Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
AM-350 is a chromium-nickel-molybdenum semi-austenitic precipitation-hardening (PH) stainless steel. This datasheet presents the material within the American (ASTM / ASME / AMS / UNS) standard system.
With about 16.5% chromium, 4.3% nickel, 2.75% molybdenum and a controlled nitrogen addition, AM-350 combines high strength and excellent weldability with corrosion resistance comparable to type 316 — superior to the other PH and the hardenable 400-series grades. It is supplied in the soft austenitic condition (Condition A), formed, then transformed to martensite and precipitation-hardened by a multi-step heat treatment. The low-temperature hardening gives minimum distortion. It is widely used in edge-welded bellows and other applications combining high strength with formability.
Typical applications include aerospace structural and bellows components, edge-welded bellows, precision seals, semiconductor-equipment couplings and high-vacuum-system hardware.
Typical values, SCT1000 condition.
| Property | Value | Unit |
|---|---|---|
| Density | 7.91 | g/cm³ |
| Melting range | 1400–1440 | °C |
| Elastic modulus | 200 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 11.7 | µm/m·°C |
| Thermal conductivity (20 °C) | 14.2 | W/m·K |
| Specific heat (20 °C) | 480 | J/kg·K |
| Structure | Semi-austenitic (precipitation-hardening) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 16.0 | 17.0 | Corrosion resistance |
| Nickel | Ni | 4.0 | 5.0 | Austenite stability |
| Molybdenum | Mo | 2.50 | 3.25 | Strength; pitting resistance |
| Nitrogen | N | 0.07 | 0.13 | Strengthening element |
| Manganese | Mn | 0.50 | 1.25 | Deoxidiser; austenite former |
| Silicon | Si | — | 0.50 | Deoxidiser |
| Carbon | C | 0.07 | 0.11 | Strengthening element |
| Phosphorus | P | — | 0.040 | Residual impurity |
| Sulphur | S | — | 0.030 | Residual impurity |
Typical values by heat-treatment condition, per ASTM A693 / AMS 5548 for UNS S35000.
| Condition | Tensile strength | 0.2% Yield | Hardness |
|---|---|---|---|
| SCT850 | ≥1410 MPa (205 ksi) | ≥1170 MPa (170 ksi) | ~48 HRC |
| SCT1000 | ≥1210 MPa (175 ksi) | ≥1050 MPa (152 ksi) | ~42 HRC |
| DA (double-aged) | ≥1140 MPa (165 ksi) | ≥1000 MPa (145 ksi) | ~40 HRC |
| Condition A (annealed) | ~1100 MPa (160 ksi) | ~380 MPa (55 ksi) | ~B95 HRB |
Confirm against the mill test report. Elongation typically ≥8–13% depending on condition.
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Very Good | Comparable to type 316 |
| Mild acids | Good | Molybdenum addition aids resistance |
| Chloride pitting | Good | Better than other PH grades (Mo) |
| Oxidation | Good | At elevated temperature |
| Seawater | Limited | Not recommended for prolonged exposure |
Corrosion resistance is comparable to type 316 in most media and superior to the other precipitation-hardening and the hardenable 400-series grades.
A semi-austenitic precipitation-hardening alloy; supplied in Condition A (soft, austenitic) and hardened by a multi-step transformation-plus-ageing sequence.
Solution Treatment (Condition A) Supplied solution-treated (~1040 °C) in the soft austenitic condition for forming.
Transformation and Precipitation Hardening SCT (sub-zero cooling and tempering): condition at ~930 °C, refrigerate (~−75 °C) to transform austenite to martensite, then temper — SCT850 (~455 °C) for maximum strength, SCT1000 (~540 °C) for higher toughness. DA (double ageing): age at ~735 °C then ~455 °C for components where refrigeration is impractical. Air cool after tempering.
Excellent weldability — a particular advantage of this alloy, especially for edge-welded bellows. Matching filler is used; heat treatment after welding develops full properties.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | Matching AM-350-type filler |
| Resistance / seam | Excellent | — (edge-welded bellows) |
| GMAW / MIG | Good | Matching filler |
Weld in Condition A; heat-treat after welding to develop strength.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Preferred condition | Condition A for best formability and machinability |
| Work hardening | Moderate-to-high rate; positive feeds, rigid setup |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good in Condition A (formable semi-austenitic PH) |
| Hot forming | ~1150–950 °C; solution treat + harden afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Aerospace | Bellows, structural parts, fittings | High strength + weldability |
| Bellows / seals | Edge-welded bellows, precision seals | Formability + fatigue resistance |
| Semiconductor | Couplings, high-vacuum hardware | Cleanliness + corrosion resistance |
| General industrial | High-strength welded components | Strength + corrosion resistance |
| Product Form | ASTM Standard | ASME / AMS |
|---|---|---|
| Plate, sheet and strip | ASTM A693 grade 633 | ASME SA-693 / AMS 5548 |
| Bar and wire | ASTM A564 (633) | AMS 5745 |
| Welded bellows stock | — | AMS 5548 |
| Welding consumables | Matching AM-350-type filler | — |
Chromium-nickel-molybdenum semi-austenitic precipitation-hardening stainless steel. UNS S35000.
| Grade | Cr % | Ni % | Mo % | Other | Best Used For |
|---|---|---|---|---|---|
| AM-350 | 16–17 | 4–5 | 2.5–3.25 | N | Semi-austenitic PH; bellows, weldability, 316-like corrosion |
| AM-355 | 15–16 | 4–5 | 2.5–3.25 | N | Semi-austenitic PH; highest strength |
| 17-7PH | 16–18 | 6.5–7.75 | — | Al | Semi-austenitic PH; springs, formability |
| PH15-7Mo | 14–16 | 6.5–7.75 | 2.0–3.0 | Al | Semi-austenitic PH; high strength at temperature |
| 17-4PH | 15–17.5 | 3–5 | — | Cu, Nb | Martensitic PH; general high strength |
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