416 STAINLESS STEEL
Stainless steel is an irreversible modern alloy of today's economy. Its distinguishing characters restore applications in the era of industrial engineering. Stainless steel is a recycled considerable amalgamation.
Stainless steel alloys are distinguished by the occurrence of chromium that offers superior corrosion resistance. Stainless steel contains 10.5% chromium at least. Levels of chromium, with additional alloying agents like molybdenum, nickel, titanium, etc determine the mechanical properties of stainless steel.
400 series includes Ferritic and Martensitic steel.Grade 410 is martensitic stainless steel.
Martensitic stainless steel is a high carbon, plain chromium steel with 12-18% chromium. It contains high carbon than ferritic or austenitic stainless steel. It offers strength, moderate corrosion resistance, and wear resistance. Martensitic stainless steel shows good ductility and machinability.
Grade 416 Stainless Steel
Grade 416 is known for its machinability in all stainless steel around. It is a free-machining grade with improved machinability of 85%. Grade 416 is chromium stainless steel with the addition of sulfur. Grade 416 attains good strength, toughness, and ductility. Mechanical properties of grade 416 can be enhanced by heat treatment. It can be hardened and temper to improve toughness. Grade 416 has excellent machinability, non-seizing, and non-galling properties. It exhibits good oxidation coupled with high strength in the hardened and tempered condition. It is used often in applications that require extensive machining with corrosion resistance. Most widely used in the manufacturing of motor parts, pumps, screw machine parts, etc.
It provides better machining properties than austenitic grades but offers lower corrosion resistance.
Composition
| Element | Element | Min % | Max % | Role |
| Chromium | Cr | 12 | 14 | Corrosion and oxidation resistance |
| Sulfur | S | 0.15 | - | Free-machining via MnS inclusions |
| Carbon | C | - | 0.15 | Hardness and strength |
| Manganese | Mn | - | 1.25 | MnS formation, deoxidiser |
| Silicon | Si | - | 1 | Oxidation resistance |
| Phosphorus | P | - | 0.06 | Controlled for toughness |
| Nickel | Ni | - | - | Trace — not a significant alloying element |
Physical Properties
| Density | 7.80 g/cm³ |
| Modulus of elasticity | 200 GPa |
| Electrical resistivity | 57 µΩ·cm |
| Melting range | 1480–1530°C |
Thermal Properties
| Thermal expansion | 9.9 µm/m·°C |
| Conductivity @ 100°C | 24.9 W/m·K |
| Conductivity @ 500°C | 28.7 W/m·K |
| Max service temp (int.) | 760°C |
| Max service temp (cont.) | 675°C |
Mechanical Properties
| Tensile strength | 517 MPa |
| Yield strength (0.2%) | 275 MPa |
| Elongation (50 mm) | 30% |
| Hardness | 82 HRB |
| Magnetic | Yes — ferromagnetic |
Magnetic Properties
Grade 416 is ferromagnetic in annealed and heat-treated conditions.
Heat Treatment
Annealing: Annealing can be done at between temperature ranges of 815-900°C, followed by air-cooling.
Hardening: Hardening can be attained by heating in the temperature range of 925 to 1010 °C followed by quenching and tempering. Mechanical properties improvised by quenching and tempering.
Tempering: Tempering can enhance mechanical properties. Material is soaked for at least one hour and then cooled in air. Tempering can be done at a temperature between 650°C-750°C but suggested to avoid between the ranges of 400 to 580°C. Tempering at the range may lead to a decrease in impact and corrosion properties.
Properties
Corrosion Resistance: Grade 416 offers considerable resistance to acids, alkalis, fresh water, and dry air. Corrosion resistance can be improved by hardening and polishing. Grade 416 is less corrosion resistant than austenitic grades.
Grade 416 stainless steel is not suitable for chloride and marine environment, as it contains sulfur.
Heat Resistance: Grade 416 stainless steel offers a scaling resistance of 760°C in intermittent conditions and 675°C in continuous operations.
Grade 416 stainless steel should not be exposed to a temperature greater than the tempering temperature./p>
Welding: Grade 416 stainless steel shows poor weldability. Welding can be done by preheating the material to 200 to 300 °C. Then re-hardening and annealing are done at 650-675 °C.
Alloy 410 low hydrogen electrodes are appropriate for welding if needed.
Machinability: Grade 416 offers the highest machinability in all available steels in the sub-critical annealed condition.
Applications
Grade 416 stainless steel is used in end products that required high machinability and corrosion resistance. Grade 416 stainless steel is commonly used for the following application:
- Cutlery and kitchen utensils
- Steam and gas turbine blades
- Fasteners
- Bushings
- Nuts, bolts, screws,
- Pump shafts and valve components
- Washing machine components
- Studs and gears
Frequently Asked Questions
Q1. What is grade 416 stainless steel?
Grade 416 is a free-machining martensitic stainless steel in the AISI 400 series. It is produced by adding a minimum of 0.15% sulfur to a base 12–14% chromium composition. The sulfur forms manganese sulfide (MnS) inclusions that act as chip-breakers during cutting, giving grade 416 the highest machinability of any stainless steel — approximately 85% relative to free-machining carbon steel. UNS designation: S41600. DIN equivalent: 1.4005. European standard: EN 10088-3.
Q2. Is grade 416 stainless steel magnetic?
Yes. Grade 416 is ferromagnetic in both the annealed and heat-treated (hardened and tempered) conditions. This is because of its martensitic body-centred cubic crystal structure. It remains magnetic regardless of heat treatment condition. This contrasts with austenitic grades such as SS 304 and SS 316, which are non-magnetic.
Q3. What are the mechanical properties of grade 416 stainless steel in the annealed condition?
In the annealed (softened) condition, grade 416 typically achieves: Tensile strength — 517 MPa; Yield strength (0.2% proof) — 275 MPa; Elongation (in 50 mm) — 30%; Hardness — 82 HRB. After hardening and tempering, tensile strength can reach up to 1030 MPa and hardness up to 26 HRC, depending on tempering temperature.
Q4. How do you heat treat grade 416 stainless steel?
Grade 416 can be heat treated in three stages: (1) Annealing — heat to 815–900°C, cool in air. Produces the softest, most machinable condition. (2) Hardening — heat to 925–1010°C, then quench in oil or air to form martensite. (3) Tempering — soak at temperature for a minimum of one hour, then cool in air. Recommended tempering range is 650–750°C. Always avoid tempering between 400–580°C — this range causes temper embrittlement, sharply reducing impact toughness and corrosion resistance.
Q5. What is the corrosion resistance of grade 416 stainless steel?
Grade 416 offers moderate corrosion resistance — better than carbon steel, but significantly lower than austenitic grades (304, 316) or even grade 410. It resists: mild acids at ambient temperature; alkalis; fresh water; dry air; food acids in neutral conditions. It does NOT resist: chlorides, salt spray, or marine atmospheres; humid industrial environments with chemicals; strong reducing acids. The sulfur content (responsible for its machinability) is the main reason for its reduced corrosion performance. Hardening and polishing can improve corrosion resistance marginally.
Q6. What is the maximum service temperature for grade 416 stainless steel?
Grade 416 offers a scaling resistance of 760°C in intermittent (cyclic) conditions and 675°C in continuous service. However, it is critical that the material is never exposed to temperatures above the tempering temperature used during heat treatment — exposure above this point will alter the tempered microstructure and reduce mechanical properties. For high-temperature continuous service above 650°C, austenitic stainless grades such as 310 or 316H are more suitable.
Q7. What is the difference between grade 410 and grade 416 stainless steel?
The sole compositional difference is the addition of sulfur (minimum 0.15%) in grade 416. This creates manganese sulfide inclusions that give 416 the highest machinability of any stainless steel — approximately 85% vs roughly 60% for grade 410. However, grade 410 offers: better weldability (no sulfur-induced cracking); slightly better corrosion resistance; higher achievable hardness (up to 35 HRC vs 26 HRC for 416). Choose 416 when machining is the primary requirement; choose 410 when weldability, higher strength, or marine exposure is a factor.
Q8. What is the difference between grade 416 and grade 304 stainless steel?
Grades 416 and 304 belong to entirely different families. Grade 304 is austenitic (18% Cr, 8% Ni) — non-magnetic, excellent corrosion resistance, non-heat-treatable, poor machinability. Grade 416 is martensitic (12–14% Cr, no significant Ni) — magnetic, moderate corrosion resistance, heat-treatable for high strength, exceptional machinability. Choose 304 for corrosion-critical applications (food, chemical, marine). Choose 416 when extensive machining is required and corrosion conditions are mild (dry indoor, neutral acids, fresh water).
Ambica steels offer superior fine quality grades 416 bars. Bars are available in round, square, flat, hexagonal, and customized shapes. Inquiry and orders are welcome.