AISI 430F Stainless Steel Plate | UNS S43020 | Free Machining 430
What is AISI 430F Stainless Steel?
As a professional China steel mill-Direct Supply and stainless steel plate supplier, SHH STEEL is pleased to present AISI 430F Stainless Steel Plate.
AISI 430F is widely known and searched under many different names and designations, including AISI 430F, UNS S43020, 430F stainless steel, 430F stainless steel plate, free machining 430, SUS430F, 1.4104, X14CrMoS17 and A240 Type 430F. All these names refer to the sulfur-bearing free-machining variant of Type 430.
AISI 430F keeps the 16–18% chromium ferritic base of A240 430, but sulfur is raised (typically 0.15% minimum) to form manganese sulfides that break chips and raise machining speed. The grade remains magnetic and is normally supplied annealed. It is used where large volumes of turning, drilling or screw-machine work are required.
Because sulfur improves machinability, AISI 430F has slightly lower corrosion resistance, weldability and toughness than standard 430. It is most common as bar, rod and machined parts; plate and sheet can be supplied when the drawing specifies UNS S43020 in flat form.
SHH STEEL supplies AISI 430F as true China steel mill-Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, complete heat traceability and reliable delivery.
AISI 430F is frequently compared with A240 430, A240 434, A240 439, A240 410, A240 429 and a240 304. SHH STEEL provides technical support to help customers choose the most appropriate grade.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade | AISI 430F / UNS S43020 | Confirmed |
| Related Standards | ASTM A240 related, ASTM A582, EN 1.4104, JIS SUS430F | Available |
| Product Form | Plate, Sheet, Bar (as specified) | Available |
| Delivery Condition | Annealed | Standard |
| Thickness Range | 0.5 mm – 50 mm plate (other sizes on request) | Custom sizes supported |
| Width | Up to 1500–2000 mm | Available |
| Length | Up to 6000 mm or cut-to-length | Available |
| Surface Finish | No.1, 2B, peeled / machined as specified | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
SHH STEEL can supply AISI 430F dual-certified to the required ASTM / EN / JIS designation when specified by the project.
Chemical Composition
Typical Chemical Composition of AISI 430F (UNS S43020):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.12 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.25 |
| Phosphorus (P) | ≤ 0.060 |
| Sulfur (S) | ≥ 0.15 |
| Chromium (Cr) | 16.00 – 18.00 |
| Molybdenum (Mo) | ≤ 0.60 |
| Nickel (Ni) | ≤ 0.75 |
| Iron (Fe) | Balance |
The defining feature of AISI 430F is the high sulfur content in a 430-type ferritic base. Manganese sulfides act as chip breakers and lubricate the cutting tool. The selenium-bearing companion grade is AISI 430FSe (UNS S43023). SHH STEEL carefully controls sulfur so machinability is consistent without unnecessary loss of formability.
Mechanical Properties
Annealed Condition (typical values)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 450 MPa |
| Yield Strength (0.2%) | ≥ 205 MPa |
| Elongation (in 50 mm) | ≥ 16–22% |
| Hardness | ≤ 183–217 HBW |
AISI 430F has mechanical strength similar to Type 430, but ductility and toughness are usually a little lower because of the sulfide inclusions. It is magnetic and cannot be hardened by conventional quench and temper. SHH STEEL supplies AISI 430F in the annealed condition unless otherwise specified.
Physical Properties
Density is approximately 7.70–7.75 g/cm³. Melting range is approximately 1425–1510°C.
Material Comparison
| Grade | UNS | Free Machining | Corrosion vs 430 | Weldability | Typical Preference |
|---|---|---|---|---|---|
| AISI 430 | S43000 | No | Baseline | Better | Formed / welded / decorative plate |
| AISI 430F | S43020 | Yes (sulfur) | Slightly lower | Lower | High-speed machining parts |
| AISI 430FSe | S43023 | Yes (selenium) | Slightly lower | Lower | Screw-machine parts |
| AISI 434 | S43400 | No | Better pitting | Good | Automotive trim / chloride atmospheres |
| AISI 439 | S43035 | No | Better welded | Better | Exhaust and welded ferritic service |
| AISI 303 | S30300 | Yes (austenitic) | Different family | Lower | Free-machining 300-series |
AISI 430F is selected only when machining productivity is the main requirement. For formed, polished or welded plate, SHH STEEL recommends standard A240 430. For better pitting resistance without free-machining additions, compare with A240 434.
Corrosion Resistance
AISI 430F has useful resistance to mild atmospheres, fresh water and many household or food-contact environments, similar in principle to Type 430. Sulfide inclusions reduce resistance to pitting and crevice corrosion, so 430F is not the first choice for wet chloride service or highly polished decorative plate.
For better corrosion performance in the same chromium range, SHH STEEL recommends A240 430, A240 434 or a240 304.
Weldability
AISI 430F has lower weldability than standard 430. Sulfur increases the risk of hot cracking and reduces toughness in the weld zone. Welding is possible with controlled procedures, but it is not the preferred fabrication method for this grade.
If the part must be both machined and welded, SHH STEEL often recommends machining from 430F bar and using standard 430 plate for welded sections, or switching to A240 430 / A240 439.
Heat Treatment
AISI 430F is normally supplied in the annealed condition by SHH STEEL.
Annealing softens the material after hot working and prepares it for machining. The grade cannot be hardened by conventional quench and temper. SHH STEEL controls heat treatment to keep hardness and machinability consistent.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| No.1 | Hot-rolled, annealed and pickled | AISI 430F No.1 – industrial plate |
| 2B | Cold-rolled, annealed, pickled, skin-passed | AISI 430F 2B – thin plate / sheet |
| Peeled / Turned | Machined bar surface | AISI 430F bar for screw-machine work |
| Special | Ground or custom finishes | AISI 430F Special – on request |
SHH STEEL supplies AISI 430F in the finish required by the machining or fabrication drawing.
Tolerances
Dimensional tolerances for AISI 430F plate supplied by SHH STEEL generally conform to ASTM A480 practices. Bar products follow the applicable bar standard.
Typical plate size range is thickness 0.5 mm – 50 mm, width up to 1500–2000 mm, and length up to 6000 mm or cut-to-length. SHH STEEL can support tighter machining allowances when required.
Equivalent Material Grades
| Grade / Designation | Standard / Region | Notes |
|---|---|---|
| AISI 430F | AISI | Main commercial keyword |
| UNS S43020 | Unified Numbering System | Primary UNS designation |
| 1.4104 / X14CrMoS17 | EN (Europe) | Closest European free-machining ferritic |
| SUS430F | JIS (Japan) | Japanese related grade |
| Related 430 / 430FSe | Multiple | Standard / Se-bearing variants |
| Related Y1Cr17 related | GB/T (China) | Chinese free-machining ferritic |
Related grades for comparison include A240 430, A240 434, A240 439, A240 429, A240 410 and a240 304.
Applications
AISI 430F is selected when high machining speed is more important than maximum corrosion resistance or weldability. Typical applications of AISI 430F include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Screw-Machine Parts | AISI 430F fittings, bushings, pins and turned components |
| Fasteners & Hardware | AISI 430F screws, nuts and machined fasteners |
| Valve & Pump Parts | AISI 430F machined seats, sleeves and small components |
| Food & Household Equipment | AISI 430F machined inserts and hardware |
| General Machining | UNS S43020 bar and plate for high-speed machining |
| Industrial Equipment | AISI 430F No.1 plate cut for subsequent machining |
SHH STEEL supplies AISI 430F for these machining-intensive applications with consistent quality. For related industry solutions, see our equipment manufacturing and machinery industry pages. Supporting services include cnc steel machining services, steel cutting services and worldwide shipping service.
Why Choose SHH STEEL
SHH STEEL is a China steel mill-Direct Supply specializing in stainless steel plate, sheet and machining grades. By working directly with major Chinese stainless steel mills, SHH STEEL supplies AISI 430F with the following advantages:
- Genuine China steel mill-Direct Supply pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1)
- Sulfur-controlled AISI 430F material optimized for high-speed machining
- Flexible dimensions and finishes (including AISI 430F No.1 and AISI 430F 2B)
- Technical support for selection among AISI 430, 430F, 434 and 439
- Value-added services including cnc steel machining services, steel cutting services and worldwide shipping service
For more information about our company and full product range, please visit China steel Mill Agent-SHH STEEL.
FAQ
- What are the other common names for AISI 430F?AISI 430F is also known as UNS S43020, free machining 430, SUS430F, 1.4104 and X14CrMoS17. SHH STEEL can certify the required designation.
- What is the difference between AISI 430F and AISI 430?AISI 430F contains added sulfur for much better machinability. Standard 430 has better corrosion resistance, weldability and formability. SHH STEEL recommends 430F only when machining is the main requirement.
- What is the difference between AISI 430F and AISI 430FSe?430F uses sulfur; 430FSe uses selenium as the free-machining addition. Both are designed for high-speed machining. SHH STEEL can supply the grade specified on the drawing.
- Is AISI 430F magnetic?Yes. AISI 430F is ferritic and remains magnetic in the annealed condition.
- What is the density of AISI 430F?Approximately 7.70–7.75 g/cm³. SHH STEEL provides mill certificates confirming chemistry and mechanical properties.
- Can AISI 430F be welded easily?eldability is lower than standard 430 because of sulfur. SHH STEEL recommends 430 or 439 when welding is a primary fabrication method.
- Does SHH STEEL supply dual-certified AISI 430F / UNS S43020 material?Yes, SHH STEEL commonly supplies dual-certified material upon request.
Conclusion
AISI 430F Stainless Steel Plate is the free-machining sulfur-bearing variant of Type 430. It is chosen for high-speed turning, drilling and screw-machine work where chip breaking matters more than maximum corrosion resistance or weldability. For formed, polished or welded plate, standard AISI 430 remains the better choice.
As a professional China steel mill-Direct Supply, SHH STEEL provides high-quality AISI 430F / UNS S43020 material with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, plate or bar sizes, surface finish options (including AISI 430F No.1 and AISI 430F 2B), or a competitive quotation.
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