1.4404 vs 1.4542 Stainless Steel: Corrosion Resistance
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What is 1.4404 stainless steel bar?
1.4404 stainless steel bar, also known as UNS S31603 (316L) austenitic stainless steel bar, complies with ASTM A479 standard, featuring chemical composition of 16.0-18.0% Cr, 10.0-14.0% Ni and 2.0-3.0% Mo (C≤0.03%), with diameter range of 5-200mm, minimum tensile strength of 485MPa, yield strength of ≥170MPa, and is manufactured via hot rolling/cold drawing followed by 1050-1100℃ solution annealing, suitable for chemical processing, marine engineering and food machinery due to its excellent chloride corrosion resistance (PREN 25-27, resisting ≤1000ppm Cl⁻).
What is 1.4542 stainless steel round bar?
1.4542 stainless steel round bar is a high-strength, precipitation-hardened (PH) martensitic alloy, also known as 17-4 PH or AISI 630, which possesses high hardness, good corrosion resistance (similar to Type 304 stainless steel), and excellent mechanical properties. Therefore, it is ideally suited for high-performance components in aerospace, oil and gas, and general engineering applications, such as shafts, valves, and gears.
1.4404 vs 1.4542 Stainless Steel: Standard & Grade Comparison
| Steel Grade | EN Number | Common Name | UNS | ASTM Equivalent | Steel Type |
|---|---|---|---|---|---|
| 1.4404 | EN 10088 | AISI 316L | S31603 | ASTM A276 / A479 Type 316L | Austenitic |
| 1.4542 | EN 10088 | 17-4 PH | S17400 | ASTM A564 Type 630 | Precipitation Hardening |
1.4404 vs 1.4542 Stainless Steel: Chemical Composition (wt.%)
1.4404 relies on Mo for corrosion resistance, while 1.4542 uses Cu + Nb precipitation hardening for high strength.
| Element | 1.4404 (316L) | 1.4542 (17-4 PH) |
|---|---|---|
| Carbon (C) | ≤ 0.03 | ≤ 0.07 |
| Chromium (Cr) | 16.5 – 18.5 | 15.0 – 17.5 |
| Nickel (Ni) | 10.0 – 13.0 | 3.0 – 5.0 |
| Molybdenum (Mo) | 2.0 – 2.5 | - |
| Copper (Cu) | - | 3.0 – 5.0 |
| Niobium (Nb) | - | 0.15 – 0.45 |
| Nitrogen (N) | ≤ 0.11 | - |
| Iron (Fe) | Balance | Balance |
1.4404 vs 1.4542 Stainless Steel: Mechanical Properties
| Property | 1.4404 (316L) | 1.4542 (H900 condition)* |
|---|---|---|
| Tensile Strength (MPa) | ≥ 515 | ≥ 1310 |
| Yield Strength (MPa) | ≥ 205 | ≥ 1170 |
| Elongation (%) | ≥ 40 | ≥ 10 |
| Hardness | ≤ 217 HB | ≤ 40 HRC |
| Impact Toughness | Excellent | Good |
*Mechanical properties of 1.4542 vary significantly depending on heat treatment condition (H900, H1025, H1150, etc.).
1.4404 vs.1.4542 Stainless Steel Bars: Corrosion Resistance
1.4404 (316L) has a PREN value of approximately 24-26, offering good corrosion resistance to general corrosion, chlorides, and oxidizing acids, but its corrosion resistance is limited in highly acidic or chloride pitting environments. 1.4542 (630, 17-4PH) is a precipitation-hardening martensitic stainless steel with a PREN value of approximately 20-22. While it is resistant to oxidation and some acids, it is more susceptible to pitting and crevice corrosion in chloride media than 1.4404.
1.4404 vs.1.4542 Stainless Steel Bars: Hardness
The typical hardness of 1.4404 in the solution-annealed state is ≤ 90 HRB (≈ 200 HV), which can be slightly increased by cold working. 1.4542 can be age-hardened to a hardness of 28-38 HRC (≈ 280-400 HV), providing higher hardness and strength, but at the cost of reduced ductility and toughness.
Differences between 1.4529 and 1.4404
1.4529 (UNS N08904, 904L) is a super austenitic stainless steel containing approximately 19-21% chromium, 24-26% nickel, and 4.5-5.5% molybdenum. Its pitting resistance equivalent number (PREN) is approximately 34-38, providing excellent resistance to sulfuric acid corrosion, chloride pitting, and stress corrosion cracking in corrosive environments. 1.4404 (316L), on the other hand, contains only 2-2.5% molybdenum, with a PREN of approximately 24-26, making it suitable for less corrosive environments and offering better weldability and lower cost.
GNEE is a reliable supplier of 17-4PH round bars, offering UNS S17400 / W.Nr. 1.4542 round bars with diameters typically ranging from Ø6 mm to Ø450 mm, available in solution annealed or solution annealed and aged conditions.
All 17-4PH stainless steel round bars are manufactured according to ASTM A276 and ASTM A479 standards and can be supplied with EN 10204 3.1 certificates.
GNEE offers various product forms, such as hot-rolled bars, forged bars, peeled bars, polished bars, and cut-to-length bars, to meet different processing and performance requirements.
For transportation and packaging, the round bars are protected with anti-rust oil, plastic wrapping, and packaged in seaworthy wooden crates or steel strapping.
