Comparison of 410 (Martensitic) and 430 (Ferritic) Stainless Steel

1. Two Families, Two Behaviors

Type 410 is a martensitic stainless steel containing 11.50-13.50% chromium, while type 430 is a ferritic stainless steel containing 16.00-18.00% chromium. Both are magnetic and both are relatively economical compared with austenitic grades, but they behave differently under heat treatment: 410 can be hardened by quenching and tempering, whereas 430 cannot be hardened by heat treatment at all.

2. Chemical Composition (ASTM A240)

The table below lists the specified limits of both grades per ASTM A240. Iron makes up the balance.

Element (wt %)	Type 410 (UNS S41000)	Type 430 (UNS S43000)
Carbon (C)	0.15 max	0.12 max
Chromium (Cr)	11.50-13.50	16.00-18.00
Nickel (Ni)	0.75 max	0.75 max
Manganese (Mn)	1.00 max	1.00 max
Silicon (Si)	1.00 max	1.00 max
Phosphorus (P)	0.040 max	0.040 max
Sulfur (S)	0.030 max	0.030 max
Nitrogen (N)	Not specified	0.10 max

3. Mechanical Properties and Heat Treatment Response

In the annealed condition, ASTM A240 requires the following minimum values.

Property (annealed, min)	Type 410	Type 430
Tensile strength	485 MPa	415 MPa
Yield strength (0.2 % offset)	205 MPa	205 MPa
Elongation in 50 mm	20 %	20 %

The decisive difference is heat treatment. After austenitizing, quenching and tempering, 410 can reach tensile strengths in the range of roughly 650-850 MPa depending on the tempering temperature, with a corresponding increase in hardness, which is why it is used for wear-resistant and load-bearing parts. Type 430 develops strength only through cold working, and its ductility is restored by annealing.

4. Corrosion Resistance

The higher chromium content of 430 gives better resistance to mild atmospheric corrosion and to nitric and organic acids. Type 410 offers useful but more limited corrosion resistance, and its behavior depends on the final heat-treated condition. Both grades are susceptible to pitting and crevice corrosion in chloride environments and neither should be specified for saltwater service. Type 430 is additionally susceptible to intergranular corrosion if heated in the 400-900 C range, for example during welding, because chromium carbides can form at grain boundaries.

5. Applications and Equivalent Grades

Typical applications of 410 include fasteners, shafts, valve trim, pump components, cutlery and surgical instruments, where hardness, wear resistance or moderate corrosion resistance is needed. Typical applications of 430 include appliance trim, automotive trim, kitchenware, sinks, architectural panels and fasteners, where appearance, formability and economy dominate. Equivalent designations are: 410 equals SUS410 per JIS G4303, material 1.4006 per EN 10088, UNS S41000; 430 equals SUS430 per JIS G4303/G4304, material 1.4016 per EN 10088, UNS S43000.

Frequently Asked Questions

Can type 430 be hardened by heat treatment? No. 430 is ferritic and cannot be hardened by quenching and tempering. Its strength can only be increased by cold working.

Which grade is stronger, 410 or 430? In the annealed condition 410 has a higher minimum tensile strength (485 MPa versus 415 MPa). After hardening and tempering, 410 can be substantially stronger and harder than any condition of 430.

Are 410 and 430 magnetic? Yes. Both are magnetic because they belong to the martensitic and ferritic families, which contain no austenite-stabilizing nickel in significant amounts.

Which grade resists corrosion better? In mild atmospheric or acidic-free environments, 430 generally resists corrosion better because of its higher chromium content. Both grades perform poorly in chloride-rich environments.

What are the standard equivalents of 410 and 430? 410 corresponds to SUS410 (JIS G4303), 1.4006 (EN 10088) and UNS S41000. 430 corresponds to SUS430 (JIS G4303/G4304), 1.4016 (EN 10088) and UNS S43000.

Which grade is better for knife blades? 410 is the better choice for budget hardenable blades because it can be hardened and tempered to a sharp, wear-resistant edge. 430 is used mainly for decorative tableware where edge holding is not critical.