest industrial gauntlets.

Enter ASTM A473 UNS S41500, a martensitic stainless steel that's become our go-to for forging high-integrity parts like valve bodies, pump shafts, and turbine blades. As a dedicated producer and exporter from China's industrial heartland, Gangsteel has hammered out (literally) over 10,000 tons of this alloy in the last decade, supplying giants in oil & gas, aerospace, and marine engineering.

If you're a forge shop manager tweaking dies for better flow or an engineer vetting materials for ASME compliance, this guide cuts through the noise with actionable forging properties, backed by our shop-floor trials and client successes.

We've all been there: a hot billet glowing under the press, only to worry about cracks or inconsistent grain. UNS S41500, often known as F6NM in forging circles, mitigates those headaches with its balanced chemistry and heat-treat response. In this hands-on breakdown, we'll explore its forging window, mechanical evolution post-forge, and why it's a smart pick for sour service. Drawing from our 25 years of dual-vacuum melting and open-die forging, expect real numbers, real pitfalls, and real savings—because at Gangsteel, we forge relationships as much as metal.

The Forging Edge: Why ASTM A473 UNS S41500?

ASTM A473 specifies stainless steel forgings for general use, and UNS S41500 fits like a glove for moderate-to-high strength apps where corrosion lurks. This spec demands tight controls on chemistry and testing, ensuring forgings like flanges or rings hold up under cyclic loads without surprise failures. What sets S41500 apart in forging? Its low carbon (0.15% max) and Ni/Mo additions make it "forgiving"—hot workability rivals 4140 carbon steel but with stainless perks like 12% Cr for oxidation resistance.

From our presses in Tianjin, we've forged S41500 up to 2,000 kg ingots into intricate shapes, hitting 95% yield rates. It's normalized at the mill for a starting microstructure that's austenitic at 1100°C, transforming to martensite post-quench for that signature toughness. No wonder it's NACE MR0175-approved for H2S environments—our forgings have powered subsea manifolds in the North Sea for years. If you're expanding into UNS stainless steel plates, consider S41500 forgings as the rugged sibling: denser at 7.85 g/cm³ but far more impact-resistant.

Forging Properties: Temperature, Strain Rates, and Microstructure Insights

Forging UNS S41500 under ASTM A473 isn't rocket science, but it rewards precision. We recommend a narrow window to avoid delta ferrite buildup or edge chilling—our trials show optimal results at 1050-1150°C start, finishing above 850°C.

Key Forging Parameters

• Forging Temperature Range: Initial 1100-1180°C (soaking 1 hr/25mm); final 900-950°C to retain ductility. Above 1200°C risks grain growth; below 800°C, work-hardening spikes fracture risk.
• Strain Rate: 0.1-1 s⁻¹for open-die; up to 10 s⁻¹for impression dies. Slow rates prevent shear bands— we've clocked 15% better surface finish at 0.5 s⁻¹.
• Reduction Ratio: 30-50% per pass; total 4:1 min for refined grain (ASTM 5-7). Over-reduction (>60%) invites centerline segregation.
• Lubrication & Die Design: Graphite-based for hot forging; draft angles 5-7° to ease ejection. Our dies for S41500 flanges incorporate vent holes to purge gases, cutting defects by 20%.

Microstructurally, S41500 starts as delta ferrite + austenite at forge temps, martensite-forming on quench. Temper at 600-650°C (2 hrs) yields tempered martensite with carbides for hardness without brittleness. Gangsteel's ESR (Electroslag Remelt) ingots minimize inclusions, ensuring clean forging flows—ultrasonic tests post-forge confirm zero laminations per ASTM A388.

M

echanical Properties Post-Forging

ASTM A473 requires tensile tests on forged blanks (machined specimens). Here's what you get after Q&T (Quench & Temper):

At 300°C service, properties dip <10%; cryogenic (-196°C) holds 85% yield. Our in-house Charpy lab (ISO 17025) routinely verifies these, with data showing forged S41500 outperforming cast equivalents by 30% in fatigue.

Equivalents and Standards Cross-Reference for Forgers

ASTM A473 UNS S41500 plays well globally, with equivalents easing multi-spec projects. Gangsteel forges to all, dual-marking for flexibility.

• ASME SA473: Pressure vessel forging twin—mandatory for Section VIII; identical props.
• EN 10222-5: 1.4313 (X3CrNiMo13-4) bars/forgings; EN 10204 3.2 certs standard.
• API 6A: F6NM forgings for wellheads; PSL-2 compliance via our NACE tests.
• DIN 17440: 1.4006 variant; tensile-matched for German machinery.

Vs. 17-4PH (austenitic-martensitic), S41500 forges easier (lower hot strength) but at lower cost—PREN 18 vs. 20, yet 25% cheaper. In a 2024 Australian mining forge, we subbed S41500 for 17-4PH in crusher jaws, trimming cycle times 15%. For sheet tie-ins, pair with ASTM A240 /A240M or ASME SA240/SA240M forgings.

Applications: Forged UNS S41500 in Action

ASTM A473 S41500 forgings dominate where strength meets corrosion: A182 F6NM flanges seal pipelines, A479 bars spin turbine rotors, A473 rings brace marine risers. In power, they're bolted for steam chests; aerospace, shaped into landing gear fittings.

Gangsteel highlight: 2023, a Korean shipyard forged 25 tons of S41500 rings for FPSO moorings—endured 5,000 cycles at 1000 psi without fatigue cracks, per Lloyd's surveys. Another: Venezuelan refinery's 500 kg valve bodies (A473 spec) handled 200°C sour crude, outlasting 410 SS by 2x. These wins stem from our forging sims (DEFORM software), predicting flows before the press drops.

Forging Best Practices and Common Pitfalls from the Trenches

Don't learn the hard way—here's our playbook. Preheat dies to 300°C; use hydraulic presses for uniform strain. Post-forge, normalize at 1050°C to dissolve carbides, then Q&T. Pitfall: Over-tempering (>700°C) softens too much— we've rescued batches by re-austenitizing.

Sustainability angle: S41500 forges with 20% less energy than duplexes, aligning with 2025 green mandates. Gangsteel recycles 95% scrap, cutting CO2 footprints.

Sourcing ASTM A473 UNS S41500 Forgings: Price and Procurement Guide

Pricing for A473 UNS S41500 forgings tracks alloy surcharges—stable at $2,600-2,800 USD per ton FOB in November 2025, up 5% on Ni volatility. Rough shapes: $2,600 base; machined +$300/ton.

• MOQ: 500 kg; samples 50 kg.
• Lead: 14-28 days; stock blanks 7 days.
• Add-Ons: UT (+$50/ton), custom heat (+$100/ton).

Gangsteel edges: In-house forging (5000-ton press), direct from melt—saves 20% vs. brokers. Quote for UNS S41500 stainless steel plate hybrids too.

FAQ: ASTM A473 UNS S41500 Forging Essentials

Q: What are the core forging properties of ASTM A473 UNS S41500?

A: Hot forge at 1050-1180°C, 30-50% reduction; yields 850 MPa tensile, 25% elongation post-Q&T. Grain refines to ASTM 6; NACE-compliant <22 HRC. Gangsteel's presses hit 95% yield, minimizing flash waste.

Q: How does UNS S41500 forging compare to 4140 alloy steel?

A: Similar workability (strain rate 1 s⁻¹), but S41500 adds Cr/Mo for corrosion—PREN 18 vs. none. Forges at lower force (15% less), ideal for stainless upgrades. We've converted 4140 runs to S41500, boosting service life 40%.

Q: What's the typical price for ASTM A473 UNS S41500 forgings?

A: $2,600-2,800/ton FOB for blanks; machined $3,000+. Volume discounts to $2,500 for 10+ tons. Q4 2025 stable; our mill-direct model undercuts imports by 25%.

Q: Can ASTM A473 UNS S41500 be forged for sour service?

A: Yes—MR0175/ISO 15156 via tempered condition, HIC <150% per ASTM A694. Forging refines structure for 35J impacts at -46°C. Supplied 10 tons to Shell; passed 1000-hr exposure.

Q: What heat treatment follows forging UNS S41500?

A: Normalize 1050°C/1hr, quench oil/water, temper 600-650°C/2hrs. Avoid 425-540°C sigma zone. Results: HRC 25-28, uniform martensite. Our protocols include full HT curves in certs.

Q: Are there equivalents for ASTM A473 UNS S41500 forgings?

A: ASME SA473 (pressure), EN 1.4313 (EU). Use SA473 for boilers; 1.4313 for DIN compliance. Dual-forged at Gangsteel—eased a French client's recert by 30 days.

Q: How do you test forging quality for UNS S41500?

 A: 100% UT (A388 Level 2), tensile per A473, macro etch for laps. ISO 17025 labs confirm; zero rejects in 2025 audits. Ties into UNS stainless steel plates for hybrid parts.

Q: What's the lead time for custom A473 UNS S41500 forgings?

A: 14 days stock shapes, 28 custom (up to 2000 kg). Expedite +$200/ton for 7 days. We've air-shipped 2-ton rings to Texas in 10 days amid shortages.