Stainless Steel 904L Bar Hardness Range
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Why Hardness Matters for 904L Stainless Steel Bars?
SAE 904L stainless steel bars are widely used in highly corrosive environments, but their mechanical strength, especially hardness, is just as critical for selecting the right material. Whether you're sourcing for chemical plant components, fasteners, or structural bars, knowing the hardness range of 904L stainless steel bars can help ensure long-term performance under mechanical stress.
This article covers the typical hardness range of 904L bars, how it compares to other stainless grades, and what influences the final hardness.
Typical Hardness Range of 904L Stainless Steel Bars
| Property | Value |
|---|---|
| Brinell Hardness (HBW) | 150 – 230 HBW (typical: ~190) |
| Rockwell B (HRB) | 80 – 95 HRB |
| Rockwell C (HRC) | Not commonly used (soft grade) |
| Condition | Annealed, solution-treated |
| Standard Reference | ASTM A276 / ASTM A479 / EN 10088-3 |
What Affects the Hardness of 904L Bars?
1. Heat Treatment Condition
904L bars are typically supplied in the solution-annealed condition (at ~1100–1150°C, water quenched), which gives the material:
Stable austenitic structure
Low hardness but good ductility
Excellent corrosion resistance
2. Cold Working / Cold Drawing
Cold working (e.g. cold drawn or peeled bars) can increase the hardness and yield strength of 904L:
Slight increase in HBW and HRB values
Used when higher mechanical properties are required (e.g. for valve stems, shafts, or flanges)
3. Bar Size and Section
Larger bar diameters may cool slower during processing, potentially affecting surface vs. core hardness. Standardized hardness is measured at room temperature on polished surfaces.
Mechanical Properties Overview (Annealed 904L Bar)
| Property | Typical Value |
|---|---|
| Tensile Strength | 490 – 710 MPa |
| Yield Strength (0.2% proof) | ≥ 220 MPa |
| Elongation (in 50mm) | ≥ 35% |
| Hardness (Brinell) | ~190 HBW |
904L vs Other Stainless Steel Grades (Hardness Comparison)
| Grade | Typical HBW Hardness | Hardening Method |
|---|---|---|
| 304L | 140 – 190 HBW | Cold working |
| 316L | 150 – 200 HBW | Cold working |
| 904L | 150 – 230 HBW | Cold working only |
| 17-4PH (H900) | 370 – 440 HBW | Precipitation hardening |
| Duplex 2205 | 250 – 290 HBW | Work + phase hardening |
904L offers slightly higher hardness than 316L due to its higher nickel and molybdenum content, but it remains a non-hardenable, highly corrosion-resistant alloy.
Applications Requiring 904L Bar Hardness
Pump shafts and impellers
Condenser tubes and fasteners in acid environments
Flanges and fittings in chemical plants
Seawater-handling equipment
Pharmaceutical and food-grade components
Stainless Steel 904L Bar in Stock
| Form | Size Range |
|---|---|
| Round Bar | Ø 6mm – 250mm |
| Hex Bar | Across flats 10mm – 70mm |
| Square/Flat Bar | Custom cut |
| Surface Finish | Peeled, ground, bright, or black |
Certified to ASTM A276, ASTM A479, EN 10088-3, and supplied with full material test certificates (MTC).
📞 Need Help Selecting the Right 904L Bar Hardness?
We supply high-quality 904L stainless steel bars in annealed or cold-worked conditions, tailored to your project requirements.
👉 Get a quote today with size, standard, and hardness requirements.
