Stainless Steel AISI 630: Properties, Applications, and Features
✅ General Technical Characteristics
Stainless steel AISI 630 (17-4PH) is a martensitic precipitation-hardening stainless steel that offers high strength, corrosion resistance, and excellent mechanical properties. Due to its alloying with copper and chromium, this steel demonstrates exceptional resistance to aggressive environments, including seawater and chemical reagents.
Main Characteristics:
- High strength and hardness after heat treatment.
- Excellent corrosion resistance, comparable to AISI 304 and AISI 316.
- High impact toughness and wear resistance.
- Good machinability and weldability.
- Resistance to fatigue failure and crack formation.
🔬 Chemical Composition AISI 630 (%)
- Carbon (C): ≤ 0.07
- Silicon (Si): ≤ 1.00
- Manganese (Mn): ≤ 1.00
- Phosphorus (P): ≤ 0.040
- Sulfur (S): ≤ 0.030
- Chromium (Cr): 15.0 – 17.5
- Nickel (Ni): 3.0 – 5.0
- Copper (Cu): 3.0 – 5.0
- Niobium (Nb): 0.15 – 0.45
💡 The addition of copper enhances strength, while niobium improves resistance to high temperatures and heat treatment.
🏭 Applications
Due to its unique properties, AISI 630 (17-4PH) steel is widely used in industries requiring high-strength and corrosion-resistant materials.
Main Application Areas:
- Aerospace industry (structural elements, engine components).
- Defense industry (weapon housings, high-load mechanisms).
- Marine and shipbuilding sector (propeller shafts, turbine components).
- Chemical and petrochemical industry (pipelines, valves, reactor systems).
- Medical equipment (orthopedic implants, surgical instruments).
📊 Mechanical Properties
- Tensile Strength (Rm): 930 – 1310 MPa (after aging)
- Yield Strength (Rp0.2): ≥ 800 MPa
- Hardness (HB): 260 – 388 HB (depending on heat treatment)
- Elongation (A5): ≥ 10 %
⭐ Features
- High strength – retains its properties even under extreme loads.
- Corrosion resistance – performs well in aggressive environments.
- Heat treatability – improves mechanical properties based on specific requirements.
- Good machinability – easily processed and polished.
- Wear resistance – ensures a long service life under high-load conditions.
This steel is an ideal choice for applications requiring strength, durability, and resistance to external influences.
Delivery forms for AISI 630 / EN 1.4542 steel products
| Circle AISI 630 / EN 1.4542 | Diameter: 6 – 500mm |
| Sheet AISI 630 / EN 1.4542 | Thickness: 0.5 – 100mm |
| Pipe AISI 630 / EN 1.4542 | – Hot-rolled round tube Ø 38 to 244.5 mm, thickness 3 to 25 mm – Cold-drawn round tube 219.1mm 0.9 to 14.2mm thick |
| Hex AISI 630 / EN 1.4542 | Diameter: 17-65mm |
| AISI 630 / EN 1.4542 strip | Thickness: 5-50mm ; Width: 50-250mm |
| Square AISI 630 / EN 1.4542 | Size: 10- 80mm |




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