ASME SA240 434 Stainless Steel Plate | SA240 Type 434
What is ASME SA240 434 Stainless Steel Plate?
As a professional stainless steel plate supplier and China Mill-Direct Supply / Mill Direct Exporter, SHH STEEL is pleased to present ASME SA240 434 Stainless Steel Plate, also known as SA240 Type 434.
ASME SA240 Type 434 is a ferritic stainless steel based on the 16–18% chromium composition of Type 430, with the intentional addition of molybdenum (typically 0.75–1.25%). The molybdenum significantly improves resistance to pitting and crevice corrosion in chloride-containing environments compared with standard Type 430, while retaining the good formability, oxidation resistance and economy of the ferritic family.
Type 434 is magnetic and cannot be hardened by heat treatment. It is commonly used in automotive trim and exterior applications, appliances, and other components exposed to mildly corrosive atmospheres where better localized corrosion resistance than 430 is required, but the higher cost of austenitic grades (304/316) is not justified.
SHH STEEL supplies ASME SA240 434 as true Mill Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, full heat traceability and shorter lead times. We offer a practical dimensional range and a selection of surface finishes suitable for both industrial and aesthetic applications.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASME SA240 / SA240M | Full compliance |
| Steel Grade | Type 434 (UNS S43400) | Confirmed |
| Product Form | Plate, Sheet, Coil | Available |
| Delivery Condition | Annealed | Standard |
| Thickness Range | 0.4 mm – 50 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 1500–2000 mm (wider on request) | Available |
| Length | Up to 6000 mm or cut-to-length / coil | Available |
| Surface Finish | 2B, BA, No.1, No.4, HL, Polished | Available |
| Certification | EN 10204 3.1 / ASME Mill Test Certificate | Available |
Chemical Composition
Heat Analysis (Ladle Analysis) according to ASME SA240 Type 434:
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.12 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 16.00 – 18.00 |
| Molybdenum (Mo) | 0.75 – 1.25 |
| Nickel (Ni) | ≤ 0.60 |
| Iron (Fe) | Balance |
Product Analysis (typical permissible variations):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.12 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 15.90 – 18.10 |
| Molybdenum (Mo) | 0.75 – 1.25 |
| Nickel (Ni) | ≤ 0.60 |
The addition of 0.75–1.25% molybdenum is the key differentiating feature of Type 434. Molybdenum enhances the stability of the passive film and significantly improves resistance to pitting and crevice corrosion in chloride environments compared with molybdenum-free Type 430.
Mechanical Properties
Annealed Condition (typical)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 450 MPa (65 ksi) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) |
| Elongation (in 50 mm) | ≥ 22% |
| Hardness | ≤ 183 HB |
Physical Properties
- Density: approximately 7.70–7.80 g/cm³
- Magnetic: Magnetic in all conditions
- Melting Range: approximately 1425–1510°C
Type 434 cannot be hardened by quenching and tempering. Strength is obtained in the annealed condition, with possible moderate increases through cold working.
Material Comparison
| Grade | Structure | Key Alloying Feature | Pitting Resistance | Typical Preference |
|---|---|---|---|---|
| SA240 Type 430 | Ferritic | 16–18% Cr | Baseline | General economical ferritic use |
| SA240 Type 434 | Ferritic | 16–18% Cr + 0.75–1.25% Mo | Improved | Better chloride resistance than 430 |
| SA240 Type 439 | Ferritic | 17–19% Cr + Ti | Good | Improved weldability & intergranular resistance |
| SA240 Type 436 | Ferritic | 16–18% Cr + Mo + Nb/Ti | Improved | Stabilized + Mo for higher performance |
| SA240 Type 304 | Austenitic | 18Cr-8Ni | Better | Superior general corrosion resistance |
ASME SA240 434 is selected when improved resistance to pitting and crevice corrosion is needed over standard 430, while remaining more economical than austenitic grades. For applications requiring both molybdenum and stabilization (better weldability), Type 436 is sometimes preferred. For maximum corrosion resistance, astm a240 type 304 stainless steel sheet plate or higher alloys should be considered. Related ferritic options include astm a240 type 430 stainless steel sheet plate and astm a240 type 439 stainless steel sheet plate.
Corrosion Resistance
ASME SA240 Type 434 offers good resistance to atmospheric corrosion, fresh water and many mild chemical environments, with noticeably better performance than Type 430 in chloride-containing atmospheres due to the molybdenum addition. It also provides excellent resistance to oxidation and scaling at elevated temperatures.
It is suitable for many outdoor and automotive exterior applications where road salt or mild chloride exposure occurs. However, it is still not recommended for severe seawater or highly aggressive chloride environments, where austenitic (316L) or duplex grades are required.
Weldability
ASME SA240 Type 434 has moderate weldability typical of ferritic stainless steels. Grain growth in the heat-affected zone can reduce toughness, so low heat input and proper procedures are recommended.
Matching or suitable ferritic/austenitic filler metals may be used. In some cases, post-weld annealing is beneficial. Overall weldability is comparable to Type 430; for significantly better welded corrosion performance, stabilized grades such as 439 are often preferred.
Heat Treatment
Type 434 is a ferritic stainless steel and cannot be hardened by quenching and tempering.
Annealing
- Temperature: typically 760 – 850°C
- Cooling: Air cool or furnace cool
Annealing is used to relieve stresses after cold working, restore ductility, and optimize corrosion resistance. Excessive time at high temperature should be avoided to limit grain growth.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | SA240 434 2B – most common for general fabrication |
| BA | Bright Annealed | SA240 434 BA – decorative and automotive trim |
| No.1 | Hot-rolled, annealed and pickled | SA240 434 No.1 – industrial plate |
| No.4 | Brushed (satin) finish | SA240 434 No.4 – architectural and visible surfaces |
| HL | Hairline finish | SA240 434 HL – decorative panels |
| Polished | Mirror or custom polish | SA240 434 Polished – high-end decorative applications |
SHH STEEL regularly supplies ASME SA240 434 in 2B and BA finishes, and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for ASME SA240 434 Stainless Steel Plate conform to ASME SA240 and the general requirements of ASTM A480.
Typical available size range for SA240 434 plate/sheet:
- Thickness: 0.4 mm – 50 mm (thicker plates available on request)
- Width: up to 1500–2000 mm (wider on request)
- Length: up to 6000 mm or supplied in coil / cut-to-length
Thickness, width, length and flatness tolerances are controlled within standard limits. Tighter tolerances for SA240 434 plate can be arranged for specific project needs. SHH STEEL provides precise dimensional control for both standard and custom-size SA240 434 material.
Equivalent Material Grades
| Grade / Designation | Standard | Notes |
|---|---|---|
| SA240 Type 434 | ASME SA240 | — |
| A240 Type 434 | ASTM A240 | Essentially identical |
| UNS S43400 | — | Unified Numbering System |
| 1.4113 / X6CrMo17-1 | EN 10088-2 | European equivalent |
| SUS434 | JIS G4305 | Japanese equivalent |
| Related Mo-bearing 430 | GB/T | Chinese approximate equivalents |
Related grades frequently evaluated with ASME SA240 434 include astm a240 type 430 stainless steel sheet plate, astm a240 type 439 stainless steel sheet plate, astm a240 type 436 stainless steel sheet plate, and astm a240 type 304 stainless steel sheet plate.
Applications
ASME SA240 Type 434 is used where improved pitting resistance over standard 430 is required at a still economical cost. Typical applications of SA240 434 include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Automotive | SA240 434 exterior trim, moldings, decorative parts |
| Appliances | SA240 434 panels and components exposed to mild chlorides |
| Architecture | SA240 434 cladding and decorative elements in mild atmospheres |
| Kitchen Equipment | SA240 434 components requiring better corrosion resistance |
| General Fabrication | SA240 434 formed parts in moderately corrosive environments |
| Industrial Equipment | SA240 434 parts needing improved pitting resistance over 430 |
Why Choose SHH STEEL
SHH STEEL is a China Mill-Direct Supply and Mill Direct Exporter of stainless steel plate. We maintain long-term strategic cooperation with major Chinese stainless steel mills and supply ASME SA240 Type 434 with the following advantages:
- Competitive mill-direct pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1 /3.2 ASME)
- Flexible dimensions and surface finishes (including SA240 434 2B, SA240 434 BA and SA240 434 No.1)
- Technical support for molybdenum-bearing ferritic material selection
- Reliable worldwide logistics and export documentation
FAQ
- What is the main advantage of SA240 434 over SA240 430?Type 434 contains molybdenum (0.75–1.25%), which significantly improves resistance to pitting and crevice corrosion in chloride-containing environments. SHH STEEL recommends 434 when better localized corrosion resistance than standard 430 is required.
- Is ASME SA240 434 magnetic?Yes, Type 434 is magnetic in all conditions. SHH STEEL supplies material that meets this characteristic.
- Can SA240 434 be hardened by heat treatment?No. As a ferritic stainless steel, it cannot be hardened by quenching and tempering. SHH STEEL supplies material in the annealed condition as standard.
- What is the density of SA240 Type 434?Approximately 7.70–7.80 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can SHH STEEL supply dual-certified ASME SA240 / ASTM A240 Type 434?Yes, SHH STEEL commonly supplies dual-certified ASME SA240 / ASTM A240 Type 434 material.
Conclusion
ASME SA240 434 Stainless Steel Plate (SA240 Type 434) is a molybdenum-bearing ferritic stainless steel that offers improved pitting and crevice corrosion resistance compared with standard Type 430, while retaining good formability, oxidation resistance and economy. It is a practical upgrade for automotive trim, appliances and other applications exposed to mild chloride environments.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASME SA240 Type 434 plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including SA240 434 2B, SA240 434 BA and SA240 434 No.1), or a competitive quotation.
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