Alloy 350 / S35000 / AM350 Stainless Steel
1. Introduction and Applications of Alloy 350
Alloy 350, also known by its UNS designation S35000 or the common trade name AM350, is a chromium-nickel-molybdenum stainless steel. It belongs to the family of precipitation-hardening (PH) stainless steels but is distinctively classified as a semi-austenitic grade. This unique classification means that FUSHUN SPECIAL STEEL produces this material to retain an austenitic structure in the annealed condition, allowing for excellent formability, similar to standard 300-series stainless steels. However, it can be transformed into a hard, high-strength martensitic structure through specific heat treatments, such as sub-zero cooling or double aging.
As a premier manufacturer, FUSHUN SPECIAL STEEL utilizes advanced melting technologies to ensure the purity and consistency of Alloy 350. This material is designed for applications requiring a combination of high strength, good corrosion resistance, and the ability to withstand elevated temperatures. It bridges the gap between the formability of austenitic grades and the strength of martensitic grades.
Typical Applications
Due to its versatile properties, S35000 is widely used in critical industries. We supply this material for:
2. Chemical Composition of S35000
The chemical balance of AM350 is critical to its semi-austenitic nature. At FUSHUN SPECIAL STEEL, we strictly control the composition, particularly the Nitrogen content, which acts as an austenite stabilizer. Below is the typical composition range we adhere to:
| Element | Min (%) | Max (%) |
|---|---|---|
| Carbon (C) | 0.07 | 0.11 |
| Manganese (Mn) | 0.50 | 1.25 |
| Silicon (Si) | – | 0.50 |
| Chromium (Cr) | 16.00 | 17.00 |
| Nickel (Ni) | 4.00 | 5.00 |
| Molybdenum (Mo) | 2.50 | 3.25 |
| Nitrogen (N) | 0.07 | 0.13 |
| Phosphorus (P) | – | 0.040 |
| Sulfur (S) | – | 0.030 |
3. Mechanical Properties
The mechanical properties of Alloy 350 vary significantly depending on the heat treatment condition. In the annealed state, it is relatively soft and formable. After hardening (e.g., SCT 850 condition), it achieves high strength. FUSHUN SPECIAL STEEL guarantees properties that meet international standards.
| Condition | Tensile Strength (MPa) | Yield Strength 0.2% (MPa) | Elongation (%) | Hardness (HRC) |
|---|---|---|---|---|
| Annealed | ~ 1100 Max | ~ 415 | 30 Min | Max 30 HRC |
| SCT 850 (Hardened) | 1310 Min | 1035 Min | 10 Min | 45-50 HRC |
*Note: SCT 850 involves Sub-Zero Cooling and Tempering. Mechanical values are typical and can be customized based on specific client requirements.
4. Heat Treatment of AM350
Proper heat treatment is essential to unlock the potential of Alloy 350. As a fully integrated manufacturer, FUSHUN SPECIAL STEEL provides materials in the annealed condition or heat-treated to your specifications.
Annealing
Typically performed at 1065°C (1950°F) followed by rapid cooling. This retains the austenitic structure for forming.
Hardening Methods
This method involves cooling the material to -73°C (-100°F) to trigger the martensitic transformation, followed by tempering at 455°C (850°F) or higher to achieve desired hardness and ductility.
An alternative method involving a two-step aging process, typically used when sub-zero facilities are not available, though SCT usually provides superior properties.
5. Equivalent Grades and Standards
We manufacture Alloy 350 to meet various international standards. While it is primarily known by its US designations, we ensure compliance with global specifications.
| Region / Standard | Grade / Designation |
|---|---|
| USA (UNS) | S35000 |
| USA (Common Name) | AM 350 / Alloy 350 |
| USA (AMS) | AMS 5548, AMS 5554, AMS 5745 |
| USA (ASTM) | ASTM A693 (Type 633) |
6. Supply Forms and Dimensions
FUSHUN SPECIAL STEEL is equipped to produce Alloy 350 in various forms through Hot Rolling or Hot Forging processes. We cater to large-scale industrial requirements and bulk orders.
Available Shapes
- Round Bars
- Flat Bars
- Plates / Sheets
- Wire / Coil
Size Range
- Round Bar: Dia 10mm – 800mm
- Flat/Plate: Thickness 10mm – 500mm, Width up to 800mm
- Forged Blocks: Custom dimensions available
- Custom Sizes: We welcome inquiries for non-standard dimensions.
We specialize in bulk manufacturing. If you have specific dimensional requirements or large tonnage needs, please contact us directly.
7. Why Choose FUSHUN SPECIAL STEEL?
As a leading manufacturer, we control every step of the production process to ensure the highest quality for our Alloy 350 products. Here are our key advantages:
Premium Smelting Technology
We utilize Electro-Slag Remelting (ESR), Vacuum Induction Melting (VIM), and Vacuum Arc Remelting (VAR) technologies. This ensures high purity, low gas content, and superior microstructure for high-end aerospace and industrial applications.
In-House Heat Treatment
Our facility is equipped with advanced heat treatment furnaces. We perform annealing, sub-zero cooling, and aging in-house. This guarantees stable mechanical properties, consistent quality control, and faster delivery times.
Machining Capabilities
Beyond raw material production, we offer value-added services including turning, peeling, and grinding. We can deliver “bright bars” or pre-machined components, saving our downstream customers significant time and processing costs.
Manufacturer Direct
Buying directly from FUSHUN SPECIAL STEEL means no middlemen. We welcome large-volume orders and can provide competitive factory-direct pricing with full material traceability.
Ready to Order Alloy 350 / S35000?
Contact FUSHUN SPECIAL STEEL today for quotes on high-quality stainless steel. We are ready to fulfill your bulk requirements.
