SS 410 Round Bars / 410 Bar / AISI 410 Bar / SAE 410 Bars

Product Description

AISI 410 (UNS S41000) is the baseline, general-purpose martensitic stainless steel. It contains 11.5% to 13.5% chromium, providing a cost-effective combination of moderate corrosion resistance, high mechanical strength, and excellent wear properties when heat-treated.

Unlike austenitic stainless steels (such as 304 or 316), Type 410 is magnetic in all conditions and can be thermally hardened via quenching and tempering, much like standard carbon alloys.

1. Chemical Composition (Weight %)

The chemistry of 410 is kept lean and balanced to allow full transformation to a hard martensitic structure during heat treatment while maintaining standard corrosion thresholds.

2. Mechanical Properties by Heat-Treated Condition

The final properties of a 410 round bar depend heavily on its heat treatment. It is typically procured in one of two distinct conditions:

Condition A (Annealed)

Supplied in a soft, highly machinable state.

• Tensile Strength: $\approx 70,000 \text{ psi}$ ($480 \text{ MPa}$)

• Yield Strength: $\approx 40,000 \text{ psi}$ ($275 \text{ MPa}$)

• Hardness: $\le 217 \text{ HBW}$ ($\approx 96 \text{ HRB}$)

Condition H (Hardened & Tempered)

Quenched from around $1750^\circ\text{F}$ ($954^\circ\text{C}$) and tempered. Depending on the tempering temperature selected, typical properties fall into these minimum brackets:

• Tensile Strength: $\ge 100,000 - 135,000 \text{ psi}$ ($690 - 930 \text{ MPa}$)

• Yield Strength (0.2% Offset): $\ge 80,000 - 100,000 \text{ psi}$ ($550 - 690 \text{ MPa}$)

• Hardness Range: $217 - 320 \text{ HBW}$ (20 to 35 HRC)

⚠️ Metallurgical Warning: Avoid tempering AISI 410 within the range of $750^\circ\text{F}$ to $1050^\circ\text{F}$ ($400^\circ\text{C}$ to $565^\circ\text{C}$). Tempering in this window causes "temper embrittlement," drastically dropping the material's impact toughness and reducing its localized corrosion resistance.

3. Fabrication & Processing Guidelines

Machinability

In the annealed state, Type 410 machines similarly to AISI 4130 alloy steel, with a machinability rating of roughly 55% of AISI 1212.

• It cuts cleanly, but because it forms tough, gummy chips, using chip breakers is recommended.

• Once hardened to Condition H, machining becomes significantly more difficult, requiring rigid setups and premium carbide tooling.

Corrosion Resistance

Type 410 resists atmosphere, fresh water, mild acids, and alkalis. However, it exhibits substantially lower corrosion resistance than Type 304 or 316. To maximize its corrosion potential, the surface must be fully polished, passivated, and hardened; the annealed state is more susceptible to localized pitting.

Welding Precautions

Because of its high air-hardenability, welding 410 bars introduces a localized zone of brittle, untempered martensite in the Heat-Affected Zone (HAZ), making it highly susceptible to cold cracking.

• Preheating: The bar must be preheated to $400^\circ\text{F} - 500^\circ\text{F}$ ($204^\circ\text{C} - 260^\circ\text{C}$).

• Post-Weld Heat Treatment (PWHT): Immediate post-weld annealing or tempering at $1200^\circ\text{F} - 1400^\circ\text{F}$ ($649^\circ\text{C} - 760^\circ\text{C}$) is mandatory to restore ductility to the joint.

4. Procurement & Compliance Standards

When ordering or validating mill certificates for 410 rods and bars, the standard governing specifications include:

Typical Applications

AISI 410 round bars are heavily utilized where high mechanical strength needs to be paired with baseline atmospheric corrosion protection:

• Pump & Valve Shafts: For handling non-corrosive or mildly treated process water.

• Fasteners & Hardware: Heavy-duty structural studs, bolts, and nuts.

• Petrochemical Equipment: Fractionating towers, valve internals, and gas turbine compressor blades operating at moderate temperatures.

• Cutlery & Hand Tools: Hardened blades, dental instruments, and scrapers.